MMSC 438 EXAM 2 SET Q&A

MMSC 438 EXAM 2 SET Q&A 1. A bloody stool sample is received in the laboratory and plated to routine stool culture media. The following results arerecorded by the laboratory scientist 24 hours after plating the patient sample:Blood agar: beta-hemolytic coloniesMacConkey: Only lactose fermenting colonies are presentSMAC: 2+ clear colonies presentFurther testing reveals: Oxidase negative, indole positive, MUG negative, motileThe most likely identification is: A. Yersinia enterocolitica B. Salmonella spp. C. Shigella spp. D. Escherichia coli 0157:H7 D. Escherichia coli 0157:H7 2. A liter of watery stool is submitted to the laboratory for enteric pathogen screening. Colonies from the blood agar plateproduce an oxidase positive result. Yellow colonies are observed on the thiosulfate citrate bile salts sucrose agar. What is the most likely pathogen? A. Vibrio cholerae B. Campylobacter jejuni C. Salmonella enterica Typhimurium D. Yersinia enterocolitica A. Vibrio cholerae 3. Two hours after eating a meal consisting of ham, potato salad and green peas, vomiting and nausea develop in the absence of diarrhea. The symptoms are most likely due to ___________. A. Enterotoxin B of Staphylococcus aureus B. Neurotoxin of Clostridium botulinum C. Type A toxin of Clostridioides difficile D. Enterotoxin of Escherichia coli A. Enterotoxin B of Staphylococcus aureus 4. While on a medical study abroad trip to Kenya, an outbreak of typhoid fever occurs. A patient is seen in the clinic complaining of symptoms consistent with typhoid for the past three days. What specimen type would be most appropriate for culture of the suspected pathogen? A. Blood B. Sputum C. Stool D. Urine A. Blood 5. Tympanocentesis (the drainage of fluid from the middle ear) is performed on a 4-year-old girl. A viral pathogen is identified.The most likely diagnosis is: A. Otitis externa B. Otitis media C. Epiglottitis D. Sinusitis B. Otitis media 6. When examining stool culture plates, suspected pathogens can best be identified as: A. Green colonies on thiosulfate citrate bile salts sucrose (TCBS) agar. B. Non-hemolytic colonies on blood agar. C. Non-lactose fermenting colonies on MacConkey agar. D. Obligate anaerobic colonies on egg yolk agar. C. Non-lactose fermenting colonies on MacConkey agar. 7. Pseudomembranous colitis______________. A. Is toxin mediated. B. Is most frequently caused by Clostridioides difficile. C. Occurs after administration of broad spectrum antimicrobials. D. All of the above. D. All of the above. 8. When evaluating respiratory samples, which of the following organisms should be reported, even if only a few colonies are present? A. Staphylococcus aureus B. Staphylococcus epidermidis C. Viridans streptococci D. Streptococcus pyogenes D. Streptococcus pyogenes