Abstract:

Objective: To investigate the distribution of Mycobacterium tuberculosis (MTB) genotypes in the Kashgar region and to analyze the correlation between these genotypes and the clinical characteristics of pulmonary tuberculosis patients. Methods: MTB strains were collected from tuberculosis-designated hospitals in Kashgar in 2020. The study included 810 tuberculosis patients with complete case information and their corresponding 810 MTB clinical isolates. Case information for the pulmonary tuberculosis patients was retrieved from the “Tuberculosis Management Information System” encompassing the patient’s name, gender, age, occupation, clinical symptoms, imaging findings, treatment history, treatment plan, and treatment outcome. MTB strains were genotyped and their lineages identified using the Illumina HiSeq second-generation sequencing platform. Results: Among the 810 MTB strains, 292 strains (36.0%) belonged to Lineage2, 321 strains (39.6%) belonged to Lineage3, and 197 strains (24.4%) belonged to Lineage4. The distribution of MTB lineages varied across different counties and cities, including Kashgar, Shufu County, and Shule County. Among the 572 effectively measured sublineages, Lineage 2.2.1 accounted for 44.6% (255/572) and Lineage2.2.2 accounted for 6.8% (39/572); the Lineage3.1.3 sublineage accounted for 14.9% (85/572). Lineage4 showed a wide differentiation into sublineages, namely Lineage4.1 to Lineage4.9, with the Lineage4.5 sublineage comprising 29.9% (171/572). There was no significant difference between the strain lineage and the clinical symptoms of the patients. However, compared with other lineages, individuals infected with Lineage3 strains had a lower proportion of sputum smear positivity (27.7%, 89/321) and a higher proportion of clear cure (37.1%, 119/321). These differences were statistically significant (χ² values were 6.192 and 24.558, respectively, with P values <0.05). Conclusion: The distribution of MTB lineages and sublineages in the Kashgar region demonstrates genetic polymorphism. Lineage3 infections are associated with a low sputum smear positivity rate and a high clinical cure rate.

Key words: Mycobacterium tuberculosis, Bacterial genome, Single nucleotide polymorphism, Disease characteristics