Siegel D, Huber W G, Enloe F
Antimicrob Agents Chemother. 1974 Dec;6(6):697-701. doi: 10.1128/AAC.6.6.697.
Fecal samples from Illinois farm animals and Montana range cattle were examined for the frequency of gram-negative enteric organisms resistant to oxytetracycline, dihydrostreptomycin, or ampicillin. The Illinois farm animals were continually fed rations containing various antibacterial drugs. The Montana range cattle had minimal exposure to antibacterial drugs. The majority of samples from Illinois farm animals demonstrated 10% or more antibiotic-resistant organisms. In contrast, resistant organisms could not be detected in the majority of samples from Montana range cattle. The majority of Escherichia coli isolated from Illinois farm animals was resistant to various antibacterial drugs, whereas less than 1.6% of the isolates from Montana range cattle were resistant to any one of the antibacterial drugs tested.
对来自伊利诺伊州农场动物和蒙大拿州牧场牛的粪便样本进行了检测，以确定对土霉素、双氢链霉素或氨苄青霉素耐药的革兰氏阴性肠道菌的出现频率。伊利诺伊州的农场动物持续食用含有各种抗菌药物的饲料。蒙大拿州的牧场牛极少接触抗菌药物。来自伊利诺伊州农场动物的大多数样本显示出10%或更多的抗生素耐药菌。相比之下，在蒙大拿州牧场牛的大多数样本中未检测到耐药菌。从伊利诺伊州农场动物中分离出的大多数大肠杆菌对各种抗菌药物耐药，而从蒙大拿州牧场牛中分离出的菌株对所测试的任何一种抗菌药物耐药的比例不到1.6%。
