Molecular Epidemiology of Mycobacterium tuberculosis strains isolated from pulmonary tuberculosis patients in south Ethiopia.

INTRODUCTION: Understanding the epidemiology of tuberculosis is limited by lack of genotyping data. We sought to characterize the drug susceptibility testing patterns and genetic diversity of M. tuberculosis isolates in southern Ethiopia. METHODOLOGY: A cross-sectional study was conducted among newly diagnosed sputum smear positive patients with tuberculosis visiting nine health facilities in southern Ethiopia from June 2015 to May 2016. Three consecutive sputum samples (spot-morning-spot) per patient were examined using acid-fast bacilli smear microscopy with all smear positive specimens having acid-fast bacilli cultures performed. M. tuberculosis isolates had drug susceptibility testing performed using indirect proportion method and were genotyped with RD9 deletion analysis and spoligotyping. Mapping of strain was made using geographic information system. RESULTS: Among 250 newly diagnosed patients with tuberculosis, 4% were HIV co-infected. All 230 isolates tested were M. tuberculosis strains belonging to three lineages: Euro-American, 187 (81%), East-African-Indian, 31 (14%), and Lineage 7 (Ethiopian lineage), 8 (4%); categorized into 63 different spoligotype patterns, of which 85% fell into 28 clusters. M. tuberculosis strains were clustered by geographic localities. The dominant spoligotypes were SIT149 (21%) and SIT53 (19%). Drug susceptibility testing found that 14% of isolates tested were resistant to > 1 first line anti- tuberculosis drugs and 11% to INH. SIT 149 was dominant among drug resistant isolates. CONCLUSIONS: The study revealed several clusters and drug resistant strains of M. tuberculosis in the study area, suggesting recent transmission including of drug resistant tuberculosis. Wider monitoring of drug susceptibility testing and geospatial analysis of transmission trends is required to control tuberculosis in southern Ethiopia.

Population-based screening for pulmonary tuberculosis utilizing community health workers in Ethiopia.

OBJECTIVE: To evaluate the utility of a volunteer health development army in conducting population screening for active tuberculosis (TB) in a rural community in southern Ethiopia. METHODS: A population-based cross-sectional survey was conducted in six kebeles (the lowest administrative units). Volunteer women community workers led a symptom screening programme to identify adults ≥15 years of age with TB in the community. Individuals with a cough for ≥2 weeks had spot and morning sputum samples taken, which were examined using acid-fast bacillus (AFB) smear microscopy, culture, and Xpert MTB/RIF. RESULTS: All 24517 adults in the study area had a symptom screen performed; 544 (2.2%) had had a cough for ≥2 weeks. Among those with a positive symptom screen, 13 (2.4%) were positive on sputum AFB smear microscopy, 13 (2.4%) had a positive culture, and 32 (5.8%) had a positive Xpert MTB/RIF test. Overall, 34 TB cases (6%) were identified by culture and/or Xpert, corresponding to a prevalence of 139 per 100000 persons. CONCLUSIONS: This study demonstrated the capability of community health workers (volunteer and paid) to rapidly conduct a large-scale population TB screening evaluation and highlight the high yield of such a programme in detecting previously undiagnosed cases when combined with Xpert MTB/RIF testing. This could be a model to implement in other similar settings.