Study on Integron in 59 Strains of Escherichia Coli

OBJECTIVE: To investigate the classification, structure and inducing drug resistance of integron in 59 strains of cefoxitin-resistant Escherichia coli. METHODS: PCR method was used to detect integrase gene (intI) and product of variable region of positive strain was performed on sequencing. Sensitiveness of experimental strains to 22 kinds of antibiotics was detected with microdilution method. RESULTS: IntI1 was identified in 45 strains (76%) of the 59 strains Escherichia coli. The most drug resistance genes cassettes were aadA5 and dfr17,only 2 strains encoding β-lactamase drug resistance gene cassettes. The MIC of integron positive groups was statistically significantly higher than negative groups. CONCLUSION: Class 1 integron resided in cefoxitin-resistant Escherichia coli widely. The cause of drug resistance of integron positive strain to aminoglycosides, sulfonamides and chloramphenicol is drug resistance gene cassettes. Gene cassettes does not play important role in integron-mediated drug resistance.