Food Animal Health Research Program, College of Food, Agricultural, and Environmental Sciences, Ohio Agricultural Research and Development Center, The Ohio State University, Wooster, Ohio 44691, USA.
J Food Prot. 2011 Oct;74(10):1618-24. doi: 10.4315/0362-028X.JFP-11-141.
To assess the potential for food contamination with Clostridium difficile from food animals, we conducted a cross-sectional fecal prevalence study in 944 randomly selected cattle harvested at seven commercial meat processing plants, representing four distant regions (median distance of 1,500 km) of the United States. In all, 944 animals were sampled in the summer of 2008. C. difficile was isolated from 1.8% (17 of 944) of cattle, with median fecal shedding concentration of 2.2 log CFU/g (range = 1.6 to 4.8, 95% confidence interval = 1.6, 4.3). Toxigenic C. difficile isolates were recovered from only four (0.4%) cattle. One of these isolates was emerging PCR ribotype 078/toxinotype V. The remaining toxigenic isolates were toxinotype 0, one of which was an isolate with resistance to linezolid, clindamycin, and moxifloxacin (by the E-test). All isolates were susceptible to vancomycin, metronidazole, and tigecycline, but the MICs against linezolid were as high as the highest reported values for human-derived isolates. The source of the linezolid-clindamycin-moxifloxacin resistance in a toxigenic C. difficile isolate from cattle is uncertain. However, since the use of these three antimicrobial agents in cattle is not allowed in North America, it is possible that resistance originated from an environmental source, from other species where those antimicrobial agents are used, or transferred from other intestinal bacteria. This study confirms that commercial cattle can carry epidemiologically relevant C. difficile strains at the time of harvest, but the prevalence at the time they enter the food chain is low.
为了评估食源性动物源艰难梭菌污染的潜在风险，我们对美国四个不同地区（平均距离 1500 公里）的七家商业肉类加工厂的 944 头随机选择的屠宰牛进行了横断面粪便流行率研究。2008 年夏季共采集了 944 头动物的样本。从 944 头牛中分离出艰难梭菌，阳性率为 1.8%（17/944），粪便脱落浓度中位数为 2.2 log CFU/g（范围 1.6 至 4.8，95%置信区间为 1.6，4.3）。仅从 4 头（0.4%）牛中分离出产毒艰难梭菌。其中一株为新兴 PCR 核糖体 078 型/毒素型 V。其余产毒分离株为毒素型 0 型，其中一株对利奈唑胺、克林霉素和莫西沙星（E-试验）耐药。所有分离株均对万古霉素、甲硝唑和替加环素敏感，但对利奈唑胺的 MIC 值高达最高报道的人源分离株的水平。牛源产毒艰难梭菌中利奈唑胺-克林霉素-莫西沙星耐药的来源尚不确定。然而，由于在北美不允许将这三种抗菌药物用于牛，因此耐药性可能来自环境来源、在其他使用这些抗菌药物的物种中，或从其他肠道细菌转移而来。本研究证实，商业牛在收获时可携带具有流行病学意义的艰难梭菌菌株，但进入食物链时的流行率较低。
