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Non-tuberculous mycobacteria isolated at the end of the world

X Ferrara Muñiz(1) C Tortone(2) S Oriani(2) P Farace(1) M Encinas(1) M E Eirin(1) M Zumárraga(1)

1:Instituto de Agrobiotecnología y Biotecnología Molecular (IABIMO), UEDD INTA-CONICET; CICVyA, Instituto Nacional de Tecnología Agropecuaria, Buenos Aires, Argentina; 2:Facultad de Ciencias Veterinarias, Universidad Nacional de La Pampa, La Pampa, Argentina

Non-tuberculous mycobacteria (NTM) are a group of mycobacteria widely distributed in the environment (e.g. soil and water). NTM can also cause infections in different mammals, mostly in immunocompromised individuals. Moreover, they may interfere with the ante-mortem diagnosis of bovine tuberculosis (BTB) by the tuberculin skin test. In this work, two isolates of NTM species were obtained from soil of Tierra del Fuego, the only province free of BTB and brucellosis in Argentina. Molecular typing of the isolates was performed by gene sequencing of the 16S rRNA, hsp65 and rpoB genes. The criterion for species identification was concordance of identity of at least two of these genes after blast comparison. Mycolicibacterium diernhoferi (M. diernhoferi) and Mycolicibacterium novocastrense (M. novocastrense) were identified in the two isolates. Furthermore, in this study the presence of esxA, esxB and espC genes was investigated by PCR. None of the three genes were detected in either M. diernhoferi or M. novocastrense. In the future, whole genome sequencing of these strains will be performed to compare them with the reference genome of M. bovis AF2122/97 to detect antimicrobial resistance, virulence genes and other genes related to BTB diagnosis. Knowledge of the presence and distribution of NTM in the environment and the evaluation of the specificity of the genes used in the diagnosis of BTB can contribute to better control of the disease, especially in areas declared free of the disease.

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