Circulation of a community healthcare-associated multiply-resistant meticillin-resistant Staphylococcus aureus lineage in South Yorkshire identified by whole genome sequencing

Summary Background A cluster of seven cases of skin and wound infections caused by a multiply resistant MRSA were detected in a small-town community in South Yorkshire. Initial microbiological investigations showed that all isolates belonged to a spa type observed rarely in England (t1476). Aim To describe the epidemiology of t1476 meticillin-resistant Staphylococcus aureus (MRSA) in South Yorkshire. Methods Retrospective and prospective case ascertainment was promoted through communication with local microbiology laboratories. Public health investigation included a detailed review of clinical notes for a subset of nine cases. Genomic and phylogenetic analysis was undertaken on t1476 MRSA. Findings Thirty-two cases of t1476 MRSA infection or colonization were identified between December 2014 and February 2018. Cases were older adults (aged 50–98 years). Healthcare exposures for a subset of nine cases indicated frequent contact with a team of district nurses, with all but one case receiving treatment on the same day as another case prior to their own diagnosis. No cases were admitted to hospital at the time of specimen collection. Despite detailed investigations, no carriers were detected among district nursing staff. A long-term carrier/super-shedder was not found. Phylogenetic analysis indicated that t1476 MRSA cases from South Yorkshire were monophyletic and distant from both MRSA of the same lineage from elsewhere in the UK (N = 15) and from publicly available sequences from Tanzania. Conclusion Genomic and epidemiological analyses indicate community-based transmission of a multiply resistant MRSA clone within South Yorkshire introduced around 2012–2013, prior to the detection of a spatial–temporal cluster associated with a distinct risk group. Surveillance data indicate continued circulation.