Prevalence and genetic basis of first-line drug resistance ofMycobacterium tuberculosisin Ca Mau, Vietnam

Abstract

Background and objectiveData on the prevalence of anti-tuberculous drug resistance and its association with genetic mutations inMycobacterium tuberculosisare limited. Our study explores the genomics of tuberculosis in Ca Mau, Vietnam.MethodsPatients ≥15 years in Ca Mau Province, Vietnam, were screened annually for tuberculosis between 2014 and 2017. Isolates underwent drug susceptibility testing (DST) using the breakpoint method. DNA was extracted and whole genome sequencing (WGS) was performed.ResultsWe identified 365 positive sputum cultures forM. tuberculosisand processed 237 for DST and 265 for WGS. Resistance to isoniazid was present in 19.8% (95% CI 14.7 to 24.9%), rifampicin in 3.5% (1.1 to 5.7%) and ethambutol in 2.5% (0.9 to 5.4%) of isolates. Relevant mutations inrpoBgene were detected in 3.8% (1.8 to 6.8%).katG, inhAorfabG1mutations were found in 19.6% (15.0 to 24.9%) withKatGbeing most common at 12.8% (9.1–17.5%). We found 38.4% of isolates were of Beijing lineage, 49.4% East-African-Indian lineage and 8.4% European-American lineage. There were no associations between resistance profiles and clinical features.ConclusionThe high burden of isoniazid resistance and thekatGmutation highlights the challenges facing Vietnam in its efforts to achieve its EndTB goals.