Department of Clinical Sciences, College of Veterinary Medicine, Kansas State University, 1620 Denison Avenue, Manhattan, Kansas 66506, USA.
Center for Outcomes Research and Epidemiology, College of Veterinary Medicine, Kansas State University, 1620 Denison Avenue, Manhattan, Kansas 66506, USA.
J Food Prot. 2022 Aug 1;85(8):1221-1231. doi: 10.4315/JFP-22-078.
This study was conducted to evaluate the association between a therapeutic dose of tulathromycin for bovine respiratory disease in beef steers and the antimicrobial and multidrug resistance profiles of the gastrointestinal tract commensals Escherichia coli and Enterococcus spp. and the foodborne pathogens Salmonella enterica and Campylobacter spp. isolated from fecal samples. Individual fecal samples were collected on days 0, 14, and 28 from 70 beef steers that were housed in a single pen and had been treated or not treated with tulathromycin. Samples were cultured for bacterial isolation, and isolates were tested for antimicrobial susceptibility with the broth microdilution method to determine the MICs of clinically relevant antimicrobials used in both human and veterinary medicine. Generalized linear mixed effects models were fitted to estimate the prevalence of the bacterial species and the prevalence of resistant isolates over time and between treated and nontreated cattle and of multidrug-resistant isolates. Model-adjusted mean prevalences of E. coli, Enterococcus spp., S. enterica, and Campylobacter spp. were 99.5, 85.9, 1.5, and 17.7%, respectively. The prevalence of erythromycin-resistant Enterococcus spp. was significantly higher on day 14 (59.7%) than on day 28 (22.2%). A higher prevalence of erythromycin-resistant Enterococcus spp. was found in samples from treated (59.3%) than in samples from nontreated (27.6%) animals. Multidrug resistance (three or more antimicrobial classes) was observed in 8.4% of E. coli isolates and 62.7% of Enterococcus isolates. The administration of tulathromycin was significantly associated with an increased prevalence of erythromycin-resistant Enterococcus spp. isolates.
本研究旨在评估牛用治疗剂量的托拉菌素对肉牛呼吸道疾病的治疗效果，以及其对胃肠道共生菌大肠杆菌和肠球菌以及粪便中分离出的食源性致病菌沙门氏菌和弯曲杆菌的抗菌和多药耐药谱的影响。从 70 头被安置在一个畜栏中的肉牛的粪便中，分别于第 0、14 和 28 天采集单个粪便样本。对样本进行细菌分离培养，采用肉汤微量稀释法对分离株进行抗菌药物敏感性试验，以确定用于人和兽医的临床相关抗菌药物的 MIC 值。采用广义线性混合效应模型来估计细菌种属的流行率、耐药分离株的流行率，以及在治疗和未治疗牛之间以及多药耐药分离株的流行率。调整模型后的大肠杆菌、肠球菌、沙门氏菌和弯曲杆菌的平均流行率分别为 99.5%、85.9%、1.5%和 17.7%。第 14 天（59.7%）时，耐红霉素肠球菌的流行率明显高于第 28 天（22.2%）。治疗组（59.3%）样本中耐红霉素肠球菌的流行率明显高于未治疗组（27.6%）。8.4%的大肠杆菌分离株和 62.7%的肠球菌分离株表现出多药耐药性（三种或更多种抗菌药物类别）。托拉菌素的使用与耐红霉素肠球菌分离株的流行率增加显著相关。
