Antimicrobial Resistance of Staphylococcus aureus among Patients with Vancomycin Resistant Enterococcus / 감염과화학요법

ABSTRACT

BACKGROUND: The transfer of vancomycin resistance from vancomycin-resistant enterococci (VRE) to Staphylococcus aureus has been predicted. The purpose of this study is to determine the prevalence and antibiotics resistance of S. aureus among patients colonized with VRE. METHODS: Between January 2001 and December 2001, a prospective study was performed at Pusan National University Hospital on 27 patients. Surveillance swabs from nasal cavity, axilla, perineum, and rectum were obtained at weekly intervals. Methicillin susceptability of S. aureus was determined by oxacillin disk diffusion test and minimum inhibitory concentration (MIC) for vancomycin by microdilution broth test. RESULTS: Total of 292 swab cultures were performed and 67 S. aureus isolates were collected. 64 isolates (95.5%) were resistant to methicillin. The prevalence of nasal MRSA carrier in 19 patients colonized with VRE was higher than that in 8 patients not colonized with VRE (58% vs. 37.5%). In 64 MRSA isolates, MIC (microgram/mL) for vancomycin ranged from 0.5 to 2. No isolates with MIC >2 microgram/mL were observed. MIC of 1 microgram/mL was shown (observed) in 54 isolates, 2 microgram/mL in 6 isolates, and 0.5 microgram/mL in 4 isolates. CONCLUSION: The prevalence of S. aureus with colonization of VRE is higher than that without colonization of VRE. Most of S. aureus isolates were resistant to methicillin. VRSA isolates were not observed.