Abstract:
Background Despite global tuberculosis (TB) interventions, the disease remains one of the major public health concerns. Kenya is ranked 15th among 22 high burden TB countries globally.
Methods A cross-sectional study was conducted in Western Kenya, which comprises 10 counties. A multistage sampling method was used where a single sub-county was randomly selected followed by sampling two high volume
health facility from each sub-county. Identifcation of spoligotype profles and their family distribution and lineage
level were achieved by comparison with SITVIT database.
Results Lineage distribution pattern revealed that the most predominant lineage was CAS 220 (39.8%) followed
by Beijing 128 (23.1%). The other lineages identifed were T, LAM, H, X, S and MANU which were quantifed as 87
(15.7%), 67 (12.1%), 16 (2.8%), 10 (1.8%), 8 (1.4%) and 5 (0.9%) respectively. CAS and Beijing strains were the most predominant lineage in both HIV negative and positive TB patients. The Beijing lineage was also the most predominant
in resistant M. tuberculosis strains as compared to wild type. A total of 12 (2.0%) were orphaned M. tuberculosis strains
which were spread across all the 10 counties of the study site. In multivariate logistic regression adjusting for potential cofounders three potential risk factors were signifcant. HIV status (OR=1.52, CI=0.29–3.68 and P value of 0.001),
Alcohol use (OR=0.59, CI=0.43–3.12 and P-value =0.001) and cross border travel (OR=0.61, CI=0.49–3.87 and P
value=0.026). Most M. tuberculosis clinical isolates showed genetic clustering with multivariate logistic regression
indicating three potential risk factors to clustering. HIV status (OR=1.52, CI=0.29–3.68 and P value of 0.001), Alcohol
use (OR=0.59, CI=0.43–3.12 and P-value =0.001) and cross border travel (OR=0.61, CI=0.49–3.87 and P value=0.026).
Conclusion There exist diverse strains of M. tuberculosis across the 10 counties of Western Kenya. Predominant distribution of clustered genotype points to the fact that most TB cases in this region are as a result of resent transmission
other than activation of latent TB.
