Microbilogy multiple choice questions (mcqs), FCPS, USMLE, PLAB, MRCP set 2

101. The causative agent of tetanus is
a. Clostridium botulinum
b. Cl. tetani
c. Cl. welchii
d. Cl. perfringens
 

102. The mode of spread of tetanus neurotoxin
from blood to brain is
a. Via lymphaties
b. Arterial blood
c. Cranial nerves
d. None of these
 

103. Tetanus is caused by spread of
a. Exotoxin in sympathetic system
b. Exotoxin in para sympathetic system
c. Endotoxin in sympathetic system
d. Endotoxin in parasympathetic system
104. The first symptom of tetanus is
a. Lock jaw b. Trismus
c. Anorexia d. Dyspagia
 

105. Of which clostridia, the neurotoxin is most
powerful?
a. Cl. tetani b. Cl. welchii
c. Cl. botulism d. Cl. septicum
106. Toxin produced by C. botulism is
a. Botulin b. Tetanospasmin
c. Tetanolysin d. Cholaragen
MEDICAL MICROBIOLOGY 
107. “Toxic shock syndrome” is caused by the
toxin of
a. Staphylococcus aureus
b. Streptococcus pyoge
c. Vibrio cholerae
d. Candida
108. Causative agent of syphilis
a. T. pallidum b. T. pertenue
c. T. carateum d. T. endemicum
109. Spirochaelis are sensitive to
a. Penicillin
b. Chloramphenicols
c. Erythromycin
d. Tetracyclins
110. Specific test for syphilis is
a. VDRL test b. ELISA
c. FTA d. None of these
111. VDRL test is a
a. Agglutination test
b. Slide flocculation test
c. Precipitation test
d. None of these
112. The following characters are true about
Neisseria gonorrhoeae except
a. Gram-negative, aerobic bacteria
b. Non-motile diplococci
c. Oxidase positive organisms
d. Air borne infection
113. Gonorrhoea is
a. Air borne disease
b. Water borne disease
c. Sexually transmitted venereal disease
d. Both a and c
114. Bartholin cyst is caused by
a. Candida b. Streptococcus
c. Staphylococcus d. Gonococcus
115. Neisseria gonorrhoeae causes
a. Urethritis b. Conjuctivitis
c. Arthritis d. All of the above
116. Virulence in gonococcus is due to
a. Pili b. Cell membrane
c. Its cellular location d. Cyclic enzymes
117. Japanese encephalitis is caused by
a. Toga Viruses b. Arbo Viruses
c. Para myxo Viruses d. Ortho myxo Viruses
118. In India, Japanese b encephalitis was first
isolated from the mosquitoes of the
a. Culex tritaeriorhynchus
b. Culex annulirostris
c. Culex vishnui
d. None of these
119. Dengue virus is transmitted from man to
man by the
a. Sand fly b. Ticks
c. Aedes aegypti d. Culex
120. Yellow fever is caused by
a. Bunya virus b. Calci virus
c. Arbo virus d. None of these
121. Vector for leishmaniasis is
a. Tick b. Mite
c. Sand fly d. Tsetse fly
122. Splenomegaly is an important manifestation
of
a. Kala-agar b. Typhoid
c. Malaria d. All of these
123. Which of the following is most severly
affected in Kala-azar?
a. Liver
b. Spleen
c. Adrenal gland
d. Bone marrow
124. In India, malaria most often spreads by
a. Anophels cucifacies
b. Anopheles fluvatis
c. Anopheles stephensi
d. Anopheles minimus
125. Man is intermediate host for
a. Guinea Worm b. Filaria
c. Malaria d. Kala-azar
     MCQs IN MICROBIOLOGY
126. Which of the following preferably infects
reticulocytes?
a. P. ovale b. P.vivax
c. P.falciparum d. P.malaria
127. In which type of material parasite in the
exoerythrocytic stage absent?
