Resistance detection and macrolide antibiotic-resistant mechanism of Streptococcus pneumoniae isolates / 中国人兽共患病学报

ABSTRACT

In order to understand the resistance against common antibiotics in clinic and macrolide antibiotic-resistant mechanism of Streptococcus pneumoniae (S.pneumoniae) isolates in Zhejiang area,both K-B slip method and E-test were applied to determine the sensitivity of 138 S.pneumoniae isolates to nine antibiotics,and the ermB and mefE genes in those isolates which associated with macrolide antibiotics-resistance closely were detected by PCR.Subsequently,correlation among ermB and mefE genes and the erythromycin resistance were analyzed.For these 138 S.pneumoniae isolates,93.5% (129/138) of the strains were resistant to erythromycin,but only 2.9%～4.3% strains were resistant to cefotaxim,cefuroxime,amoxicillin and levofloxacin.The positive rate of ermB gene in the isolates (91.3%,126/138) was significantly higher than that of mefE gene (33.3%,46/138) (P<0.05).Both of these two genes existed in 27.5 % (38/138) of the strains and all of the strains without ermB and mefE genes were sensitive to erythromycin.The erythromycin resistance rate (62.5%) of mefE gene positive strains was remarkably lower than that of the mefE&ermB gene positive strains (100%) and the ermB gene positive strains (97.7%) (P<0.05).All the data mentioned above demonstrated that erythromycin is not an appropriate antibiotic to treat the infectious diseases caused by S.pneumoniae.Moreover,ermB is the predominant erythromycin resistance gene in S.pneumoniae isolates and ermB gene could inspire stronger erythromycin resistance than mefE gene.