Free Bacteriology MCQs with Answers
167 Bacteriology MCQs from Microbiology, each with the correct answer and a written explanation of why it is correct. Free and unlimited, with no account needed.
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- A. Tissue culture
- B. Chick embryos
- C. Artificial media
- D. Rabbit testis only
Explanation: Pathogenic Treponema pallidum cannot be grown on ordinary artificial media and is classically maintained by passage through rabbit testes.
Correct answer: Rabbit testis only- A. Mycoplasma
- B. Mycobacteria
- C. Spirochaete
- D. Chlamydia
Explanation: Borrelia vincentii is a spiral-shaped bacterium, so it belongs to the spirochaetes.
Correct answer: Spirochaete- A. Gram staining
- B. Fermentation of mannitol and sorbital
- C. Production of intracellular and extracellular adherent polysacharide
- D. Colony morphology on saliva agar
Explanation: Gram staining cannot distinguish Streptococcus mutans from other oral streptococci because all are Gram-positive cocci.
Correct answer: Gram staining- A. Pasturella spp
- B. Francisella spp
- C. Bartonella spp
- D. Brucella spp
Explanation: Brucella is a small Gram-negative coccobacillus associated with animal exposure and is oxidase positive, often requiring special culture…
Correct answer: Brucella spp- A. Type of hemolysis
- B. Gram staining
- C. Growth characteristics
- D. Bile solubility
Explanation: Streptococcus pneumoniae is identified among alpha-haemolytic streptococci by its bile solubility, along with optochin sensitivity and a…
Correct answer: Bile solubility- A. M Protein
- B. Cultural characteristics
- C. Bile Solubility
- D. Cell wall carbohydrate
Explanation: The major Lancefield classification of streptococci is based on antigenic differences in cell-wall carbohydrate.
Correct answer: Cell wall carbohydrate- A. Foot paid on nine branded armadilo
- B. Tail of guinea pig
- C. Testes of albino rats
- D. Testes of guinea pig
Explanation: Mycobacterium leprae cannot be grown on artificial culture media and is experimentally propagated in the footpads of the nine-banded…
Correct answer: Foot paid on nine branded armadilo- A. Ziel Nelson
- B. Kin Young stain
- C. Auramine-Rhodamine stain
- D. Giemsa stain
Explanation: Auramine-rhodamine staining uses fluorescence to detect acid-fast bacilli and can screen a larger smear area more rapidly than…
Correct answer: Auramine-Rhodamine stain- A. M. leprae
- B. M. avium intracellulare
- C. M. tuberculosis
- D. Kansasi
Explanation: Mycobacterium tuberculosis causes the commonest mycobacterial infection worldwide, including tropical countries. M.
Correct answer: M. tuberculosis- A. Theta toxin
- B. Lecithinase
- C. Desmolase
- D. Cytokinin
Explanation: Lecithinase, or alpha toxin, hydrolyses lecithin in egg-yolk media and produces an opaque, opalescent zone around Clostridium perfringens…
Correct answer: Lecithinase- A. Clostridium tetani
- B. Clostridium welchii
- C. Coli
- D. Strep. Faecalis
Explanation: Gas gangrene is classically caused by Clostridium perfringens, formerly called Clostridium welchii.
Correct answer: Clostridium welchii- A. Multiply within living cell
- B. Transmitted by arthropod vectors
- C. Respond to tetracycline therapy
- D. All of the above
Explanation: Rickettsiae are obligate intracellular bacteria, commonly spread by arthropods such as ticks, lice and mites, and are generally…
Correct answer: All of the above- A. Yaws
- B. Lepromatous Leprosy
- C. Malaria
- D. All of the above
Explanation: VDRL detects reagin antibodies, which may occur in infections or conditions other than syphilis, including yaws, lepromatous leprosy and…
Correct answer: All of the above- A. Tellurite Medium
- B. Cary Blair Medium
- C. Venkatraman - Ramakrishnan Medium
- D. B & C
Explanation: Cary-Blair medium is a standard transport medium for stool specimens containing Vibrio cholerae, while Venkatraman-Ramakrishnan medium is…
Correct answer: B & C- A. Bacteroides fragilis
- B. Fusobacterium nucleatum
- C. Peptostreptococcus anaerobius
- D. Actinomyces Israeli
- E. All of the above
Explanation: Bacteroides fragilis, Fusobacterium nucleatum, Peptostreptococcus anaerobius and Actinomyces israelii are non-spore-forming anaerobic…
Correct answer: All of the above- A. Compliment fixation tests
- B. Pili agglutination tests
- C. Haemagglutination tests
- D. All of the above tests
Explanation: Older serological approaches to gonorrhoea included complement fixation, agglutination against gonococcal pili and haemagglutination…
Correct answer: All of the above tests- A. Streptococcus viridans
- B. Haemolytic streptococci
- C. Staphylococcus aureus
- D. Nisseria
Explanation: Subacute bacterial endocarditis classically affects previously abnormal valves and is most characteristically caused by the relatively…
Correct answer: Streptococcus viridans- A. Tryptophan
- B. Niacin
- C. B-12
- D. Citrate
Explanation: Salmonella requires tryptophan as a growth factor in certain culture conditions.
Correct answer: Tryptophan- A. Neisseria gonorrhea
- B. Escherichia coli
- C. T-strain mycoplasma
- D. Streptococcus fecalis
Explanation: Escherichia coli is the commonest cause of urinary tract infections, especially uncomplicated community-acquired infections, because it is…
Correct answer: Escherichia coli- A. Synapse
- B. Muscle
- C. Brain
- D. Spinal card
Explanation: Tetanospasmin blocks inhibitory neurotransmitter release from interneurons in the spinal cord, particularly glycine and GABA.
Correct answer: Spinal card