Studies On Persistence Of E.coli To Enrofloxacin

Resistance to antibiotic is inevitable for bacterium, we can know the resistance tendency of bacterium in time by testing drug sensitivity of pathogenic from clinical, it can supply theory support to product new antibiotic by researching drug resistance mechanism.This study tested the drug sensitivity of pathogenic from Shandong Province, researched the resistance mechanism of E.coli to enrofloxacin, created slope plate which can measuermen MPC quickly, reaserched the peresistance mechanism of E.coli to enrofloxacin.We tested drug sensitivity of E. coli from pigs and poultries in Shandong Province by large flux drug susceptibility test kit. The results indicated:Bacterium present high multi-resistance in Shandong Province, the ratio of multi-resistance is more than 90%, the drug resistance of E.coli from poultries is higher than pigs obviously.Researched the effect of enrofloxacin on gene expression of E.coli by gene array and RT-PCR. The results showed:(1)519 genes of E.coli appeared difference affected by enrofloxacin compared with the control group. Efflux pump gene expressed higher; outer membrane protein gene expressed decrease sharp; the target enzyme of enrofloxacin gene parC expressed higher. It illustrated the physiology of E.coli changed extensive and complicated. (2)The target enzyme of test group did not mutant, it illustrated low persistence was not caused of mutation.Experiment results indicated the drug resistance is high of bacterium in Shandong Province, E.coli can adapt low antibiotic pressure by physiologic change and genes expression change, called persistence, can adapt high antibiotic pressure by gene mutantion, called resistance.