【摘要】 目的了解老年患者大肠埃希菌分离株对复方新诺明(SXT)耐药相关基因的流行状况及与耐药表型的关系。方法对20株大肠埃希菌进行耐药性分析,采用PCR法对SXT耐药相关基因(sul1、dfrA1、dfrA12和dfrA17)检则,扩增产物纯化后,基因测序分析。结果20株大肠埃希菌中,SXT耐药19株(95.0%),3种基因sul1、dfrA12和dfrA17阳性率分别为80.0%、20.0%和65.0%,dfrA1基因为阴性,有17株检出dfrA基因(85.0%),共有18株检出sul1和(或)dfrA基因(90.0%)。结论大肠埃希菌中dfrA基因和sul1基因同时表达或单独表达均可导致SXT耐药,在大肠埃希菌检出sul1、dfrA12和dfrA17基因均为国内首次报道。更多还原

【Abstract】 OBJECTIVE To investigate the prevalence of sulfamethoxazole/trimethoprim(SXT)-resistance genes and drug resistance in Escherichia coli isolates from the old patients.METHODS Drug resistance of 20 E.coli strains were analyzed.The SXT-resistance genes(sul1,dfrA1,dfrA12 and dfrA17)were detected by polymerase chain reaction(PCR).The PCR products were purified and sequenced.RESULTS In 20 E.coli strains,95.0% were SXT resistant.The positive rate of genes of sul1,dfrA12 and dfrA17 were 80.0%,20.0% and 65.0%.Gene of dfrA1 was not detected out,17 strains of E.coli were found dfrA gene.The SXT-resistance gene dfrA or sul1 was detected in 18 of the 20 strains.CONCLUSIONS The SXT resistance of E.coli can be caused mainly by gene expression of dfrA and sul1,and the genes of sul1,dfrA12 and dfrA17 are all firstly found and reported in China.更多还原