Mechanism of Resistance Against Erythromycin in Streptococcus Egui

摘要

Streptococcus egui was screened for resistance against erythromycin by the disk diffusion . It showed constitutive resistance to erythromycin (cMLS phenotype). The minimum inhibitory concentration (MIC) was determined by broth microdilution. The MIC against erythromycin was determined, MIC >64 μg/ml. The ermb and the mefA/E gene were amplified by PCR assay. It was positive for the ermb gene, but negative for the mefA/E gene. A 639bp fragment of the ermb genes of Streptococcus egui was sequenced and compared with ermb genes of Streptococcus gallolyticus and Staphylococcus intermedius. A 99. 8% identity was found among them. This study demonstrated that resistance mechanism against erythromycin in Streptococcus egui was mediated by ribosome methylation, which encoded by the ermb gene.