The relationship between ermB gene and transposon Tn1545 and Tn917 in erythromycin-resistant enterococcal isolates
Objective To characterize ermB gene transposition by Tn1545 and Tn917 in macrolide-re- sistant 158 enterococcal isolates in Beijing Children's Hospital.Methods Agar dilution was used to study the drug resistance to erythromycin and polymerase chain reaction was used to test ennB gene,mefA gene,Tn1545 and Tn917 of enterococcal isolates.Results Among all the 158 enterocoeeal isolates in pediatrics,MIC_(50) and MIC_(90) of erythromycin were same as 256μg/ml.The total ermB gene carriage rate is 70.7%,the ermB gene in E.faecalis,E.faecium,E.durans,E.avium and E.hirae accounted for 78.3%,58.1%,100%, 100%,100%,respectively.The ennB gene carriage rate in E.faecalis was higher than that in E.faecium. There was no mefA gene in E.faecalis,only one E.faecium was positive for mefA gene.The ermB gene existed only in Ta1545 was 40.6%,the ermB gene existed only in Tn917 was 0.9%.The ermB gene existed in Ta1545 and Tn917 was 46.2%.Conclusion Resistance to erythromyein in enterococcal isolates in Beijiag Children's Hospital was generally mediated via ermB gene,which was mainly transported by Tn1545 in resistance to macroli- de in enterococcal isolates.