| The aim of this study was to understand the resistance to antibacterial drugs and the carrying of resistance genes of E.coli strains derived from pigs in different growth stage in Aksu region of Xinjiang.To compare the resistance of E.coli.from different growing period to antibiotics,analyze the epidemic characteristics of resistance genes and their contribution to resistance phenotype.A total of 443 strains of E coli were isolated and identified from pigs in different growth stages(97 from lactating sows,124 from lactating piglets,110 from pregnant sows,33 from reserve pigs,and 79 from nursery pigs)in Aksu.The minimum inhibitory concentrations(MIC)of E.coli were determined by agar dilution method to six kinds of 13 antimicrobial drugs.The resistance 13 genes were detected by PCR.The results of drugs sensitivity test showed that:(1)The resistance rate of pigs-derived E.coli to the 8 antibacterial drugs tested was over 70.0%,among which the resistance rate to enrofloxacin,streptomycin,spectinomycin,chlortetracycline and oxytetracycline were as high as 90.0%,has a good sensitivity to amikacin,apramycin,ceftiofur,polymyxin E,the resistance rate does not exceed 25.0%;the multidrug resistance test results revealed that the resistance strains were mainly resistant to 7?9 drugs,accounting for 63.6%,a total of 41 drug resistance profiles.(2)the resistance rates of E.coli from different growing period were as follows:conservation pigs>pregnant sows>lactating piglets>lactating sows>reserve pigs.The resistance rate of pregnant sows to ampamycin were significantly higher than that of other growing period.The resistance rate of lactating piglets to gentamicin were higher than that of lactating sows.The resistance rate of conservation pigs to ciprofloxacin,norfloxacin and enrofloxacin were higher than that of lactating sows The rate was higher than that of reserve pigs;The results of multidrug resistance in different growing periods showed that:the resistance strains were mainly resistant to 9 drugs in suckling piglets(29.8%),pregnant sows(32.7%)and nursery pigs(54.4%),7 drugs(26.8%)in lactating sows and 6 drugs(30.3%)in reserve pigs.The results of drug resistance genes test showed that:(1)E.coli derived from swine in Aksu region mainly carried resistance genes of floR(66.4%),ant(3")-Ia(66.4%)and blaTEM(71.1%),and the coexistence type of floR+ant(3 ")-Ia+blaTEM genes were dominant;(2)The detection rates of floR,ant(3")-Ia and blaTEM were higher than 50.0%in E.coli of different growth stages,and that of ant(3")-Ia in reserve pigs were higher than that of other growth stages.Only qnrD gene was detected in pregnant pigs and nursery pigs,but no tetK gene,mcr-1 gene and blaOXA gene were detected in E.coli of different growth stages.Conclusion:the multi drug resistant strains of E,coli from pigs in different growth stages are very popular in Aksu area,Xinjiang,and the drug resistance spectrum shows diversified development.From the analysis of drug resistance phenotype and genotype,it was found that the main reason for drug resistance of the isolates was to carry antibiotic related drug resistance genes,which suggested that scientific feeding should be carried out,and the results of drug sensitivity test could be used to guide the clinical rational use of drugs. |
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