A 24-year-old man come to the physician because of left-sided neck swelling that has slowly progressed over the past 4 weeks. He has a recurrent history of boils and skin abscesses. Temperature is 38.0°C (100.4°F). Physical examination shows a nontender, mobile mass in the left submandibular region with overlying erythema. A biopsy culture is performed to determine colonization by the culprit bacteria, which yields gram-positive cocci in clusters. The bacteria are able to grow in a media containing oxacillin. PCR testing reveals the pathogen has acquired the mecA gene. These bacteria are most likely to be resistant to which of the following antibiotics?

Question

A 24-year-old man come to the physician because of left-sided neck swelling that has slowly progressed over the past 4 weeks. He has a recurrent history of boils and skin abscesses. Temperature is 38.0°C (100.4°F). Physical examination shows a nontender, mobile mass in the left submandibular region with overlying erythema. A biopsy culture is performed to determine colonization by the culprit bacteria, which yields gram-positive cocci in clusters.  The bacteria are able to grow in a media containing oxacillin.  PCR testing reveals the pathogen has acquired the mecA gene.  These bacteria are most likely to be resistant to which of the following antibiotics?

Quizplus · Accepted Answer

Eductional Objective: Methicillin-resistant Staphylococcus aureus (MRSA) is resistant to most beta-lactam medications (eg, oxacillin, methicillin, cephalosporins) due to the acquisition of a mobile genetic element that contains the mecA gene. This gene encodes for a specialized penicillin-binding protein that has low affinity for beta-lactam antibiotics. Treatment of MRSA therefore requires a non-beta-lactam medication such as trimethoprim-sulfamethoxazole, clindamycin, doxycycline, or vancomycin.

A 24-Year-Old Man Come to the Physician Because of Left-Sided