Failure of mecA/mecC PCR Testing to Accurately Predict Oxacillin Resistance in a Patient with Staphylococcus aureus Infective Endocarditis.

Genotypic testing for / is heavily relied upon for rapid optimization of antimicrobial therapy in infections due to Staphylococcus aureus. Little is known regarding optimal reporting and/or therapy for patients demonstrating lack of genotypic evidence of or but phenotypic oxacillin resistance. We report a case of a 77-year-old patient with S. aureus bloodstream infection and infective endocarditis with discordance between genotypic results and phenotypic susceptibility testing.