US Department of Agriculture, Animal and Plant Health Inspection Service, Veterinary Services, Centers for Epidemiology and Animal Health, Fort Collins, Colorado 80526-8117, USA.
J Food Prot. 2012 Sep;75(9):1562-71. doi: 10.4315/0362-028X.JFP-12-012.
The objectives of this study were to estimate the prevalence of Salmonella for individual, pooled, and composite fecal samples and to compare culture results from each sample type for determining herd Salmonella infection status and identifying Salmonella serovar(s). During the U.S. Department of Agriculture National Animal Health Monitoring System Dairy 2007 study, data and samples were collected from dairy operations in 17 major dairy states. As part of the study, composite fecal samples (six per operation) were collected from cow areas, such as holding pens, alleyways, and lagoons, where manure accumulates. Fecal samples also were collected from individual cows (35 per operation), and fecal sample pools were created by combining samples from 5 cows (7 per operation). A total of 1,541 composite fecal samples were collected from 260 operations in 17 states, and 406 (26.3%) of these samples were culture positive for Salmonella. Among the 116 operations for which all three sample types were obtained, 41.4% (48 operations) were Salmonella culture positive based on individual samples, 39.7% (46 operations) were positive based on pooled samples, and 49.1% (57 operations) were positive based on composite fecal samples. Relative to individual samples, the sensitivity of composite fecal samples for determining herd infection status was 85.4% and the sensitivity of pooled fecal samples was 91.7%. On 33.6% of operations (39 of 116), Salmonella was cultured from all three fecal sample types (individual, pooled, and composite), and 20 (51.3%) of these operations had exactly the same serovar in all three sample types. Use of composite fecal samples is less costly and time-consuming than use of individual or pooled samples and provides similar results for detecting the presence and identifying serovars of Salmonella in dairy herds. Therefore, composite sampling may be an appropriate alternative to culture of individual samples when assessing Salmonella status in dairy herds.
本研究的目的是估计个体、混合和复合粪便样本中沙门氏菌的流行率，并比较每种样本类型的培养结果，以确定畜群沙门氏菌感染状况和鉴定沙门氏菌血清型。在美国农业部国家动物健康监测系统乳制品 2007 年研究期间，数据和样本从 17 个主要乳制品州的奶牛场收集。作为该研究的一部分，从牛区（如畜栏、过道和粪坑等粪便积聚的地方）采集了复合粪便样本（每个畜场 6 个）。还从个体奶牛（每个畜场 35 个）中采集了粪便样本，并通过将 5 头奶牛的样本混合（每个畜场 7 个）创建了粪便样本池。总共从 17 个州的 260 个畜场采集了 1541 个复合粪便样本，其中 406 个（26.3%）样本培养出沙门氏菌阳性。在获得所有三种样本类型的 116 个畜场中，基于个体样本，41.4%（48 个畜场）为沙门氏菌培养阳性，基于混合样本，39.7%（46 个畜场）为阳性，基于复合粪便样本，49.1%（57 个畜场）为阳性。与个体样本相比，复合粪便样本用于确定畜群感染状况的敏感性为 85.4%，混合粪便样本的敏感性为 91.7%。在 33.6%的畜场（116 个畜场中的 39 个）中，从所有三种粪便样本类型（个体、混合和复合）中培养出了沙门氏菌，其中 20 个畜场（51.3%）在所有三种样本类型中均存在相同的血清型。与个体或混合样本相比，复合粪便样本的采集成本和时间更经济，并且在检测奶牛场沙门氏菌的存在和鉴定血清型方面提供了相似的结果。因此，在评估奶牛场沙门氏菌状况时，复合采样可能是个体样本培养的一种合适替代方法。
