Clindamycin-resistant methicillin-resistant Staphylococcus aureus: Epidemiologic and molecular characteristics and associated clinical factors

In this prospective, observational study of 618 consecutive adult patients with skin and soft tissue infections (SSTI) caused by methicillin-resistant Staphylococcus aureus (MRSA), the clinical characteristics, molecular epidemiology, and outcome of patients with clindamycin-resistant MRSA (n = 64) and clindamycin-susceptible MRSA (n = 554) were compared (including factors predictive of clindamycin-resistant MRSA SSTI). Patients with clindamycin-resistant MRSA were more likely to have had antibiotic exposure within 3 months (37.5% versus 17%, P < 0.01), surgery (25% versus 8%, P < 0.01), MRSA infection/colonization within 12 months (23% versus 7%, P < 0.01), or intravascular catheters (5% versus 0.5%, P = 0.02). On multivariate analysis, previous surgery (adjusted odds ratio [AOR] 2.97; 95% confidence interval [CI] 1.5-6.0), history of MRSA (AOR 3.4; 95% CI 1.7-7.1), and exposure to clindamycin (AOR 8.5; 95% CI 2.3-32) and to macrolides (AOR 7.2, 95% CI 1.6-31.8) were independently associated with presence of clindamycin-resistant MRSA. Clinical resolution was similar between groups (77% versus 68%; P = 0.26). Clindamycin-resistant MRSA was less often USA-300 (82% versus 98%, P = 0.004). Clindamycin resistance did not affect MRSA-SSTI clinical outcomes.