Disseminated Tuberculosis in Hyrax (Procavia capensis) Caused by Mycobacterium africanum

Gudan, Andrea; Artuković, Branka; Cvetnić, Željko; Špičić, Silvio; Beck, Ana; Hohšteter, Marko; Naglić, Tomo; Bata, Ingeborg; Grabarević, Ž.

doi:10.1638/06-041.1

Cited by 11 publications

(5 citation statements)

References 11 publications

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“…M . africanum has been found in animals, including monkeys, cows, pigs and hyrax [ 89 – 94 ]. Unfortunately, given genomic data from human clinical isolates alone, we cannot address this hypothesis directly.…”

Section: Discussionmentioning

confidence: 99%

Whole Genome Sequencing of Mycobacterium africanum Strains from Mali Provides Insights into the Mechanisms of Geographic Restriction

et al. 2016

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BackgroundMycobacterium africanum, made up of lineages 5 and 6 within the Mycobacterium tuberculosis complex (MTC), causes up to half of all tuberculosis cases in West Africa, but is rarely found outside of this region. The reasons for this geographical restriction remain unknown. Possible reasons include a geographically restricted animal reservoir, a unique preference for hosts of West African ethnicity, and an inability to compete with other lineages outside of West Africa. These latter two hypotheses could be caused by loss of fitness or altered interactions with the host immune system.Methodology/Principal FindingsWe sequenced 92 MTC clinical isolates from Mali, including two lineage 5 and 24 lineage 6 strains. Our genome sequencing assembly, alignment, phylogeny and average nucleotide identity analyses enabled us to identify features that typify lineages 5 and 6 and made clear that these lineages do not constitute a distinct species within the MTC. We found that in Mali, lineage 6 and lineage 4 strains have similar levels of diversity and evolve drug resistance through similar mechanisms. In the process, we identified a putative novel streptomycin resistance mutation. In addition, we found evidence of person-to-person transmission of lineage 6 isolates and showed that lineage 6 is not enriched for mutations in virulence-associated genes.ConclusionsThis is the largest collection of lineage 5 and 6 whole genome sequences to date, and our assembly and alignment data provide valuable insights into what distinguishes these lineages from other MTC lineages. Lineages 5 and 6 do not appear to be geographically restricted due to an inability to transmit between West African hosts or to an elevated number of mutations in virulence-associated genes. However, lineage-specific mutations, such as mutations in cell wall structure, secretion systems and cofactor biosynthesis, provide alternative mechanisms that may lead to host specificity.

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Section: Discussionmentioning

confidence: 99%

Whole Genome Sequencing of Mycobacterium africanum Strains from Mali Provides Insights into the Mechanisms of Geographic Restriction

et al. 2016

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“…Another possibility relies on M. africanum being zoonotic with an animal reservoir limited to West Africa. Infection of animals with M. africanum have been described (Thorel, 1980; Alfredsen and Saxegaard, 1992; Gudan et al, 2008), and a novel MTBC strain closely related to L6 has been isolated from a wild chimpanzee (Coscolla et al, 2013). However, evidence of person to person transmission of M. africanum has also been reported (Winglee et al, 2016), thus suggesting that an animal reservoir is not fully required.…”

Section: Introductionmentioning

confidence: 99%

Experimental Evidence for Limited in vivo Virulence of Mycobacterium africanum

et al. 2019

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Tuberculosis remains a public health problem and a main cause of death to humans. Both Mycobacterium tuberculosis and Mycobacterium africanum cause tuberculosis. In contrast to M. tuberculosis, which is geographically spread, M. africanum is restricted to West Africa. Differences have also been found in the growth rate and type of disease caused by M. africanum, globally suggesting an attenuation of this bacteria. In this study, we used the mouse model of infection to follow the dynamics of M. africanum infection in terms of bacterial burdens and tissue pathology, as well as the immune response triggered. Our findings support a lower virulence of M. africanum as compared to M. tuberculosis, including in mice lacking IFN-γ, a major protective cytokine in tuberculosis. Furthermore, the lung immune response triggered by M. africanum infection in wild-type animals was characterized by a discrete influx of leukocytes and a modest transcriptional upregulation of inflammatory mediators. Our findings contribute to elucidate the pathogenesis of M. africanum, supporting the hypothesis that this is an attenuated member of the tuberculosis-causing bacteria. Understanding the biology of M. africanum and how it interacts with the host to establish infection will have implications for our knowledge of TB and for the development of novel and better tools to control this devastating disease.

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“…2006 ) and M. africanum (Gudan et al . 2008 ), respectively. However, the organism described as M. microti in the former report had the same spoligotype as the dassie bacillus isolated from hyraxes in Australia (Lutze-Wallace et al .…”

Section: Dassie Bacillusmentioning

confidence: 98%

Animal-adapted members of the <i>Mycobacterium tuberculosis</i> complex endemic to the southern African subregion

Clarke

Helden

Miller

et al. 2016

J. S. Afr. Vet. Assoc.

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Members of the Mycobacterium tuberculosis complex (MTC) cause tuberculosis (TB) in both animals and humans. In this article, three animal-adapted MTC strains that are endemic to the southern African subregion – that is, Mycobacterium suricattae, Mycobacterium mungi, and the dassie bacillus – are reviewed with a focus on clinical and pathological presentations, geographic distribution, genotyping methods, diagnostic tools and evolution. Moreover, factors influencing the transmission and establishment of TB pathogens in novel host populations, including ecological, immunological and genetic factors of both the host and pathogen, are discussed. The risks associated with these infections are currently unknown and further studies will be required for greater understanding of this disease in the context of the southern African ecosystem.

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Disseminated Tuberculosis in Hyrax (Procavia capensis) Caused by Mycobacterium africanum

Cited by 11 publications

References 11 publications

Whole Genome Sequencing of Mycobacterium africanum Strains from Mali Provides Insights into the Mechanisms of Geographic Restriction

Whole Genome Sequencing of Mycobacterium africanum Strains from Mali Provides Insights into the Mechanisms of Geographic Restriction

Experimental Evidence for Limited in vivo Virulence of Mycobacterium africanum

Animal-adapted members of the <i>Mycobacterium tuberculosis</i> complex endemic to the southern African subregion

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