Identification of ribosomal RNA methyltranferase gene ermf in Riemerella anatipestifer.

We report for the first time the identification of a macrolide resistance mechanism in R. anatipestifer that is mediated by the ribosomal RNA methyltransferase ermF. We identified the presence of the ermF gene in 64/206 (31%) R. anatipestifer isolates from different regions in China. An ermF deletion strain was constructed to investigate the function of the ermF gene on the resistance to high-levels of macrolides. The ermF mutant strain showed significantly decreased resistance to macrolide and lincosamide, exhibiting 1024-, 1024-, 4-, and >2048-fold reduction in the minimum inhibitory concentrations for erythromycin, azithromycin, tylosin, and lincomycin, respectively. Furthermore, functional analysis of ermF expression in E.coli XL1-blue showed that R. anatipestifer ermF gene was functional in E.coli XL1-blue and conferred resistance to high-levels of erythromycin (100 µg/ml), supporting the hypothesis that the ermF gene is associated with high-level macrolide resistance. Our work suggests that ribosomal RNA modification mediated by the ermF methyltransferase is the predominant mechanism of resistance to erythromycin in R. anatipestifer isolates.
PMID: 25690020 [PubMed - as supplied by publisher]

Source: Avian Pathology - February 18, 2015 Category: Pathology Authors: Luo H, Liu M, Wang L, Zhou W, Wang M, Cheng A, Jia R, Chen S, Sun K, Yang Q, Chen X, Zhu D Tags: Avian Pathol Source Type: research