Old drugs to treat resistant bugs: Methicillin-resistant Staphylococcus aureus isolates with mecC are susceptible to a combination of penicillin and clavulanic acid
Ba, Xiaoliang; Harrison, Ewan M.; Lovering, Andrew L.; Gleadall, Nicholas; Zadoks, Ruth; Parkhill, Julian; Peacock, Sharon J.; Holden, Matthew T. G.; Paterson, Gavin K.; Holmes, Mark A.
Ewan M. Harrison
Andrew L. Lovering
Sharon J. Peacock
Matthew T. G. Holden
Gavin K. Paterson
Mark A. Holmes
β-Lactam resistance in methicillin-resistant Staphylococcus aureus (MRSA) is mediated by the expression of an alternative penicillin-binding protein 2a (PBP2a) (encoded by mecA) with a low affinity for β-lactam antibiotics. Recently, a novel variant of mecA, known as mecC, was identified in MRSA isolates from both humans and animals. In this study, we demonstrate that mecC-encoded PBP2c does not mediate resistance to penicillin. Rather, broad-spectrum β-lactam resistance in MRSA strains carrying mecC (mecC-MRSA strains) is mediated by a combination of both PBP2c and the distinct β-lactamase encoded by the blaZ gene of strain LGA251 (blaZLGA251), which is part of mecC-encoding staphylococcal cassette chromosome mec (SCCmec) type XI. We further demonstrate that mecC-MRSA strains are susceptible to the combination of penicillin and the β-lactam inhibitor clavulanic acid in vitro and that the same combination is effective in vivo for the treatment of experimental mecC-MRSA infection in wax moth larvae. Thus, we demonstrate how the distinct biological differences between mecA- and mecC-encoded PBP2a and PBP2c have the potential to be exploited as a novel approach for the treatment of mecC-MRSA infections.
|Journal Article Type||Article|
|Publication Date||Dec 1, 2015|
|Journal||Antimicrobial agents and chemotherapy|
|Publisher||American Society for Microbiology|
|Peer Reviewed||Peer Reviewed|
|APA6 Citation||Ba, X., Harrison, E. M., Lovering, A. L., Gleadall, N., Zadoks, R., Parkhill, J., …Holmes, M. A. (2015). Old drugs to treat resistant bugs: Methicillin-resistant Staphylococcus aureus isolates with mecC are susceptible to a combination of penicillin and clavulanic acid. Antimicrobial agents and chemotherapy, 59(12), (7396-7404). doi:10.1128/AAC.01469-15. ISSN 0066-4804|
|Keywords||β-lactams, MRSA, mecC|
|Copyright Statement||© 2015, American Society for Microbiology. All Rights Reserved.|
|Additional Information||Copy of article first published in: Antimicrobial agents and chemotherapy, 2015, v.59, issue 12|
© 2015, American Society for Microbiology. All Rights Reserved.
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