【摘要】 在相同的管理背景下，探讨不同养殖模式对牛源及环境源大肠杆菌耐药性及其携带耐药基因的影响。采集新疆博乐地区某肉牛养殖场集约化与放牧养殖区的173份牛源及环境样品，分离鉴定大肠杆菌。采用琼脂稀释法检测菌株对10种常用抗菌药物的敏感性，并通过PCR方法对分离的大肠杆菌进行21种常见耐药基因的检测。从173份样品中分离大肠杆菌104株，分离率为60.1%，其中集约化养殖区牛源样品中大肠杆菌分离率最高，为82.0%，集约化养殖区环境源样品中大肠杆菌分离率最低，为36.5%。分离的大肠杆菌对氨苄西林（61.5%）、氟苯尼考（66.3%）和头孢噻呋（53.8%）的耐药率最高。三耐及以上菌株占57.7%，集约化养殖区牛源大肠杆菌的耐药谱型最复杂。共检出9种耐药基因，牛源大肠杆菌中bla_TEM、floR、sul2的检出率显著高于环境源（P<0.05）。研究表明，在统一管理条件下不同养殖模式牛源及环境源大肠杆菌的耐药性与耐药基因携带情况不同，需制定差异化用药策略。更多还原

【Abstract】 To explore the impact of different cattle farming systems on antimicrobial resistance and associated resistance genes of Escherichia coli isolated from bovine and environmental sources under uniform management conditions. A total of 173 samples were collected,including rectal swabs from cattle and environmental samples from intensive and grazing systems. Escherichia coli isolates were obtained and tested for antimicrobial susceptibility to 10 antibiotics using the agar dilution method. PCR was employed to detect 21 commonly encountered antimicrobial resistance genes. E. coli was isolated from 104 out of 173 samples,yielding an overall isolation rate of 60. 1%. The highest rate was observed in bovine samples from intensive systems（82. 0%）,while the lowest occurred in environmental samples from intensive systems（36. 5%）. The isolates exhibited highest resistance rates to ampicillin（61. 5%）,florfenicol（66. 3%）,and ceftiofur（53. 8%）. Multidrug resistance （≥3 classes） was observed in 57. 7% of isolates,with isolates from intensively raised cattle showing the most diverse resistance profiles. A total of nine antimicrobial resistance genes were detected,and the detection rates of bla_TEM, floR,and sul2 in bovine-origin E. coli were significantly higher than those in environmental-origin isolates（P<0. 05）. Under uniform management conditions,farming system significantly influenced both the antimicrobial resistance and gene carriage patterns of E. coli from bovine and environmental sources. Differential antimicrobial strategies should be tailored to specific farming contexts.更多还原