OBJECTIVES
Recently we detected a new CA-MRSA strain (ST97-MRSA-SCCmecV) which can harbour an arcA locus encoded on an Arginine Catabolic Mobile Element (ACME). ACME may be associated with survival on skin or transmissibility of USA300. We sought to determine the dissemination of ACME-arcA positive ST97-MRSA-SCCmecV in England and Wales.

METHODS
Putative CA-MRSA isolates referred to the England and Wales Staphylococcus Reference Unit from 2005-September 2007, that were PCR positive for ACME-arcA and staphylococcal enterotoxins D and J only, were further characterised by; PFGE, spa-, SCCmec- and ccr-typing. MICs of a range of antibiotics were determined. Patient demographic and clinical data were collated.

RESULTS
Fourteen SCCmecV MRSA with ACME-arcA and staphylococcal enterotoxins D and J were detected. The isolates occurred in three geographically distinct centres in patients with an age range 61-93 years (median 81 years, mode 89 years). The available data (from 7 individuals) indicated isolates were associated with skin and soft tissue infections. The fourteen isolates were agr 1, harboured SCCmecV and ccrC, and were closely related by PFGE (<= 2 band changes) and spa typing (1 repeat difference). The isolates were borderline-resistant to beta-lactams and ciprofloxacin, and had variable resistance to erythromycin, clindamycin and/or trimethoprim.


CONCLUSIONS
This new strain was identified in elderly patients in multiple diverse locations in the UK, often associated with skin and soft tissue infections. Despite the presence of mecA the strain has a low oxacillin MIC, thus increased vigilance is essential to maximise ascertainment of disease associated with this strain.