The emergence of mecC methicillin-resistant Staphylococcus aureus

Abstract

The report of methicillin-resistant Staphylococcus aureus (MRSA) encoding a divergent mecA gene in 2011 was highly significant. This homologue, designated mecC, poses diagnostic problems with the potential to be misdiagnosed as methicillin-sensitive S. aureus, with important potential consequences for individual patients and for the surveillance of MRSA. mecC MRSA have now been reported from 13 European countries and have been isolated from 14 different host species, with evidence of a recent increase in Denmark. The emergence of mecC MRSA is a topic of interest to human and veterinary microbiology, and we consider it timely to review here its discovery and subsequent investigation.

Keywords: antibiotic resistance; genome sequencing; mecC; methicillin-resistant Staphylococcus aureus (MRSA); molecular epidemiology; zoonosis.

Figure 1

Comparison of the mecC1 region in Staphylococcus xylosus strain S04009 (EMBL accession number HE993884), SCCmec type XI in Staphylococcus aureus LGA251 (EMBL FR821779), and a hybrid SCCmec–mecC in S. sciuri strain GVGS2 (EMBL HG515014). Areas in red show regions conserved between the two sequences; homologous coding sequences are marked in the same colour. Blue and red dots indicate the SCCmec attachment sites (attL and attR) and inverted repeats (IR), respectively. The %G/C content of the region is shown above each genome schematic. Abbreviations: ABC, ATP-binding cassette; ACME, arginine catabolic mobile element; SCCmec, staphylococcal cassette chromosome.