Ciprofloxacin MIC was tested by the disc diffusion method in 25 Escherichia coli isolated from diseased livestock and fowl.There were 15 susceptible and intermediate(MIC≤1.0 mg/L) and 10 resistant(MIC≥32 mg/L) isola...Ciprofloxacin MIC was tested by the disc diffusion method in 25 Escherichia coli isolated from diseased livestock and fowl.There were 15 susceptible and intermediate(MIC≤1.0 mg/L) and 10 resistant(MIC≥32 mg/L) isolates.The expressing level of AcrA(an obligatory component of the AcrAB multidrug efflux system) was determined by Western-blotting,and gene mutations in gyrA and parC were determined by PCR.The results showed that the expression of AcrA protein was exceeded 170% and had gene mutations in gyrA and parC in 9 of 10 clinical isolates of Escherichia coli with high-level ciprofloxacin resistance but not in any of the 15 isolates for which the MIC was less than 1.0 mg/L.These results suggested that Topoisomerase and AcrAB efflux pump mediated high-level fluoroquinolone-resistance in Escherichia coli.展开更多
文摘Ciprofloxacin MIC was tested by the disc diffusion method in 25 Escherichia coli isolated from diseased livestock and fowl.There were 15 susceptible and intermediate(MIC≤1.0 mg/L) and 10 resistant(MIC≥32 mg/L) isolates.The expressing level of AcrA(an obligatory component of the AcrAB multidrug efflux system) was determined by Western-blotting,and gene mutations in gyrA and parC were determined by PCR.The results showed that the expression of AcrA protein was exceeded 170% and had gene mutations in gyrA and parC in 9 of 10 clinical isolates of Escherichia coli with high-level ciprofloxacin resistance but not in any of the 15 isolates for which the MIC was less than 1.0 mg/L.These results suggested that Topoisomerase and AcrAB efflux pump mediated high-level fluoroquinolone-resistance in Escherichia coli.
