污水中大肠埃希菌携带第1类整合子的鉴定和特征分析

ANALYSIS OF IDENTIFICATION AND CHARACTERIZATION OF CLASS 1 INTEGRON IN E.COLI IN CONTAMINATED WATER.

目的:探讨污水中大肠埃希菌携带第1类耐药整合子的分布、特征及所含基因盒的种类。方法:常规方法分离大肠埃希菌;纸片扩散法对9种抗生素进行耐药性监测和分析;PCR鉴定1类整合子阳性株;PCR产物测序并对结果进行分析。结果:42份标本中分离出24株大肠埃希菌,为多重耐药菌株,耐药谱为氨苄西林-复方磺胺-红霉素-四环素-链霉素-庆大霉素。有3株(12.5%)鉴定出1.6 kb 1类整合子,PCR产物测序得知携带pse-1-aadA1、pse-1-aadA2、pse-1-aacA1基因盒,传递对β-内酰胺类-氨基糖苷类抗生素的耐药性。结论:1类整合子存在于污水来源的大肠埃希菌中,并携带相应的耐药基因盒,决定着对β-内酰胺类-氨基糖苷类抗生素的耐药性。

Objective： To explore the distribution and characteristic of class 1 integrons in E. coli in contaminated water, and to elucidate the status of gene-cassettes. Methods： Routine method was used to isolate E. coli; Antibiotics susceptibility was tested by the disk diffusion method; Class 1 integron was detected by PCR assay; PCR products were sequenced and analyzed. Results： 24 strains isolated from 42 samples were identified as E. coli and all strains were mutiple-drug resistant. The antibiogram was sulfamethoxazole, ampicillin, streptomycin, tetracycline, erythromycin, gentamycin. 3 of the 24 strains carried class 1 integrons whose size was 1.6kb. The sequenced PCR product demonstrated that the 1.6kb integron laboured pse-1-aadA1, pse-1- aadA2, pse-1-aacA1 gene cassettes confered the resistance of β- lactamas aminoglyocosides resistively. Conclusion： The class 1 integrons exists in E. coli in contaminated water which determines the resistance of β-lactamas aminoglycosides.