Free American Society for Microbiology ABMM Exam Questions

A patient develops a severe diarrheal illness after consuming raw seafood. Stool culture yields a Gramnegative, comma-shaped bacterium that is oxidase-positive and grows on thiosulfate-citrate-bile salts-sucrose (TCBS) agar, producing blue-green colonies. The MOST significant virulence factor contributing to the severe, cholera-like diarrhea caused by this organism is:

During an investigation of a foodborne outbreak linked to a church supper, 80 people ate the suspected chicken dish, and 32 subsequently developed gastroenteritis. Among 50 people who did not eat the chicken dish, 5 developed similar symptoms. What is the attack rate among those who ate the chicken dish? 

A microbiology laboratory is processing a stool sample for ova and parasites. A large (approximately 100 µm), thick-shelled, oval egg with a flattened side is observed. This egg MOST likely belongs to:

The human virome, the collection of viruses that reside in and on the human body, is increasinglyrecognized for its role in health and disease. Which of the following statements regarding the human virome is MOST accurate?

A patient with HIV infection and a CD4+ T-cell count below 50 cells/µL develops a progressive neurological illness characterized by confusion, motor deficits, and seizures. Brain MRI reveals multiple white matter lesions without mass effect. PCR of the CSF is positive for JC virus. Thepathogenesis of this condition, progressive multifocal leukoencephalopathy (PML), involves: