Isolation And Identification Of Quail-derived Escherichia Coli And Detection Of Resistance Genes And Virulence Genes

In recent years,the quail breeding industry in Chongqing,Meishan,Chengdu and other places has continued to develop.In the process of gradual transformation of breeding methods to large-scale and intensified breeding,the phenomenon of death of quail infected with E.coli still often occurs.After investigating the cause,it was found that E.coli infection is one of the main causes of quail disease.In order to prevent and treat animal diseases,promote the rapid growth of animals,and improve economic benefits,a large number of antibiotics are used in the breeding process,which makes a large number of resistant strains of E.coli have been produced,which has brought some difficulties to the prevention and treatment of this disease.Monitoring and analysis of pathogenicity is particularly important.In this study,quail-derived E.coli from Chongqing,Meishan,Chengdu and other places were cultured and isolated by using MAC and EMB media,and then morphological identification and specific PCR identification were carried out.From 2018 to 2019,it was collected from Chongqing City and Meishan City.72 strains of E.coli were isolated from120 dead quails collected in Chengdu.The KB disc method was used to detect the resistance of the isolated bacteria.The results showed that the resistance rate of 72quail-derived E.coli to 20 antibacterial drugs ranged from 27.78% to 100%,and to penicillin,oxacillin,ampicillin,and cephalexin.,Ceftazolin,cefuroxime,ceftazidime,and tetracycline are highly resistant,with a resistance rate of 100%;to piperacillin,cefradine,ciprofloxacin,amikacin,neomycin,kanamycin,Gentamicin,minocycline,compound trimethoprim,polymyxin B resistance rate is more than 50%;resistance to norfloxacin and ofloxacin is low,the resistance rate is lower 50%.The 72 isolates of quail-derived E.coli were further tested for their drug resistance and virulence genes.In Chongqing,Meishan,Chengdu and other places,TEM,OXA,qnr D,qnr S,oqx A,oqx B,arm A 14 drug resistance genes,such as tet A,tet B,tet C,sul1,sul2,sul3,and flo R have detection rates of 26.39%(19/72),12.5%(9/72),45.83%(33/72),44.44%(32/72),19.44%(14/72),16.67(12/72),16.67%(12/72),100%(72/72),27.78%(20/72),9.72%(7/72),23.61%(17/72),48.61%(35/72),29.17%(21/72),75%(54/72),among which tet A and flo R genes have the highest detection rate;quail in various places Seven virulence genes,including STa,STb,ast A,stx1,eae,irp2,and aaf A were detected in the source E.coli,and the detection rates were 44.44%(32/72),13.89%(10/72),6.94%(5/72),100%,15.28%(11/72),45.83%(33/72),18.06%(13/72),of which the stx1 gene has a100% detection rate in Chongqing,Meishan,Chengdu and other regions.This experiment has isolated quail-derived E.coli in Chongqing,Meishan,Chengdu and other places,and studied its carrying resistance genes and virulence genes.It is of great significance to epidemiological research and provides important research for the prevention and control of bacterial diseases in the future.The theoretical basis also helps to improve public health safety.