Molecular Typing and Resistance Profiles of Vancomycin-Intermediate Staphylococcus aureus in Korea: Results from a National Surveillance Study, 2007-2013

• Published in: Annals of clinical microbiology Vol. 19; no. 4; pp. 88 - 96
• Main Authors: Kim, Jung Wook, Kang, Gi Su, Yoo, Jae Il, Kim, Hwa Su, Lee, Yeong Seon, Yu, Jae-Yon, Lee, Kwang-Jun, Park, Chan, Kim, Il-Hwan
• Format: Journal Article
• Language: English
• Published: 대한임상미생물학회 01.12.2016
• Subjects: 임상병리학
• ISSN: 2288-0585; 2288-0585; 2288-6850
• DOI: 10.5145/ACM.2016.19.4.88

Background: To investigate the national molecular epidemiology and resistance profiles of vancomycinintermediate Staphylococcus aureus (VISA), we analyzed the characteristics of methicillin-resistant Staphylococcus aureus (MRSA) collected from clinical samples at tertiary or general hospitals participating in a nationwide surveillance program for VISA and vancomycin-resistant Staphylococcus aureus (VRSA) in Korea during an 12-week period in each year from 2007 to 2013. Methods: VISA was defined by agar dilution, broth dilution and E-test methods with vancomycin minimum inhibitory concentrations of ＞2 μg/mL. All VISA isolates were characterized by multilocus sequence typing, staphylococcal cassette chromosome mec typing, spa typing, accessory gene regulator typing, Diversilab analysis, and antibiogram analysis. Results: Of 109,345 MRSA isolates, 87,354 were screened and 426 isolates were identified as positive on brain heart infusion agar containing 4 μg/mL vancomycin (BHI-V4). Of 426 isolates, 76 isolates were identified as VISA. No VRSA isolates were detected among the isolates. Overall, a total of 6 genotypes were identified among VISA strains and the predominant clones were ST5-II-t2460, ST72-IV-t324, and ST239-III-t037 (44.7%, 15.8%, and 10.5%, respectively). Of note, ST72-IV-t324 clones are known to be a typical community-associated MRSA. ST239-IIIt037 strains were more resistant to trimethoprim-sulfamethoxazole than any other type of strain. ST72- IV-t324 strains were susceptible to all of the antimicrobial agents tested except erythromycin and daptomycin. All of the VISA isolates were susceptible to linezolid and quinupristin-dalfopristin. Conclusion: Although VRSA is still rare, continuous monitoring of VRSA occurrence is needed, as well as VISA prevalence, epidemic clonal shift, and antimicrobial resistance. KCI Citation Count: 0