Year 3 Medical Bacteriology Past Paper — OmpathStudy

Year 3 Medical Bacteriology Past Paper ⚠️ Answers added by AI : some answers in this document were generated by AI from general medical knowledge, not the original exam paper. Verify against your course material before relying on them for the exam. Unit: MBMM 3311 Medical Bacteriology Format: 20 MCQs, three short-answer questions, and three structured cases Source note: The handwritten markings on the scan are not treated as an official answer key. Section A — Multiple-choice questions 1. Heat-labile toxin of ETEC acts by which of the following mechanisms? A. Attachment and effacement B. Activation of adenylyl cyclase C. Aggregative adherence D. Ribosomal dysfunction E. None of the above Answer: B 2. Which of the following statements about Pseudomonas aeruginosa is correct? A. P. aeruginosa is typically susceptible to penicillin G B. P. aeruginosa readily grows in anaerobic blood cultures C. P. aeruginosa can penetrate intact normal human skin by elaborating the enzyme invasin D. P. aeruginosa seldom, if ever, causes pneumonia E. P. aeruginosa has fimbriae that promote attachment to epithelial cells Answer: E 3. Long-term carriage and shedding is most likely after gastrointestinal infection with which species? A. Escherichia coli O157:H7 B. Shigella dysenteriae C. Vibrio cholerae D. Campylobacter jejuni E. Salmonella typhi Answer: E 4. A patient presents to the emergency department with non-bloody diarrhoea for 12 hours. The patient lives in Thika and has not recently travelled out of the area. Which is unlikely to be the cause? A. Salmonella typhimurium B. Campylobacter jejuni C. Shigella sonnei D. Vibrio cholerae E. Escherichia coli Answer: D 5. A 19-year-old man presents with urethral discharge. Neisseria gonorrhoeae is cultured and found to be β-lactamase positive and resistant to high levels of tetracycline. Which statement about these resistance factors is correct? A. β-lactamase production and high-level tetracycline resistance are both mediated by plasmid genes B. β-lactamase production is chromosomal, whereas high-level tetracycline resistance is plasmid-mediated C. β-lactamase production is plasmid-mediated, whereas high-level tetracycline resistance is chromosomal D. Both are mediated by chromosomal genes Answer: A 6. Which component of Neisseria gonorrhoeae is responsible for attachment to host cells? A. Lipooligosaccharide B. Fimbriae C. IgA1 protease D. Outer-membrane porin protein E. Iron-binding protein Answer: B 7. A six-year-old boy has meningitis caused by Neisseria meningitidis serogroup B. What should be considered for his household contacts? A. No prophylaxis is necessary B. N. meningitidis pilin vaccine C. Serogroup B polysaccharide capsule vaccine D. Rifampin prophylaxis E. Sulfonamide prophylaxis Answer: D 8. A common sequela of gonococcal pelvic inflammatory disease is: A. Cancer of the cervix B. Urethral stricture C. Uterine fibroid tumours D. Infertility E. Vaginal–rectal fistula Answer: D 9. Which statement best describes the pathogenesis of Clostridium botulinum ? A. It elaborates a toxin that inhibits acetylcholine release at cholinergic synapses B. It elaborates a lecithinase exotoxin that causes tissue necrosis C. It produces an antiphagocytic capsule that contributes to CNS invasion D. It elaborates a toxin that suppresses release of inhibitory neurotransmitters E. It produces a leukotoxin that causes abscess formation Answer: A 10. A photochromogenic acid-fast bacillus is cultured from a patient with cavitary lung disease. The organism is most likely: A. Mycobacterium tuberculosis B. Mycobacterium kansasii C. Mycobacterium gordonae D. Mycobacterium avium complex E. Mycobacterium fortuitum Answer: B 11. A patient with fever, weight loss, anaemia, abnormal liver tests, and granulomas containing acid-fast bacilli in liver and bone marrow is most likely infected with: A. Mycobacterium leprae B. Mycobacterium fortuitum C. Mycobacterium ulcerans D. Mycobacterium gordonae E. Mycobacterium tuberculosis Answer: E 12. A concern in Question 11 is infection with a mycobacterium that is: A. Susceptible only to isoniazid B. Resistant to streptomycin C. Resistant to clarithromycin D. Susceptible only to ciprofloxacin E. Resistant to isoniazid and rifampin Answer: E 13. A pregnant woman treated for syphilis seven years ago has a non-reactive RPR and reactive TP-PA. Which statement is most correct? A. Her previous treatment was effective B. The baby is at high risk for congenital syphilis C. She needs repeat treatment D. She needs lumbar puncture and CSF VDRL testing E. None of the above Answer: A 14. A 20-year-old woman has a relatively painless 2-cm ulcer with a raised border on the labia majora. Which listed pathogen is most likely? A. Haemophilus ducreyi B. Papillomavirus C. Neisseria gonorrhoeae D. Chlamydia trachomatis E. All of the above 15. Which bacterium is a frequent cause of community-acquired pneumonia? A. Legionella pneumophila B. Chlamydia pneumoniae C. Streptococcus pneumon