Macrolide resistance phenotype and resistance gene to streptococcus pneumoniae

Objective To investigate the prevalence of erythromycin resistance gene and the relationship of drug resistance and gene in streptococcus pneumoniae.Methods Antibiotic susceptibility was determined by E-test or K-B disk diffusion method for 42streptococcus pneumoniae isolates.Macrolide resistance phenotypes were identified using double disc test with erythromycin and clindamycin discs.The ermB,mefAand mefE genes were amplified by PCR.Results The prevalence of resistance genes was:ermB,95.2%;mefE,26.1%;mefA,0%;The most common macrolide-resistant phenotype was cMLSB(95.2%),which and ermB(+) mefE(-)and ermB(+)mefE(+)genotypes.About 4.8% was M phenotype,which had ermB(-)mefE(+)pattern.Conclusion The ermB-mediated cMLSBis the most prevalent phenotype among erythromycin-resistant streptococcus pneumoniae isolates.Obviously the erythromycin is not useful in treating streptococcus pneumoniae infection.