Community-onset Staphylococcus aureus infections presenting to general practices in South-eastern Australia

Abstract

Community-acquired Staphylococcus aureus infections are a public health concern, yet little is known about infections that do not present to hospital. We identified community-onset S. aureus infections via specimens submitted to a community-based pathology service. Referring doctors confirmed eligibility and described infection site, severity and treatment. Isolates were characterized on antibiotic resistance, PFGE, MLST/SCCmec, and Panton-Valentine leukocidin (PVL), representing 106 community-onset infections; 34 non-multiresistant methicillin-resistant S. aureus (nmMRSA) (resistant to <3 non-β-lactam antibiotics), 15 multiply antibiotic-resistant MRSA (mMRSA) and 57 methicillin-sensitive S. aureus (MSSA). Most (93%) were skin and soft tissue infections. PVL genes were carried by 42% of nmMRSA isolates [95% confidence interval (CI) 26-61] and 15% of MSSA (95% CI 8-28). PVL was associated with infections of the trunk, head or neck (56·4% vs. 24·3%, P=0·005) in younger patients (23 vs. 52 years, P<0·001), and with boils or abscesses (OR 8·67, 95% CI 2·9-26·2), suggesting underlying differences in exposure and/or pathogenesis.

Fig. 1.

Recruitment. mMRSA, Multiresistant methicillin-resistant S. aureus; nmMRSA, non-multiresistant MRSA; MSSA, methicillin-sensitive S. aureus.

Fig. 2.

Antibiotic resistance and antibiotic treatment by S. aureus resistance type. Shaded areas denote antibiotic resistance; ●, antibiotic initially prescribed for the infection; ○, change of antibiotic. mMRSA, Multiresistant methicillin-resistant S. aureus; nmMRSA, non-multiresistant MRSA; MSSA, methicillin-sensitive S. aureus.