Molecular Analysis of Mycobacterium tuberculosis Isolated in the North Central Zone of Nigeria

Abstract

Tuberculosis (TB) incidence in Nigeria is high, with a significant burden of TB/Human Immunodeficiency Virus (HIV). Genotyping and drug susceptibility of Mycobacterium tuberculosis Complex (MTBC) are important in order to improve the control of the disease. This study sought to determine drug susceptibility and genetic diversity of MTBC in the country. The sputum samples of 202 patients [133 (65.8%) males/69 (34.2%) females] were collected in the North Central zone of Nigeria and cultured using Lowenstein-Jensen medium. Immunochromatography for the primary identification and Drug Susceptibility Testing (DST) by proportion method, as well as IS6110 typing, regions of difference 1, 4, 9, 12, 702, and 711, and spoligotyping were carried out on the isolates. Following the DST on 202 isolates, 51 (25.2%) showed resistance to at least one drug. Multidrug resistance was observed in 29/202 (14.4%) cases. HIV positivity [37/202 (18.3%) patients] was associated with rifampicin 9/37 (24.3%) resistance (p = 0.012) as well as gender (p = 0.009). Of the 202 isolates, 150 (74.3%) were identified as the Cameroon sublineage, followed by the UgandaI, Haarlem, and West Africa 1 with 18 (8.9%), 10 (5%), and 6 (3%), respectively. The LAM10_ CAM was the most prevalent genetic family [128/202 (63.4%)], with the shared international type 61 [111 (55%) isolates] the largest cluster. Gender (p = 0.038) and age (p = 0.015) had significant associations with the LAM10_CAM family but neither with HIV (p = 0.479) nor drug resistance. Rifampicin resistance in TB/HIV coinfected patient is a major concern in the study area. The Mycobacterium africanum lineage showed a marked decrease, and the need to educate females most at risk of TB/HIV coinfection is advocated.

Molecular snapshot of drug-resistant Mycobacterium tuberculosis strains from the Plateau State, Nigeria

“…Molecular epidemiology of human TB in Nigeria has been investigated in a limited number of studies, mainly based on isolates collected in 2014 or before [ 8 – 14 ]. Most of these works have explored M .…”

Molecular epidemiology and multidrug resistance of Mycobacterium tuberculosis complex from pulmonary tuberculosis patients in the Eastern region of Ghana

“…has been proposed earlier [16,32]. Nevertheless, the reduced virulence of M. africanum, its slower rate to progression to active disease as well as its longer latency compared to MTB [33,34] might be factors possibly leading to its decrease over time.…”

“…It could thus be hypothesized that the Cameroon sub-lineage (44.1% in the study area) might be gradually and successfully replacing the Africanum lineages in the Eastern region of Ghana. Opinions are currently divided on the contribution of M. africanum to the burden of TB in the west African region and research on its real impact has been proposed earlier [ 16 , 32 ]. Nevertheless, the reduced virulence of M. africanum , its slower rate to progression to active disease as well as its longer latency compared to MTB [ 33 , 34 ] might be factors possibly leading to its decrease over time.…”

“…Although we cannot infer active transmission of the Cameroon and Ghana genotype clusters in our study considering the low discriminatory power of spoligotyping, the presence of the Cameroon lineage has been largely shown to be present in West African countries including Ghana, Nigeria, Burkina Faso and Cameroon, and could be a reflection of intra-regional free movement of population within the Economic Community of West African States [ 36 ]. The other MTBc lineages belonging to especially to Lineage 4 have been largely observed in the country as well as within other African regions [ 16 , 30 , 32 ]. Lineage 4 has been shown to be geographically widespread [ 18 ], and high recent transmission rate of this lineage has been shown to occur recently in Ghana [ 37 ].…”

“…The emulsified media was subjected to IS6110 and RD deletion typing identifying RD 1, 4, 9, 12, 702, 711 using the methods and primers described elsewhere [16]. Further testing using spoligotyping following manufacturer's instructions (Isogen Bioscience, The Netherlands) was carried as described by Kamerbeek et al [17], on a membrane using the 43-spacer, and the MTBc lineages were grouped as previously defined [18].…”