The dairy farm environment is a well-documented reservoir for zoonotic pathogens such as Salmonella enterica, Shiga-toxigenic Escherichia coli, and Listeria monocytogenes, and humans may be exposed to these pathogens via consumption of unpasteurized milk and dairy products. As part of the National Animal Health Monitoring System Dairy 2014 study, bulk tank milk (BTM, n = 234) and milk filters (n = 254) were collected from a total of 234 dairy operations in 17 major dairy states and analyzed for the presence of these pathogens. The invA gene was detected in samples from 18.5% of operations and Salmonella enterica was isolated from 18.0% of operations. Salmonella Dublin was detected in 0.7% of operations. Sixteen Salmonella serotypes were isolated, and the most common serotypes were Cerro, Montevideo, and Newport. Representative Salmonella isolates (n = 137) were tested against a panel of 14 antimicrobials. Most (85%) were pansusceptible; the remaining were resistant to 1 to 9 antimicrobials, and within the resistant strains the most common profile was resistance to ampicillin/clavulanic acid, ampicillin, cefoxitin, ceftiofur, ceftriaxone, chloramphenicol, streptomycin, sulfisoxazole, and tetracycline. Listeria spp. were isolated from 19.9% of operations, and L. monocytogenes was isolated from 3.0% of operations. Serogroups 1/2a and 1/2b were the most common, followed by 4b and 4a. One or more E. coli virulence genes were detected in the BTM from 30.5% of operations and in the filters from 75.3% of operations. A combination of stx₂, eaeA, and γ-tir genes was detected in the BTM from 0.5% of operations and in the filters from 6.6% of operations. The results of this study indicate an appreciable prevalence of bacterial pathogens in BTM and filters, including serovars known to infect humans.

奶牛场环境是人畜共患病原体（如肠炎沙门氏菌，志贺氏毒素大肠埃希氏菌和单核细胞增生李斯特氏菌）的有据可查的储存库，人类可能会通过食用未经巴氏消毒的牛奶和奶制品而暴露于这些病原体。作为《 2014年美国国家动物健康监控系统乳制品》研究的一部分，从17个主要奶牛州的234个奶牛场中收集了散装罐装牛奶（BTM，n = 234）和牛奶过滤器（n = 254），并进行了分析。这些病原体。所述invA的在样品中检测到的操作的18.5％基因和肠道沙门氏菌从操作的18.0％分离。沙门氏菌都柏林在0.7％的业务中被检测到。分离出十六种沙门氏菌血清型，最常见的血清型是塞罗，蒙得维的亚和纽波特。代表沙门氏菌分离株（n = 137）针对一组14种抗微生物药进行了测试。大多数（85％）易感；其余的对1到9种抗菌药物具有耐药性，并且在耐药菌株中，最常见的特征是对氨苄青霉素/克拉维酸，氨苄青霉素，头孢西丁，头孢噻呋，头孢曲松，氯霉素，链霉素，磺胺异恶唑和四环素的耐药性。李斯特菌属 从19.9％的手术中分离出单核细胞增生李斯特菌与3.0％的操作隔离。血清群1 / 2a和1 / 2b是最常见的，其次是4b和4a。在BTM中从30.5％的操作中检测到一种或多种大肠杆菌毒力基因，在过滤器中从75.3％的操作中检测到一种或多种大肠杆菌毒力基因。在BTM中从0.5％的操作中检测到stx ₂，eaeA和γ-tir基因的组合，而从6.6％的操作中的过滤器中检测到stx ₂，eaeA和γ-tir基因的组合。这项研究的结果表明，BTM和过滤器（包括已知感染人类的​​血清型）中细菌病原体的流行率很高。