Question: Malignant pustule is seen in

Cutaneous anthrax Anthrax is primarily a disease of the domestic animals. Humans are usually accidental hosts when brought into contact with infected animals There are three major forms of disease: Cutaneous anthrax Acquired, skin Inhalational anthrax --> Inhalated, spores Gastrointestinal anthrax Analogus to cutaneous anthrax but occurs on intestinal mucosa. The most common form of anthrax is cutaneous anthrax which is usually occurred injured skin or musous membrane Cutaneous anthrax Cutaneous anthrax usually begins 2-5 days after inoculation of spores into an exposed pa of the body typically the forearm or the hand. The initial lesion is an erythematous papule which may be mistaken .for insect bite. This papule usually progresses through vesicular and ulcerative stages in 7-10 days to form a black eschar surrounded by edema The lesion is known as "malignant pustule" although it is neither malignant nor pustule. Associated .symptoms are usually mild and the lesion typically heals very slowly after the eschar separates. Cutaneous anthrax generally resolves spontaneously but 10-20% of untreated patients may develop septicemia. Cutaneous anthrax generally resolves spontaneously but 10-20% of untreated patients may develop fatal septicemia or meningitis.


Question: Subacute Sclerosing Panencephalitis is a rare and dangerous complication of;

SSPE Subacute sclerosing Pan encephalitis (SSPE) is a rare complication of measles. SSPE occurs in about 1 in every 300,000 natural cases of measles. It is a form of chronic progressive brain inflammation caused by slow infection with ceain defective strains of hypermutated measles virus It is also known as Dawsondisease,Dawsonencephalitis, andmeaslesencephalitis


Question: Sulphur granules are composed of

Granules are bacterial colonies and will be found to consist of a dense network of thin gram-positive filaments surrounded by a peripheral zone of swollen radiating club shaped structures - sun Ray appearance ( antigen antibody complex ). Ref: Textbook of Microbiology, Ananthanarayan and Paniker; 9th edition


Question: Battey bacillus is

M.intracellulare: it is commonly known as Battey bacillus because it was first identified as human pathogen at the Battey state hospital for Tuberculosis, Georgia, USA. M.intacellulare and M.avium and are so similar that they can be considered as one group, the M.avium complex (MAC). They cause lymphadenopathy, pulmonary lesions or disseminated disease, paicularly in AIDS patient. Ref: Textbook of microbiology; Ananthanarayan and paniker's; 10th edition; Pg: 367


Question: Transplacental transfer of antibodies from immunized mother to her newborn is

Ans. b (Natural passive immunity). (Ref. Textbook of Microbiology by Anantanarayan 6th/72)# Natural active immunity results from either clinical or inapparent infection by a parasite.# A person who has recovered from attack of chickenpox or of measles develops natural active immunity (lifelong).# Artificial active immunity is by vaccines.# Artificial passive immunity is immune horse serum administration# Transplacental transfer of antibodies from immunized mother to her newborn is natural passive immunity.


Question: The first gene to be knocked out in the carcinogenesis of the endometrium is

The primary gene involved in the transformation of a normal or a hyperplastic endometrium to a neoplastic endometrium is the loss of PTEN gene function.


Question: Anthrax bacilli differs from anthracoid bacilli by being

Differentiating features between anthrax and anthracoid bacilli Anthrax bacilli Anthracoid bacilli Non-motile Generally motile Capsulated Non-capsulated Grows in long chains Grow in sho chains Medusahead colony Not present Hemolysis absent or weak Usually well marked Susceptible to gamma phage Not susceptible No growth at 45 deg. C Usually grows No turbidity in broth turbidity usual Ref: Textbook of microbiology; Ananthanarayan ana paniker's; 10th Edition; Pg:253


Question: Most common drug causing peudomembranous enterocolitis is

C.difficile causes acute colitis with bloody and watery diarrhea and pseudomembranous colitis. C.difficle is the most common cause of healthcare-associated diarrhea in many developed countries following the use of broad-spectrum antibiotics like clindamycin, ampicillin, or fluoroquinolones to which the organism is resistant. Ref: Textbook of microbiology; Ananthanarayan and paniker's; 10th Edition; Pg: 270


Question: Streptococci with butterscotch or caramel odour is

S.angionosus produce small colonies which give off a distinct odour of butterscotch or caramel.


Question: Aseptate hyphae are seen in

They are lower fungi that have non-septate hyphae Reference: Textbook of Microbiology; Anathanarayan and paniker&;s; 9th edition


Question: Most common fungal infection in febrile neutropenia is

Candida albicans is the normal inhabitant of skin, GIT, oral and vaginal cavities. Candidiasis is an oppounistic endogenous infection. Neutropenia is an immunocompromised condition, so candida infection is more common in them. Ref: Textbook of Microbiology, Ananthanarayan and Paniker; 9th edition .


Question: Doc for nasal carriers of MRSA

Topical mupirocin 2 % is the Doc for nasal carriers of MRSA.


Question: NIH is used for

NIH swabs are used to collect eggs of Pinworm (Enterobius) Eggs are collected from the perianal skin by NIH swab or cellophane tape. Pinworms are not released in feces, the diagnosis cannot be made by conventional fecal ova and parasite tests


Question: For hot air oven holding time at 160degC is

Recommended holding time of hot air oven At 160 C is 1.5-2 hour At 170 C for 60 min At 180 C is 30 min

General Microbiology (Sterilization and Bacterial Genetics)


Question: The Duffy antigen is associated with

Duffy blood group antigen (alleles Fya and Fyb) is the receptor for the attachment of merozoites of Plasmodium vivax. Its absence confers protection against merozoite invasion.Ref: K.D Chatterjee 13th edition, p97-100


Question: Stain used for degenerated fungi in tissue is


Question: Bacterial spores are destroyed by


Question: Frie's test is useful for diagnosis of


Question: Pasteurised milk is most commonly tested by

Phosphatase test:This is a check on whether milk has been pasteurized. The enzyme phosphatase, which is normally present in milk, is inactivated if pasteurization has been performed properly. Residual phosphatase activity indicates that pasteurization has been adequate. This test, if positive after proper pasteurization of milk shows contamination after pasteurization. (Ref: Ananthanarayan 9th edition, p631-632)


Question: Ahropod vector involved in causing Scrub typhus is

Ref: Ananthanarayana textbook of Microbiology 9th edition Pgno : 405-406 Infections Caused by Rickettsiae and Close Relatives Group Disease Bacterium Ahropod Vector Reservoir Host Rocky MountainSpotted Fever R. rickettsii Ticks Ticks, dogs, rodents Epidemic Typhus R. prowazekii Human louse Humans Endemic Typhus R. typhi Fleas Rodents Scrub Typhus Orientia tsutsugamushi Mites Rodents Ehrlichiosis E. chaffeensisA. phagocytophilum Tick Small mammals


Question: Pharyngoconj unctiva I fever is caused by

o Pharyngo-conjunctival fever is caused most commonly by serotypes 3 and 7, but serotypes 2, 4 and 14
also have been documented as etiologic agents,
o Ocular infections caused by Adenovirus -
i. Epidemic keratoconjunctivitis → Serotypes 8, 19, 37
ii. Follicular conjunctivitis → Serotypes 3,7
iii. Pharyngoconjunctival fever - Serotypes 3, 7 Adeno Virus
o Non-enveloped, DNA (ds DNA) Virus
o Has characteristic morphology consisting of an icosahedral shell composed of 20 equilateral
triangular faces and 12 vertices → space vehicle appearance.
o Human adenovirus grows only in tissue culture of human origin, such as human embryonic kidney, HeLa
or HEP-2.
o Cytopathic effect in tissue culture → cell rounding and aggregation into grape like clusters.
o Adenovirus has been used as a vector for gene therapy.
o Adenovirus cause infections of the respiratory tract and eyes and less often of the intestine and urinary tract.
o Most frequently affect infants and children
o Clinical manifestations
□ Most common manifestation in children is an acute upper respiratory tract infection with prominent rhinitis,
□Most common manifestation in adult is ARDS


Question: Cyst form is found in


Question: Negative staining is used to demonstrate


Question: Infected tissues demonstrating budding fungal cells are seen in

Cryptococcus neoformans causes cryptococcosis, especially cryptococcal meningitis. The organisms can be seen in cerebrospinal fluid (CSF) in India ink preparations as an oval budding yeast surrounded by a wide, unstained polysaccharide capsule. Candida albicans, the most important species of Candida, causes thrush and vaginitis, as well as other diseases. It may appear in tissue as a budding yeast or as elongated pseudohyphae (non-septate). Sporothrix schenckii is a dimorphic fungus which appears as round or cigar-shaped budding yeasts in tissue. It causes a local pustule or ulcer that may become chronic.

Tinea versicolor, tinea nigra, candidiasis

Candidiasis, cryptococcosis, and sporotrichosis


Question: Langerhans cells in skin are

Ans. is 'a' i.e., Antigen presenting cells


Question: An adolescent male developed vomiting and diarrhoea 1 hour after having food from a restaurant. The most likely pathogen is

Incubation period: Staphylococcus aureus - 2 to 6 hours Salmonella - 12 to 24 hours Clostridium perfringens - 8 to24 hours Vibrio parahemolyticus-24hrs to 5 days Ref: Textbook of Ananthanarayan and paniker's; 10th Edition; Pg:204,307,260,313


Question: Pneumocystis carinii is diagnosed by

Pneumocystis infection - specimen is induced sputum, bronchoalveolar lavage or lung biopsy. On microscopy - trophozoites can be demonstrated by Giemsa , toludine blue, methenamine silver and calcofluor white stain. Ref: Textbook of Microbiology, Ananthanarayan and Paniker; 9th edition

Sputum examination for trophozoites and cysts under microscope


Question: A patient is diagnosed with malaria had fever periodicity of 72 hours. Organism implicated is

An attack usually stas with shivering and chills, followed by a high fever, followed by sweating and a return to normal temperature. Ref ananthnarayana and panikers microbiology textbook 8/e


Question: Erythromycin is given in intestinal hypomotility because

Erythromycin stimulates motilin receptors in the g.i.Lthereby induces gastric contractions, hastens gastric emptying and promotes intestinal motility.


Question: Most common accepted theory for antibody production is

(Clonal selection theory) (149-150-AN 7th)Clonal selection theory proposed this theory which shifted immunological specificity to the cellular level According to the clonal selection hypothesis, during immunological development, cells capable of reacting with different antigens were formed by a process of somatic mutation, clones of cells that has immunological reactivity with self antigens were eliminated during embryonic life. Such clones are called forbidden clones. Their persistence or development in later life by somatic mutation could lead to autoimmune process.* The clonal selection theory is more widely accepted than the other theories, though it is unable to account for all the features of the immune response.


Question: One virus paicle prevents multiplication of the 2nd virus. This phenomena is

Viral interferenceit is the infection of a cell by one virus inhibits simultaneous or subsequent infection by another virus.Most impoant mediator of interference is interferon.Interference produced by destruction of cell receptors is seen with myxoviruses and enterovirus.It is applied in the field in controlling poliomyelitis outbreaks by introducing into the population, the live attenuated poliovirus vaccine.


Question: Drugs least effective against MRSA

Drugs effective against MRSA are SS Cotrimoxazole, SS Ceain cephalosporins, SS Vancomycin, SS Teicoplanin, SS Dalfopris n, SS Quinupris n SSLinezolid.


Question: The protective titre of antitoxin to diphtheria following vaccination is

Active immunization by vaccination with diphtheria toxoid is the key in preventing diphtheria. . Serum antitoxin concentration of 0.01 IU/mL is usually accepted as the minimum protective level. 0.01 IU/mL is considered to provide basic protection and 0.1 IU/ml is considered to provide complete or total protection.

