Relationship between in-vitro sensitivity of telithromycin and antibiotic resistance gene erm from MSSA
Objective To investigate the distribution of antibiotic resistance gene erm,which related to erythromycin resistance,in clinically isolated methicillin-sensitive staphylococcus aureus(MSSA)and to analyze the effect of erm on the in-vitro sensitivity to the novel macrolides telithromycin.Methods 121 non-duplicated MSSA strains identified from different departments and specimens and preserved in Huazhong University of Science and Technology Union Shenzhen Hospital from 2011 to 2015,were adopted in this experiment.The MIC values of the strains to telithromycin and 10 antimicrobial drugs were determined by broth microdilution method and K-B disk diffusion method.D-tests were performed to distinguish the MLSB resistant phenotype of all the erythromycin resistant strains,and the distribution of ermA,ermB,and ermC,the most common subtypes of the erm gene,were detected by PCR.Results 51 strains of MSSA was resistant and 1 strain intermediate resistant to telithromycin,with a antibiotic resistance rate of 43.0%,and an erythromycin resistance rate of 61.2%.All MSSA were sensitive to the commonly used drugs including amoxicillin/clavulanic acid,oxacillin,vancomycin,linezolid,and teicoplanin;among 121 strains of MSSA,74(61.2%)carried erm gene,and 25(20.7%)strains with cMLSB phenotypes carried ermB;10(8.3%)strains carried ermA were all iMLSB phenotypes;40(33.1%)strains carried ermC,of which 9 strains were cMLSB phenotypes and the other 31 strains were iMLSB phenotype.Only one strain of MSSA carried both ermB and ermC and showed cMLSB phenotype,which was resistant to telithromycin.The MIC of telithromycin to the MSSA of erm gene positive were significantly higher than erm negative group.Conclusion MSSA has a high antibiotic resistance rate to telithromycin in this hospital,but it's more potent than the classic macrolides erythromycin and the in-vitro sensitivity of telithromycin is closely related to whether the erm gene is carried in MSSA.The MSSA with erm gene positive and cMLSB phenotype is more likely to cause drug-resistance to telithromycin.
NETL
NSTL
万方数据
维普
