Abstract:
Non-tuberculous mycobacteria (NTM) are ubiquitous in the environment and an increasing
number of NTM species have been isolated and characterized from both humans and animals,
highlighting the zoonotic potential of these bacteria. Host exposure to NTM may impact on
cross-reactive immune responsiveness which may affect diagnosis of bovine tuberculosis and
may also play a role in the variability of the efficacy of Mycobacterium bovis BCG
vaccination against tuberculosis. In this study we characterized 10 NTM isolates originating
from water, soil, nasal swabs of cattle and African buffalo as well as bovine tissue samples.
These isolates were previously identified during an NTM survey and were all found, using
16S rDNA sequence analysis to be closely-related to Mycobacterium moriokaense. A
polyphasic approach that includes phenotypic characterization, antibiotic susceptibility
profiling, mycolic acid profiling and phylogenetic analysis of four gene loci, viz 16S rDNA,
hsp65, sodA, and rpoB was employed to characterize these isolates. Sequence data analysis of
the four gene loci revealed that these isolates belong to a unique Mycobacterium species. This
evidence was further supported by several differences in phenotypic characteristics between
the isolates and the closely related species. We proposed the name, Mycobacterium
malmesburyense sp. nov. for this new species. The type strain is WCM 7299T (ATCC® BAA-
2759TM =CIP 110822T). The Genbank accession numbers for the partial gene sequences [16S
rDNA , hsp65, rpoB and sodA] for the type strain are as follows: 16S rRNA= KJ 873241;
hsp65=KJ 873243; rpoB= KJ 873245; sodA= KJ 873247.