Systemic Bacteriology (Gram Positive Bacilli, Gram Negative Bacilli)


Question: Skin test useful in hydatid disease is

casoni's test It is an immediate hypersensitivity skin test introduced by casoni using fresh sterile hydatid fluid. The antigen in hydatid fluid is collected from animal or human cysts and is sterilised by seitz or membrane filtration. The fluid is injected intradermally in one arm and an equal volume of saline as control is injected in other aarm. In a positive reaction ,a large wheal of about 5 cm in diameter with multiple pseudopodia appears within half an hour at the test side and fades in about an hour. Ref : panickers textbook of medical parasitology 8th edition page 134


Question: The time interval between introduction of bacteria into a culture medium and starting of multiplication is

Ans. a (Lag phase) Ref:Ananthanarayan, 7th ed, p. 19Bacterial growth curve: Growth curve obtained by plotting viable count in relation to time gives bacterial growth curve which shows the following phases;a. Lag phaseb. Log phasec. Stationary phased. Phase of declineLag phase: no increase in number but increase in size of the cells occur. The necessary enzymes & metabolic intermediates are built up in adequate quantitiesLog phase (exponential/ logarithmic): cells start dividing and their no. increases exponentially with time.Stationary phase: cell division stops due to depletion of nutrients and accumulation of toxic products.Viable count becomes stationary as there occurs an equilibrium between dying cells and newly formed cells.Phase of decline: Population decreases due to cell death caused by:1. Depletion of nutrients2. Toxic accumulation3. Autolytic enzymesBacteria with maximum cell size: end of lag phaseSmall, uniform staining cells: log phaseSporulation. storage granules: stationary phaseInvolution forms: stage of decline


Question: Molecular mass of IgG (in K D

Ans. is 'a' i.e., 150Physical, chemical, and Biologic Properties of Human ImmunoglobulinsPropertyIgGIgAIgMIgDIgEUsual molecular formMonomerMonomer, dimerPentamer, hexamerMonomerMonomerOther chainsNoneJ chain, SCJ chainNoneNoneSubclassesG1, G2, G3, G4Al, A2NoneNoneNoneHeavy chain allotypesGm (=30)No Al, A2m (2)NoneNoneNoneMolecular mass, kDa150160, 400950, 1150175190Sedimentation constant, Sw206.6S7S, 1 IS19S7S8SCarbohydrate content, %3710913Serum level in average adult, mg/mL9.5-12.51.5-2.60.7-1.70.040.0003Percentage of total serum Ig75-857-155-100.30.019Serum half-life, days236532.5Synthesis rate, mg/kg per day336570.40.016Antibody valency22, 410, 1222Classical complement activation+ (Gl, 2?, 3)----Alternate complement activation+(G4)+-+-Binding cells via FcMacrophages neutrophils, large granular lymphocytesLymphocytesLymphocytesNoneMast cells, basophils, B cellsBiologic propertiesPlacental transfer, secondary Ab for most antipathogen responsesSecretory immunoglobulinPrimary Ab responsesMarker for mature B- cellsAllergy, antiparasite responses


Question: 1)Paul bunnel tests A.Rickettsial Diseases 2)Weil felix reaction B. Infectious mononucleosis 3)Tzank test C. Herpes virus 4)Sabin Feldman dye D. Toxoplasmosis

1Paul bunnel tests A. Infectious mononucleosis 2)Weil felix reaction B. Rickettsial Diseases 3)Tzank test C. Herpes virus 4)Sabin Feldman dye D. Toxoplasmosis Other test VDRL and RPR: Treponema pallidum Microscopic agglutination test: Leptospirosis Standard agglutination test: Brucella Elk's gel precipitation test: Corneybacterium diphtheria Widal test: typhoid Sabin fieldman dye test: Toxoplasmosis


Question: Enterotest is used for diagnosis of

Stringtest / enterotest is done in Giardia lambia in which bile stained mucus is collected for examination of Trophozoites.


Question: A patient was hospitalized after an automobile accident. The wounds became infected and the patient was treated with tobramycin, carbenicillin, and clindamycin. Five days after antibiotic therapy was initiated, the patient developed severe diarrhea and pseudomembranous enterocolitis. Antibioticassociated diarrhea and the more serious pseudomembranous enterocolitis can be caused by

Patients treated with antibiotics develop diarrhea that, in most cases, is self-limiting. However, in some instances, paicularly in those patients treated with ampicillin or clindamycin, a severe, life-threatening pseudomembranous enterocolitis develops. This disease has characteristic histopathology, and membranous plaques can be seen in the colon by endoscopy. Pseudomembranous enterocolitis and antibiotic-associated diarrhea are caused by an anaerobic Gram-positive rod, Clostridium difficile. It has been recently shown that C. difficile produces a protein toxin with a molecular weight of about 250,000. The "toxin" is, in fact, two toxins, toxin A and toxin B. Both toxins are always present in fecal samples, but there is approximately one thousand times more toxin B than toxin A. Toxin A has enterotoxic activity--that is, it elicits a positive fluid response in ligated rabbit ileal loops-- whereas toxin B appears to be primarily a cytotoxin. Reference: Ananthanarayan and Paniker&;s Textbook of Microbiology Tenth edition


Question: Kerion is a

Ans. (d) FungusRef: Microbiology by Ananthanarayan and Paniker 8,th ed. /605* Kerion is the result of the hosts response to a fungal ringworm infection of the hair follicles of the scalp and beard accompanied by secondary bacterial infection.* It is usually caused by Zoophilic dermatophytes like Trichophyton verrucosum and T. mentagrophytes.* Treatment: Oral Griseofulvin is the treatment of choice.


Question: Reassoment is seen in aEUR'

Rotavirus If a virus has a segmented genome and if two variants of that virus infect a single cell, progency virions can result with same segments from one parent and some from the other. This process is called "reassoment" of the virus. - Normally when a segmented virus infects a cell, the individual RNA segments enter the nucleus of the host. - There they are copied many times over to form RNA genomes, for new infectious virions. - The new RNA segments are expoed to the cytoplasm where they are assembled into new virus paicles which buds from the cell. If a cell is infected simultaneously with two different segmented viruses, the RNA of both the viruses are copied in the nucleus. These segmented viruses undergo a kind of "gene swapping or exchange" i.e., segments from viruses are interchanged or transferred to each other. - As a result new virus paicles emerge that contain RNA segments from both the viruses. - These new viruses are called "reassoants" and the process is called reassoment. Reassoment is an efficient process but is limited to the viruses with "segmented genomes". So far the only human viruses characterized with segmented genomes are RNA viruses e.g., ohomyxoviruses, reo viruses, arenaviruses, Bunya viruses. - In paicular reassoment is characteristic of "influenza viruses" whose genomes consists of eight distinct segment of RNA. - Reassoment is responsible for some of the major genetic shifts in the history of influenza virus which has lead to epidemics. Reassoment in Rotavirus Rotavirus is an impoant cause of severe diarrhea in infants and young children. Rotavirus are segmented virus - Due to segmented nature of their genome rotavirus can exchange (reasso) genes during coinfection a features that ispredicted to generate new possibly more dangerous virus strains. - However the amount of gene reassoment occurring in nature is not known as very few Rotavirus genomes have been segmented. - In contrast to what was previously thought very few Rota viruses exchanged gene segments with each other: instead the genomic constillations of the viruses remained relatively stable.


Question: Pneumocystis carinii causes primary infection in

There are two known species of Pneumocystis - Pneumocystis carinii, commonly found in rats and Pneumocystis jirovecii seen in humans. Ref: Textbook of Microbiology, Ananthanarayan and Paniker; 9th edition


Question: Encapsulation in bacteria helps in


Question: Jail fever is related to

Epidemic typhus due to infection with R. Prowazekii is transmittal by the human body louse which lives on clothes and is found in poor hygienic conditions (especially in jails) and usually in cold areas.


Question: In vivax and Ovale malaria, Relapses are due to

Relapse is due to hypnozoites ( resting state) which may reactivate after 2-3 years of malaria.


Question: Diagnostic method of choice for leptospirosis

A definitive diagnosis of leptospirosis is based on: - * Isolation of the organism from the patient or * A positive result in the polymerase chain reaction (PCR) or * Seroconversion or a rise in antibody titer. (MAT) * In cases with strong clinical evidence of infection, a single antibody titer of 1:200-1:800 (depending on whether the case occurs in a low- or high-endemic area) in the microscopic agglutination test (MAT) is required. Ref:- Harrisons T.B of internal medicine 19th edition; pg num:- 1144


Question: Food poisoning has occurred due to ingestion of contaminated fired rice, most likely organism

Bacillus cereus: an impoant cause of food poisoning. Two patterns: diarrheal and emetic. Emetic: associated with consumption of cooked rice, usually fried rice from restaurants. Nausea and vomiting 1-5 hours after the meal. Bacilli present in large numbers in cooked rice and fecal samples from these patients. Diarrheal: associated with a wide range of foods including cooked meat and vegetables. It is characterized by diarrhea and abdominal pain, 8-16 hrs after ingestion of contaminated food. Reference: Textbook of Microbiology; Anathanarayan and paniker's; 10th edition; Page no: 253


Question: The causative organism of hemolytic uremic syndrome is

The hemolytic uremic syndrome may occur as a complication in severe cases due to shigella. EHEC can give rise to diarrhea to fatal hemmorhagic colitis and hemmorhagic uraemic syndrome paicularly in young children and the elderly. Ref: Textbook of microbiology; Ananthanarayan and paniker's; 10th Edition; pg: 293


Question: Corynebacterium diphtheriae is

Corynebacterium diphtheriae is a gram-positive bacillus that is unencapsulated, nonmotile, and nonsporulating. The bacteria have a characteristic club-shaped bacillary appearance and typically form clusters of parallel rays, or palisades, that are referred to as "Chinese characters."Recommended treatment options for patients with respiratory diphtheria are as follows:* Procaine penicillin G, 600,000 U IM q12h (for children: 12,500-25,000 U/kg IM q12h) until the patient can swallow comfoably; then oral penicillin V, 125-250 mg qid to complete a 14-day course* Erythromycin, 500 mg IV q6h (for children: 40-50 mg/kg per day IV in two or four divided doses) until the patient can swallow comfoably; then 500 mg PO qid to complete a 14-day courseRef: Harrison&;s Principles of Internal Medicine; 19th edition; Chapter 175; Diphtheria and Other Corynebacterial Infections


Question: First released immunoglobulin after primary immunization


Question: Virus quantification is done by

Quantification assays : plaque and pock assay.


