A novel hybrid SCCmec-mecC region in Staphylococcus sciuri

Harrison, E. M. et al. (2014) A novel hybrid SCCmec-mecC region in Staphylococcus sciuri. Journal of Antimicrobial Chemotherapy, 69(4), pp. 911-918. (doi: 10.1093/jac/dkt452)

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Objectives: Methicillin resistance in Staphylococcus spp. results from the expression of an alternative penicillin-binding protein 2a (encoded by mecA) with a low affinity for β-lactam antibiotics. Recently, a novel variant of mecA known as mecC (formerly mecALGA251) was identified in Staphylococcus aureus isolates from both humans and animals. In this study, we identified two Staphylococcus sciuri subsp. carnaticus isolates from bovine infections that harbour three different mecA homologues: mecA, mecA1 and mecC.<p></p> Methods: We subjected the two isolates to whole-genome sequencing to further understand the genetic context of the mec-containing region. We also used PCR and RT–PCR to investigate the excision and expression of the SCCmec element and mec genes, respectively.<p></p> Results: Whole-genome sequencing revealed a novel hybrid SCCmec region at the orfX locus consisting of a class E mec complex (mecI-mecR1-mecC1-blaZ) located immediately downstream of a staphylococcal cassette chromosome mec (SCCmec) type VII element. A second SCCmec attL site (attL2), which was imperfect, was present downstream of the mecC region. PCR analysis of stationary-phase cultures showed that both the SCCmec type VII element and a hybrid SCCmec-mecC element were capable of excision from the genome and forming a circular intermediate. Transcriptional analysis showed that mecC and mecA, but not mecA1, were both expressed in liquid culture supplemented with oxacillin.<p></p> Conclusions: Overall, this study further highlights that a range of staphylococcal species harbour the mecC gene and furthers the view that coagulase-negative staphylococci associated with animals may act as reservoirs of antibiotic resistance genes for more pathogenic staphylococcal species.<p></p>

Item Type:Articles
Glasgow Author(s) Enlighten ID:Zadoks, Professor Ruth
Authors: Harrison, E. M., Paterson, G. K., Holden, M. T.G., Ba, X., Rolo, J., Morgan, F. J.E., Pichon, B., Kearns, A., Zadoks, R. N., Peacock, S. J., Parkhill, J., and Holmes, M. A.
College/School:College of Medical Veterinary and Life Sciences > School of Biodiversity, One Health & Veterinary Medicine
Journal Name:Journal of Antimicrobial Chemotherapy
Publisher:Oxford University Press
ISSN (Online):1460-2091
Copyright Holders:Copyright © 2013 The Authors
First Published:First published in Journal of Antimicrobial Chemotherapy 69(4):911-918
Publisher Policy:Reproduced under a Creative Commons License
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