a. P.ovale b. P.vivax
c. P.falciparum d. P. malariae
128. In falciparum malaria, all of the following
stages are seen except
a. Ring stage b. Schizont
c. Gametocyte d. None of these
129. Sporozite vaccine in malaria has
a. Induces antibodies
b. Prevents only asexual forms with reproduction
c. No effects on clinical illness
d. None of the above
130. Growing trophozoites and schizonts are
not seen in the peripheral blood in malaria
due to
a. P. falciparum b. P.vivax
c. P.ovale d. P. malaria
131. Thin blood smear for malaria is used to
identify
a. Plasmodium b. Gametocytes
c. Type of parasite d. Schizont
132. The radical teatment of malaria is to half
a. Gametocyte
b. Exo-erythrocytic phase
c. Erythrocytic phase
d. All of these
133. Symptoms of acute aflatoxicosis
a. Osteogenic sarcoma
b. Lymphatic leukemia
c. Malaise & Anorexia
d. Both a and b
134. Most important Penicillium toxins are
a. Citrinin
b. Patulin
c. Penicillic acid
d. All of the above
135. Penicillic acid is produced by
a. A. ochraceus b. P. puberulum
c. Both a and b d. None of the above
136. Fungi producting mycelium are called
a. Moulds b. Filamentous fungi
c. Both a and b d. Yeasts
137. Candidiasis is caused by
a. Candida albicans b. Aspergillus spp.
c. E. floccosum d. M. audouinii
138. Candida albicans is capable to form
a. Single cells b. Pseudomonas
c. Multicellular forms d. None of these
139. Aspergillus fumigatus can infect
a. A. niger b. A. fumigatus
c. A. flavus d. A. oryzae
140. A.fumigates can produce
a. Endotoxins b. Exotoxins
c. Enterotoxins d. None of these
141. The drug of choice for dermal, oral and
vaginal candidiasis is
a. Griseofulvin b. Amphotericin B
c. Gentian violet d. Nystatin
142. The following Penicillium species are
pathogenic except
a. P. commune b. P. bicolor
c. P. glaucum d. P.notatum
143. Tinea versicolor is caused by
a. Candida albicans b. Malassezia furfur
c. Aspergillus niger d. None of these
144. Causative agent of Tinea nigra
a. Malassezia furfur
b. Exophiala werenekii
c. Candida albicans
d. Aspergillus flavus
145. Causative agent of African histoplasmosis
a. Histoplasma capsulatum
b. Histoplasma duboissi
c. Aspergillus niger
d. Aspergillus flavus
MEDICAL MICROBIOLOGY 

146. Sun ray fungus is
a. Actinomyces irraeli
b. Chromoblastomycosis
c. Streptomyces griseus
d. Cryptococcosis
147. Which agent on addition to a colony
inhibits its growth and on removal the
colony regrows is?
a. Bacteriostatic b. Bactericidal
c. Antibiotic d. Antiseptic
148. Griseofluvin is obtained from
a. Penicillium notatum
b. Streptomyces griseus
c. Penicillium griseofluvin
d. None of these
149. β-lactum ring is present in
a. Erythromycin b. Penicillin
c. Tetracyclins d. Chloramphenicol
150. All of the following drugs act on cell
membrane, except
a. Novobiocin b. Nystatin
c. Chloromycetin d. Colicins
151. Cycloserine related to the amino acid in
structure
a. Serine b. Aspergine
c. Alanine d. None of these
152. In Tuberculosis therapy mainly used
antibiotic is
a. Penicillin b. Streptomycin
c. Chloramphenol d. Cycloserine
153. The antibacterial action of penicillin is due
to its effect on
a. Cell membrane permeability
b. Cell wall synthesis
c. DNA synthesis
d. Protein synthesis
154. The antibiotic produced from Bacillus
subtilis is
a. Vancomycin b. Bactiracin
c. Both a and b d. None of these
155. bacitracin sensitivity test is done for
a. Pneunocci
