Antimicrobial Resistance Practice Test

A 45-year-old man with a history of intravenous drug use is admitted to the hospital with a fever, chills, and a new heart murmur. Blood cultures are drawn and grow a gram-positive coccus in clusters that is catalase-positive and coagulase-positive. The isolate is found to be resistant to nafcillin. Further genetic analysis reveals the presence of the mecA gene.

A 68-year-old woman with a prolonged hospital stay for a complicated abdominal surgery develops a urinary tract infection. Urine culture grows Enterococcus faecalis that is resistant to vancomycin. The resistance is determined to be mediated by the vanA gene cluster.