Erythromycin Resistant Genes And Conjugative Transposon In Streptococcus Pyogenes Of Children In Shanghai

Objective : To know the resistance rate to erythromycin of the Streptococcus pyogenes strains isolated in Shanghai, and the different patterns of erythromycin resistant genes in these strains, in order to provide a genetic basis for reasonable use of erythromycin.Methods: Erythromycin and clindamycin susceptibility test of the Streptococcus pyogenes strains isolated in Shanghai. The presences of ermA, ermB, mefA genes and the conjugative transposon Tn916 were determined by polymerase chain reaction amplification.Results :Ninety-eight percent of the isolates were erythromycin resistant and ninety-five percent were clindamycin resistant. The ermB gene was determined in 94% of the strains, all of which were erythromycin resistant. The mefA gene was determined in 15% of the strains, 100% of which were erythromycin resistant, while no ermA gene was detected. There were 2 strains without any of the 3 genes sensitive to erythromycin, while 3 strains showed resistance without any of the 3 genes detected. The conjugative transposon Tn916 was determined in 95% of the strains.Conclusions: There is a high resistance rate to erythromycin among the Streptococcus pyogenes strains isolated in Shanghai, and the cross resistance to clindamycin was severe, which indicated the repeated use of Macrolide-Lincosamide-Streptogramin B(MLS_B) antibiotics should be avoided in clinical work. The ermB gene is important erythromycin resistance determinants of the Streptococcus pyogenes in Shanghai. The conjugative transposon Tn916 is the important determinants of the resistance spreading of the Streptococcus pyogenes.