African Journal of
Microbiology Research

  • Abbreviation: Afr. J. Microbiol. Res.
  • Language: English
  • ISSN: 1996-0808
  • DOI: 10.5897/AJMR
  • Start Year: 2007
  • Published Articles: 5183

Full Length Research Paper

Molecular genotypes of Mycobacterium tuberculosis strains circulating in Dakar, Senegal

Awa Ba Diallo
  • Awa Ba Diallo
  • Mycobacteriology Unit, Bacteriology Virology Laboratory at CHU Aristide Le Dantec, Dakar, Senegal.
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Ossaga Gedeon Walbang
  • Ossaga Gedeon Walbang
  • Mycobacteriology Unit, Bacteriology Virology Laboratory at CHU Aristide Le Dantec, Dakar, Senegal.
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Makhtar Camara
  • Makhtar Camara
  • Mycobacteriology Unit, Bacteriology Virology Laboratory at CHU Aristide Le Dantec, Dakar, Senegal.
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Seynabou Lo
  • Seynabou Lo
  • Faculty of Health Sciences, Gaston Berger University, Saint Louis Senegal.
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Abigail Ayorinde
  • Abigail Ayorinde
  • Medical Research Council Unit, Fajara, The Gambia.
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Aliou Niang
  • Aliou Niang
  • Pulmonology Clinic at CHU Fann Hospital, Dakar Senegal.
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Souleymane Mboup
  • Souleymane Mboup
  • Mycobacteriology Unit, Bacteriology Virology Laboratory at CHU Aristide Le Dantec, Dakar, Senegal.
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Aissatou Gaye Diallo
  • Aissatou Gaye Diallo
  • Mycobacteriology Unit, Bacteriology Virology Laboratory at CHU Aristide Le Dantec, Dakar, Senegal.
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Bouke Catherine de Jong
  • Bouke Catherine de Jong
  • Medical Research Council Unit, Fajara, The Gambia.
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Florian Gehre
  • Florian Gehre
  • Medical Research Council Unit, Fajara, The Gambia.
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  •  Received: 19 June 2016
  •  Accepted: 19 August 2016
  •  Published: 21 September 2016

Abstract

Tuberculosis is a contagious infectious disease, in which epidemiologic monitoring by molecular approaches is a critical element of prevention and control. The population structure of the Mycobacterium tuberculosis complex (MTBc) in Senegal was last described in the 1970’s using biochemical methods. In this present study, we applied molecular approaches to genotype M. tuberculosis isolates from active pulmonary tuberculosis patients who participated in a prospective cohort study between 2004 to 2006. Genetic characterization, using standard spoligotype analysis and Line Probe Assay for resistance to isoniazid and rifampicin, was applied after culture on egg based solid media. The prevalence of resistance to isoniazid was 1.0% and to rifampicin 0.0% among 203 isolates tested. Of the 203 isolates, spoligotype patterns present in the TB-insight database were identified  in 178 (87.6%) while 25 (12.3%) showed patterns suggestive of mixed infection. The major spoligotypes identified were the Haarlem lineage (22%), followed by the T (19%), Beijing (12%), LAM (12%), and M. africanum West African 2 (10%). Patterns suggestive of mixed infections, such as the sole lack of spacers 33 and 34, suggested a combination of Euro-American M. tuberculosis and Beijing lineage,  which were confirmed by polymerase chain reactions (PCRs) for lineage defining deletions in a subset of isolates. The population structure of the M. tuberculosis complex in Dakar reflects a predominance of Euro-American M. tuberculosis (Haarlem, T and LAM), with a decreased prevalence of M. africanum West African 2, compared with reports from the 1970’s based on biochemical speciation, which reported prevalence of M. africanum around 20% in Dakar.

Key words: Tuberculosis, Mycobacterium tuberculosis complex, polymerase chain reactions (PCRs).