ABSTRACT
To elucidate the local epidemiology of Staphylococcus aureus bacteraemia; we characterised blood culture isolates using molecular methods and prospectively collected clinical data to determine the occurrence of community-acquired; methicillin-resistant S. aureus (MRSA). Consecutive S. aureus blood culture isolates were collected over a one-year period from patients who were admitted to Tygerberg Academic Hospital in the Western Cape. A multiplex polymerase chain reaction (PCR) was used for the detection of spa; mecA and lukS/F-PV genes. Strain typing was performed using spa typing. Multiplex PCR for staphylococcal cassette chromosome mec (SCCmec) typing was also performed; as well as multilocus sequence typing (MLST) on selected isolates. Cases were categorised by clinical data as either hospital-acquired; healthcare-associated or community-acquired. One hundred and thirteen S. aureus isolates (30 MRSA) were collected from 104 cases of bacteraemia. According to clinical data; all community-acquired infections; 54 of hospital-acquired cases and the majority of healthcare-associated cases were due to methicillin-sensitive S. aureus (MSSA). Furthermore; all Panton-Valentine leukocidin (PVL)-positive isolates (15.9 of all S. aureus) were MSSA. MRSA strains were isolated from hospital-acquired cases (with a minority of healthcare-associated cases) and clustered mainly in spa-CC701 and CC012. SCCmec type IV was predominant. MLST clones included ST239-MRSAIII; ST36-MRSA-II and ST612-MRSA-IV. The predominant source for S. aureus bacteraemia was catheter-related infection (39). Community-acquired S. aureus infections in our setting remain sensitive to methicillin and current treatment guidelines suffice. The majority of hospital-acquired and healthcare-associated infections were catheter-related. Prevention and treatment should be targeted accordingly