b. Group ‘A’ Streptococci
c. Gonococci
d. Staphylococci
156. The effect of antibiotics on micro organisms
is mainly due to
a. Inhibition of cell-wall synthesis
b. Damage to the cytoplasmic membrane
c. Inhibition of nucleic acid and protein
synthesis
d. All of the above
157. The antibiotic acting on cell wall is
a. Penicillin b. Bacitracin
c. Cyclosporin d. All of the above
158. Erythromycin belongs to chemical class
of antibiotics
a. â-lactose b. Tetracyclines
c. Macrolides d. Aminoglycosides
159. Bacterial resistance to antibiotics is
transmitted by
a. Transduction b. Transformation
c. Mutation d. Plasmids
160. Erythromycin inhibits protein synthesis by
a. Attaching to 30 S ribosome unit
b. Attaching to 50 S unit or ribosome
c. By the attachment to t-RNA
d. By the attachment to m-RNA
161. The function of (THFA) Tetrahydrofolic acid
coenzyme include
a. Amino acid synthesis
b. Thymidine synthesis
c. Protein synthesis
d. Both a and b
162. Resistant to drugs in tuberculosis
develops by
a. Transduction b. Transformation
c. Conjugation d. Mutation
 MCQs IN MICROBIOLOGY
163. Which of the following is penicillinase
resistang acid labile penicillin?
a. Amoxycillin b. Cloxacillin
c. Carbenicillin d. Methicillin
164. Which of the following does not inhibit
cell wall synthesis?
a. Penicillin b. Carbenicillin
c. Amikacin d. Vancomycin
165. The anti tumor antibiotics act by inhibiting
a. Cell wall synthesis
b. RNA synthesis
c. Cell membrane synthesis
d. The DNA structure & function
166. Drug resistance to sulphonamides is due
to
a. Production of PABA
b. Folic acid synthetase
c. Drug alteration
d. Low affinity for drug synthesis by bacteria
167. Amoxycillin is combined with clavulanic
acid to inhibit
a. DNA gyrace b. Cell synthesis
c. Protein synthesis d. β-lactamase enzymes
168. Drug of choice for methicillin resistant
staph. Aureus is
a. Ampicillin b. Erythromycin
c. Neomycin d. Vancomycin
169. Nalidixic acid activity is due to
a. The inhibition of DNA synthesis
b. Inhibition of protein synthesis
c. The inhibition of cell wall synthesis
d. Both b and c
170. The best test for the susceptibility of a
microorganism to antibiotics and other
chemotherapeutic agents:
a. Tube-dilution test b. Paper-disc test
c. Both a and b d. None of these
171. The smallest amount of chemotherapeutic
agents required to inhibit the growth of
the organism in Vitro is known as
a. MIC (minimum inhibitory concentration)
b. Thermal death point (TDP)
c. Death rate
d. None of these
172. Clear-zones formation around antibiotic
disc is due to
a. Growth of the bacterium surrounding of the
disc
b. Lysis of the bacterial cells surrounding the disc
c. The destruction of paper disc (antibiotic)
d. None of these
173. Bacitracin is obtained from
a. B. subtilis b. B. anthracis
c. B. cereus d. B. anthracoid
174. Vancomycin is obtained from
a. Streptococcus species
b. Aspergillus niger
c. Streptomyces orientalis
d. Bacillus anthracis
175. â-lactum antibiotics are
a. Penicillin b. Cephalosporin
c. Both a & b d. None of these
176. Following are the test organisms used for
the I.P microbiological assay of antibiotics
match them correctly:
1. Rifampicin A. Escherichia Coli
2. Tetracyclin B. Klebsiella pneumonia
3. Streptomycin C. Micrococcus luteus
4. Chloramphenol D. Bacillus subtilis
E. Bacillus cereus
177. The drugs mentioned below are produced
by the species mentioned from Ato E.
