ABSTRACT
BACKGROUND: This study evaluated the clinical characteristics and risk factors associated with community and hospital onset MRSA isolated from patients admitted to a tertiary care teaching hospital. METHODS: The study was carried out on MRSA isolated from clinical specimens of patients admitted into the wards and the intensive care unit in a 2,200-bed tertiary care teaching hospital from January 1st through December 31st, 2007. In order to identify the risk factors associated with MRSA acquisition, the medical records were reviewed. All statistics were computed using SPSS version 14.0. RESULTS: Of the 835 MRSA isolates, 179 (21.4%) were CO-MRSA and 656 (78.6%) were HO-MRSA. Of the 179 CO-MRSA isolates, 6 (3.4%) were CA-MRSA. Multiple logistic regression analysis showed that a history of using medical device or antibiotics within 1 year before the isolation of MRSA were significant risk factors for HO-MRSA, and a history of hospitalization within 1 year before the isolation of MRSA was a significant risk factor for CO-MRSA. Analysis on the antibiotics administered within 1 year before the isolation of MRSA showed that levofloxacin, macrolides, 1st generation cephalosporins, 3rd generation cephalosporins, 4th generation cephalosporins, vancomycin, metronidazole, and carbapenem were all significant risk factors for HO-MRSA and that TMP/SMX was a significant risk factor for CO-MRSA. Of the 6 (3.4%) CA-MRSA isolates, 1 (16.7%) was the pathogen responsible for soft tissue infection. No patients died from the CA-MRSA infection. CONCLUSION: MRSA isolated from clinical specimens of patients admitted into the wards and the ICU in a tertiary care teaching hospital was usually HO-MRSA, CO-MRSA and HO-MRSA usually had at least one of the risk factors associated with MRSA acquisition, and CO-MRSA was mainly HACO-MRSA.