MRSA with a Novel mecA Homologue

A newly identified strain of methicillin-resistant Staphylococcus aureus evades detection by the genetic assays commonly used to confirm such resistance.

First reported in England in 1961, methicillin-resistant Staphylococcus aureus (MRSA) has spread globally in hospitals and the community. Methicillin resistance can spread when bacteria acquire a staphylococcal cassette chromosome mec (SCCmec) element with the mecA gene, which encodes a penicillin-binding protein (PBP) with low affinity for β-lactam antibiotics.

Phenotypic resistance is detected by measuring zones of bacterial growth inhibition around antibiotic-impregnated discs. Laboratories confirm resistance using genetic assays, such as mecA polymerase chain reaction (PCR), a DNA microarray, and a PBP latex agglutination assay. In two new studies, researchers describe S. aureus isolates that were phenotypically resistant to methicillin …

Reviewing Author

Mary E. Wilson, MD

Disclosures

Consultant/Advisory BoardOneHealthTrust (formerly Center for Disease Dynamics, Economics, and Policy); Global Health Institute, University of Wisconsin

RoyaltiesUpToDate

Editorial BoardsJournal of Travel Medicine

Mary E. Wilson, MD

Disclosures

Consultant/Advisory BoardOneHealthTrust (formerly Center for Disease Dynamics, Economics, and Policy); Global Health Institute, University of Wisconsin

RoyaltiesUpToDate

Editorial BoardsJournal of Travel Medicine