Match them correctly :
1. Rifampicin A. Streptomyces griseus
2. Nystatin B. Bacillus polymyxa
3. Amphotericin B C. Streptomyces mediterranei
4. Candicidin D. Streptomyces nodosus
E. Streptomyces noursei
MEDICAL MICROBIOLOGY 
178. Match the correct method of sterilization
listed A to E for the following drugs :
1. Tetracyclin injection A. Sterilised by dry heat
2. Insulin injection B. Sterilised by heating with a
bacteria
3. Quinine injection C. Sterilised by aseptic method
4. Morphine injection D. Prepared by aseptic method
E. Sterilised by heating in an
autoclave
179. Match the following rickettsial disease
with their respective organisms:
1. Epidemic typhus A. Rickettsia rickettsi
2. Scrub typhus B. Rickettsia prowazeki
3. Trench typhus C. Rickettsia typhus
4. Murine typhus D. Rickettsia Quintana
E. Rickettsia typhus
180. Match the following antimicrobial with
their respective side effects A to E:
1. Acridines A. Showed adverse effects on
proteins
2. Benzalkonium B. exhibit synergism and
chloride unsuitable for preservative in
eye drops
3. Parahydroxy C. Haemolytic
benzoates
4. Formalin D. Very toxic
E. Toxic to leucocytes and retard
granulation process
181. Match the following antibiotics with their
respective modes of administration A to E:
1. Penicillin V A. Intramuscular suspension
2. Benzathine B. Oral
penicillin
3. Methicillin sodium C. Both as oral and injection
4. Ampicillin D. Locally applied
E. Intramuscular injection
182. Match the following antibiotics with
respective strains A to E used for their
production :
1. Tetracyclin A. Streptomyces erythreus
2. Chloramphenicol B. Streptomyces garyphalous
3. Erythromycin C. Streptomyces niveus
4. Cycloserine D. Streptomyces viridifaciens
E. Streptomyces venezuelae
183. Match the following strains with their
respective produced antibiotics A to E:
1. Streptomyces A. Oxytetracycline
griseus.
2. Streptomyces B. Neomycin sulphate
aureofaciens
3. Streptomyces C. Viomycin
rimosus
4. Streptomyces D. Chlortetracycline
griseus var. E. Streptomycin
purpurea
184. Match the following antibiotics with their
respective disease A to E to be cured :
1. Streptomycin A. Staphylococcus infections
2. Cycloserine B. Tuberculosis
3. Novobiocin C. Fungal tuberculosis
4. Griseofulvin D. Pulmonary tuberculosis
E. Anti-spirochaetes
185. Match the following antibiotics with their
respective side effects A to E:
1. Novobiocin A. Damages 8th cramial nerve
2. Neomycin B. Damages CNS
3. Cycloserine C. Damages haemopoietic
system
4. Chloramphenol D. Skin rashes
E. Kidney problems
186. Match the following antibiotics with their
modes of action A to E:
1. Tetracyclines A. Form an irreversible complex
with sterols
2. Erythromycin B. Chelation of light divalent salts
3. Novobiocin C. Blocks protein synthesis
4. Griseofulvin D. Interferes with the conjugation
of bilirubin
E. Influences mitosis
187. Match the following dosage forms with
their respective antibiotics A to E:
1. Tablets A. Vancomycin Hcl
2. Intravenous injection B. Colistin
3. Capsules C. Polymixin B sulphate
4. Intramuscular D. Gentamycin
injection
E. Paromomycin sulphate

MCQs IN MICROBIOLOGY
188. Match the following side effects with their
respective antibiotics A to E:
1. Nephrotoxic A. Triacetyloleandomycin
2. Rashes B. Polymixin B sulphate
3. Hypersensitivity C. Cephaloridine
4. Gastric irritation D. Gentamycin
E. Sodium fusidate
189. Match the following antibiotics with their
respective activity spectra A to E:
1. Bacitracin A. Gram negative
2. Gentamycin B. Mainly staphylococci
3. Sodium fusidate C. Mainly Ps. Aeruginosa
4. Framycetin D. Gram positive
190. Match the following enzymes with their
