A novel hybrid SCCmec-mecC region in Staphylococcus sciuri

Abstract

ObjectivesMethicillin 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.MethodsWe 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.ResultsWhole-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.ConclusionsOverall, 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.

Antimicrobial susceptibility profile and research of mec A and erm genes in coagulase-negative staphylococci isolated from platelet concentrates bags

“…This mecC gene has also been reported in CoNS as Staphylococcus stepanovicii, Staphylococcus xylosus and Staphylcoccus scirui (Harrison et al, 2013a(Harrison et al, , 2013bLoncaric et al, 2013). As already suggested for the mecA gene, we can probably infer that the origin of the mecC gene is also among the CoNS (Tsubakishita et al, 2010;Couto et al, 2013).…”

Livestock-Associated MRSA and Its Current Evolution

“…This appears similar to what is observed for mecA-carrying SCCmec elements in coagulasenegative staphylococci; however, for mecC of course fewer strains are available to date, and the diversity is still difficult to assess. The gene mecC has been detected in Staphylococcus xylosus, S. sciuri, and Staphylococcus stepanovicii [108][109][110]. The mecC allotypes in the S. sciuri and S. xylosus strains are different and are integrated in different SCCmec structures, demonstrating the potential diversity in SCCmec mecC-carrying elements in staphylococci other than S. aureus.…”

Isolation of <i>Staphylococcus sciuri</i> from horse skin infection

“…S. sciuri possesses a certain pathogenic potential and is able to induce infections in both, animals (Frey et al, 2013;Dos Santos et al, 2015) and humans (Stepanovic et al, 2003). Some isolates of the S. sciuri group are known to carry different homologues of the methicillin resistance genes mecA, B and C and display methicillin/oxacillin resistance (Becker et al, 2014a,b;Harrison et al, 2014). In the present study, we report the identification of an oxacillin-resistant S. sciuri isolate from a purulent skin lesion of a horse, determined activity of coagulase and hyaluronidase and characterized the antibiotic resistance profile.…”

“…Thus, it has been reported that phenotypic methicillin (and other β-lactam) -resistance in Staphylococcaceae members is conferred not only by mecA, but also by different mecA allotypes and also by homologous genes such as mecB and mecC (Becker et al, 2014a,b). Moreover, a hybrid SCCmec consisting of a mecA-encoding SCCmec type VII element and a separate mecC region in terms of a ΨSCCmec element was published for S. sciuri (Harrison et al, 2014;Becker et al, 2014a). These reports might suggest the presence of a further mechomolog or a mec gene hybrid within the genome of the isolated S. sciuri strain, which could not be amplified by the mecA and mecC-specific oligonucleotides.…”