Experimental study of multidrug-resistant genes transferred horizontally in Escherichia coli

Objective To investigate antibiotic resistance of Escherichia coli in ICU,and the mechanism of multidrug-resistant genes transferred horizontally between clinical Escherichia coli and Rifampicin-resistant Escherichia coli.Methods Antibiotic resistance test was used by method of K-B.Extended-spectrum β-lactamase(ESBLs)-producing strains among clinical isolates of ICU Escherichia coli,and antibiotic resistance transferability were analyzed by conjugation experiments.Donator strains were ESBLs positive strains of Escherichia coli,Rifampicin-resistant Escherichia coli were receptors.The presence of class Ⅰ integron and TEM gene among bacterium examined by PCR.Results The positive rate of ESBLs-producing isolates in Escherichia coli was 46.7%.All conjugation strains could be obtained large plasmids(23 kb or 25 kb) after mixed culturing,but no small plasmids.Class Ⅰ integrons were distributed in donator strains and conjugation strains.Conclusions Escherichia coli had high drug resistance to several antibiotics and had multi-resistance.Drug resistance gene transfer by conjugation experiments to sensitive bacteria.