| Colibacillosis is an intestinal infectious disease caused by pathogenic Escherichia coli and its toxins,which is explosive and has a high fatality rate.It is the most common and frequent in rabbit breeding.Rabbits are important industrial animals in Shandong Province.Due to the complex serotype of Escherichia coli,regional and diverse distribution,vaccine is difficult to be widely used,prevention and control is difficult,and the treatment of diseased rabbits mainly depends on antibiotics.However,with the widespread emergence and spread of drug resistance in recent years,the sensitivity of pathogenic bacteria to antibiotics has gradually decreased,the therapeutic effect is not good,and there are fewer and fewer sensitive drugs to treat the disease in clinic.Rabbit colibacillosis has gradually become one of the main diseases seriously harmful to the rabbit breeding industry.Isolating pathogenic strains from diseased rabbits and screening sensitive specific drugs for the treatment of rabbit colibacillosis through drug sensitivity test is the most effective way to control death and reduce economic losses.The sensitivity and drug resistance of pathogenic Escherichia coli isolated from rabbit farms in different areas were different to different antibiotics.Therefore,through the data of drug resistance phenotypes and drug resistance genotypes in different regions,we can not only understand the situation of drug resistance in rabbit farms in different regions and grasp the information of drug resistance in time,but also for the selection of clinical drug use and real-time monitoring of drug resistance in rabbits.It is of great practical significance to reduce economic loss and multiple drug resistance.In this study,anal swab samples of diarrhea rabbits were collected from 7 large-scale rabbit farms in Chiping,Mengyin,Taian,Zhucheng and Laiwu,Shandong Province.The rabbit intestinal pathogenic Escherichia coli(REPEC)causing diarrhea in rabbits was screened by Escherichia coli isolation and culture,specific PCR and microbiological mass spectrum identification,virulence gene detection and so on.The drug sensitivity test of 15 kinds of antibiotics commonly used in clinic was carried out by Kmurb disk diffusion method recommended by WHO to screen the sensitive drugs in different areas,and 11 kinds of drug resistance genes with high carrying rate of Escherichia coli were detected.Combined with the characteristics of drug resistance phenotype and drug resistance genotypes,the phenomena of drug resistance and multiple drug resistance in different areas were analyzed,so as to provide reference data for the scientific use of drugs in rabbits.In this study,123 strains of rabbit-derived Escherichia coli were isolated from 152 anal swab samples of rabbits with diarrhea.53 strains of rabbit intestinal pathogenic Escherichia coli(REPEC)carrying eae A virulence gene were screened,including 11 strains of Chiping,8strains of Mengyin,15 strains of Taian and 19 strains of Zhucheng.The results of drug sensitivity showed that the sensitivity of REPEC isolated from different areas to common antibiotics was different.The sensitive rates of pathogenic Escherichia coli isolated from Taian rabbits to gentamicin and sulfamethoxazole were 93.33% and 73.33% respectively.The pathogenic strains of Zhucheng rabbit farm maintained high sensitivity to most drugs,and the sensitivity to florfenicol,ciprofloxacin and enrofloxacin was as high as 100%.The sensitive rate to gentamicin,kanamycin,doxycycline and chloramphenicol was more than 80%;the pathogenic strain of Mengyin rabbit farm was more sensitive to compound sulfamethoxazole and ciprofloxacin,and the sensitive rate was more than 70%.However,the strains isolated from Chiping rabbit farm were not sensitive to most antibiotics.The resistance rates of 53 strains of pathogenic Escherichia coli to penicillin and bacitracin were 100%,and to streptomycin,tetracycline and ampicillin were more than 60%.The resistance rates to gentamicin,enrofloxacin,sulfamethoxazole,chloramphenicol,amoxicillin and sulfamethoxazole were between 30.19% and 45.28%.The drug resistance spectrum of pathogenic bacteria showed that 42 of 53 strains of pathogenic Escherichia coli were multiple drug resistant strains,accounting for 79.25%.The types of drug resistance were3 kinds of drugs(15.09%),5 kinds of drugs(15.09%)and 11 kinds of drugs(11.32%),and concentrated among 2 to 6 kinds of drugs and 11 to 12 kinds of drugs.There were significant differences in the distribution of multiple drug-resistant strains among rabbit farms in different areas.The phenomenon of multiple drug resistance of pathogenic strains in Chiping and Mengyin rabbit farms was the most prominent,with wide drug resistance spectrum and serious drug resistance,while the spectrum of isolated strains from Zhucheng rabbit farm was narrow.The phenomenon of drug resistance is mild.Drug resistance genes of 53 strains of pathogenic Escherichia coli were detected,and eight drug resistance genes including bla TEM,tet A,tet B,qnr S,sul1,sul2,sul3 and aac(6')-Ib-cr were detected,and the detection rates were 66.04%,56.60%,62.26%,26.42%,35.85%,37.74% and 28.30%,respectively,but no bla PSE,bla SHV and bla CTX-M resistance genes were detected.45 strains detected drug resistance genes,accounting for 84.91%.Most strains carried 1 to 7 kinds of drug resistance genes,the proportion of 3 kinds of drug resistance genes was the highest,and 8 strains were not detected.There were great differences in the type and number of drug resistance genes detected in rabbit farms in different areas.Most of the isolates from Chiping and Mengyin rabbit farms carried 6 to 8 drug resistance genes,while most of Taian and Zhucheng rabbit farms carried 1 to 5 drug resistance genes.To sum up,there is a certain correlation between drug resistance phenotype and drug resistance genotype.In the rabbit farms with serious drug resistance,there are few sensitive drugs,high drug resistance rate,wide drug resistance spectrum and high detection rate of drug resistance genes,while in the rabbit farms with mild drug resistance,the isolates have high sensitivity to drugs,low drug resistance rate,narrow drug resistance spectrum and low detection rate of drug resistance genes.In this study,we screened the sensitive drugs of REPEC isolated from some areas of Shandong,and understood the sensitivity and resistance characteristics of REPEC isolates from rabbit farms in different areas by drug-resistant phenotype and drug-resistant genotype,which provided corresponding reference data for the clinical treatment of rabbit colibacillosis. |
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