Abstract

Background Staphylococcus argenteus and Staphylococcus schweitzeri, previously known as divergent Staphylococcus aureus clonal lineages, have been recently established as novel, difficultly delimitable, coagulase-positive species within the S.aureus complex. Methicillin-resistant S.argenteus are known from Australia and U.K.. Knowledge on their epidemiology, medical significance and transmission risk is limited and partly contradictory, thus, hampering definitive recommendations. There is mounting evidence that S.argenteus´ pathogenicity is similar to “classical” S.aureus while hitherto no S.schweitzeri infections have been reported. Aim Provide decision support whether and how to distinguish and report both species. Sources PubMed search about S.argenteus and S.schweitzeri. Content This position paper reviews the main characteristics of both species and draws conclusions for microbiological diagnostics, surveillance as well as infection prevention and control measures. Implications We propose not distinguishing within the S.aureus complex for routine reporting purposes until there is evidence that pathogenicity or clinical outcome differ markedly between the different species. Primarily for research purposes, suitably equipped laboratories are encouraged to differentiate between S.argenteus and S.schweitzeri. Caution is urged if these novel species are explicitly reported. In such cases, a specific comment should be added (i.e. “member of the S.aureus complex”) to prevent confusion with less or non-pathogenic staphylococci. Prioritizing aspects of patient safety, methicillin-resistant isolates should be handled as recommended for MRSA. In these cases, the responsible clinician should be directly contacted and informed by the diagnosing microbiological laboratory, as they would be for MRSA. Research is warranted to clarify their epidemiology, clinical impact and implications for infection control.