Abstract:
BACKGROUND : The tuberculosis (TB) epidemic remains a major global health problem and Eswatini is not excluded.
Our study investigated the circulating genotypes in Eswatini and compared them at baseline (start of treatment)
and follow-up during TB treatment.
METHODS : Three hundred and ninety (n = 390) participants were prospectively enrolled from referral clinics
and patients who met the inclusion criteria, were included in the study. A total of 103 participants provided specimens
at baseline and follow-up within six months. Mycobacterium tuberculosis (M.tb) strains were detected by GeneXpert
® MTB/RIF assay (Cephied, USA) and Ziehl -Neelsen (ZN) microscopy respectively at baseline and follow-up
time-points respectively. The 206 collected specimens were decontaminated and cultured on BACTEC™ MGIT™
960 Mycobacteria Culture System (Becton Dickinson, USA). Drug sensitivity testing was performed at both baseline
and follow-up time points. Spoligotyping was performed on both baseline and follow-up strains after DNA extraction.
RESULTS : Resistance to at least one first line drug was detected higher at baseline compared to follow-up specimens
with most of them developing into multidrug-resistant (MDR)-TB. A total of four lineages and twenty genotypes were
detected. The distribution of the lineages varied among the different regions in Eswatini. The Euro-American lineage
was the most prevalent with 46.12% (95/206) followed by the East Asian with 24.27% (50/206); Indo-Oceanic at 9.71%
(20/206) and Central Asian at 1.94% (4/206). Furthermore, a high proportion of the Beijing genotype at 24.27%
(50/206) and S genotype at 16.50% (34/206) were detected. The Beijing genotype was predominant in follow-up
specimens collected from the Manzini region with 48.9% (23/47) (p = 0.001). A significant proportion of follow-up
specimens developed MDR-TB (p = 0.001) with Beijing being the major genotype in most follow-up specimens
(p < 0.000).
CONCLUSION : Eswatini has a high M.tb genotypic diversity. A significant proportion of the TB infected participants
had the Beijing genotype associated with MDR-TB in follow-up specimens and thus indicate community wide
transmission.
