Clinical Characteristics and Risk factors of Community-Acquired Methicillin-Resistant Staphylococcus aureus Infections: Comparison of Community-Acquired Methicillin-Susceptible Staphylococcus aureus Infections / 감염과화학요법

ABSTRACT

BACKGROUND: Methicillin-resistant Staphylococcus aureus (MRSA) is an emerging cause of infections in many communities. MRSA is usually resistant to beta-lactam antibiotics which are commonly used to treat methicillin-susceptible S. aureus (MSSA) infections, and initial discordant therapy for community-acquired (CA)-MRSA infections frequently lead to treatment failure. This study evaluated the clinical characteristics and risk factors associated with CA-MRSA infections among patients admitted to a large urban public hospital. MATERIALS AND METHODS: From January 1st 2001 through December 31st 2004, all patients for whom S. aureus was isolated from clinical specimen cultures within first 72 hours after admission to Gyeongsang National University Hospital were retrospectively analyzed. CA-MRSA isolate was defined as MRSA isolates from patients who had no established risk factors for MRSA infections. Patients with CA-MRSA infections were compared with patients with CA-MSSA infections. RESULTS: During the 4 years of the study, 41 patients with CA-MRSA infection and 102 patients with CA-MSSA infection were included, respectively. In univariate analysis, CA-MRSA infections were more common in such conditions that were the previous isolation of MRSA from 1 year through 3 years before admission (17.5% vs. 1.0%, O.R=21.4, P=0.001), previous hospitalization from 1 year through 3 years before admission (33.3% vs. 10.7%, O.R=4.16, P=0.007), and previous alcohol drinking history (22% vs. 6.9%, O.R=3.81, P=0.017). Bone and joint infections (22.0% vs. 7.8%, O.R=3.30, P=0.025) were more common in CA-MRSA infections than CA-MSSA infections. Multiple logistic regression analysis showed that the previous isolation of MRSA from 1 year through 3 years before admission (OR6.59 [95% CI, 1.040-41.741]) was the only significant risk factor for CA- MRSA infections. CONCLUSION: The previous isolation of MRSA from 1 year through 3 years before admission was an independent risk factor for CA-MRSA infections.