antibiogram of methicillinresistant staphylococcus aureus isolates from mrsa colonized patients in two tertiary hospital emergency departments

Methicillin-resistant staphylococcus aureus (mrsa) colonized patients are at increased risk of developing mrsa infections. this study was undertaken to evaluate the minimum inhibitory concentration (mic) of antimrsa antibiotics for mrsa isolates from mrsa colonized patients. from november 2009 to march 2011, a prospective study was performed in two emergency departments. patients at high risk for mrsa colonization were identified, and mrsa surveillance cultures obtained. the mic for antimrsa antibiotics in cultures from each patient was evaluated. a total of 276 patients were assessed. of these, 23.6% (65/276) were mrsa culture positive. the mic 50 and mic 90 for vancomycin with these mrsa isolates by etest were both 2 µg/ml. the mic 50 and mic 90 for teicoplanin were 2 µg/ml and 3 µg/ml, respectively, among mrsa isolates. nearly all (62/65, 95.4%) mrsa isolates were sensitive to trimethoprim /sulfamethoxazole. of all patients, 47.7% (31/65) of the mrsa isolates were sensitive to gentamicin, 40% (26/65) to minocycline, 13.8% (9/65) to clindamycin, 6.2% (4/65) to erythromycin, and 1.5% (1/65) to levofloxacin. the average value of the vancomycin mic for isolates from mrsa colonized patients was 2 µg/ml. trimethoprim /sulfamethoxazole was the second most effective antimrsa oral antibiotic in vitro.