리팜핀에 내성이 있는 황색포도알균의 유병률

Abstract

Antibiotic resistance remains an important problem around the world and the frequency of Staphylococcus aureus (S. aureus) resistant to rifampin (RIF) has increased dramatically. Mutations in the rifampin resistant determining region (RRDR) of rpoB have been shown to confer resistance to RIF in S. aureus. This study aimed to investigate the prevalence of RIF resistance in clinical isolates, and to analyze mutation of rpoB in 1615 S. aureus. The samples obtained from Asan Medical Center, Seoul, Republic of Korea from 2008 to 2017. The MIC of RIF was carried out by using the broth microdilution method following standards recommended by the CLSI. The molecular typing of the isolates was performed MLST, spa and SCCmec and tested for rpoB mutation by PCR. Of the 843 MRSA isolates, 52(6.2%) were resistant to RIF and among 772 MSSA isolates, 5 (0.6%) were resistant to RIF (p<0.001). Of the 52 isolates, 51 (98.1%) were high-level RIF resistant (MIC≥8 ㎎/L) while only one (1.9%) has a low-level resistance to RIF (MIC4 ㎎/L). We identified 19 different types of mutations in the rpoB gene mutation analysis. Of these, single mutation (33/48, 68.8%) and multiple mutations (15/48, 31.3%) were confirmed. The most common single mutation is A477D (17/48, 35.4%) and the most common spa is t2460 (27/52, 51.9%). We found ST5-MRSA-Ⅱ-spa t2460 (26/52, 50%) molecular type with high resistance to RIF. In conclusion, RIF R of S. aureus is closely associated with mutations in the rpoB gene and these data suggest that ST5-MRSA-II-spa t2460 confers resistance to RIF.