Question: The earliest discovery of a pathogenic microorganism was made by

The earliest discovery of a pathogenic microorganism was probably made by Augustino Bassi(1835), showed that the muscardine disease of silkworms was caused by a fungus.Ref: Ananthanarayan; 7th edition; Page no: 1


Question: The medium of choice for culturing yeast form of dimorphic fungi is

Dimorphic fungi exist as yeast in the host tissue and in the culture at 37C. Reference: Textbook of Microbiology; Baveja; 4th edition


Question: Tzanck smear is useful for the diagnosis of

(B) Herpes Virus infection # TZANCK SMEAR is a rapid, fairly sensitive and inexpensive diagnostic method.> Smears are prepared from the lesions, preferably from the base of vesicles and stained with 1% aqueous solution of toludene bleu '0' for 15 seconds.> Multinucleated giant cells with faceted nuclei and homogenously stained 'ground glass' chromatin (Tzanck cells) constitute a positive smear.> Intranuclear type A inclusion bodies may be seen in Giemsa stained smears.> Acantholytic cells present in Pemphigus vulgaris, Senear-Usher syndrome, Pemphigus foliaceous & Pemphigus vegetans


Question: Stain used to make the wetted area of filter paper strip more visible is


Question: Medusahead appearance on agar plates is characteristic of

When grown on blood agar plates, Bacillus anthracis produce nonhemolytic grey to white, tenacious colonies with a rough texture and a ground-glass appearance. Comma-shaped outgrowths (Medusa head, "curled hair") may project from the colony.Jawetz 27e pg: 180


Question: Stool examination is required for diagnosis of infection with

In Staph food poisoning, Enterotoxin is responsible for the manifestations of food poisoning - nausea, vomiting and diarrhoea 2-6 hours after consuming food contaminated by the preformed toxin. The source of infection is usually food handler who is a carrier. In food poisoning, faeces and remains of suspected food should be collected. Ref: Ananthanarayan and Paniker&;s Textbook of Microbiology, 9th edition; pg no: 204


Question: Main cause of diarrhea in children of developing country is

Enterotoxigenic E.coli: diarrhea caused by ETEC is endemic in developing countries in the tropics. Common in all age groups. Traveler's diarrhea adheres to the intestinal mucosa which is mediated by colonization factor antigens. Produces enterotoxin which may be heat liable or heat stable. Reference: Textbook of Microbiology; Anathanarayan and paniker's; 10th edition; Page no: 285


Question: Problem village if water is in depth more than

A "problem Village" has been defined as one where :No source of safe water is available within a distance of 1.6 km ORWater source has excess salinity, iron, fluorides & other toxic elements ORWater is exposed to the risk of choleraWater is available at a depth of more than 15 mts OR


Question: Negri bodies in brain are seen in

(C) Rabies # Demonstration of inclusion bodies IN RABIES:> This is still the method most commonly used as facilities for immunofluorescence and biological tests are not available in many laboratories.> Impression smears of the brain are stained by Seller's technique (basic fuchsin and methylene blue in methanol), which has the advantage that fixation and staining are done simultaneously.> Negri bodies are seen as intracytoplasmic, round or oval, purplish pink structures with characteristic basophilic inner granules. Negri bodies vary in size from 3-27 urn> Other types of inclusion bodies may sometimes be seen in the brain in diseases such as canine distemper but the presence of inner structures in the Negri bodies makes differentiation easy.> Negri bodies are intracytoplasmic inclusion bodies seen in brain cells as purplish pink structures with characteristic basophilic granules.> These are characteristic of Rabies infection.


Question: Maurer&;s dots are seen in infection with

Plasmodium vivax - Schuffners dotsPlasmodium falciparum- Maurer&;sdotsPlasmodium malariae - Ziemann&;s dotsPlasmodium ovale - James&;s dotsIn P. falciparum, RBCs are normal in size with large red dots (Maurer's dots) and sometimes, with basophilic stippling.Panicker 7e pg:80


Question: Beta phage is seen in

The toxigenicity of the diphtheria bacillus depends on the intracellular presence of corynephages (tox+), which acts as genetic controlling toxin production. Non-toxigenic strains are rendered toxigenic by infecting them with the beta or some other phages This is known as lysogenic or phage conversion. REF:Textbook of microbiology; Ananthanarayan and paniker's; 10th Edition; Pg: 240


Question: Cryptococcus rarely cause infection of

Cryptococcus neoformans, a capsulated yeast is the causative agent, it is the only deep mycoses present in India .
It has a spherical budding cell with a prominent polysaccharide capsule.
It is a true yeast and gram positive the capsule can be demonstrated using india ink or nigrosin staining
Disease is usually asymptomatic and seen in immunocomprmised individuals, pulmonary cryptococcosis may lead to mild pneumonitis, cryptococcal meningitis occurs by haematogenous spread, skin, bone and lymph nodes are most commonly affected.

Ref : Textbook of Microbiology, C P Baveja 5th Edition pg no:556


Question: Bronchoscopes are best sterilized with

Ans. a (Glutaraldehyde) (Ref. Ananthanarayan, Microbiology, 7th/ 31, 86)# Glutaraldehyde:- Is specifically effective against tubercle bacilli, fungi, and viruses.- Glutaraldehyde has a short shelf life (<2 weeks), and is expensive.- It is less toxic and irritant to eyes than formaldehyde.- It has no deleterious effect on the cement or lenses of instruments like cystoscopes and bronchoscopes.- It can safely be used to treat corrugated rubber anaesthetic tubes and face masks, plastic endotracheal tubes, polythene tubing, and metal instruments.# CIDEX (2% gluteraldehyde) is commonly used for sterilization of endoscopes.# Most rigid endoscopes are compatible with steam,formaldehyde,ethylene oxide and certain liquid chemical disinfectants.# Flexible scopes can also be sterilized by peracetic acid.Ethylene oxide (EO or EtO) gas# Is commonly used to sterilize objects sensitive to temperatures greater than 60degC such as plastics, optics and electrics.# Ethylene oxide treatment is generally carried out between 30degC and 60degC with relative humidity above 30% and a gas concentration between 200-800 mg/L for at least three hours.# Ethylene oxide penetrates well, moving through paper, cloth, and some plastic films and is highly effective.# Ethylene oxide sterilizers are used to process sensitive instruments which cannot be well sterilized by other methods.# EtO can kill all known viruses, bacteria and fungi, including bacterial spores and is satisfactory for most medical materials, even with repeated use.# However it is highly flammable, and requires a longer time to sterilize than any heat treatment.# Ethylene oxide is the most common sterilization method. used for over 70% of total sterilizations. and for 50% of all disposable medical devices.# Bacillus subtilis, a very resistant organism, is used as a rapid biological indicator for EO sterilizers. If sterilization fails, incubation at 37degC causes a fluorescent change within four hours, which is read by an auto-reader. The color change indicates a pH shift due to bacterial metabolism.Formaldehyde solutions# Like Glutaraldehyde, it is also accepted liquid sterilizing agents# Immersion time is sufficiently long (To kill all spores in a clear liquid can take up to 12 hours with glutaraldehyde and even longer with formaldehyde). Formaldehyde is also used as a gaseous sterilizing agent.# Many vaccines, such as the original Salk polio vaccine, are sterilized with formaldehyde.OZONE# Is used in industrial settings to sterilize water and air, as well as a disinfectant for surfaces.# It has the benefit of being able to oxidize most organic matter.# It is a toxic and unstable gas that must be produced on-site, so it is not practical to use in many settings.CHLORINE BLEACH# Household bleach consists of 5.25% sodium hypochlorite.# It is usually diluted to 1/10 immediately before use; however to kill M. tuberculosis it should be diluted only 1/5.# Bleach will kill many organisms immediately, but for full sterilization it should react for 20 min.# Bleach will kill many, but not all spores.# It is highly corrosive and may corrode even stainless steel surgical instruments.# Chlorine and NaOH are the most consistent agents for prions. Chlorine is too corrosive to use on certain objects.Educational point:# COLD STERILIZATION is done b\: y -radiation, Cosmic rays.


Question: Best confirmatory test for syphilis is

FTA-ABS: FTA-absorption test in which the test serum is preabsorbed with sonicate of the Reiter treponemes to eliminate group-specific reactions. FTA-ABS is as specific as the TPI test and is now accepted as a standard reference test. Ref: Textbook of microbiology; Ananthanarayan and paniker's; 10th edition; Pg:382


Question: A malignant pustule is

Cutaneous anthrax: lesion stas as a papule 1-3 days after infection and becomes vesicular, containing a fluid which may be clear or bloodstained. The whole area is congested, edematous and several satellite lesions filled with serum or yellow fluid are arranged around a central necrotic lesion which is covered by a black eschar. This is a malignant pustule. The disease is used to be common in dock workers carrying loads of hides and skins on their bare backs and hence, was known as hide poers disease. Reference: Textbook of Microbiology; Anathanarayan and paniker's; 10th edition; Page no: 250


Question: Collapsing glomerulopathy, features are

Hyperophy and necrosis of visceral epithelium It is the characteristic glomerulopathy associated with HIV infection. HIV can result in various glomerulopathies such as acute diffuse proliferative glonterulonephritis, inesangioproliferative glomerulonephritis including IgA nephropathy, MPGN and membranous glomerulopathy. But the classical glomerulopathy associated with HIV infection is collapsing ehnnerulopathy. Collapsing glomerulopathy is actually an aggressive form of focal segmental glonzerulosclerosis. Focal segmental glomerulosclerosis is characterized by sclerosis of some but not all glomeruli (thus it is focal) and in the affected glomeruli only a poion of the capillary tuft is involved. In contrast, collapsing glomerulopathy is characterized by collapse and sclerosis of the entire glomerular tuft (in addition to the usual. focal segmental glomerular lesions). Characteristic feature is proliferation and hyperophy of glomerular visceral epithelial cells. Remember this The minimum diagnostic criteria for defining a collapsing variant of focal segmental glomerulosclerosis is : The presence by light microscopy of at least one glomerulus showing segmental or global obliteration of the glomerular capillary lumen by wrinkling and collapse of glomerular basement membrance in association with hyperophy and hyperplasia of overlying visceral epithelial cells. The other characteristic features which distinguishes HIV associated nephropathy from FSGS. - Presence of tubuloreticular inclusions Aggresive clinical course.


Question: Mercaptoethanol splits Ig molecule into

It cleaves only disulphide bonds thus forming two H and two L chains.


Question: Malignant pustule is caused by

Ans. d (Bacillus anthrax) (Ref. Ananthanarayan, Microbiology, 8th/ p. 245).Bacillus anthrax causes anthrax and disease fee seen in Joans:1. Cutaneous,2. Pulmonary,3. Intestinal- Cutaneous is the most common form (malignant pustule, hide porter's disease).- Pulmonary is wool sorter's disease.0BACILLUS ANTHRAX# Bacillus anthrax and Clostridia are Gram-positive spore-forming rods.# B. anthracis is the bacterium which causes anthrax in cows, sheep, and sometimes humans.# Anthrax is transmitted to humans via direct contact with animal products or inhalation of endospores.# Under the microscope, B. anthracis cells appear to have square ends and seem to be attached by a joint to other cells.# The spores are best observed when the bacterium is cultured on artificial media.# Anthrax is a zoonosis. The infected animals shed the bacilli in their discharges, which sporulate in soil and remain as source of infection.# LAB features:# Cultural characteristics of B. anthrax:- Nonhemolytic (sheep blood agar).1. M'Fadyean's reaction - Non-motile2. 'Frosted glass' appearance- Gel hydrolysis -3. 'Medusa head' appearance - Catalase +4. 'Inverted tree' appearance 5. PLET media is used as selective media.


Question: Most common staphylococcal phage strain causing hospital infection

Option 1 Phage typing - Method used for detecting single strains of bacteria. Trace the source of outbreaks of infections. Identify different strains of bacteria within a single species. National reference center for phage typing - MAMC New Delhi. Phage type 80/81 (epidemic strains) Cause hospital infections throughout the world Possess PVL (Panton-Valentine leucocidin) Penicillin-resistant. Option 2, 3, 4 No associated with hospital infections.

Systemic Bacteriology Pa 1 (Gram Positive Cocci, Gram Negative Cocci)


Question: The resolution provided by the light microscope is

Resolving Power:Light microscope: 0.25 um - 0.3 um Electron microscope: 2-10 A = 0.2 - 1 nm


Question: Pathogenesis of diphtheria is attributed to


Question: Influenza belongs to

Ohomyxoviruses are medium-sized, 80 to 120-nm enveloped viruses exhibiting helical symmetry. The genome is linear, segmented, negative-sense, single-stranded RNA, totaling 10-13.6 kb in size. Segments range from 890 to 2350 nucleotides each. Ohomyxoviruses include influenza viruses that infect humans or animals.Ref: Jawetz, Melnick, & Adelberg's Medical Microbiology; Twenty-Seventh Edition; Chapter 29; General Propeies of Viruses


Question: Most common genetic factor in Neisseria infection is

Complement deficiencies are said to comprise between 1 and 10% of all primary immunodeficiencies. The genetic deficiency of early components of the classical pathway (C1q, C1r/s, C2, C4) tends to be linked with autoimmune diseases, whereas C5 to C9 deficiency may have enhanced susceptibility to meningococcal disease. Reference: Textbook of Microbiology; Anathanarayan and panicker's; 10th edition; Pg: 232


Question: Complement C1 is produced by

C1 - Intestinal epithelium
C2, C4 - Macrophages
C5, C8 - Spleen
C3, C6, C9 - Liver


Question: Pseudomonal infection not cleaned by

Pseudomonas species grow comparatively well in Dettol.

