Department of Ruminant Production, Institute of Agrifood Research and Technology (IRTA), 08140 Caldes de Montbui, Spain.
Department of Bacterial and Endoparasitic Infections, Centre de Recerca en Sanitat Animal (CReSA)-IRTA, 08193 Barcelona, Spain.
J Dairy Sci. 2017 Oct;100(10):7967-7979. doi: 10.3168/jds.2017-13040. Epub 2017 Jul 26.
The aim of this study was to evaluate the effects of feeding pasteurized waste milk (pWM) to calves on antimicrobial resistance of fecal Escherichia coli at both phenotypic and genotypic levels. Fifty-two Holstein female calves (3 ± 1.3 d of age) were fed 1 of the 2 different types of milk: milk replacer (MR) without antimicrobials or pWM with β-lactam residues until weaning at 49 d of age. Fecal swabs of all calves were obtained on d 0, 35, and 56 of the study and 3 E. coli isolates per sample were studied. Phenotypic resistance was tested by the disk diffusion method against a panel of 12 antimicrobials. A total of 13 resistance genes consisting of β-lactam, sulfonamide, tetracycline, and aminoglycoside families were examined by PCR. Feeding pWM to calves increased the presence of phenotypic resistance to ampicillin, cephalotin, ceftiofur, and florfenicol in fecal E. coli compared with MR-fed calves. However, the presence of resistance to sulfonamides, tetracyclines, and aminoglycosides was common in dairy calves independent of their milk-feeding source, suggesting other factors apart from the feeding source are involved in the emergence of antimicrobial resistance.
本研究旨在评估给犊牛喂食巴氏消毒废奶（pWM）对粪便大肠杆菌表型和基因型水平的抗药性的影响。52 头荷斯坦雌性犊牛（3 ± 1.3 日龄）接受 2 种不同类型的牛奶中的 1 种喂养：不含抗生素的代乳粉（MR）或含有β-内酰胺残留的 pWM，直到 49 日龄断奶。在研究的第 0、35 和 56 天，对所有犊牛的粪便拭子进行了取样，并对每个样本的 3 个大肠杆菌分离株进行了研究。通过圆盘扩散法对 12 种抗生素进行了表型耐药性测试。通过 PCR 检查了包括β-内酰胺、磺胺类、四环素和氨基糖苷类家族在内的 13 个耐药基因。与 MR 喂养的犊牛相比，给犊牛喂食 pWM 增加了粪便大肠杆菌对氨苄西林、头孢噻肟、头孢噻呋和氟苯尼考的表型耐药性。然而，无论其牛奶喂养来源如何，对磺胺类、四环素和氨基糖苷类的耐药性在奶牛犊牛中都很常见，这表明除了喂养来源之外，还有其他因素参与了抗药性的出现。
