Phenotype and Genotype of SXT-resistance in Escherichia coli Isolates from Old Patients / 中华医院感染学杂志

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.