ABSTRACT
Although detection of drug-susceptible TB by Anti-Persoonsmijnen Ontmijnende Product Ontwikkeling-trained African giant pouched rats has been known for more than a decade, the detection of drug-resistant TB (DR-TB) using rats has never been explored before. We present what we believe to be the first report on rifampicin-resistant TB (RR-TB) detected using Xpert® MTB/RIF Ultra, comparably identified by rats sniffing sputum samples from presumptive TB patients: 88% of RR-TB detected using Ultra were identified by the rats. Further evaluation of the usefulness of rats for large-scale DR-TB contact triage testing is needed, especially in low- and middle-income countries, where resources are limited.
Bien que la détection de la TB pharmacosensible par des rats géants de Gambie dressés par APOPO (Anti-Persoonsmijnen Ontmijnende Product Ontwikkeling) soit connue depuis plus d'une décennie, la détection de la TB pharmacorésistante (DR-TB) à l'aide de rats n'a jamais été explorée auparavant. Nous présentons ce que nous pensons être le premier rapport sur la TB résistante à la rifampicine (RR-TB) détectée par test Xpert® MTB/RIF Ultra, identifiée de manière comparable par des rats reniflant des échantillons d'expectorations de patients avec une TB présumée : 88% des RR-TB détectées par test Ultra ont été identifiées par les rats. L'évaluation de l'utilité des rats dans le cadre de tests de triage des contacts de cas de DR-TB à grande échelle doit être poursuivie, en particulier dans les pays à revenu faible ou intermédiaire, où les ressources sont limitées.
ABSTRACT
BACKGROUND: Mycobacterium tuberculosis complex (MTBC) and its human host are the most competent organisms with co-evolutionary trajectory. This review determined the phylogeography, clinical phenotype-related genotype and transmission dynamics of MTBC in Africa.METHODS: Spoligotyping and mycobacterial interspersed repetitive units-variable number tandem repeats (MIRU-VNTR) based articles from Africa published in the English language were included. Articles were retrieved from PubMed and Scopus on 12 May 2018.RESULTS: In Africa, respectively 92% and 7% of tuberculosis (TB) cases were caused by M. tuberculosis and M. africanum. Among M. tuberculosis lineages (L), L4 was the predominant, at 67%, followed by L3/Central Asian (CAS; 10%). L7/ETH1 and L5/6/Maf were restricted to the Horn and Western Africa, respectively. L4.6/SIT37, H37Rv like, L4.1.2/Haarlem and H3-Ural were proportionally more frequent among tuberculous lymphadenitis (TBLN) than among pulmonary tuberculosis (PTB) cases. On 24-locus MIRU-VNTR, clustering rate was 31%; the secondary case rate from a single primary source case was 20%.CONCLUSION: Africa in general, and the east-west pole of Africa in particular, harboured a genetically diverse population of MTBC, with characteristics of geographic segregation. Both generalist and specialist genotypes are circulating in the region. L4 is dominant across the continent, while M. bovis is rarely detected as a cause for human TB. The clinical significance of genetic diversity of MTBC in the different geographic and population groups of Africa is not fully understood. Both person-to-person transmission and reactivation mode of TB is significant in Africa. Prevention and control strategies should therefore envisage these two scenarios.
