title: Widespread Environmental Contamination with Mycobacterium tuberculosis Complex Revealed by a Molecular Detection Protocol.
abstract: Environmental contamination with Mycobacterium tuberculosis complex (MTC) has been considered crucial for bovine tuberculosis persistence in multi-host-pathogen systems. However, MTC contamination has been difficult to detect due to methodological issues. In an attempt to overcome this limitation we developed an improved protocol for the detection of MTC DNA. MTC DNA concentration was estimated by the Most Probable Number (MPN) method. Making use of this protocol we showed that MTC contamination is widespread in different types of environmental samples from the Iberian Peninsula, which supports indirect transmission as a contributing mechanism for the maintenance of bovine tuberculosis in this multi-host-pathogen system. The proportion of MTC DNA positive samples was higher in the bovine tuberculosis-infected than in presumed negative area (0.32 and 0.18, respectively). Detection varied with the type of environmental sample and was more frequent in sediment from dams and less frequent in water also from dams (0.22 and 0.05, respectively). The proportion of MTC-positive samples was significantly higher in spring (p<0.001), but MTC DNA concentration per sample was higher in autumn and lower in summer. The average MTC DNA concentration in positive samples was 0.82 MPN/g (CI95 0.70-0.98 MPN/g). We were further able to amplify a DNA sequence specific of Mycobacterium bovis/caprae in 4 environmental samples from the bTB-infected area.
authors.affiliation: Life and Health Sciences Research Institute (ICVS), School of Health Sciences, University of Minho, Braga, Portugal.|ICVS/3B's, PT Government Associate Laboratory, Braga/Guimarães, Portugal.
authors.forename: Nuno
authors.initials: N
authors.lastname: Santos
authors.affiliation: Life and Health Sciences Research Institute (ICVS), School of Health Sciences, University of Minho, Braga, Portugal.|ICVS/3B's, PT Government Associate Laboratory, Braga/Guimarães, Portugal.
authors.forename: Catarina
authors.initials: C
authors.lastname: Santos
authors.affiliation: Earth Sciences Institute (ICT), Pole of the University of Minho, Earth Sciences Department, University of Minho, Braga, Portugal.
authors.forename: Teresa
authors.initials: T
authors.lastname: Valente
authors.affiliation: SaBio (Health and Biotechnology), IREC, National Wildlife Research Institute (CSIC-UCLM-JCCM), Ciudad Real, Spain.
authors.forename: Christian
authors.initials: C
authors.lastname: Gortázar
authors.affiliation: Centro de Investigação Interdisciplinar em Sanidade Animal (CIISA), Faculdade de Medicina Veterinária, Universidade de Lisboa (FMV-ULisboa), Lisboa, Portugal.
authors.forename: Virgílio
authors.initials: V
authors.lastname: Almeida
authors.affiliation: Life and Health Sciences Research Institute (ICVS), School of Health Sciences, University of Minho, Braga, Portugal.|ICVS/3B's, PT Government Associate Laboratory, Braga/Guimarães, Portugal.
authors.forename: Margarida
authors.initials: M
authors.lastname: Correia-Neves
mesh_terms: D000818:Animals; D002417:Cattle; D004269:DNA, Bacterial; D009163:Mycobacterium bovis / Q000302:isolation & purification*; D009169:Mycobacterium tuberculosis / Q000302:isolation & purification*; D060888:Real-Time Polymerase Chain Reaction; D012680:Sensitivity and Specificity; D014380:Tuberculosis, Bovine / Q000175:diagnosis* / Q000635:transmission*
chemical_list: D004269:DNA, Bacterial