5个品种白羽肉鸡大肠杆菌耐药差异分析

【目的】通过开展5个品种白羽肉鸡养殖过程中大肠杆菌流行病学研究及耐药性差异情况调查，了解不同品种肉鸡大肠杆菌耐药现状及其差异，为科学指导肉鸡相关疾病诊治和兽药监管提供参考依据。【方法】选用5个品种白羽肉鸡（2个为江苏养殖量较大的国外引进品种， 3个为我国自主选育配套系）为研究对象，分别采集0日龄胎粪样品及4、 8、 12、 16、 20、 24、 28、 32、 36和40日龄的泄殖腔棉拭子，经麦康凯培养基分离大肠杆菌后进行PCR鉴定，并采用Kirby-Bauer （K-B）法进行药敏试验。【结果】从1075份样品中共分离获得978株大肠杆菌，总分离率为91.0%。其中，广明2号（A品种）和圣泽901（C品种）的大肠杆菌分离率最高，均为93.0%； WOD168（E品种）的分离率最低，为88.4%。5个品种白羽肉鸡的胎粪样品分离率、 2个重复的分离率、 5个品种白羽肉鸡大肠杆菌总分离率及不同日龄的分离率均无显著差异 （P>0.05）。5个品种白羽肉鸡大肠杆菌对氨苄西林 （AMP）、阿莫西林 （AML）、红霉素 （E）、四环素 （TE）和氯霉素 （C）已产生较强的耐药性，对阿米卡星 （AK）、磷霉素 （FOS）、阿奇霉素 （AZM）和头孢曲松 （CRO）仍然较敏感；5个品种白羽肉鸡大肠杆菌分离株产生明显的多重耐药，但不同品种的优势耐药谱有所差异。【结论】不同品种白羽肉鸡大肠杆菌耐药情况受用药习惯、饲养方式及条件状况等环境因素的多重影响，但其多重耐药性具有一定的遗传稳定性。因此，在实际生产中应从动物饲养的源头抓起，鼓励和发展集约化养殖，加强饲料安全检测，改善饲养和防疫条件，严格进行合理规范用药，减少同一药物的使用频率，降低细菌耐药性，有效保障动物产品安全及维护人类健康。

Drug resistance difference analysis of Escherichia coli in 5 species of white-feathered broilers

【Objective】To conduct epidemiological research and drug resistance difference investigation of Escherichia coli during breeding process of 5 species of white-feathered broilers，and to get information about E.coli drug resistance of different species of white-feathered broilers and difference founded among them，so as to provide reference for guidance of diagnosis and veterinary drug control of broiler diseases.【Method】 Five species of white-feathered broilers（2 imported species with large breeding scale in Jiangsu Province and 3 self-breeding lines in China）were selected as experimental objects，0-day-old meconium samples and 4-，8-，12-，16-，20-，24-，28-，32-，36-and 40-day-old cloacal cotton swab samples were collected.E.coli was isolated by MacConkey medium and identified by PCR.Kirby-Bauer（K-B）method was used for drug sensitivity test.【Result】 978 strains of E.coli isolated from 1075 samples，with a total isolation rate of 91.0%.Guangming No.2（variety A）and Shengze 901（variety C）had the highest isolation rates of E.coli，both of which were 93.0%.WOD168（variety E）had the lowest isolation rate of 88.4%.There was no significant difference in the isolation rate of meconium samples，the isolation rate of 2 replicates，the total separation rate of E.coli and the separation rate of different days of age among the 5 varieties of white-feathered broilers（P>0.05）.The 5 varieties of white-feathered broilers had high resistance to ampicillin（AMP），amoxicillin（AML），erythromycin（E），tetracycline（TE）and chloramphenicol（C），and high sensitivity to amikacin（AK），fosfomycin（FOS），azithromycin（AZM）and ceftriaxone （CRO）.The E.coli strains from 5 species performed obvious multidrug resistance and the drug resistance spectrums of 5 species were different.【Conclusion】 Drug resistance of E.coli in different varieties of white-feathered broilers was affected by environmental factors such as drug habits，feeding methods and conditions，but its multi-drug resistance had certain genetic stability.Therefore，in production，the source of animal breeding should be supervised，intensive breeding should be encouraged and developed，feed safety testing should be strengthened，breeding and epidemic prevention conditions should be improved，the use of drugs should be strictly regulated，the frequency of use of the same drug and bacterial resistance should be reduced to guarantee animal product safety and human health.