The objective of this study was to determine whether skin and soft tissue infections (SSTIs) caused by methicillin-resistant Staphylococcus aureus (MRSA) in patients presenting to The Ottawa Hospital emergency departments (TOHEDs) differed from SSTIs caused by methicillin-susceptible Staphylococcus aureus (MSSA) with regard to risk factors, management, and outcomes.

All patients seen at TOHEDs in 2006 and 2007 with SSTIs who yielded MRSA or MSSA in cultures from the site of infection were eligible for inclusion. We excluded patients with decubitus ulcers and infections related to diabetes or peripheral vascular disease. We used an unmatched case-control design. Cases were defined as patients with MRSA isolated from the infection site, and controls were defined as patients with MSSA isolated from the infection site. Data were collected retrospectively from health records and laboratory and hospital information systems.

A total of 153 patients were included in the study (81 cases and 72 controls). The mean age of cases was 37 years, compared to 47 years for the controls (p < 0.001). Cases were more likely to have transient residence (31% v. 3% [OR 15.6, 95% CI 3.9–61.8, p < 0.001]), present with abscesses (64% v. 15% [OR 9.9, 95% CI 4.3–23.7, p < .001]), have a documented history of hepatitis C infection (28% v. 3% [OR 13.9, 95% CI 3.9–55.0, p < 0.001]), and have a history of substance abuse (53% v. 10% [OR 10.5, 95% CI 4.4–25.1, p < 0.001]). Cases most commonly used crack cocaine and injection drugs.

SSTIs caused by MRSA at TOHEDs mainly occur in a population that is young and transient with comorbidities such as hepatitis C and substance abuse.