activities A to E:
1. Hyaluronidase A. Inactivate leucocytes and aid
bacterial invasion
2. Collagenase B. Reversibly catalyzes the
breakdown of a major
component
3. Lecithinase C. Disintegrates a constituent of
muscle, cartilage and bone
4. Leucocidins D. Haemolysis of erythrocytes
and the necrosis of other cells
E. Clots plasma and surrounds
the bacteria
191. Match the following aggresins with their
respective modes of action from A to E:
1. Hyaluronidase A. Destroys RBC’s and other
tissues
2. Haemolysis B. Breaks down connective
tissues, increases permeability
of tissue space
3. Streptokinase C. Causes lysis of RBC’s and other
tissues
4. Lecithinase D. Digest the fibrin of blood
E. Dissolves collagen
192. Match the following terms with their
respective effects A to E:
1. Brucella melitensis A. Causes trachoma, conjunctivitis
and nongonococcal gamets
2. Flavobacterium B. Causes influenza like fever
species
3. Chlamydia C. Causes Malta fever in goats
trachomatis
4. Leptospira D. Contaminates pharmaceutical
icterohaemorrhagiae products
E. Weil’s disease (jaundice)
193. Virus causing mumps is also responsible
for
a. Measles b. Hepatitis A
c. Rabies d. Variola
194. Epidemic pleurodynia and myocarditis of
new born infants are both caused by
a. Group B cox sack virus
b. Reovirus
c. Polyomavirus
d. Cytomegalovirus
195. Human papillomavirus causes following
tumors:
a. Hepatic carcinoma
b. Cervical cancer
c. Condyloma acuminatum
d. Plantar wart
196. Viral infection is caused due to
a. Acute self limited illness
b. No apparent symptoms
c. Chronic infection with persistent viral shedding
d. All of these
197. Viruses which do not carry enzymes for
DNA synthesis as a part of their virion are
a. Hepatitis B virus
b. Poxyviruses
c. Heepes simplex virus
d. Retroviruses
e. All of these
198. Following virus is known to establish
latent infections:
a. Adeno virus b. Varicella-zoster virus
c. Cytomegalovirus d. Hepes simplex virus
e. All of these
199. Viruses which have teratogenic property
are
a. Herpes simplex virus
b. Cytomegalovirus
c. Rubella virus
d. All of these
MEDICAL MICROBIOLOGY 
200. Kawasaki syndrome is
a. Most prevalent in Japan and Hawaii
b. Patients show rickettsia like bacteria in skin
biopsies
c. Strain involved may be propionibacterium
d. All of these
201. Mode of action of quinolone antibiotics
on growing bacteria was thought to be
a. Inhibition of â lactamase
b. Prevention of the cross linking of glycine
c. Inhibition of DNA gyrase
d. Inhibition of reverse transcriptase
202. The role that human play in the plague
life cycle is
a. Secondary reservoir
b. Primary transmission vector
c. Primary host
d. Accidental intruder in rat flea cycle
e. None of these
203. Patient with presence of penile chancre
should be advised by physician –
a. To take rest at home
b. To swab the chancre and culture on Thayer-
Martin agar
c. To Gram stain the chancre fluid
d. To repeat VDRL test in 10 hours
e. Perform dark field microscopy for treponemes
204. Which organism is responsible for causing
fever to a man dealing with goats?
a. Trepanema Pallidum
b. M.tuberculosis
c. Clostridium novyl
d. Brucella melitensis
e. None of these
205. Diphtheria toxins are produced from the
strains of C.diphtheriae, which are
a. Encapsulated
b. Sucrose fermentors
c. Of the mitis and strain
d. Glucose fermentors
e. Lysogenic for β prophase
206. Skin of the healthy person has normal
microbial flora which includes
a. Enterobacteriaceae
b. Aerobic diphtheria bacilli
c. Anaerobic diphtheriae bacilli
d. Nonhemolytic staphylococci
e. All of these
207. Which of the following organisms can
infect humans if improperly cooked meat
is used?
