Non-multiresistant and multiresistant methicillin-resistant Staphylococcus aureus in community-acquired infections.

Objective: To survey Staphylococcus aureus strains isolated from patients presenting from the community, comparing clinical features and antibiotic sensitivity profiles between multiresistant and non-multiresistant methicillin-resistant and methicillin-sensitive isolates.

Design: Retrospective case series.

Participants And Setting: Patients who presented to emergency or dermatology departments in hospitals served by the South Western Sydney Area Health Service between 1 May 1998 and 30 April 1999. All patients with methicillin-resistant S. aureus (MRSA) and the first 100 with methicillin-sensitive S. aureus were eligible.

Main Outcome Measures: Patient demographic characteristics; risk factors; clinical presentation; treatment; outcome; and isolate antibiotic susceptibility.

Results: 139 patients were eligible, and 122 had clinical records available. Ten of these 122 (8%) had multiresistant MRSA, 26 (21%) non-multiresistant MRSA and 86 (70%) methicillin-sensitive S. aureus. Among patients with non-multiresistant MRSA, 29% (7/24) were born in New Zealand, Samoa or Tonga, a higher proportion than among those with multiresistant MRSA or methicillin-sensitive S. aureus (P= 0.03). Nearly half (44%) of non-multiresistant MRSA strains were community-acquired in patients with no risk factors. Two-thirds of patients with non-multiresistant MRSA (17/26) presented with cellulitis or abscess, and 58% (11/19 evaluable patients) required surgical treatment.

Conclusions: Non-multiresistant MRSA strains are common, especially among people born in New Zealand, Samoa or Tonga, and are usually community acquired. Medical practitioners should routinely swab all staphylococcal lesions for culture and sensitivity.