Cetrimide & dettol have been incorporated in the media for the selective isolation of pseudomonas.
Gram negative bacilli.
Motile by polar flagellum.
Non capsulated but many stains have mucoid slime layer especially the organisms which are isolated from cystic fibrosis patient.
Obligate aerobe.
Colonies emit a distinctive, musty, mawkish, earthy or sweet grape-like odor or corn tocolike odor.
Cetrimide agar is a selective media.
Pseudomonas aeruginosa produces a numbers of pigments. The production of these pigments accounts for the colour of colonies.

Various pigments are:

Pyocyanin (most important): - It is produced only by Pseudomonas aeruginosa and gives bluish green color. It inhibits the growth of many other bacteria.
Pyoverdin (fluorescein):- gives greenish yellow color.
Pyorubin:- Produces red color.
Pyomelanin: - Produces black color.

Pseudomonas is an important cause of life threatening bacteremia in immunocompromised patients. Ecthyma gangrenosum is the pathognomic skin lesion of P.aeruginosa bacteremia.
P.aeruginosa is the most common and most serious cause of infection in burns.
MC infection outside hospital is suppurative otitis.
P.aeruginosa causes shanghai fever.
It produces blue pus with characteristic fruity odor.


Question: Dark ground microscopy is used for diagnosis of

Ans. a (Spirochete). (Ref. Harrison, Principles of Medicine, 18th/Chapter 169. Syphilis)# Dark ground microscopic examination is useful but negative results does not exclude diagnosis of syphilis.# Diagnosis by microscopy is applicable in primary and secondary stages and congenital syphilis.# Wet film prepared with exudates is seen under dark ground microscope.# T.pallidum show slow movement with slender spiral structure.# However, serology remains the best diagnostic test for syphilis.Educational point:# In blood transfusion and in congenital syphilis, no chancre occurs.


Question: Graft versus host reaction is caused by


Question: The number of pairs of flagella in the below organism is

Trophozoite of Giardia lamblia:*Shape: viewed flat-tennis or badminton racket; viewed side- pear shaped*Dorsal surface: convex*Ventral surface: concave with sucking disc*Anterior end: broad and rounded*Posterior end: tapers to a sharp point*Bilaterally symmetrical and there are 2 axostyles, 2 nuclei and 4 pairs of flagellaRef: K.D Chatterjee 13th edition, p47-48


Question: Vaccination causing intussusception is

Rotavirus vaccination - there is a potentially high risk of intussusception with the first dose when this vaccine is given to infants aged more than 12weeks. Ref: Park&;s textbook of preventive and social medicine; 23rd edition.


Question: Deficiency of C1 inhibitor can produce

C3 def can lead to recurrent pyogenic infections C1 inhibitor deficiency can lead to hereditary angioneurotic edema Ref: Textbook of Microbiology Baveja 5th ed Pg 125


Question: Daisy head colonies are seen with

A round grey or black colony with a narrow translucent scalloped border, typically produced by Corynebacterium diphtheriae on tellurite blood agar. Tellurite inhibits the growth of most other bacteria, acting as a selective agent. Diphtheria bacilli reduce tellurite to metallic tellurium, which is incorporated in the colonies giving them a grey or black colour. Reference: Textbook of Microbiology; Anathanarayan and panicker&;s; 9th edition; Page no: 237


Question: The most common mechanism of resistance to drugs in Staphylococcus is

Transduction is phage-mediated genetic recombination in bacteria. In simplest terms, a transducing paicle might be regarded as a bacterial nucleic acid in a phage coatStaphylococci are variably susceptible to many antimicrobial drugs. Resistance is caused by several mechanisms, one of these is: b-Lactamase production is common, is under plasmid control, and makes the organisms resistant to many penicillins (penicillin G, ampicillin, ticarcillin, piperacillin and similar drugs). The plasmids are transmitted by transduction and perhaps also by conjugation.Reference: Jawetz, Melnick, & Adelberg's Medical Microbiology; 27th edition; Chapter 13; The Staphylococci


Question: Dimorphic with subcutaneous Mycosis is

Sporotrichosis:

Dimorphic fungi
Causes subcutaneous infections.


Question: Black water fever is a special manifestation of malaria caused by;

Ans. A. P. falciparumBlackwater fever (BWF) is a severe clinical syndrome, characterized by intravascular hemolysis, hemoglobinuria (with passage of black urine), and acute renal failure caused by a variety of factors in patients with P. falciparum infestation.


Question: Incubation period of herpes zoster is


Question: Oropharyngeal carcinoma is caused by


Question: Nosocomial infection occurs in hospital in

The term hospital infection, hospital-acquired infection or nosocomial infection are applied to infections developing in hospitalized patients, not present or in incubation at the time of their admission.
Such infections may become evident during their stay in hospital or, sometimes, only after their discharge.
Infections are considered nosocomial if they first appear 48 hours or more after hospital admission or within 30 days after discharge.


Question: The binding site for complement on the lgG molecule is in the


Question: Cutaneous Larva currens is a feature of

Cutaneous larva currens / racing larva, is a feature of strongyloides stercoralis.


Question: Leptospira is a

Ans. c (Spirochete). (Ref. Harrison, Chap. 171)LEPTOSPIROSIS# Leptospira is a spirochetal organism causing leptospirosis or Weils disease.# It is characterized by renal failure, jaundice and fever.# It disappears from blood after 1st week, blood examination is helpful only in early stages.# EMJH media can be used to cultivate them.# Microscopic agglutination is specific for it, but done in reference labs.# Immunofluroscence has no role.


Question: Direct uptake of free DNA by bacterial cell is

Ans. c (Transformation) (Ref. Anantanarayan, Microbiology, 6th ed., 53; Ref. Q. 101 of MH-2005)Method of transmissionCommentTransformation# A phenomenon in which transfer of genetic information occurs through the agency of free DNA.# Certain cell lines, such as cancer cells, are also able to grow indefinitely in culture by this mechanism.Transduction# Transfer of a portion of DNA from one bacteria to another by bacteriophage.# It is not confined to transfer of chromosomal DNA; it transduces episomes and plasmids also.# Bacteriophages are viruses that parasitise bacteria and consist of nucleic acid core and a protein coat.# It is excellent tool for genetic mapping of bacteria.Lysogenic conversion# Phage DNA becomes integrated with bacterial chromosome as prophage, which multiplies synchronously with host DNA and is transferred to daughter cells; this is lysogeny and bacteria harbouring prophages are lysogenic bacteria.# In transduction, phage acts only as vehicle carrying bacterial genes from one cell to another, but in lysogenic conversion, phage DNA itself is new genetic element.Conjugation# The process whereby 'male' or 'donor' bacteria mates or makes physical contact with female or recipient bacteria and transfers genetic element into it.Sexduction# Process of transfer of host genes through f factor, resembles transductionTransfection# Transfer of a gene into a cell, enabling the transfected cell to form a new gene product.


Question: C. albicans is recognized in microscopic examination of infected tissues by the presence of

C. albicans is the most important species of Candida and causes thrush, vaginitis, skin and nail infections, and other infections. It is part of the normal flora of skin, mouth, GI tract, and vagina. It appears in tissues as an oval budding yeast or elongated pseudohyphae. It grows well on laboratory media and is identified by germ-tube formation. A vaccine is not available and serologic and skin tests have little value.


Question: In blood culture the ratio of blood to reagent is

Ans. is 'c' i.e., 1:10 Blood specimens of 5 or 10 ml generally are added to bottles containing, 50 or 100 ml of reagent (medium) to achieve a 1:10 blood medium ratio. All bottles should be transpoed to the laboratory as soon as possible and immediately incubeted at 35 +- 2degC in an upright position (Note - Lower incubation temperature may be preferred for isolation of some specific bacteria, e.g. Listeria grows well at 20-25degC). A total incubation period of 7 days is generally sufficient for routine isolation procedure, which can be extended up to 14 days before discarding those that do not show evidence of growth.


Question: The treatment of early stage of East African sleeping sickness is by

Early stage (Normal CSF)Late stage (Abnormal CSF = CNS involvement)W. African (T. brucei gambiense)PentamidineEflornithineE. African (T. brucei rhodesiense)SuraminMelarsoprol


Question: Most impoant drug for persisters of TB

Rifampicin is a powerful bactericidal drug. It is a better sterilizing agent than INH. It permeates all tissue membranes including the blood-brain and placental barriers. It is equally effective against intracellular as well as extracellular bacilli.It is the only bactericidal drug active against the "persisters" or dormant bacilli which are found in the solid caseous lesions, all other drugs being inactive. In this regard, it has a distinct advantage over INH.Rifampicin is of special value when the bacilli resist other drugs. In combination with INH, it can cure even extensive tuberculosis in about 9 months.


Question: Opacity around colonies of clostridium perfringens is due to

Alpha toxin is produced by all thoracic clostridium perfringes. Alpha toxin is lecithinase C. Demonstrated by Nagler's reaction. Nagler reaction; When Clostridium perfringes are grown in media containing 6 % agar, Fildes peptic digest of sheep blood and 20% human serum, with antitoxin spread on one half of plate, colonies in the other half without antitoxin will be surrounded by a zone of opacity. No opacity around the colonies on the half of plate with antitoxin. This is due to the specific neutralization of the alpha-toxin or lecithinase C. Reference: Textbook of Microbiology; Anathanarayan and paniker's; 10th edition; Page no: 259


Question: Measles is caused by a

Answer: a) Single stranded RNA enveloped virus (PANIKER 9th EDITION P-305)DNA virusesFully double strandedPartially double strandedSingle strandedNaked DNAHerpesvirusPoxvirusAdenovirusPapovavirusHBVParvovirusCircovirusParvovirusAdenovirusPapovavirus RNA virusesDouble stranded RNA virus: Reovirus, PicobirnavirusSingle stranded RNASS - Enveloped RNASS- Nonenveloped RNAPositive sense* Picorna* Toga* Calci* Flavi* CoronaNegative sense* Rhabdo* Orthomyxo* Paramyxo* Arena* Bunya* Arena* Retro* Filo* Bunya* Orthomyxo* Paramyxo* Toga* Rhabdo* Corona* Picorna* Calci* ReoMEASLES (RUBEOLA)* Measles virus (Paramyovirus) - hemagglutinin present; neuraminidase absent* Measles is a winter disease* Children 1-5 years are mostly affected* Source of infection is a case of measles* No carrier state* No animal reservoir* IP: 9-lldays; 7 days following vaccine* Secondary attack rate 80%* Communicability 4 days before and 5 days after the appearance of rash* Pathognomic feature - Koplik's spots in the buccal mucosa appears 2 days before rash, opposite to lower first and second molars, fade with the onset of rash; sometimes seen on the conjunctiva and intestinal mucosa* The red maculopapular rash first appears on the forehead and spreads downwards* In malnourished children it can cause hemorrhagic rashes - black measles* Most common complication - otitis media* Most common life-threatening complication - bacterial pneumonia* Streptococcus pneumoniae and H influenzae type b - common causes of bacterial pneumonia* Giant cell pneumonia - serious complication in those with deficiencies in cell-mediated immunity* Protracted diarrhea may occur in children* Spontaneous abortion and premature delivery can occur in pregnant women* No congenital anomalies reported* Children may develop acute vitamin A | and treated with vitamin A which reduces morbidity and mortality* Multinucleated giant cells called Warthin-Finkedly cells are pathognomic of measles* Acute encephalitis occurs 1 in 1000 cases* Subacute sclerosing panencephalitis (SSPE) or Dawson inclusion body encephalitis is a rare complication> Develops 5-15 years after initial measles infection> Frequency 1 in 10000 to 1 in 100000 cases.> Progressive mental deterioration, involuntary movements, muscular rigidity, coma.> Usually fatal within 1-3 years after onset> Defective measles virus in brain cells seen> Demonstration of high titre measles antibody in CSF and serum is diagnostic> Most often develops in persons infected with measles virus at <2 years of ageCell surface receptors for Measles virus* CD46 complement regulatory protein that inactivates C3 convertases)* SLAM (Signaling lymphocytic activation molecule)* Nectin 4 (adherens junction protein)Measles vaccine* Live attenuated vaccine (Edmonston Zagreb strain)* One dose of vaccine gives 95% protection; Vaccine efficacy is 85%* No spread of virus from vaccinees to contacts* Susceptible contacts over 9 months can be given the vaccine within 3 days of exposure, as IP of measles induced by vaccine is 7 days compared to 10 days for the naturally acquired virus* Toxic shock syndrome occurs when the vaccine is contaminated or the same vial is used for more than one session on the same day. The vaccine should not be used 4 hrs after opening the vial* Eradication of measles requires immunization coverage of 96%* Atypical measles - measles infection due to formalin inactivated vaccine; rash begin in palms and soles* Modified measles - in individuals who have received serum Ig after exposure to measles virus.


