Isolation,Identification And Drug Sensitivity Of Escherichia Coli In Piglets In Chengde Area Of Hebei

Pathogenic Escherichia coli is an important cause of piglet diarrhea,and E.coli serotypes are very different in the different regions.Also,different isolates also have significant differences in drug resistance.Therefore,the isolation and identification of E.coli around a specific area,virulence factor detection and drug sensitivity analysis have important guiding significance for the control of E.coli infection.In this study,E.coli infection in piglets was investigated in some pig farms of Chengde,Hebei Province.A total of 564 suspected E.coli infected piglets in Chengde County,Xinglong County and Pingquan County were selected from June 2014 to June 2016,and 200 anal swab samples and 20 samples of contents of the duodenum were collected.Then E.coli..was isolated and identified.The results showed that 140 strains of E.coli were obtained,of which 109 strains were definite for O serotypes,accounting for 77.8%of the isolates;O serotypes of 31 strains were unidentified,accounting for 22.2%.According to the analysis of O serotypes,0101,020,0149 and 0107 were the main serotypes.The highest proportion was 0101,and the number of detected isolates was 27,accounting for 24.8%of the total strain.The rest were 020,0149 and 0107,accounting for 17.4%,14.7%and 8.2%of the total strain,respectively.The results of virulence genes showed that fimbriae F4,F18(fedA),heat stable enterotoxin a(sta),heat stable enterotoxin b(sib),enteroaggregative heat-stable enterotoxins(astA),intimin(eaeA),shiga toxin 2e(stx2e)and resistance factor sepA,The number of strains bearing astA and eaeA was relatively high,accounting for 57.14%and 54.28%of the total isolates,followed by stx2e,accounting for 42.86%;sta accounted for 31.43%.The detection rate of sib was relatively low,accounting for 18.57%.The resistances of 140 strains of E.coli to penicillin,rifampicin and clarithromycin were found to be 100%resistant.Then the bacterial resistances to ampicillin(AMP),carbenicillin(CB),chloramphenicol(CL),amoxicillin(AMX),ciprofloxacin(CIP),kanamycin(KAN),gentamicin(GM),tobramycin(TOB),amikacin(AN),cephalexin(CEL)and cefradine(RAD)were follwed.It can be found that the E.coli isolates were highly resistant to most of antibiotics,while the resistance to RAD was relatively low,only 10.71%.The results showed that the most resistant type was 11 resistant(17.86%),followed by 10 resistant(15.71%).The rests were 9 resistant(11.44%),8(11.44%),(10.00%),4(7.85%),5(7.14%),6(6.42%),(3.57%),3(3.57%),13(2.86%)and 14(2.14%).In this study,the epidemiological investigation of E.coli infection in the Chengde area and the drug susceptibility analysis of the bacterial strains were systematically performed,and the main causes of piglet diarrhea were analyzed.This study will lay the foundation for prevention and control of piglet colibacillosis in Chengde area.