Quality Milk Production Services, College of Veterinary Medicine, Cornell University, Ithaca, NY 14850, USA.
J Dairy Sci. 2011 Feb;94(2):1045-51. doi: 10.3168/jds.2010-3603.
Klebsiella spp. are a common cause of mastitis, milk loss, and culling on dairy farms. Control of Klebsiella mastitis is largely based on prevention of exposure of the udder to the pathogen. To identify critical control points for mastitis prevention, potential Klebsiella sources and transmission cycles in the farm environment were investigated, including oro-fecal transmission, transmission via the indoor environment, and transmission via the outdoor environment. A total of 305 samples was collected from 3 dairy farms in upstate New York in the summer of 2007, and included soil, feed crops, feed, water, rumen content, feces, bedding, and manure from alleyways and holding pens. Klebsiella spp. were detected in 100% of rumen samples, 89% of water samples, and approximately 64% of soil, feces, bedding, alleyway, and holding pen samples. Detection of Klebsiella spp. in feed crops and feed was less common. Genotypic identification of species using rpoB sequence data showed that Klebsiella pneumoniae was the most common species in rumen content, feces, and alleyways, whereas Klebsiella oxytoca, Klebsiella variicola, and Raoultella planticola were the most frequent species among isolates from soil and feed crops. Random amplified polymorphic DNA-based strain typing showed heterogeneity of Klebsiella spp. in rumen content and feces, with a median of 4 strains per 5 isolates. Observational and bacteriological data support the existence of an oro-fecal transmission cycle, which is primarily maintained through direct contact with fecal contamination or through ingestion of contaminated drinking water. Fecal shedding of Klebsiella spp. contributes to pathogen loads in the environment, including bedding, alleyways, and holding pens. Hygiene of alleyways and holding pens is an important component of Klebsiella control on dairy farms.
产酸克雷伯氏菌是引起乳腺炎、产奶量下降和奶牛淘汰的常见原因。克雷伯氏菌乳腺炎的控制主要基于预防乳房暴露于病原体。为了确定乳腺炎预防的关键控制点,本研究调查了农场环境中潜在的克雷伯氏菌来源和传播循环,包括口-粪传播、通过室内环境传播和通过室外环境传播。2007 年夏天,从纽约北部的 3 个奶牛场共采集了 305 个样本,包括土壤、饲料作物、饲料、水、瘤胃液、粪便、垫料和来自过道和畜栏的粪便。在 100%的瘤胃液样本、89%的水样和大约 64%的土壤、粪便、垫料、过道和畜栏样本中检测到了产酸克雷伯氏菌。在饲料作物和饲料中检测到产酸克雷伯氏菌的情况较少见。使用 rpoB 序列数据进行的种基因型鉴定表明,肺炎克雷伯氏菌是瘤胃液、粪便和过道中最常见的物种,而产酸克雷伯氏菌、奇异变形杆菌和植生拉乌尔菌则是土壤和饲料作物分离株中最常见的物种。随机扩增多态性 DNA 基于菌株分型的结果表明,瘤胃液和粪便中产酸克雷伯氏菌存在异质性,每 5 个分离株中有 4 个菌株。观察和细菌学数据支持口-粪传播循环的存在,该循环主要通过与粪便污染的直接接触或通过摄入污染的饮用水来维持。产酸克雷伯氏菌的粪便脱落导致环境中的病原体负荷增加,包括垫料、过道和畜栏。过道和畜栏的卫生是奶牛场克雷伯氏菌控制的重要组成部分。