Question: A patient was hospitalized after a road accident. The wounds became infected and the patient was treated with tobramycin, carbenicillin, and clindamycin. Five days after antibiotic therapy was initiated, the patient developed severe diarrhoea and pseudomembranous enterocolitis. Antibiotic associated diarrhoea and the more serious pseudomembranous enterocolitis can be caused by

Pseudomembranous enterocolitis and antibiotic-associated diarrhea are caused by an anaerobic Gram-positive rod, Clostridium difficile. Patients treated with antibiotics develop diarrhea that, in most cases, is self-limiting. However, in some instances, paicularly in those patients treated with ampicillin or clindamycin, a severe, life-threatening pseudomembranous enterocolitis develops. This disease has characteristic histopathology, and membranous plaques can be seen in the colon by endoscopy. It has been recently shown that C. difficile produces a protein toxin with a molecular weight of about 250,000. The "toxin" is, in fact, two toxins, toxin A and toxin B. Both toxins are always present in fecal samples, but there is approximately one thousand times more toxin B than toxin A. Toxin A has enterotoxic activity--that is, it elicits a positive fluid response in ligated rabbit ileal loops-- whereas toxin B appears to be primarily a cytotoxin.

Systemic Bacteriology (Gram Positive Bacilli, Gram Negative Bacilli)


Question: An inhibitor was designed to block a biologic function in H. influenzae. If the goal of the experiment were to reduce the virulence of H. influenzae, the most likely target would be

The major determinant of virulence in H. influenzae is the presence of a capsule. There is no demonstrable exotoxin and the role of endotoxin is unclear. While one would expect that IgA protease would inhibit local immunity, the role of this enzyme in pathogenesis is yet unclear.

Systemic Bacteriology (Haemophilus, Yersinia, Spirochaetes, Ricketssia, Chlamydia, Mycoplasma and Miscellaneous Bacteria)


Question: Disorder of T cell is

PNP deficiency is autosomal recessive disorder
T cell defect.

Purine nucleoside phosphorylase (PNP) deficiency


Question: The most impoant source of Infection for meningococci is

The human nasopharynx is the only reservoir of the Meningococcus. Natural infection is limited to the nasopharynx. Asymptomatic nasopharyngeal carriers rarely contract the illness but serve right infect their contacts. During the inter-epidemic period, the carrier rate is 5-10 percent. An increase in carriers rate heralds the onset of an epidemic. During epidemics, the carrier rates of closed communities may go up to 90 percent. Reference: Textbook of Microbiology; Anathanarayan and panicker's; 10th edition; Page no: 232


Question: The endotoxin of the following gram negative bacteria does not play any pa in the pathogenesis of the natural disease.

Ans. is 'c' i.e., Vibrio cholerae . Cholera vibrios possess the lipopolysaccharide 0 antigen (LPS endotoxin), but it has no role in pathogenesis. About other options . Somatic lipopolysaccharide surface 0 antigen of E.coli has endotoxic activity and also protect the bacilli from phagocytosis . Long chain lipopolysaccharide (endotoxin) of klebsiella protects it from the action of serum complement . Endotoxin of pseudomonas causes fever, leukocytosis or leukopenia, shock, DIC, hypotension, ARDS, SIRS.


Question: Drug induced pseudomembraneous colitis is caused by

Ans: b) Cl.difficile* CLdifficile is a gram positive bacillus* Non haemolytic, saccharolytic, weakly proteolytic* Pseudomembraneous colitis is due to enterotoxin (toxin A) & cytotoxin (toxin B) and Binary toxin* The toxin is neutralised by Clostridium sordelli antitoxin* Drug of choice: Metronidazole* Most common clinical feature: diarrhoea* Entire colon is affected in 90% patients, 70% have rectal sparing* Most sensitive test: stool culture for Cl.difficile* Probiotic medicine in treatment of it: saccharomyces boulardi* Drugs, causing this : clindamycin, ampicillin, cephalosporins (ceftriaxone, cefotaxim, cefuroxime, ceftazidime) & fluoroquinolone (ciprofloxacin, levofloxacin, gatifloxacin, moxifloxacin)


Question: An example of high level disinfectant is


Question: Central tendon of diaphragm develops from

Development of DiaphragmSeptum transversum: it is a mass of mesodermal tissue arising from the coelomic wall at the 4th week of gestation. It forms the central tendon of the diaphragm.Dorsal meso-esophagus forms the median poion of diaphragm and the crurae.Cervical myotomes (from C3-C5 somites) of lateral body wall form the peripheral pas of the diaphragm.Pleuro-peritoneal membranes.Chromosome 15q plays a major role in diaphragm developmentDuring the initial period of development, it lies at a higher level (cervical) and then migrates caudally and hence the nerve supply is from C3, C4, C5 (Phrenic nerve).Embryonic structuresAdult derivativesSeptum transversumCentral tendon of the diaphragmPleuroperitoneal membranesSmall peripheral pa of the diaphragmDorsal mesentery of esophagusCrura of the diaphragmMesoderm of the body wallLarge peripheral pas of diaphragm external to pas derived from pleuroperitoneal membranes


Question: Nucleic acid is not found in

o Prions are infectious particle which contains protein only
o They do not have nucleic acid. Prions have been defined as
- Small proteinaceous infectious particle which resist inactivation by procedures that modify nucleic acids


Question: Salmonella typhi is the causative agent of typhoid fever. The infective does of S.typhi

Ans. is 'c' i.e., 102-105 bacilli In human volunteer experiments, the infective dose was found to be 103-106 bacilli. Organism Infective dose . ETEC . EIEC . EHEC . Shigella . Campylobactor jejuni . Yersinia enterocolitica . Vibrio 106-101deg 108-10m 10-100( 104 108-109 1010 (if source of infection is water) 102-104 (if source of infection is food)


Question: Lepra bacilli are best cultured in

Footpad of mouse: lepra bacilli multiply in the footpad of mice kept at a low temperature (20 deg). This has become the standard procedure for experimental work with the bacillus. Following intradermal injection into the footpad of mice, a granuloma develops at the site in 1-6 months. If cell-mediated immunity is suppressed by thymectomy or the administration of an anti-lymphocyte serum, generalised infection is produced, simulating lepromatous leprosy. Ref: Textbook of microbiology; Ananthanarayan and paniker's; 10th edition; Pg: 372


Question: Antigenic drift and antigenic shift is seen in

ANTIGENIC DRIFT It is a minor change occuring due to point mutations in the HA/NA gene ,resulting in alteration of amino acid sequence of the antigenic sites on HA/NA , such that virus can escape recognition by the host's inmune system. Seen in both influenza type A and B More frequent- every 2-3 years ANTIGENIC SHIFT It is an abrupt , major drastic , discontinuous variation in the sequence of a viral surface protein , that occurs due to genetic reassoment between genomes of 2 or more influenza viruses infecting the same host cells , resulting in a new virus strain, unrelated anti genetically to the predecessor strains Occurs only in influenza type A Less frequent - every 10 -20 yrs Ref : essentials of Medical microbiology apurba sastry 1st edition page 459


Question: Intravenous resuscitation is needed for any child with burn greater than

In children with burns over 10% total body surface area and adults with burns over 15% total body surface area, consider the need for intravenous fluid resuscitation.


Question: An outbreak of streptococcal pharyngitis has occurred in a remote village. In order to carry out the epidemiological investigations of the outbreak, it is necessary to perform the culture of the throat swab of the patients suffering from the disease. The transpo media of choice would be

For culture, the throat swab of streptococcal pharyngitis case has to be sent to a laboratory in a suitable transpo medium. Pike's medium: transpo media for streptococcus. It is a blood agar containing 1 in 10,00,000 crystal violet and 1 in 16,000 sodium azide. Reference: Textbook of Microbiology; Anathanarayan and paniker's; 10th edition; Page no: 216


Question: Cryptococcus is least likely to cause infection of

Pulmonary cryptococcus - mild pneumonitis. Cryptococcal meningitis: disseminated infection to the skin, lymph node and bone. Ref: Textbook of Microbiology, Ananthanarayan and Paniker; 9th edition


Question: Gastrointestinal enteritis necroticans is caused by

Necrotizing enteritis: severe and fatal enteritis. Caused by Clostridium perfringes type C strains produce heat-resistant spores that germinate in intestine producing a beta toxin causing mucosal necrosis. Immunization with type C toxoid has been shown to protect against this condition. Reference: Textbook of Microbiology; Anathanarayan and paniker's; 10th edition; Page no: 260


Question: Biological value is maximum in

NPU (Net protein Utilisation) is the combination of Biological value & Digestibility, which is 100 for egg, compared to 80 for meat and 75 for milk.


Question: Arrangement of lens from eye to source of light, in light microscope

Ocular lens: Objective lens: Condensor lens

Objective lens: Ocular lens: Condensor lens

Condensor lens: Objective lens: Ocular lens

Objective lens: Condensor lens: Ocular lens

General Microbiology Pa 1 (History, Microscopy, Stains and Structure and Physiology of Bacteria)


Question: Causative agent of angular conjunctivitis

Angular conjunctivitis commonly caused by Moraxella lacunata and S. Aureus.


Question: Forschheimer spots are seen on

Forscheimer spots are pin - head sized petechiae seen on soft palate and uvula, seen in Rubella.


