A 42-year-old wig manufacturer returned 5 days ago from Iran where he was inspecting herds for raw material. He had init

1. A 5 year old boy is seen in the paediatric respiratory clinic for regular review of his cystic fibrosis. He has a productive cough and a specimen is forwarded to the laboratory. Select the culture medium which would be most appropriate to isolate Haemophilusinfluenzae from this patient. A) Blood agar B) Chocolate agar C) MacConkey agar D) Mannitol salt agar E) XLD agar

2. A 23 year old male student was recently admitted with invasive meningococcal disease. He has recovered but gives a history of a previous episode of meningococcal septicemia when he was 15 years old. There is no history of other recurrent infections. Select the most likely immunodeficiency state. A) Adenosine deaminase dificiency B) C7 deficiency C) Job’s syndrome (hyperimmunoglobulinaemia E, defective chemotaxis) D) Myeloperoxidase deficiency E) Selective IgM deficiency

3. A 42-year-old wig manufacturer returned 5 days ago from Iran where he was inspecting herds for raw material. He had initially experienced only mild upper respiratory tract symptoms, but 2 days later was brought to the emergency room with fever, severe dyspnea, cyanosis, and tachycardia. Blood cultures were drawn and after 16 hours of incubation, the smears revealed large, gram-positive rods with subterminal spores. The organism was nonhemolytic on blood agar and nonmotile. What is the most probable identity of this organism? A. Clostridium tertium B. Bacillus anthracis C. Clostridium perfringens D. Bacillus subtilis E. Bacillus cereus

4. A previously normal, full-term infant developed bilateral conjunctivitis at 2 weeks of age. The conjunctivitis was followed by severe coughing, but the infant remained afebrile. When the infant was 4 weeks old, a chest X ray showed bilateral symmetrical interstitial infiltrates. The white blood cell (WBC) count was 14,000/mm3 with 32% segmented neutrophils, 58% lymphocytes, 2% monocytes, and 4% eosinophils. Which of the following is the most probable infectious agent? A. Chlamydia trachomatis B. Streptococcus agalactiae C. Haemophilus influenzae D. Mycoplasma pneumoniae E. Rickettsiae rickettsiae

5. The mucoid appearance of these organisms is related to which property? A. pilus B. capsule C. plasmid D. peptidoglycan E. cell membrane

6. Which of the following microorganisms is not matched correctly with the appropriate isolation media? A. Streptococcus pyogenes - XLD agar B. Neisseria gonorrhoeae – Thayer-Martin agar C. Legionella pneumophilia – Buffered charcoal yeast extract D. Mycobacterium tuberculosis - Lowenstein-Jensen agar E. Mycoplasma pneumoniae SP4 agar

7. Which of the following diseases and bacteria is matched up incorrectly? A. Otitis media – Streptococcus pneumoniaeB. Scarlet Fever – Streptococcus pyogenesC. Gastritis – Heliobacter pyloriD. Lyme disease – Yersinia pestis E. Urethritis – Chlamydia trachomatis

8. Which of the following is not true concerning diseases caused by Staphylococcus aureus? A. S. aureus is related to inflammation. B. S. aureus can cause pneumonia C. S. aureus can lead to acute bacterial endocarditis D. S. aureus is a common cause of cystitis

11. Characteristics of primary gonococcal disease include the fact that: A. it is always treatable with penicillin B. it rarely occurs simultaneously with chlamydial urethritis in men C. it produces efficient immunity so that recurrent infections rarely occur D. it can be accurately diagnosed in males by a gram-stain of urethral discharge E. it can only occur in the lower urogenital tract due to specific tissue tropisms of Neisseria gonorrhoeae

12. Evasion of phagocytosis by host cells plays a major role as a virulence factor in which one of these bacterial pathogens? A. Streptococcus B. Chlamydia C. Mycobacterium D. Legionella E. Ehrlichia

13. Which virulence factor is respinsible for the persistent cough in mycoplasmal pneumonia? • Endotoxin • P1 adhesin • Exotoxin A • Phospholipase C • IgA protease

14. What is the most common source of Shigella infections? • Contact with infected persons • Steamed rice • Undercooked chicken • Undercooked hamburger • Contaminated water

15. A toxoid vaccine is protective against which of these infectious diseases? • Diphtheria • Meningococcal meningitis • Bubonic plague • Pneumococcal pneumonia • Cholera

16. A man presents with diffuse maculopapular rash over his body, including palms and soles. Upon questioning he mentions that he has had a sore in his mouth recently and that he has had oral sex with a prostitute several times. Which of these conditions is most likely present? A. gonorrhea B. syphilis C. trichomoniasis D. herpes E. chancroid Which lab test will confirm the diagnosis? A. Gram stain of urethral discharge B. darkfield microscopy of saliva C. Measurement of antibody in serum D. PCR for chlamydia E. Bacterial culture on blood agar

17. Which of these bacteria is an obligate anaerobe? • Bacillus • Clostridium • Campylobacter • Pseudomonas • Ureaplasma

18. A child develops acute rheumatic fever following a streptococcal pharyngitis. The mechanism of this illness is related to which of the following? • Exotoxin that destroys heart valves • Autoimmune reaction • Endotoxin that causes blood clots • Bacterial growth in cardiac muscle • Concurrent viral myocarditis

19. A febrile patient with a clinical diagnosis of bacterial endocarditis has a positive blood culture. Based on this gram-stained smear from a blood culture bottle, the most likely bacterial cause of this infection is: • Staphylococcus • Corynebacterium • Streptococcus • Listeria • Bacillus

20. A patient with hospital-acquired pneumonia has a sputum gram stain that shows the organisms in the photomicrograph at the upper left. The culture grows an organism on MacConkey with the appearance as shown on the upper right. • Which of these organisms is most likely represented in these illustrations? • Klebsiella • Proteus • Bordetella • Legionella • Mycoplasma • The gram stain shows: • gram-positive cocci in pairs • encapsulated gram-negative rods • Gram-negative diplococci • Gram-variable rods • No bacteria present

21. Which one of the following specimens should NOT be cultured for anaerobic bacteria? A. blood B. feces C. lung tissue D. brain tissue E. peritoneal fluid

22. Which one of the following is the primary function of Protein A in Staphylococcus aureus? A. It provides a structural framework for the protein capsule. B. It helps the organism attach to slick surfaces. C. It binds antibodies. D. It masks carbohydrate antigens on the cell surface. E. It mediates production of beta lactamase.

23. Clinical manifestations of diphtheria are mediated primarily by which one of the following processes? A. interruption of protein synthesis B. endotoxic shock C. induction of autoantibodies D. stimulation of natural killer cells E. widespread intravascular hemolysis

24. Mycobacterium tuberculosis virulence is due primarily to which one of the following properties? A. Exotoxins that interfere with host cell metabolism B. Capacity for intracellular growth in macrophages C. Rapid growth in vitro and in vivo D. Endotoxin E. Immunoglobulin protease

25. Which one of the following is a correct statement about the epidemiology and pathogenesis of Rocky Mountain Spotted Fever? A. The etiologic agent rarely occurs outside of Colorado, New Mexico, Wyoming, and Utah. B. Control of infection would be improved if rat and fleas are exterminated in high risk areas. C. The etiologic agent is a spirochete that lives in the saliva of lone star ticks. D. It is a mild, self-limited disease that rarely requires antimicrobial treatment. E. The etiologic agent replicates in endothelial cells resulting in vasculitis.