Molecular characterization of Rifr mutations in Enterococcus faecalis and Enterococcus faecium.
Mutation rate is an important factor affecting the appearance and spread of acquired antibiotic resistance. The frequencies and types of enterococci mutations were determined in this study. The MICs of rifampicin in enterococci and their rifampicin-resistant mutants were determined by the Clinical and Laboratory Standards Institute (CLSI) agar dilution method. The Enterococcus faecalis isolates A15 and 18165 showed no significant differences in mutation frequencies or mutation rates. In Enterococcus faecium, the mutation frequency and mutation rate were both 6·4-fold lower than in E. faecalis. The spectrum of mutations characterized in E. faecium B42 differed significantly from that of E. faecalis. The types and rate of mutations indicated that E. faecalis had a higher potential to develop linezolid resistance. Rifampicin resistance was associated with mutations in the rpoB gene. Rifampicin MICs for the E. faecalis mutant were 2048 mg/l, but rifampicin MICs for E. faecium mutants ranged from 64 to 1024 mg/l.
Xiaoxing
X
Du
Xiaoting
X
Hua
Tingting
T
Qu
Yan
Y
Jiang
Zhihui
Z
Zhou
Yunsong
Y
Yu
D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D001426:Bacterial Proteins / Q000235:genetics*; D004305:Dose-Response Relationship, Drug; D004352:Drug Resistance, Microbial / Q000235:genetics*; D013293:Enterococcus faecalis / Q000187:drug effects / Q000235:genetics*; D016984:Enterococcus faecium / Q000187:drug effects / Q000235:genetics*; D008826:Microbial Sensitivity Tests; D009154:Mutation / Q000235:genetics*; D012293:Rifampin / Q000494:pharmacology*; D013329:Structure-Activity Relationship
D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins; D012293:Rifampin
Antibiotic resistance,; Enterococcus,; Rifampicin