Question: Interleukin 2 is secreted by

(A) CD4 cells / T helper cell# Interleukin - 2: Is produced by - T-helper cell or CD4 cells Function - It causes T cell growth & activation> Interleukin -1: Is secreted by phagocytes Function - T cell activation; Fever; Cachexia> Interleukin - 3: Produced by T cells Function: Hematopoiesis> Also remember: II-4, IL-6, IL-8, IL-10, IL-12 T cell, Mast cell, T cell Macrophage, Macrophages, T cells, B cells, macrophage


Question: Watery diarrhea in children is caused by

Enteropathogenic E.coli: associated mainly with diarrhea in children and infants usually occurring as an institutional outbreak. The pathogenesis of EPEC diarrhea is not fully understood. EPEC is non-invasive and does not produce enterotoxin. Another mechanism is by adherence to the enterocyte membrane. This activity is regulated by the chromosomally coded locus of enterocyte effacement (LEE). This is a pathogenicity island by an intimin protein coded for by the eae gene. This results in the disruption of the brush border microvilli. Reference: Textbook of Microbiology; Anathanarayan and paniker's; 10th edition; Page no: 285


Question: Scarlet fever is caused by

Ans. is 'b' i.e., Streptococcus pyogenes Infections caused by streptococcus pvogenes Respiratory infections Sore throat is the most common of streptocococcal disease . It may be localised as tonsillitis as in older children and adults or it may involve the pharynx more diffusely (pharyngitis) as in younger children. Otitis media


Question: Fully embryonated egg of trichuris trichiura contains


Question: Antonie van Leeuwenhoek is associated with

Antony van Leeuwenhoek: The Microscopist The first person to observe and describe microorganisms accurately was an amateur microscopist Antony van Leeuwenhoek (1632-1723) .

General Microbiology Pa 1 (History, Microscopy, Stains and Structure and Physiology of Bacteria)


Question: SI unit of the brightness of a point light source is

DescriptionQuantity measured nameRecommended unitBrightness of point sourceLuminous intensityCandelaFlow of lightLuminous fluxLumenAmount of light reaching surfaceIllumination IlluminanceLuxAmount of light re-emitted by surfaceBrightness luminanceLambe


Question: Pseudohpyhae are seen in

Candida is a yeast like fungus that produces Pseudohyphae.


Question: "Black dot" ring worm is caused by

In endothrix, a Trichophyton infection, the hair shaft breaks off at the skin surface, leaving the hairs visible as black dots in the scalp.


Question:
The type of immunoglobulin most commonly
increased in multiple myeloma is


Question: Toxic shock syndrome occurs after one of the following vaccinations

TSS occurs when measles vaccine is contaminated or the same l is used for more than one section on the same day or next day, the vaccine should not be used after 4hrs of opening the l. Symptoms - watery diarrhoea, vomiting and high fever are repoed within few hours of measles vaccine. Ref: Park&;s textbook of preventive and social medicine; 23rd edition

Recombinant DNA vaccine against hepatitis B


Question: The most common organism causing food poisoning in canned food is

Clostridium botulinum: strict anaerobic, cause botulism. Source of foodborne botulism is preserved food, meat and meat products, canned foods. Proteolytic varieties can digest food, which appears spoiled. The cans are often inflated and show bubbles on opening. Non-proteolytic varieties have food unchanged. Reference: Textbook of Microbiology; Anathanarayan and paniker's; 10th edition; Page no: 269


Question: Tinea Nigra is caused by

Tinea nigra is characterised by painless, black, non scaly patches over palms & sole, caused by Hortaea werneckii.


Question: Lysogenic conversion is seen in

The toxigenicity of the diphtheria bacillus depends on the presence of corynephages(tox+) in it which acts as the genetic determinant controlling toxin production. Non-toxigenic strains may be rendered toxigenic by infecting them with the beta or some other phage. This is known as lysogenic or phage conversion. The toxigenicity remains only as long as the bacillus is lysogenic. Reference: Textbook of Microbiology; Anathanarayan and panicker's; 10th edition; Page no: 240


Question: HLA gene is located in chromosome

HLA is located in short arm of chromosome-6.


Question: The main causative organism of Gas gangrene is

Gas gangrene is caused by Clostridium PerfringensRef: Harrison&;s Principles of Internal Medicine; 19th edition; Chapter 156; Infections of the Skin, Muscles, and Soft Tissues


Question: In tandem caridge, the number of bullets fired is

Duplex or tandem caridge: this is used in military rifles and contains two bullets which enter the target at different points, separated by as much as 30 cm. The base of the forward bullet is notched, into which the second bullet fits closely.


Question: Elek&;s gel precipitation test is for

Elek's gel precipitation test: a rectangular strip of filter paper impregnated with diphtheria antitoxin is placed on the surface of a 20% normal horse serum agar in a Petri dish while the medium is still fluid. When the agar has set, the surface is dried and narrow streaks of strains are made at right angles to filter paper strip. A positive and negative control should be put up. The plate is incubated at 37degC for 24-48 hours. The toxin produced by the bacterial growth will diffuse in agar and where it meets the antitoxin at optimum concentration, will produce a line of precipitation. The presence of such arrow headlines of a precipitate indicates the strain is toxigenic. No precipitate is formed in the case of non-toxigenic strains. Reference: Textbook of Microbiology; Anathanarayan and panicker's; 10th edition; Page no: 243


Question: The following bacteria doesn't produce any spores

Pseudomonas doesn't produce spores. Bacillus and Clostridium produce spores Ref: Textbook of Microbiology Baveja 5th ed Pg 21


Question: Doc for Cryptosporidium parvum is

Nitazoxanide is Doc for Cryptosporidium.
Cotrimoxazole is Doc for Cyclospora and isospora.


Question: The congenital rubella syndrome

Congenital rubella syndrome cause communication problem& developmental retardation REF:<\p> ANATHANARAYANAN MICROBIOLOGY NINTH EDITION PAGE.555

May be prevented by vaccination in early pregnancy

Causes deafness only if acquired only if acquired before 16 weeks of gestation


Question: Swollen belly syndrome is caused by

Strongyloides Fuelleborni causes swollen belly syndrome.


Question: Most common age group affected by streptococcus pyogenes

Sore throat(tonsilitis) is the most common manifestation of streptococcal infection and affects 5-15 years age group.


Question: Morris Index positive in ECG is suggestive of

The index proposed by Morris (amplitude of the negative deflection in V1 in mm multiplied by its duration in seconds) is positive if greater than 0.03Morris Index positive in ECG is suggestive of Another sign of Left atrial enlargement in ECG is P wave width >2.5 mm in lead II.Right, atrial enlargement P wave height >2.5mm in lead II and area of the Positive phase of P wave in Lead V1 >0.06mmsec.


Question: Endotoxins differ from exotoxins in that endotoxins

activate complement by the alternate pathway


Question: The Earliest sign of male pubey is

In boys, the first visible sign of pubey and hallmark of SMR2 is testicular enlargement, beginning as early as 9 1/2 years. This is followed by penile growth during SMR3. Peak growth occurs when testis volumes reach approximately 9-10 cm3 during SMR4. Under the influence of LH and testosterone, and prostate enlarges. The left testis normally is lower than the right. Some degree of breast hyperophy, typically bilateral, occurs in 40-65% of boys during SMR2-3 due to a relative excess of estrogenic stimulationIn girls, the first visible sign of pubey and the hallmark of SMR2 is the appearance of breast buds, between 8 and 12 years of age. Menses typically begins 2-2 1/2 years later, during SMR3-4 (median age, 12 years; normal range, 9-16 years), around the peak height velocity. Less obvious changes include enlargement of the ovaries, uterus, labia, and clitoris, and thickening of the endometrium and vaginal mucosa


Question: Skin transplant was done from sister to brother. After few years, brother to sister skin transplant was done, but rejection occurred. This phenomenon is known as

Eichwald-Silmser effect, which is a unilateral sex-linked histoincompatibility. While transplants between same sex siblings are successful, grafts from female to male are also successful, but an exception is seen when the donor is a male and the recipient is a female. Such grafts are rejected as the grafted male tissue (XY) will have antigens determined by the Y chromosome which will be absent in the female (XX) recipient. Reference: Ananthanarayan and Paniker&;s Textbook of Microbiology Tenth edition


Question: Probiotics are useful for

Probiotics are live bacteria or yeast that are good for health, especially digestive system. Lactobacillus and Bifidobacterium are common probiotics. They treat the ceain condition like 1. Irritable bowel syndrome 2. Inflammatory bowel disease 3. Infectious diarrhoea ( by viruses, bacteria, parasite) 4. Antibiotic-related diarrhoea. Ref: Baveja textbook of microbiology; 4th edition


Question: Neutrilization test is

Ans. is `d' i.e., Nagler reaction Neutralization reaction When antibody reacts with a toxin or other biologically active antigen, it may neutralize the effect of toxin or antigen. This ability to used in neutralization test. Neutralization tests are of two types


Question: Cerebral malaria is caused by Plasmodium

(B) Falciparum # Cerebral Malaria - one of commonest complication of falciparum malaria> In cerebral malaria, lesions occur in the central nervous system.> These consist of congestion of the meninges and brain, occlusion of capillaries in brain, numerous petechial perivascular hemorrhages, and necrotic lesions in mid zonal brain tissue, with peripheral glial reaction (malarial granuloma) around occluded blood vessels.


Question: Septic shock is due to

Ans. is 'b' i.e., Lipopolysaccharide Septic shock is due to endotoxin of gram negative bacteria. Therefore it is also called as endotoxic shock. Endotoxin is lipopolysaccharide.


Question: Dental Plaque adheres to tooth surface by


Question: Most common cause of Traveller's diarrhoea

Enterotoxigenic E. coil Most common cause of traveller's diarrhoae -f Enterotoxigenic E. coli Harrison states "The most- frequently identified pathogen causing traveller's diarrhoea is toxigeic Escherichia coll." Most common cause of traveller's diarhoea Toxigenic E.coli Most common cause of traveller's diarrhea in Campylobacter South East Asia and Africa Most common viruses associated with traveller's --> Rotavirus and Norovirus diarrhea


Question: Dermatophytosis is caused by

Dermatophytosis is caused by Microsporum, Trichophyton and Epidermophyton. Candida causes candidiasis. Reference: Textbook of Microbiology; Baveja; 4th edition .


Question: Maternal antibodies donot provide protective immunity to neonate


Question: Scrub typhus vector

Tromboculid mite 8"/e, p. 574 (17th /e page 543)] Mites are vectors for the following diseases: Diseases Vector Scabies Itch mite Scrub Typhus Trombiculid mite Rickettsial pox Trombiculid mite This topic has been discussed in detail earlier. Mostly they keep on asking about Ticks and mites so remember the diseases caused by Ticks too. Vector Disease Vector (a) Soft tick * Q fever, Relapsing fever (b) Hard tick * Tick typhus * Viral encephalitis * Viral fevers * Viral hemorrhagic fever (KFD) * Tuleremia * Human babesiosis, Tick paralysis


Question: ABO antibodies are


Question: After splenectomy, most common infection is

Streptococcus pneumoniae cause infection when host resistance is lowered by contributory factors such as respiratory viral infection, pulmonary congestion, stress, malnutrition, immunodeficiency and alcoholism. Splenectomy and sickle cell disease are impoant predisposing conditions. Reference: Textbook of Microbiology; Anathanarayan and panicker's; 10th edition; Page no: 227


Question: The most common portal of entry for C. tetani, the cause of tetanus, is the

Organisms may be transmitted in a number of ways, such as by air, food, hands, sexual contact, and infected needles. However, for each disease or disease category, there is usually a portal of entry not always unique to the organism. The respiratory tract is a common portal of entry to such airborne organisms as M. tuberculosis. This is why respiratory precautions must be taken when patients are harboring viable M. tuberculosis.The gastrointestinal tract is usually infected from ingestion of contaminated food or water (Shigella, Salmonella, Campylobacter) or by an alteration of the normal microbial flora such as with C. difficile disease. The skin is a tough integument and intact, is resistant to most infectious organisms except those that may break down human skin. Breaches of the skin as by wounds, burns, and the like predispose patients to a variety of infections such as tetanus caused by wound contamination with spores of C. tetani, or direct infection by Staphylococcus, Streptococcus, or Gram-negative rods (such as Serratia or Pseudomonas).The genital tract may become infected either by sexual contact or by alteration of the genital environment as often occurs with yeast infections. Several bacteria such as N. gonorrhoeae, Chlamydia, and Treponema pallidum are transmitted by direct sexual contact with infected partners.


