Title : Genetic strains of mycobacterium tuberculosis among indigenous populations: A molecular epidemiology analysis of first nation communities in Northern Saskatchewan
Abstract:
Background: Despite national progress towards the elimination of new infections, Tuberculosis (TB) remains a significant public health concern in Northern Saskatchewan (NS), Canada, disproportionately affecting Indigenous populations. The transmission dynamics and genetic strains of Mycobacterium TB (MTB) in this population are poorly understood.
Objective: Our study sought to:
1. Identify the predominant MTB strain among First Nation on-reserve Communities in Northern Saskatchewan.
2. Test associations of the predominant MTB strain with key demographic and clinical characteristics of First Nation on-reserve Communities in Saskatchewan.
Methods: This cross-sectional study utilized anonymized secondary data extracted from the Roy Romanow Provincial Laboratory (RRPL) database in Saskatchewan. We included all confirmed cases of active Mycobacterium Tuberculosis between 2013 and 2023 who had Mycobacterial Interspersed Repetitive-Unit Variable Number of Tandem Repeats (MIRU-VNTR) genotyping results in the database and were from the First Nations On-reserve communities in Northern Saskatchewan. Lineages and strain nomenclature were determined using the TB Profiler 6.4.0. Outcome Measure: A categorical (nominal) variable signifying the genetic strains (lineage) of MTB
genotype in the First Nation on-reserve population. Data Analysis: Pearson’s chi-square test of independence compared proportions, and multivariate logistic regression was performed to test associations between the predominant MTB genetic strain and key independent variables. All statistically significant (p < 0.25) were considered for inclusion in multivariate analysis, and results were reported as adjusted odds ratios (aOR) with 95% confidence intervals (CI) and statistical significance at p value ?0.05.
Results: Of the 181 TB cases with genotyping results, the mean age was 37.4 ± 17.6, 118 (65.2%) male, 76 (41.9%) from the Far North-East region. Majority, 179 (98.9%), had initiated treatment with a 78% completion rate and 166 (91.7%) HIV - negative. The predominant genotype lineage was the Euro-American-L4.4.1.1, found in 70.1% of the cases. Individuals residing in the Far North-West were 14 (p < 0.001, aOR 14.2; CI: 4.9 – 40.8) times more likely to have the predominant genotype compared to those in the Far North-East.
Conclusions/Recommendations: Although this study determined a molecular homogeneity of MTB in Northern Saskatchewan with the predominant genotype Euro-American L4.4.4.1, addressing regional differences in strain distribution is relevant for developing culturally appropriate TB programs aimed at eliminating TB among specific Indigenous sub-populations in Northern Saskatchewan.
