| Escherichia coli(escherichia coli)is a kind of conditioned pathogenic bacterium,which can cause escherichia coli infection and escherichia coli disease when the flora in human or animals is out of balance or the immunity is low.Ningxia and Qinghai are the two major breeding provinces of cattle and sheep in China.Drug resistance monitoring and epidemiological investigation of drug resistance genes of escherichia coli from sheep are helpful to understand the epidemic situation and transmission mechanism of drug resistance.escherichia coli was isolated and identified by means of McConkey,ebonite blue,biochemical identification and polymerase chain reaction(PCR).MIC assay of 4antimicrobial agents was performed on 320 strains of escherichia coli.The drug resistance of48 strains with drug resistance phenotypes to 4-lactam drugs was tested by paper susceptibility test.The-lactamase gene was detected and analyzed by polymerase chain reaction(PCR).Strains with high MIC resistance of-lactam drugs were selected for conjugation experiment in order to preliminarily explore the prevalence and transmission mechanism of drug-resistant genes in escherichia coli.The results are as follows:(1)The study showed that from April 2018 to December 2018,tissues,swabs and feces of sheep in parts of Ningxia and Qinghai were collected,and escherichia coli was cultured,isolated and purified.A total of 320 escherichia coli strains were isolated and identified by various means,including 210 strains from Ningxia and 110 strains from Qinghai,with a separation rate of 65.43%;(2)the MIC test results showed that the drug resistance rates of ampicillin(AMP),cefaladine(CAZ),gentamicin(GEN),and grandamycin(SPT)were 30.93%,4.37%,15.62%,and 9.68% respectively.Of 48 strains with drug-resistant strains of phenotypic four beta lactam drugs resistance,the results show that,the highest percentages of ampicillin(AMP),52.08%,cefepime(AML),he totally to amoxicillin(CAZ)resistant rate of 29.17%,14.58%,is sensitive to beauty e.faecalis 100%,33.33% of multiple drug-resistant strains;(3)the detection results of ESBLs and AmpC resistance genes of-lactamase showed that the detection rate of TEM was the highest,reaching 40.00%.The detection rates of ctx-m,OXA,CIT,ACC and EBC were 15.00%,7.19%,13.44%,9.69% and 13.44%,respectively.SHV,DHA,MOX and FOX were not detected.(4)99 strains with amexicillin resistance phenotype were selected for the conjugation test,and 53 strains successfully conjugated,with the conjugation rate up to 53.53%.To sum up,this research part of ningxia,qinghai regional separation to sheep source320 strains of e.coli,the separation rate was 65.43%,320 strains of isolates,the highest percentages of ampicillin,at 30.93%,is sensitive to beauty e.faecalis 100%,beta lactam enzymes resistance gene detection rate for TEM(40%),CTX-M(15.00%),OXA(7.19%),CIT(13.44%)and ACC(9.69%),EBC type(13.44%),The zygotes of 53 strains with the same or similar MIC and-lactam resistance genotypes were successfully obtained.The isolation rate,drug resistance and prevalence of-lactam resistant genes of sheep escherichia coli in these two regions were obtained,providing data for clinical rational drug use and research on the epidemic and transmission mechanism of-lactam resistant genes. |
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