Question: Bacteria used in Griffith's experiment is

Griffith's experiment is done on mice using pneumoccal strains.


Question: Cytokine produced by TH1 cells

IL-2 produced by TH1 cells induces proliferation of activated T4 cells, Tc cells and some Nk cells.


Question: "Owl Eye" appearance of inclusion bodies are seen in

(B) CMV # Cytomegalic cells in vivo (presumed to be infected epithelial cells) are two to four times larger than surrounding cells and often contain an 8- to 10-m intranuclear inclusion that is eccentrically placed and is surrounded by a clear halo, producing an "owl's eye" appearance.> Cytomegalic cells are found in a wide variety of organs, including the salivary gland, lung, liver, kidney, intestine, pancreas, adrenal gland, and central nervous system.> Viral inclusion bodies:A. Examples of viral inclusion bodies in animals are Intracytoplasmic eosinophilic:1. Negri bodies in Rabies2. Guarnieri bodies in Small pox3. Henderson-Peterson bodies in Molluscum contagiosumB. Intranuclear acidophilic:1. Cowdry type A in Herpes simplex virus and Varicella zoster virus and Torres bodies in Yellow fever2. Cowdry type B in PolioC. Intranuclear basophilic:1. Cowdry type B in Adenovirus2. "Owl eyes" in cytomegalovirusD. Both intranuclear and intracytoplasmic:1. Warthin fmkeldey bodies in Measles.


Question: Toxoids are


Question: Latex agglutination study of the antigen in CSF helps in the diagnosis of

Latex agglutination test - cryptococcal capsular polysaccharide antigen can be detected in CSF, serum or urine by latex agglutination test. Ref: Textbook of Microbiology, Ananthanarayan and Paniker; 9th edition


Question: Germ theory of disease was proposed by

Louis Pasteur proposed :

Principle of fermentation
Pasteurization of milk
Sterilization techniques
Germ theory of disease.


Question: Suckling mice is used for isolation of

It is necessary to employ suckling mice for the isolation of coxsackieviruses.
 Inoculation is usually made by intracerebral, subcutaneous and intraperitoneal route.
 Adult mice are not susceptible.
 Human diploid fibroblasts (HDF) cell line is used for cultivation of coxsackie A7,9,16; CMV; Echovirus; enteroviruses; HSV-1,2; Poliovirus: parainfluenzavirus, rhinovirus and VZV.

Cultivation of viruses
‘As viruses are obligate intracellular parasites they cannot be grown on any inanimate culture medium.' Three
methods are employed for cultivation of viruses :
1. Animal Inoculation

 Earliest method
 Mice are most widely employed animals
 Other animals used are guinea pigs, rabbits and ferrets.

2. Embryonated eggs

 Sites of inoculation are:

a) Chorioallantoic Membrane ------- visible pocks are produced → HSV, Vaccinia, Smallpox
b) Amniotic Sac
c) Allantoic cavity
→  Influenza o Some paramyxoviruses
d) Yolk Sac → o Some viruses o Chlamydia o Rickettsia
3.Tissue culture

 Most important method for virus isolation.
 Three types of tissue culture are available

I. Organ Culture
II Explant Culture
III. Cell Culture - (routinely employed)

 Cell culture may be

1. Primary cell culture: Rhesus monkey kidney, human amnion, chick embryo fibroblast, human embryonic kidney.
2. Diploid cell strains:- Human diploid fibroblast HL-8, WI-38.
3. Continuous cell line:- Hela, HEP-2, McCoy, Vero


Question: Concentration of agar used for solid agar to Inhibit Proteus swarming

For solid agar - 1-2%
For Semisolid agar - 0.5%
For solid agar to inhibit proteus swarming - 6%


Question: Pentavalent immunoglobin is


Question: Pontiac fever is caused by

Pontaic fever is a mild ,non fatal ,influenza like illness with fever chills,myalgia and headache.caused by legioneola pneumophila belongs to family legionellaceae. Ref:anantnarayan and panikers 10 the edition


Question: Medical management of kernicterus is

Treatment for kernicterus may include :Phototherapy for kernicterus: exposure to ultraviolet light breaks down bilirubin in the bloodstream.Exchange transfusion: Removing blood that contains bilirubin, with blood that does not contain bilirubin.Medications that reduce the amount of bilirubin in the bloodstream: Albumin (albuminar, albutein, plasbumin)Immune globulin intravenous Phenobarbital


Question: Cell mediated immunity is markedly depressed in

(B) Lepromatous leprosy# In untreated LL patients, lymphocytes regularly fail to recognize either M. leprae or its protein constituents, and lepromin skin tests are negative.> This loss of protective cellular immunity appears to be antigen-specific, as patients are not unusually susceptible to opportunistic infections, cancer, or AIDS and maintain delayed-type hypersensitivity to Candida, Trichophyton, mumps, tetanus toxoid, and even purified protein derivative of tuberculin.> Lepromatous leprosy, has the greatest number of bacilli and is characterized by early, widespread, ill-defined, erythematous or hypopigmented papules and plaques. Later findings include facial infiltration (leonine facies), ocular effects, neurologic involvement, and hypogonadism.


Question: Vibrio cholerae was discovered (1883) by

Ans. c (Robert Koch) (Ref. Ananthanarayan Microbiology, 7th/ pg.2)Robert Koch is known for -# Co-founder of bacteriology,# Koch's postulates of germ theory,# Isolator of anthrax# Isolator of tuberculosis and choleraVibrio# Vibrio cholerae, was discovered in 1883 by the German physician and bacteriologist Robert Koch.# Vibrio cholerae is short curved cylindrical rod (typically comma shaped).# Are gram-negative and non-acid fast.# They are asporogenous and noncapsulated.# It is actively motile with single sheathed polar flagellum showing darting type.# It ferments glucose, mannitol, maltose, mannose and sucrose. Indole is formed and nitrates are reduced.# These two properties give "cholera red" reaction.# It is transported in alkaline medium. The media used are:1. Venkatraman -Ramakrishna medium: 20 g crude sea salt + 59 peptone in 1L of distilled water + pH of 8.6-8.8.2. Carry-Blair medium: NaCl + sodium thioglycolate + CaCl2 + disodium phosphate at pH 8.4.3. Autoclaved seawater.# V. cholerae exotoxin ADP ribosylates Gsa, leading to cAMP & subsequent diarrhea.# Vibrios that have a high requirement of NaCl are known as halophilic vibrios. which include:- V. parahaemolyticus- V. alginolyticus- V. vulnificus- V. fluvitalisAlso Know:# Main discoveries of Antonie van Leeuwenhoek: 1) RBCs, 2) Infusoria, 3) Spermatozoa and 4) Bacteria.# Staphylococci were first observed and cultured by Pasteur and Koch, but the initial detailed studies on staphylococci were made by Ogston in 1881 and Rosenbach in 1884.# The name 'genus Staphylococcus' was given by Ogston when he obs grape-like clusters of bact in pus from abscesses.# Three years later, Rosenbach was able to isolate and grow these microorganisms in pure culture. He gave these bacteria the specific epithet Staphylococcus aureus because of the yellow-to-orange pigmented app. of their colonies.


Question: Chlamydia are isolated by

Isolation of chlamydiae can be done by :Inoculation into yolk sac/embryonated eggs of 6-8 day old chick embryo which may be pretreated by streptomycin or polymyxin B.Inoculation into experimental animals (mice)Tissue/cell culture:Preferred modeCommonly used cell lines are McCoy and HeLa cells.Cell cultures are pretreated by irradiation or chemicals such as 5-iodo-2 deoxyuridines or cycloheximide to enhance replication and detection of inclusion bodies.Pretreatment with DEAE dextran or centrifugation after inoculation promotes contact between chlamydiae paicles and cell monolayer.


Question: Most common cause of meningitis in renal transplant patients is

Listeria monocytogenesDistinguishing Features* Small gram-positive rods* Beta-hemolytic, nonspore-forming rod on blood agar, CAMP positive* Tumbling motility in broth; actin jet motility in cells* Facultative intracellular parasite* Cold growth* Transplacental--granulomatosis infanti-septica* Neonatal septicemia and meningitis (third most common cause)* Meningitis in renal transplant or cancer patients (most common cause)Ref: Jawetz; 27th edition; Page no: 197


Question: River blindness is caused by

Onchocerciasis is also known as River blindness and Robles disease. REF : paniker book of parasitology 8th Ed.


Question: Waterhouse friederichsen syndrome is caused by

Waterhouse friederichsen (WF) syndrome is fulminant meningococcemia characterized by shock, disseminated intravascular coagulation, petechial rash and multisystem failure due to the lipo-oligosaccharide mediated damage of the vascular endothelium. it is caused by N.meningitidis

Systemic Bacteriology (Gram Positive Cocci, Gram Negative Cocci)


Question: A 40 year man comes to hospital with a ulcerative lesion in his Right thumb. It happened while working in garden. On culture, moist creamy colonies appear. Most common organism is

Sporotrichoisis - Rose gardener disease.
On culture - at 37oC creamy white colonies.


Question: pH of Sabouraud's dextrose agar is adjusted to

Sabouraud's dextrose agar (SDA), contains glucose and modified peptone, suppos the growth of fungi, and restricts the growth of bacteria.The pH of SDA is 5.6Jawetz 27e pg: 663


Question: Immunoglobulin secreted by fetus as primary response

Ans. is 'b' i.e., IgM IgM is the first immunoglobulin class produced in a primary response to an antigen. IgM antibodies are relatively sho lived, disappearing earlier than IgG. IgM is the earliest immunoglobulin to be synthesized by the fetus beginning by about 20 weeks of age. IgM can not cross the placenta. The presence of IgM in the fetus or newborn indicates intrauterine infection and its detection is useful in the diagnosis of congenital infections such as Toxoplasmosis, syphilis, rubella, cytomegalovirus infection and HIV infection.


Question: Bacteria reproduce mainly by

bacterial components produced by host cells


Question: Monoclonal antibody that neutralizes anthrax toxin

Raxibacumab is Intended for the prophylaxis and treatment of inhaled anthrax.


Question: Cigar body is seen in

Sporothrix schenckii occurs in yeast phase in the tissues and in the culture at 37C and in mycelial phase in the culture at 23C. The yeast phase appears as the cigar- shaped cells and mould form contains hyphae carrying flower-like clusters of small conidia borne on delicate sterigmata. Sporothrix schenckii causes sporotrichosis. Ref: Textbook of Microbiology, Ananthanarayan and Paniker; 9th edition


Question: Polysaccharide capsular resistance to phagocytosis is seen in

The virulence of Streptococcus pneumoniae depends on the capsular polysaccharide. The capsular polysaccharide because of its acidic and hydrophilic propeies, protects the cocci from phagocytosis. Capsulated streptococcus pneumoniae are not phagocytosed efficiently in fluid media or exudates, however, they are susceptible to surface phagocytosis, being engulfed against a firm surface, such as a fibrin clot or epithelium. The enhanced virulence of type 3 Streptococcus pneumoniae is due to an abundance of its capsular material. Non-capsulated strains are avirulent. Reference: Textbook of Microbiology; Anathanarayan and panicker's; 10th edition; Page no: 226


Question: Antibiotic sensitivity and resistance of micro organisms is determined by


Question: Staphylococcus in stool occurs in

Enterotoxin is responsible for the manifestation of staphylococcal food poisoning-nausea, vomiting, and diarrhoea 2-6 hrs after consuming food contaminated by a preformed toxin. In food poisoning, feces and the remains of suspected food should be collected.


Question: Infection with colitis is caused by

Ans. is 'c' i.e., Strongyloides Strongvloidiosis . It is most frequently asymptomatic . In symptomatic cases the following lesions may be observed.


