Free ABMM Mock Exam – Practice Online Confidently

A clinical laboratory performs a cefoxitin disk diffusion test on a Staphylococcus aureus isolate from a wound culture. The zone of inhibition measures 18 mm. According to current CLSI M100 guidelines, how should this result be interpreted regarding oxacillin/methicillin susceptibility?

A clinical microbiology laboratory is investigating a cluster of Clostridium difficile infections in a hospital. Which of the following methods is MOST appropriate for determining if the isolates from different patients are related?

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? 

During the investigation of a foodborne illness outbreak linked to raw sprouts, several bacterial isolates are obtained from patient stool samples and the implicated food source. Which of the following molecular methods would be MOST useful for establishing a definitive link between the clinical isolates and the food isolate?

A clinical microbiology laboratory is using flow cytometry to analyze lymphocyte subsets in a patient with suspected immunodeficiency. Which of the following cell surface markers is typically used to identify helper T cells?