Detection And Analysis Of Drug Resistance Genes Among Escherichia Coli Isolated From Companion Animals In Yangzhou Area

Escherichia coli(E.coli)is one of the most common zoonotic disease pathogen,which causes serious damage to human health and animal husbandry.Antibacterial drugs exhibit an important role in control the infection.Emergence of antibiotic resistance of E.coli has become an increasing problem worldwide.With the development of resistance,the effects of antibacterial durgs were challenged,what’s worse,as the drug resistance genes can horizontally spread between humans and animals through frequently contact between humans and animals,the resistance may affect the public health security.In order to explore the prevalence of resistance in E.coli isolated from companion animals,the main resistance genes of Escherichia coli in Yangzhou area were investigated and the spread mechanism of florfenicol floR gene was analyzed,aiming at providing a theoretical basis for the control of drug resistance spreading via E.coli from companion animals.226 E.coli were isolated from companion animals.The susceptibilities of 226 E.coli from companion animals to 7 categories of antimicrobials((fluoro)quinolones,aminoglycosides,β-lactams,sulfanilamide,tetracyclines and chloramphenicol)were determined by agar dilution method.For aminoglycoside,The resistance rate to streptomycin was 35.84%,followed by gentamicin 28.32%,amikacin 6.19%;for(3-lactam,the resistance rate to ampicillin was 72.12%,followed by amoxicillin 59.73%,Cefacizime 48.23%,ceftriaxone 44.25%,ceftiofur 21.68%.No isolate was resistance to meropenem.The resistance rate to fluoroquinolones(enrofloxacin),colistin,was 21.68%and 23.45%respectively;for tetracyclines,the resistance rate to tetracycline was 64.60%,doxycycline 36.73%;for amide alcohol,the resistance rate to florfenicol was 59.29%,chloramphenicol 32.30%,fosfomycin only 4.42%.the rate of multiple drug resistance is very serious as high as to 87.5%.Among them,the rate of resistance to four kinds of drugs or seven drugs were account for 12.83%respectively;while 2 strains were resistant to 13 kinds of drugs.Aminoglycosides,β-lactam,fluoroquinolones and florfenicol floR resistance genes were detected by PCRs.The detection rates are as follows:aminoglycoside 31.42%,(3-lactam 94.69%,fluoroquinolones 8.8%,florfenicol floR 74.34%.Among them,the rate of β-lactam resistance gene is the highest.By comparing the compliance rate between the drug resistant phenotype and resistance genotype of E.coli,the drug resistance genotype and drug resistance phenotype are not completely consistent,suggesting that there may exist other resistance mechanisms.The conjunction tests of 168 strains carrying floR gene showed that the conjunction rate was 58.33%.The drug sensitivity test find that the MIC value of the 98-conjugate to florfenicol is higher than that of the receptor,but lower than that of the donor.Moreover,the MIC of the conjugate to other drugs is also changed.Preliminary explorations find that florfenicol has co-delivery effect with other common drug resistance,but its propagation mechanism needs to be further explored.