Department of Animal, Dairy and Veterinary Sciences, Utah Veterinary Diagnostic Laboratory, Utah State University, Logan 84321, USA.
J Dairy Sci. 2010 Jan;93(1):192-202. doi: 10.3168/jds.2009-2474.
Mycoplasma spp., usually Mycoplasma bovis, are important bovine pathogens that can cause mastitis, metritis, pneumonia, and arthritis. The currently documented routes of transmission of Mycoplasma spp. are through contaminated milking equipment and by direct animal contact. The existence of environmental sources for Mycoplasma spp. and their role in transmission and clinical disease is poorly characterized. Mycoplasma spp. (confirmed as M. bovis in 2 of 4 samples tested using PCR) was found in recycled bedding sand originating from a dairy experiencing an outbreak of clinical mycoplasma mastitis. Mycoplasma spp. were subsequently found in bedding sand from 2 other dairies whose bulk-tank milk was mycoplasma-positive. The association between the occurrence of Mycoplasma spp. in recycled bedding sand and mycoplasma mastitis in cows was further investigated using a pile of recycled sand from dairy 1. Study objectives included the determination of factors associated with the concentration of Mycoplasma spp. in recycled bedding sand and the duration of survival of mycoplasmas in the sand. We also evaluated the efficacy of 2 disinfectants at 2 different concentrations each for the elimination of Mycoplasma spp. from contaminated sand. Mycoplasma spp. survived in the sand pile for 8 mo. The concentration of Mycoplasma spp. within the sand pile was directly related to temperature and precipitation. It was also positively associated with the growth of gram-negative microorganisms, suggesting the possibility of the formation of a biofilm. Ideal temperatures for replication of Mycoplasma spp. occurred between 15 and 20 degrees C. Moisture in the sand and movement of the sand pile also appeared to play a role in replication of mycoplasmas. We found that 0.5% sodium hypochlorite or 2% chlorhexidine were efficacious in eliminating Mycoplasma spp. from contaminated bedding sand. Recycled bedding sand could be an environmental source of Mycoplasma spp., including M. bovis, infections in dairy cows. Future studies should investigate the contribution of this environmental source to the epidemiology of mycoplasma infections in dairy cattle.
支原体属，通常为牛支原体，是重要的牛病原体，可引起乳腺炎、子宫炎、肺炎和关节炎。目前记录的支原体属传播途径是通过受污染的挤奶设备和直接动物接触。支原体属的环境来源及其在传播和临床疾病中的作用尚未得到充分描述。在经历临床支原体乳腺炎爆发的奶牛场的回收垫料沙中发现了支原体属（通过 PCR 在 4 个测试样本中的 2 个样本中证实为牛支原体）。随后在来自另外 2 个牛奶支原体阳性的奶牛场的垫料沙中发现了支原体属。使用来自奶牛场 1 的一堆回收垫料沙进一步研究了回收垫料沙中支原体属的出现与奶牛支原体乳腺炎之间的关联。研究目的包括确定与回收垫料沙中支原体属浓度相关的因素以及支原体属在沙中的存活时间。我们还评估了 2 种消毒剂在 2 种不同浓度下从受污染的沙中消除支原体属的效果。支原体属在沙堆中存活了 8 个月。沙堆中支原体属的浓度与温度和降水直接相关。它还与革兰氏阴性微生物的生长呈正相关，这表明形成生物膜的可能性。支原体属复制的理想温度在 15 至 20 摄氏度之间。沙中的水分和沙堆的移动似乎也在支原体属的复制中起作用。我们发现 0.5%次氯酸钠或 2%洗必泰可有效消除受污染垫料沙中的支原体属。回收垫料沙可能是奶牛支原体属感染的环境来源，包括牛支原体。未来的研究应调查该环境来源对奶牛支原体感染流行病学的贡献。
