title: Application of cattle slurry containing Mycobacterium avium subsp. paratuberculosis (MAP) to grassland soil and its effect on the relationship between MAP and free-living amoeba.
abstract: Slurry from dairy farms is commonly used to fertilize crops and pastures. This mixture of manure, urine and water can harbor multiple microbial pathogens among which Mycobacterium avium subsp. paratuberculosis (MAP) is a major concern. Persistence of MAP in soil and infection of soil Acanthamoeba was evaluated by culture, real-time IS900 PCR, and by staining of amoeba with acid-fast and vital stains comparing soils irrigated with MAP-spiked or control dairy farm slurry. MAP DNA was detected in soil for the 8 month study duration. MAP was detected by PCR from more soil samples for plots receiving MAP-spiked slurry (n=61/66) than from soils receiving control slurry (n=10/66 samples). Vital stains verified that intracellular MAP in amoeba was viable. More MAP was found in amoeba at the end of the study than immediately after slurry application. There was no relationship between MAP presence in soil and in amoeba over time. Infection of amoeba by MAP provides a protected niche for the persistence and even possibly the replication of MAP in soils. As others have suggested, MAP-infected amoeba may act like a "Trojan horse" providing a means for persistence in soils and potentially a source of infection for grazing animals.
authors.affiliation: Department of Biochemistry and Microbiology, Faculty of Sciences, Universidad Austral de Chile, Valdivia, Chile. Electronic address: miguelsalgado@uach.cl.
authors.forename: M
authors.initials: M
authors.lastname: Salgado
authors.affiliation: Institute for Agricultural Research (INIA), Remehue Research Centre, Osorno, Chile. Electronic address: malfaro@inia.cl.
authors.forename: M
authors.initials: M
authors.lastname: Alfaro
authors.affiliation: Institute for Agricultural Research (INIA), Remehue Research Centre, Osorno, Chile. Electronic address: fsalazar@inia.cl.
authors.forename: F
authors.initials: F
authors.lastname: Salazar
authors.affiliation: Department of Biochemistry and Microbiology, Faculty of Sciences, Universidad Austral de Chile, Valdivia, Chile. Electronic address: xbadilla@gmail.com.
authors.forename: X
authors.initials: X
authors.lastname: Badilla
authors.affiliation: Department of Biochemistry and Microbiology, Faculty of Sciences, Universidad Austral de Chile, Valdivia, Chile. Electronic address: p.troncoso.condeza@gmail.com.
authors.forename: E
authors.initials: E
authors.lastname: Troncoso
authors.affiliation: Department of Biochemistry and Microbiology, Faculty of Sciences, Universidad Austral de Chile, Valdivia, Chile. Electronic address: angarahzambrano@gmail.com.
authors.forename: A
authors.initials: A
authors.lastname: Zambrano
authors.affiliation: Clinical Microbiology Department, Faculty of Medicine, Universidad Austral de Chile, Valdivia, Chile. Electronic address: mario.gonzalez@uach.cl.
authors.forename: M
authors.initials: M
authors.lastname: González
authors.affiliation: Department of Population Medicine and Diagnostic Sciences, Cornell University, Ithaca, NY, USA. Electronic address: rmm257@gmail.com.
authors.forename: R M
authors.initials: RM
authors.lastname: Mitchell
authors.affiliation: Department of Pathobiological Sciences, School of Veterinary Medicine, University of Wisconsin, Madison, USA. Electronic address: mcollin5@wisc.edu.
authors.forename: M T
authors.initials: MT
authors.lastname: Collins
mesh_terms: D000048:Acanthamoeba / Q000166:cytology / Q000382:microbiology*; D000562:Amebiasis / Q000469:parasitology / Q000662:veterinary; D000818:Animals; D002417:Cattle; D002418:Cattle Diseases / Q000382:microbiology* / Q000469:parasitology; D003612:Dairying; D065948:Grassland; D008372:Manure / Q000382:microbiology*; D016927:Mycobacterium avium subsp. paratuberculosis / Q000235:genetics / Q000302:isolation & purification / Q000502:physiology*; D010283:Paratuberculosis / Q000382:microbiology; D060888:Real-Time Polymerase Chain Reaction / Q000662:veterinary; D012987:Soil / Q000469:parasitology*; D012988:Soil Microbiology
chemical_list: D008372:Manure; D012987:Soil
keywords: Cattle slurry; Free-living amoeba; Grassland soil; MAP; Persistence