The Study Of Resistance And Growth Characteristics Of Escherichia Coli Isolated From Food In Part Of North Xinjiang

Objective: In recent years, there were more and more reports about antibiotic resistance in bacteria and a large number of study about resistant genes in Escherichia coli of bacteria toantimicrobial resistance. Along with the rising of bacteria to antibiotic resistance, the infection of drug-resistant bacteria brought more challenges to human disease prevention and food hygiene. Monitoring the local E.coli contamination of food, drug resistance of bacteria and the simulation E.coli growth in food, the experiment data provided theoretical basis for control of multi-drug resistance Escherichia coli, predictive and control of Escherichia coli growth in food, formulate hygiene measures and establishment of good food safety management system.Methods: This study collected parts of northern Xinjiang in various food samples and monitored the growth characteristics of the isolated Escherichia coli. In view of the contamination of E.coli from food in northern Xinjiang were investigated preliminarily. The multi-drug resistance and drug sensitive Escherchia coli from different food were taken as the research object in this article, the growth models of the strains in meat and stewed chicken leg were simulated and studied the viability in vitro simulated gastrointestinal tract environment.Results: 1. A total of 56 Escherichia coli isolates recovered from 238 samples of retail meats and ready-to-eat food purchased at different supermarkets in North Xinjiang were examined in this study. 23.95% of the samples were contaminated by Escherichia coli. The Escherichia coli from pork separation rate was the highest, followed by the mutton, beef and chicken. Ready-to-eat food, fish and vegetable for Escherichia coli separation rate was lower. A total of 4 test samples of cold fresh shrimp, the isolation rate was zero.2. The result showed that the 56 isolates were most resistent to Tetracycline at 66.07%, followed by Ampicillin at 50.00%, Compound sulfamethoxazole at 48.21%, Ceftazidime and Amoxicillin at 42.86%, Nalidixic acid at 33.93%, Piperacillin and Chloramphenicol at 32.14%, Cefotaxime at 17.86%, Streptomycin at 16.07%, Ciprofloxacin and Erythromycin at 14.29%, Gentamicin at 10.71%, Amikacin at 8.93%, levofloxacin at 7.14%, polymyxin B at 1.79%. All of the subjects of Escherichia coli was sensitive to Imipenem, resistant rate and intermediary rate was zero. 3. Part of cross resistance rate was 100%, such as the cross resistance rate of Amoxicillin, Tetracycline, Nalidixic acid, Compound sulfamethoxazole to levofloxacin. The effection rate of Polymyxin B to the rest of antibiotics was the lowest, only was 0~10.00%. The drug resistance rate between each other antibiotics was not the same.4. The 56 isolates of Tet A、Tet B、Tet C、Bla OXA、Bla TEM、Bla PSE、flo R、Sul1、Sul2、add A1a、add B、Str A and Str B genes of the positive detection rate were 42.86%、14.28%、0、23.21%、28.57%、0、21.43%、10.71%、25.00%、12.50%、10.71%、35.71% and 25.00%. The test strains E6 and E28 carried 7 kinds of resistance genes at the same time, most of test strains only carried one resistance gene. Six strains of tested strains not detected any resistance gene. 5. The results showed that the modified Gompertz and Logistic models can well simulate the growth parameters of two strains in beef. The lag phase of drug-sensitive E.coli was shorter than lag phase of drug-resistance strain. And the modified Gompertz can well simulate the growth parameters of the sensitive strain in stewed chicken leg in different temperature. 6. The number of survival bacteria of Escherichia coli in artificial gastrointestinal fluid were gradually decreased. The tolerance was good for E.coli E13 in vitro gastrointestinal juice. And the tolerance was not high for E.coli E12 in vitro gastrointestinal juice. The decreasing trend of sensitive bacteria E13 was slower than multi-drug resistant bacteria E12.Conclusion: According to the results of this study, The contamination rate of E.coli from retail meats in parts of northern Xinjiang wsa higher and we shouldn’t be underestimated. The development direction was multi-drug resistance. The use of antibiotics in the various aspects of the act should be a wake-up call, the strain grew well in the artificial environment, visible to the meat food safety should be paid more attention.