title: Environmental mycobacteria in soil and water on beef ranches: association between presence of cultivable mycobacteria and soil and water physicochemical characteristics.
abstract: 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.
authors.affiliation: Department of Veterinary Integrative Biosciences, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, TX 77843-4458, USA. bnorby@cvm.tamu.edu
authors.forename: Bo
authors.initials: B
authors.lastname: Norby
authors.forename: Geoffrey T
authors.initials: GT
authors.lastname: Fosgate
authors.forename: Elizabeth J B
authors.initials: EJ
authors.lastname: Manning
authors.forename: Michael T
authors.initials: MT
authors.lastname: Collins
authors.forename: Allen J
authors.initials: AJ
authors.lastname: Roussel
mesh_terms: D000818:Animals; D000907:Antibodies, Bacterial / Q000097:blood*; D002417:Cattle; D002418:Cattle Diseases / Q000453:epidemiology* / Q000209:etiology; D015169:Colony Count, Microbial / Q000662:veterinary; D003429:Cross Reactions; D003430:Cross-Sectional Studies; D004783:Environmental Microbiology; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods / Q000662:veterinary; D005189:False Positive Reactions; D006863:Hydrogen-Ion Concentration; D009161:Mycobacterium / Q000276:immunology / Q000302:isolation & purification*; D009164:Mycobacterium Infections / Q000453:epidemiology / Q000209:etiology / Q000662:veterinary; D016927:Mycobacterium avium subsp. paratuberculosis / Q000276:immunology / Q000302:isolation & purification; D010283:Paratuberculosis / Q000453:epidemiology* / Q000209:etiology; D012680:Sensitivity and Specificity; D016036:Seroepidemiologic Studies; D012987:Soil / Q000032:analysis; D012988:Soil Microbiology; D013045:Species Specificity; D014871:Water Microbiology
chemical_list: D000907:Antibodies, Bacterial; D012987:Soil