Norby Bo, Fosgate Geoffrey T, Manning Elizabeth J B, Collins Michael T, Roussel Allen J
Department of Veterinary Integrative Biosciences, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, TX 77843-4458, USA.
Vet Microbiol. 2007 Sep 20;124(1-2):153-9. doi: 10.1016/j.vetmic.2007.04.015. Epub 2007 Apr 8.
Exposure to environmental mycobacteria has been reported to be a factor contributing to false-positive results on bovine serological tests detecting antibodies to Mycobacterium avium subsp. paratuberculosis (Mptb). This study was conducted to investigate the association between recovery of mycobacteria from the environment of cattle and both (i) historically high or low seroprevalence to Mptb, and (ii) soil and water physicochemical characteristics. Eighty-two samples (soil and water) from nine beef cattle ranches in South-central and South Texas were assessed for the presence of mycobacteria. Twelve mycobacterial species were cultured from soil and water from four herds; no Mptb were detected in environmental samples. A positive culture of environmental mycobacteria from soil was significantly associated with lower pH and calcium as well as higher iron, zinc and manganese contents. Beef cattle are likely to be exposed to environmental mycobacteria that may contribute to false-positive results on ELISAs for Mptb infection. Exposure rates to these mycobacteria likely vary across small geographical areas and may be related to soil and/or water physicochemistry.
据报道，接触环境分枝杆菌是导致检测禽分枝杆菌副结核亚种（Mptb）抗体的牛血清学检测出现假阳性结果的一个因素。本研究旨在调查从牛的环境中分离出分枝杆菌与以下两方面之间的关联：（i）历史上对Mptb的高血清阳性率或低血清阳性率，以及（ii）土壤和水的理化特性。对来自德克萨斯州中南部和南部九个肉牛牧场的82个样本（土壤和水）进行了分枝杆菌检测。从四个牛群的土壤和水中培养出了12种分枝杆菌；在环境样本中未检测到Mptb。土壤中环境分枝杆菌的阳性培养与较低的pH值和钙含量以及较高的铁、锌和锰含量显著相关。肉牛可能接触到环境分枝杆菌，这可能导致Mptb感染ELISA检测出现假阳性结果。这些分枝杆菌的暴露率可能在小地理区域内有所不同，并且可能与土壤和/或水的物理化学性质有关。