Question: In Gonorrhea, the selective media is

(A) Thayer-Martin medium # Gonococci are more difficult to grow than meningococci. They are aerobic but may grow anaerobically also. Growth occurs best at pH 7.2-7.6 and at a temperature of 35-36 degC. It is essential to provide 5-10% CO2. They grow well on chocolate agar and Mueller-Hinton agar. A popular selective medium is the Thayer-Martin medium (containing vancomycin, colistin and nystatin) which inhibits most contaminants including nonpathogenic neisseria.


Question: Trichophyton species can infect

Trichophyton - hair, skin and nail. Microsporum- hair and skin. Epidermophyton- skin and nail. Reference: Textbook of Microbiology; Baveja; 4th edition .


Question: Toxic shock syndrome is caused by

Toxic shock syndrome is a potentially fatal multisystem disease caused by Staphylococcus aureus. Present as fever, hypotension, myalgia, vomiting, diarrhea, mucosal hyperemia and an erythematous rash which desquamates subsequently. This is associated with infection of mucosal or sequestered sites by toxic shock syndrome toxin (TSST)-Producing S.aureus strains usually belonging to bacteriophage group I.TSST type I (formerly known as enterotoxin type F or pyrogenic exotoxin C)is most often responsible, though enterotoxin B or C may also cause the syndrome . Staphylococcal enterotoxins and TSST -1 are superantigens which are a potent activator of T lymphocytes. Being Vbeta-restricted T cell mitogens, such superantigens stimulates large numbers of T cells without relation to their epitope specificity. This leads to excessive and deregulated immune response, with the release of cytokines interleukins 1,2, tumour necrosis factor and interferon gamma. This explains multisystem involvement and florid manifestation in staphylococcal food poisoning and TSS. Soft tissue infections with some M types of S.pyogens (1,3,12,28) may sometimes cause a toxic shock syndrome resembling staphylococcal TSS. Streptococcal TSS and necrotizing fasciitis occur in persons not immune to the infecting M types Ref: Textbook of Microbiology; Ananthanarayanan and Panicker; Tenth Edition; Page No: 204, 215


Question: Temperature and time period in hot air oven is

160 for 2hrs or 170 for 1 hr. or 180 for 30min is temperature and time in hot air oven Hot air oven, red heat, incineration, flaming are eg for dry heat sterilization Ref: CP Baveja 4th ed Pg:30


Question: Most common cause of native valve endocarditis

Infective endocarditis in intravenous drug abusers commonly involves the tricuspid valve and are caused by Staphylococcus aureus.
M. C. cause of native valve endocarditis → Staph. Aureus
M.C. cause of early-onset prosthetic valve endocarditis (< 2 mts & 2-12 mts) → Coagulase-negative staphylococci
M. C. cause of late-onset prosthetic valve endocarditis (> 12 mts) → Streptococci (e.g. streptococcus viridans)
M.C. cause of endocarditis in I. V drug abusers → Staph aureus.


Question: The 1st stage of life cycle of bacteriophage includes

Life cycle of phages include lytic phase, lysogenic phase and eclipse phase Eclipse phase represents time required for synthesis of new phage components Lytic phase includes adsorption, penetration, synthesis of phage components, maturation and release of progeny phages Ref: Baveja 5th ed Pg: 436


Question: Recommended transpo medium for stool specimen suspected to contain enteric pathogen is

Transpo media: Transpo media are used to maintain the bility of ceain delicate organisms in clinical specimens during their transpo to the laboratory. They typically contain only buffers and salt. They lack carbon, nitrogen, and organic growth factors, hence do not facilitate microbial multiplication. Transpo media used for common bacteria: Bacteria Transpo media Streptococcus Neisseria Vibrio Salmonella & Shigella Pike's medium Amies medium and Stua's medium Cary Blair medium, V. R. medium, Autoclaved sea-water Buffered glycerol saline, Cary Blair medium

General Microbiology Pa 1 (History, Microscopy, Stains and Structure and Physiology of Bacteria)


Question: Superantigens area) Erythrotoxin of Staph. aureusb) Clostridium difficile toxinc) Staphyloccocal toxic shock syndrome toxind) Cholera toxin


Question: Standard test for syphilis

Ans. a (VDRL) (Ref. Ananthanarayan Microbiology 7th ed., Fig. 36.2, p. 381)Diagnosis of SYPHILIS# Detection of abs in CSF by FTA-Abs is most specific test for neurosyphilis.# Treponemal ab tests (FTA-Abs, MHATP) measures abs reactive with T. pallidum.Serological Tests for SxphilisThese tests form the mainstay of laboratory diagnosis.These are follows:1. Test for antibodies reacting with cardiolipin antigen reagin tests; standard tests for syphilis; STS2. Tests for antibodies reacting with group-specific treponemal arftigen3. Tests for specific antibodies to pathogenic treponema (T. pallidum).Reagen Antibody Tests (VDRL mainly)# These tests use the lipoid or cardiolipin antigens and are known as 'standard tests for syphilis' or STS.# The first of the reagin antibody test was the Wassermann complement fixation test (1906). It is no longer in use now.- The first flocculation test used widely was tube flocculation test of Kahn.- The Kahn test been replaced by the simpler and more rapid VDRL test, which gives more quantitative result.- VDRL test can be used for testing CSF also, but not plasma. CSF need not be heated prior to test.- A number of modifications of the VDRL have been developed, of which the Rapid Plasma Reagin (RPR) test is the most popular.Sensitivity of Serodiagnostic Tests in Untreated SyphilisMean Percentage Positive (Range) at Indicated Stage of DiseaseTestPrimarySecondaryLatentTertiaryVDRL, RPR78 (74-87)10095 (88-100)71 (37-94)FTA-ABS84 (70-100)10010096TP-PA89100100NA


Question: Systemic fungal infections can be caused by the followinga) Cryptococcus neoformansb) Histoplasma capsulatumc) Paracoccidioides brasiliensisd) Naegleria fowlerie) Isospora belli


Question: Meningitis is caused by

Ans. d (Cryptococcus neoformans). (Ref. Anantanarayan, Microbiology, 6th/pg.574)CRYPTOCOCCUS NEOFORMANS# Capsulated yeast# Not dimorphic fungus# Four serotypes known - ABCD# Has ability to hydrolyse urea# Indian ink preparation: the yeast cell stain positive with mucicarmine# Latex agglutination test is the most useful test to detect capsular ags in blood or urine.# Pigeon droppings transmit the infection.# Causes pulmonary and meningeal infection.


Question: Strain of Japanese encephalitis vaccine is

Nakayama strain and beijing strain are strains of JE vaccine.


Question: In plasma sterilization control used is aEUR'

Bacillus stearothermophilus Sterilization is generally defined as the process of completely destroying ble microorganisms including structures such as spores. Standandard practice in sterilization process is to include sterility indicator along with the aicles to be sterilized. The use of sterility indicators allows a direct and sensitive approach to test the effectiveness of the sterilization process. Sterility indicators can be biological or chemical. Biological indicators A biological indicator is broadly defined as a characteristic preparation of specific microorganism that provides a defined and stable ressitance to specific sterilization procedures. The biological indicators selected should provide a greater challenge to the sterilization process than the bioburden in or on the product. Microorganisms widely recognized as biological indicators are spore forming bacterias because these organisms are significantly more resistant than the normal. - With the exception of ionizing radiation process, these microorganisms are significantly more resistant than the normal micro flora. A biological indicator can be used to assist in the performance qualification of the sterilization equipment and in the development and establishment of a validated sterilization process for a paicular process. "Biological indicator used in plasma sterilization is Bacillus stearothermophilus". Plasma sterilization Plasma is described as the fouh state of matter (It is neither liquid, gas or solid). it is defined as reactive cloud of ionized atoms, electrons and neutral atomic paicles. In order to generate the plasma for sterilization, matter (for example H202) a gaseous state is exposed to strong electrical or magnetic .field. This is performed in a vaccum so that high temperature are not required. In practice, a hydrogen peroxide solution is dispersed in a vaccum chamber creating a plasma cloud. This result in the generation (ionisation) of a cloud of charged paicles and free radicals that interact with vital cell component. The free radicals generated during this process interacts with vital cell component (mainly nucleic acids and destroy them). Sterilization occurs as a result of the dual phase process of the oxidative propeies of the vapour and plasma. Gas plasma is capable of penetrating medical packaging, is safe to use and the sterilization cycles are easy to control and monitor. The temperature attained in these process is not very high so there is no risk of damage of the instruments as in Heat methods. Biological indicators for various sterilization methods B. stearothernzophilus spores are used to monitor -Steam sterilization - Plasma sterilization (hydrogen peroxide) - Liquid peracetic acid sterilizers


Question: Post zone phenomenon is due to

Prozone - Antibodies are excess.
Postzone - Antigen excess.


Question: This serum immunoglobulin constitutes 80% of immunoglobulins in our body is

80% of immunoglobulins in our body is IgG -major ig Half-life is 23 days Transpoed through placenta Ref: Text book of Microbiology Baveja 5th ed Pg 99


Question: Enterovirus causes

Option 1:is an epidemic form of highly contagious conjunctivitis and is characterized by sudden onset of painful, swollen, red eyes, with conjunctival hemorrhage and excessive tearing. AHC typically is caused by one of two enteroviruses (Coxsackie A24 or enterovirus 70). This disease is transmitted person-to-person usually through contact with contaminated hands or through sharing of contaminated personal-care items. fig:- acute hemorrhagic conjuctivitis Diseases caused by Enterovirus: Enterovirus 68: Pneumonia Enterovirus 70: Acute hemorrhagic conjunctivitis. Enterovirus 71: Pulmonary edema, herpangina, aseptic meningitis, and hand-foot-and mouth disease. Enterovirus 70, 71: Paralysis and encephalitis. Option 2: Acute follicular conjunctivitis is usually associated with: viral (epidemic keratoconjunctivitis, Herpes zoster keratoconjunctivitis, infectious mononucleosis, Epstein-Barr virus infection) chlamydial infections (Inclusion conjunctivitis). Option 3: Hepatitis is caused by hepatotropic virues like Hepatitis A, B, C. Option 4: Epidemic keratoconjunctivitis (EKC) is a viral conjunctivitis caused by a group of adenoviruses.

Virology Pa-2 (RNA Virus Pa-1,2 & Miscellaneous Viruses)


Question: Most common virus causing common cold

The rhinovirus is the most common viral infectious agent in humans and is the predominant cause of common cold. Rhinovirus infection proliferates in temperatures of 33-35deg, the temperature found in nose. Rhinoviruses belong to the genus Enterovirus in the family picornaviridae. Ref : Essentials of Medical microbiology apurba sastry 1st edition


Question: Hydatid cyst is caused by

Hydatid disease is caused by Echinococcus granulosus or dog tapeworm. The dog is the definitive host and man, sheep, pig, cattle, horse, and goat act as intermediate host. The disease is characterised by hydatid cyst which involves liver, lung, brain, hea, kidney, spleen, bone, muscle. Ref: Baveja textbook of microbiology; 4th edition.


Question: The culture medium used for corynebacterium diphtheriae

• The usual media employed for cultivation of diphtheria bacillus are
1) Loeffler’s serum slope
■ It is used for rapid diagnosis as growth is shown within 4-8 hours.
2) Tellurite blood agar (Tinsdale medium)
■ It acts as selective media, as tellurite inhibits the growth of most other bacteria.
■ Growth may take two days to appear.


Question: Hemoperfusion with charcoal is useful in poisoning with

Hemoperfusion should be considered in cases of severe poisoning due toCaffeineDisopyramidePhenytoinCarbamazepineHypnotic-sedatives (barbiturates)ProcainamideCarbon tetrachlorideMethotrexateTheophyllineChloramphenicolMushrooms (amatoxin-containing)vaIproateDapsoneParaquat