Screening for fosfomycin resistance genes in Enterococcus faecium via high-throughput sequencing / 中华传染病杂志

ABSTRACT

Objective To screen fosfomycin-resistant genes in the clinical isolates of Enterococcus faecium Efm-HS0661 and verify their functions. MethodsAntimicrobial susceptibility and conjugation experiments were carried out to determine if the antimicrobial resistance in clinical strain was transferable.By Solexa high-throughput sequencing,the genes conferring fosfomycin resistance were screened. The function of resistance gene was identified by cloning.ResultsThe clinical isolates of Enterococcus faecium Efm-HS0661 were resistant to glycopeptide antibiotics and fosfomycin, and the fosfomycin resistance was found to be transferred by conjugation. Within the 2414 bp nucleotide sequence obtained by high-throughput sequencing, fosB, a plasmid-mediated fosfomycin resistance gene was found. The fosB gene was 420 bp in length, which shared 99. 8％ amino acid identity with other fosB from Staphylococcus spp. The minimal inhibitory concentration (MIC) of DH5α transformant containing fosB gene against fosfomycin was higher than that of DHSa transformant without fosB gene. ConclusionsThe high-throughput sequencing can be used to screen unknown resistance genes in clinical isolates. The plasmidmediated resistance gene fosB can confer fosfomycin resistance in Enterococcus faecium.