| Racing pigeons,as specific breeding birds for competition,have a wide range of activities and cross trajectories between different groups,so they are also one of the vectors for cross-regional transmission of bacterial resistance.E.coli and Enterococcus are the main commensal bacteria in the digestive tract of racing pigeons,and they are also reservoirs of many drug resistance genes,which can be used as indicators of bacterial resistance,but there are few relevant studies,and the resistance to antibiotics commonly used in racing pigeons is still unclear,so the investigation of drug resistance in E.coli and Enterococcus in racing pigeons has important public health significance in both veterinary and human medicine.In this study,E.coli and Enterococcus were isolated from fresh pigeon faeces collected from some pigeon lofts in Chengdu and tested for resistance to common antibiotics and resistance genes in pigeon lofts,and the following results were obtained.1.196 fresh pigeon faecal samples were collected from 6 racing pigeon lofts in Qingbaijiang and Shuangliu districts of Chengdu.After selecting the culture medium,microscopic examination,16S rRNA gene amplification and sequencing,179 E.coli strains(91.32% isolation rate)and 151 Enterococcus strains(77.04% isolation rate)were finally isolated.Four antibacterial drug susceptibility tests were performed on the isolated E.coli and Enterococcus using the Disk diffusion method and Microbroth dilution method,and the results showed that the 179 E.coli strains tested exhibited a high level of resistance to dolfenacol,reaching 57.54%,and relatively low resistance to doxycycline and ciprofloxacin,31.28% and 35.75%,respectively.No polymyxin B resistant strains were found.The resistance to doxycycline in young pigeon source E.coli was highly significant higher than that in subpigeon and adult pigeon source E.coli(P<0.01);the resistance to doxycycline and florfenicol in the high frequency dosing group was highly significant higher than that in the low frequency dosing group(P<0.01).Fifteen strains of E.coli showed resistance to 3 or more classes of antimicrobial drugs,with a multi-drug resistance rate of 8.37%;the 151 strains of Enterococcus tested showed the highest resistance rate to doxycycline,56.29%,followed by ciprofloxacin,41.05%,and the lowest resistance rate to florfenicol,28.47%.All strains were resistant to polymyxin B.The resistance to doxycycline,ciprofloxacin and florfenicol in young pigeons was significantly higher than that in subpigeons and adult pigeons(P<0.01),and the resistance to doxycycline,ciprofloxacin and florfenicol in the high frequency group was significantly higher than that in the low frequency group(P<0.01).Twenty-eight strains of Enterococcus showed resistance to 3 or more classes of antimicrobial drugs,with a multi-drug resistance rate of18.54%.2.The results showed that the detection rate of tetracycline resistance genes tetA and tetB in 15 multi-drug resistant E.coli was 100%,and tetM was not detected;the detection rate of PMQR gene qnrS was 53.53%,and qnrD was not detected;the detection rate of florfenicol resistance gene floR was 86.67%,and fexA and fexB were not detected;the detection rate of polymyxin resistance gene mcr-1 was 40% in 28 multi-drug resistant E.coli.The detection rate of floR was 86.67%,and fexA and fexB were not detected;the detection rate of polymyxin resistance gene mcr-1 was 40%.tetracycline resistance gene tetM was detected in 7.14% of 28 multi-drug resistant Enterococcus,and tetA and tetB were not detected;the detection rates of florfenicol resistance gene fexA and fexB were10.71% and 7.14%,respectively,and floR was not detected.The PMQR genes qnrS,qnrD and polymyxin resistance gene mcr-1 were not detected in the tested Enterococcus. |
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