Active case finding, diagnosis, and genotyping for tuberculosis in the central Andean zone of Ecuador: a cross-sectional study

Objective Conduct a systematic screening for active TB in the urban population of La Maná, central Andean region of Ecuador, to diagnose and molecularly characterize Mycobacterium tuberculosis strains. Methods An observational cross-sectional study was implemented in La Maná, Cotopaxi Province, Ecuador, from January 20, 2022 to January 21, 2023. The target population included patients with respiratory symptoms aged over 18 years who provided sputum samples. These were subjected to smear microscopy, Lowenstein–Jensen culture, microscopic drug susceptibility testing, 24-loci MIRU-VNTR genotyping, and whole-genome sequencing. Results The active case finding, made it possible to diagnose tuberculosis patients in real time. A total of 161 patients were treated across four urban areas of La Maná. Among them, 40.37% were respiratory symptomatic patients, who provided 119 sputum samples; 15.38% of the patients tested positive by smear microscopy. Two patients with non-tuberculous mycobacteria and two patients with tuberculosis susceptible to isoniazid and rifampicin were identified. These patients were infected with strains of LAM and S sublineage. Conclusions The active case finding identified patients with tuberculosis, facilitating early diagnosis and reducing transmission rates. We obtained genotypic information of the strains circulating in this region, which will be useful for the epidemiological diagnosis of possible outbreaks.