Spoligotyping-based molecular typing of complex isolated from Metahara sugar factory workers in Central Ethiopia.

BACKGROUND

Understanding the genetic makeup of complex (MTBC) strains is crucial, as lineage differences influence transmissibility, pathogenicity, and drug resistance patterns, all of which are essential for understanding MTBC transmission dynamics and designing effective TB control strategies. The present study investigated the genetic diversity of complex among pulmonary tuberculosis (TB) patients employed at Metahara Sugar Factory, located in Fentale district, East Showa Zone Oromia, central Ethiopia.

METHODS

A cross-sectional study was conducted among 390 suspected pulmonary TB patients. Sputum samples were examined using Ziehl-Neelsen staining and cultured, followed by molecular characterizations of the isolates using region of difference 9 (RD9) deletion typing and spoligotyping.

RESULTS

Out of 390 participants, 96 (24.6%) were smear positive, and 89 (22.8%) were culture positive. RD9 deletion typing confirmed 88 isolates as . Further characterization of the 88 isolates using spoligotyping revealed 28 distinct spoligotyping patterns of which 15 unique (single isolates), and 13 shared among 73 clustered isolates. Among these, 19 matched shared international type (SITs) in the SpolDB4 database, while, 9 were novel (orphan) patterns. The predominant SITs were SIT523 (19.32%), SIT53 (13.6%), SIT149 (9.1%) and SIT289 (7.95%). Lineage analysis using TB-insight RUN TB-Lineage classified the strains primarily as Euro-American (63.64%), followed by Indo-Oceanic (20.45%), East-African-Indian (14.77%) and (1.14%).

CONCLUSION

The high clustering rate observed may suggest recent transmission; however, this must be interpreted cautiously due to the limited discriminatory power of spoligotyping, which may overestimate clustering and underestimate diversity. This underscores the need for targeted TB control strategies informed by enhanced molecular surveillance.