The benefit of empiric treatment for methicillin-resistant Staphylococcus aureus

Community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA) has emerged as a major pathogen causing skin and soft tissue infections (SSTI). It is unclear whether treatment with antibiotics active in vitro against CA-MRSA improves patient outcomes. At our institution, where there is a high rate of CA-MRSA SSTI, we have adopted an empiric treatment algorithm that promotes both the use of antibiotics likely active against CA-MRSA and early incision and drainage of abscesses. The objective of this research was to study the effectiveness of an empiric treatment algorithm for SSTI directed against CA-MRSA. The study was a retrospective chart review. Treatment was categorized as either conforming or not conforming to the algorithm. Outcomes were categorized as worsening of infection or improvement, according to predefined criteria. There were 50 consecutive Emergency Department patients treated as outpatients for MRSA SSTI. Treatment conformed to the algorithm in 29 of 50 cases. Clinical failure occurred in 3% of cases treated according to the algorithm, compared with 62% of those not treated according to the algorithm (p < 0.001). Among 37 cases that underwent immediate incision and drainage, initial treatment with antibiotics active in vitro against the MRSA isolate was associated with a decreased clinical failure rate when compared to those treated with inactive antibiotics (0% vs. 67%, p < 0.001). Empiric treatment of CA-MRSA SSTI according to an algorithm that promotes use of antibiotics active in vitro against CA-MRSA is associated with improved clinical outcomes.