Abstract
Non-tuberculous mycobacteria (NTM) are not only emerging and opportunistic pathogens of both humans and animals, but from a veterinary point of view some species induce cross-reactive immune responses that hamper the diagnosis of bovine tuberculosis (bTB) in both livestock and wildlife. Little information is available about NTM species circulating in wildlife species of South Africa. In this study, we determined the diversity of NTM isolated from wildlife species from South Africa as well as Botswana. Thirty known NTM species and subspecies, as well as unidentified NTM, and NTM closely related to Mycobacterium goodii/Mycobacterium smegmatis were identified from 102 isolates cultured between the years 1998 and 2010, using a combination of molecular assays viz PCR and sequencing of different Mycobacterial house-keeping genes as well as single nucleotide polymorphism (SNP) analysis. The NTM identified in this study include the following species which were isolated from tissue with tuberculosis- like lesions in the absence of Mycobacterium tuberculosis complex (MTBC) implying their potential role as pathogens of animals: Mycobacterium abscessus subsp. bolletii, Mycobacterium gastri, Mycobacterium species closely related to Mycobacterium goodii/Mycobacterium smegmatis, Mycobacterium brasiliensis, Mycobacterium sinense JMD 601, Mycobacterium avium subsp. avium, Mycobacterium sp. GR-2007, Mycobacterium bouchedurhonense, and Mycobacterium septicum/M. peregrinum. Mycobaterium brasiliensis, Mycobacterium gastri, Mycobacterium sp. GR-2007, and a potential novel Mycobacterium species closely related to Mycobacterium goodii were found for the first time in this study to be potential pathogens of animals. Mycobacterium simiae was isolated from a sample originating from a tuberculin skin test positive reactor, demonstrating its potential to elicit inappropriate immune responses in animals that may interfere with diagnosis of tuberculosis by immunology. Mycobacterium abscessus subsp. bolletti was the most frequently detected NTM identified in 37 of the 102 isolates. Other NTM species were also isolated from animals not showing any pathological changes. Knowledge gained in this study contribute to the understanding of NTM species circulating in wild animals in South Africa and the pathogenic potential of certain species, whose role in disease causation need to be examined, as well as to a certain extent the potential of M. simiae to hamper the diagnosis of bTB.
Highlights
Non-tuberculous mycobacteria (NTM), otherwise known as “mycobacteria other than tuberculosis” (MOTT) or environmental mycobacteria (EM) are believed to be natural inhabitants of the environment, found as saprophytes, commensals, and symbionts in the ecosystem
In this study 30 known NTM species, a species closely related to Mycobacterium goodii and M. smegmatis as well-unidentified species were detected from 102 isolates originating from wild animals in South Africa and Botswana, collected between the years 1998 and 2010
These findings demonstrate a wide diversity of NTM species circulating in the wildlife ecosystems of Southern Africa
Summary
Non-tuberculous mycobacteria (NTM), otherwise known as “mycobacteria other than tuberculosis” (MOTT) or environmental mycobacteria (EM) are believed to be natural inhabitants of the environment, found as saprophytes, commensals, and symbionts in the ecosystem. Botha et al (2013) have reported isolation of the following NTM from different wildlife species including lions, rhinos, banded mongooses, cattle, baboons, elephants, and monkeys: M. abcessus, M. asiaticum, M. avium, M. brasilienses, M. chelonae, M. elephantis, M. engbackii, M. farcinogenes, M. fortuitum, M. gilven, M. gordonae, M. heraklionense, M. hiberniae, M. intracellulare, M. interjectum, M. lentiflavum, M. marseillense, M. moriokaense, M. nonchromogenicum, M. palustre, M. pulveris, M. paraffinicum, M. phlei, M. senegalense, M. simiae, M. sherrisii, M. sphagni, M. terrae, and M. vulneris. This study forms the basis for understanding the diversity of NTM species which are circulating in the South African wildlife as well as potential pathogens of different animal species as well as NTM that may have potentially induced in-appropriate immune responses which interfered with the diagnosis of tuberculosis This information may hopefully aid in the efforts for control of bovine tuberculosis in wildlife through development of diagnostic assays and vaccination strategies
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