Untitled | MCQ Quiz | OmpathStudy Kenya

Question 1

A paroxysm is a and is characteristic of

Accepted Answer

Rapid-fire cough; pertussis — A paroxysm is a sudden, uncontrollable series of coughs characteristic of pertussis (whooping cough) caused by Bordetella pertussis. The paroxysmal stage features severe coughing fits followed by an inspiratory "whoop" sound, often accompanied by post-tussive vomiting. ---

Question 2

To treat patients who have ingested botulism toxin, large doses of must be administered.

Accepted Answer

Antitoxin — Botulism requires administration of botulinum antitoxin (trivalent or heptavalent). The antitoxin neutralizes circulating toxin but cannot reverse already bound toxin. Early administration is critical. Antibiotics are ineffective against the preformed toxin. ---

Question 3

The organism Clostridium perfringens multiplies in foods only under conditions.

Accepted Answer

Anaerobic — Clostridium perfringens is an obligate anaerobe that multiplies only in oxygen-free environments. Improper food storage (inadequate cooling or reheating) creates anaerobic conditions that allow spore germination and toxin production, leading to food poisoning. ---

Question 4

Woolsorter disease applies to the form of

Accepted Answer

Inhalation; anthrax — Woolsorter's disease is pulmonary anthrax caused by inhaling Bacillus anthracis spores from contaminated animal products (wool, hides). It causes severe hemorrhagic mediastinitis, septic shock, and high mortality. The name comes from textile workers who processed contaminated wool. ---

Question 5

Ophthalmia is associated with what two STDs?

Accepted Answer

Gonorrhea and chlamydia — Ophthalmia neonatorum (neonatal conjunctivitis) is caused by Neisseria gonorrhoeae and Chlamydia trachomatis acquired during passage through an infected birth canal. Both can cause severe conjunctivitis and, if untreated, corneal scarring and blindness. ---

Question 6

The first microorganism to satisfy Koch's postulates (in the late 19th century) was

Accepted Answer

Bacillus anthracis — Robert Koch first proved Bacillus anthracis as the causative agent of anthrax in 1876, establishing Koch's postulates. He isolated the organism from diseased animals, cultured it in pure form, reproduced the disease in healthy animals, and re-isolated the same organism. ---

Question 7

Which of the following best describes the mechanism of action of diphtheria toxin?

Accepted Answer

Inhibits elongation factor 2 — Diphtheria toxin is an A-B toxin. The A subunit catalyzes ADP-ribosylation of elongation factor 2 (EF-2), irreversibly inactivating it and blocking protein synthesis. One toxin molecule can kill a cell by halting translation. ---

Question 8

The identification of bacteria by serological test is based on the presence of specific antigens. Which of the following bacterial components is least likely to contain useful antigens?

Accepted Answer

Ribosome — Ribosomes are internal structures with highly conserved proteins across species, making them poor serological markers. Capsule (K antigens), cell wall (O antigens for LPS), and flagella (H antigens) are surface-exposed and variable, making them excellent for serotyping. ---

Question 9

Which of the following species of Pasteurella species has been associated with infection of female genital tract and newborn?

Accepted Answer

Pasteurella bettyae — Pasteurella bettyae (formerly CDC group HB-5) is associated with genital tract infections and neonatal infections. P. multocida is primarily associated with animal bites and respiratory infections, not genital tract infections. ---

Question 10

Which of the following disease is best diagnosed by serologic means?

Accepted Answer

Q Fever — Q fever (Coxiella burnetii) is best diagnosed serologically by detecting antibodies to phase I and II antigens. The organism is difficult to culture due to obligate intracellular nature. TB, gonorrhea, and actinomycosis are diagnosed by culture/microscopy. ---

Question 11

Which of the following is not most important cause of acute bacterial meningitis?

Accepted Answer

Streptococcus pyrogens — S. pyogenes (Group A Strep) rarely causes meningitis. The three most common causes of bacterial meningitis are S. pneumoniae (most common overall), N. meningitidis (especially in young adults), and H. influenzae type b (reduced since Hib vaccine). ---

Question 12

Which of the following is most likely to be associated with the formation of a bacterial biofilm?

Accepted Answer

Airway colonization in a cystic fibrosis patient with a mucoid (alginate-producing) strain of Pseudomonas aeruginosa — Mucoid P. aeruginosa produces alginate exopolysaccharide that forms thick biofilms in CF patient airways. These biofilms protect bacteria from antibiotics and immune clearance, causing chronic infection. Biofilm formation is a hallmark of CF pulmonary infection. ---

Untitled | MCQ Quiz | OmpathStudy Kenya

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