Mapping Mycobacterium tuberculosis genetic diversity in the gulf of guinea – africa

Abstract

Aims and objectives: Tuberculosis (TB) worldwide re-emergence constitutes a major public health problem with multi-drug resistant (MDR) strains becoming a greater threat. 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 three West/Central African countries, namely Cameroon, Nigeria and Ghana located in the Gulf of Guinea. Methods: A collection of 498 isolates (150 from Cameroon, 202 from Nigeria and 146 from Ghana) obtained from culture using Lowenstein–Jensen medium, Middlebrook 7H9 Broth and/or Xpert MTB/RIF and Line Probe Assay (LPA) were included in the study and some isolates tested for drug susceptibility using the proportion method. Isolates were further subjected to IS6110 typing, region of difference 1, 4, 9, 12, 702, 711, spoligotyping and hsp65 gene sequencing analysis. Results: The LAM10_CAM was the most prevalent genetic family [128/202 (63.4%) in Nigeria, 46/123 (37.4%) in Ghana and 54/150 (36%) in Cameroon] and SIT 61 the largest cluster with 111/202 (55%) and 43/150 (27%) isolates in Nigeria and Cameroon respectively. Multidrug resistance (MDR) was observed in 29/202 (14.4%) cases in Nigeria, and 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). In Cameroon, 13/147 (8.8 %) were resistant to rifampicin (RIF), with 6 (46.2%) of the 13 RIF resistant isolates associated with UgandaI sub-lineage (p=0.0007). Other sublineages such as Haarlem, Ghana, West African 1 were recorded in the three countries. Conclusion: Rifampicin resistance in TB/HIV co-infected patient and its association with a sublineage calls for a reinforced surveillance strategy to curb drug resistance development in the Gulf of Guinea.