a. Trichinella spiralis
b. Taenia saginata
c. Taenia solium
d. Diphyllobothrium latum
e. Both a and c
208. The parasite related to ancylostoma
duodenale is
a. Wuchereria bancrofti
b. Necatur americanes
c. Loa loa
d. Trichinella spiralis
209. Which of the following amoeba does not
live in large intestine ?
a. Entamoeba coli
b. Entamoeda histolytica
c. Endolimax nana
d. Entamoeba gingivalis
210. Which of the following is not related to
congenital syphilis?
a. Aneurysm b. Saddle nose
c. Still birth d. Hutchiso’s teeth
211. Streptococcus pyogens produce infection –
a. Streptococcal sore throat
b. Acute glomerulo nephritis
c. Rheumatic fever
d. None of these
212. Salmonella which can cause prolong
septicaemia.
a. Salmonella anetum
b. Salmonella cholerasuis
c. Salmonella typhimurium
d. Salmonella entritidis
 MCQs IN MICROBIOLOGY
213. E.coli produce which type of toxins?
a. Exotoxins b. Endotoxins
c. Leucocidin d. Both a and b
214. Main causative organism of gas gangrene
is
a. B.anthrax b. Clostridium tetani
c. Cl.deficile d. Cl.perfringens
215. Causative organism of whooping cough
is
a. Bordetella pertussis
b. Bordetella parapertussis
c. Bordetella bronchi septica
d. None of these
216. Pfeiffer phenomenon is related to
a. Vibrio cholerae b. B.anthrax
c. Rickettsial pox d. All of these
217. Diagnostic test for the identification of
primary syphilis:
a. VDRL test
b. Treponema pallidum immobilization test
c. Kahn’s test
d. Dark ground microscopic examination
218. Sporadic summer diarrhea may be
caused by
a. E.coli b. Enterobacter
c. Hafnia d. Serratia
219. Biological false reaction in VDRL is related
to
a. Lepra bacilli
b. Corynebacterium diphtheria
c. Cl.welchi
d. None of these





ANSWERS:

101. b 102. c
103. a 104. b 105. c 106. a 107. a 108. a
109. b 110. a 111. b 112. d 113. c 114. d
115. d 116. a 117. b 118. c 119. c 120. c
121. c 122. d 123. b 124. a 125. c 126. b
127. c 128. b 129. a 130. a 131. c 132. c
133. d 134. d 135. c 136. a 137. a 138. b
139. d 140. a 141. c 142. d 143. b 144. b
145. b 146. a 147. a 148. c 149. b 150. d
151. c 152. d 153. b 154. b 155. b 156. d
157. d 158. c 159. d 160. b 161. d 162. d
163. d 164. c 165. d 166. b 167. d 168. d
169. a 170. c 171. a 172. b 173. a 174. c
175. c 176. 1.d, 2.e, 3.a, 4.a 177. 1.c, 2.e, 3.d, 4.b
178. 1.d, 2.c, 3.e, 4.b 179. 1.b, 2.c, 3.d, 4.e 180.1.e,2.c,3.b,4.a
181. 1.b, 2.a, 3.e, 4.c 182. 1.d, 2.e, 3.a, 4.b 183. 1.e, 2.d, 3.a, 4.c
184.1.b,2.d,3.a,4.c 185. 1.d, 2.e, 3.b, 4.c 186. 1.b, 2.c, 3.d, 4.e
187. 1.b, 2.a, 3.e, 4.c 188.1.b,2.c,3.a,4.e 189. 1.e, 2.a, 3.d, 4.b
90. 1.b, 2.c, 3.d, 4.a 191. 1.b, 2.a, 3.d, 4.c 192.1.c,2.b,3.a,4.e
193. a 194. a 195. a 196. d 197. e 198. e
199. d 200. d 201. c 202. d 203. e 204. d
205. e 206. e 207. e 208. b 209. d 210. a
211. a 212. b 213. d 214. d 215. a 216. a
217. d 218. a 219. a