Document Type
Article
Publication Date
7-25-2019
Publication Source
Antimicrobial Agents and Chemotherapy
Abstract
Staphylococcus aureus strains that possess a mecA gene but are phenotypically susceptible to oxacillin and cefoxitin (OS-MRSA) have been recognized for over a decade and are a challenge for diagnostic laboratories. The mechanisms underlying the discrepancy vary from isolate to isolate. We characterized seven OS-MRSA clinical isolates of six different spa types from six different states by whole-genome sequencing to identify the nucleotide sequence changes leading to the OS-MRSA phenotype. The results demonstrated that oxacillin susceptibility was associated with mutations in regions of nucleotide repeats within mecA. Subinhibitory antibiotic exposure selected for secondary mecA mutations that restored oxacillin resistance. Thus, strains of S. aureus that contain mecA but are phenotypically susceptible can become resistant after antibiotic exposure, which may result in treatment failure. OS-MRSA warrant follow-up susceptibility testing to ensure detection of resistant revertants.
ISBN/ISSN
Print: 0066-4804; Electronic: 1098-6596
Document Version
Published Version
Publisher
American Society for Microbiology
Volume
63
Peer Reviewed
yes
Issue
8
Keywords
MRSA, emergence of resistance, mecA, oxacillin susceptible, whole-genome sequencing
eCommons Citation
Goering, Richard V.; Swartzendriber, Erin A.; Obradovich, Anne E.; Tickler, Isabella A.; and Tenover, Fred C., "Emergence of Oxacillin Resistance in Stealth Methicillin-Resistant Staphylococcus aureus Due to mecA Sequence Instability" (2019). Biology Faculty Publications. 342.
https://ecommons.udayton.edu/bio_fac_pub/342
Included in
Biology Commons, Biotechnology Commons, Cell Biology Commons, Genetics Commons, Microbiology Commons, Molecular Genetics Commons
Comments
The document is made available in compliance with the publisher's policy on self-archiving. Permission documentation is on file. DOI: https://doi.org/10.1128/aac.00558-19