肺炎链球菌Tn1545及Tn917对大环内酯耐药性研究

Effects of transposon Tn1545 and Tn917 in Streptococcus pneumoniaeon macrolides-resistance mechanism

目的探讨儿童临床标本中分离的肺炎链球菌耐药特性及ermB基因与转座子Tn1545和Tn917的相互关系。方法采用E-test法对临床分离的102株肺炎链球菌进行8种抗菌药物的敏感性试验,用PCR扩增检测肺炎链球菌耐药基因ermB和Tn1545、Tn917基因。结果 102株临床分离的肺炎链球菌对红霉素的耐药率为80.3%,中介率为13.7%;ermB基因总检出率为95.1%,84株ermB基因阳性菌株中Tn1545的检出率为86.9%,Tn917的检出率为16.9%;其中,9.5%的ermB基因型菌株检出于Tn1545和Tn917,77.4%的ermB基因型菌株检出Tn1545,7.1%的ermB基因型菌株检出Tn917。结论肺炎链球菌主要通过ermB基因介导对大环内酯类抗菌药物的耐药性,而ermB基因则主要通过接合转座子Tn1545携带,因此,Tnl545可能在肺炎链球菌耐药基因的播散中起重要作用。

OBJECTIVE To determine the correlation between the drug resistance and ermB harboring transposon Tn1545 and Tn917 in Streptococcus pneumoniae（S.pneumoniae） from the clinical specimens of children.METHODS The antimicrobial susceptibility testing of 102 strains of S.pneumoniae to 8 antibiotics was performed by using E-test,and PCR was used to amplify the ermB gene and Tn1545 and Tn917 in the S.pneumoniae isolates.RESULTS Among all of the 102 strains of S.pneumoniae,the drug resistance rate to erythromycin was 80.3%,and the intermediate rate was 13.7%.The total detection rae of ermB genre was 95.1%.Of 84 strains of ermB-harboring strains,the detection rates of the Tn1545 and Tn917 were 86.9 % and 16.9 %,respectively.Tn1545 and Tn917 were detected in 9.5% of the ermB-positive strains,Tn1545 was detected in 77.4% of the ermB-positive strains,and Tn917 was detected in 7.1 % of the ermB-positive strains.CONCLUSION The resistance to macrolides in S.pneumoniae isolates is generally mediated via ermB gene which is mainly transported by Tn1545,thereby,the Tnl545 may play a significant role in the spread of drug resistance genes in S.pneumoniae strains.