Molecular Detection of Multidrug-Resistant Tuberculosis Reveals High Prevalence among Previously Treated Tuberculosis Patients in Burkina Faso

Abstract

Multidrug-resistant tuberculosis (MDR-TB) is a major public health problem worldwide, particularly in Eastern Europe, Russia, and Sub-Saharan Africa due to its prevalence, burden, treatment management difficulties, and socio-economic impacts. Burkina Faso is also facing the challenge of MDR-TB, which is a major public health threat in the country, given the trends in the prevalence and burden of the disease in recent years. The effective control of tuberculosis for its elimination needs to strengthen the prevention and control of MDR-TB. Therefore, assessment, efficient diagnostic tools, prevention of transmission, and effective management of treatment of MDR-TB are very important key measures. The aim of this study was to assess the prevalence of MDR-TB within new and previously treated tuberculosis cases in Burkina Faso. It is a descriptive cross-sectional study conducted from October 2022 to March 2023 at the National Reference Laboratory for Mycobacteria, Ouagadougou, Burkina Faso. Molecular diagnostic tests such as Xpert MTB/RIF and GenoType MTBDR P lus v1, a line probe assay (LPA), were used to detect Mycobacterium tuberculosis complex and to identify drug resistance-associated gene mutations to predict resistance. Among 500 suspected tuberculosis patients’ samples analyzed by the Xpert MTB/RIF assay, 169 (33.7%) patients were positive for Mycobacterium tuberculosis complex, including 100 (59.17%) new TB cases and 69 (40.83%) previously treated patients. Of these 169 TB-positive cases, the global prevalence of MDR-TB predicted based on Xpert MTB/RIF results was 24.26% (41/169). Considering new TB cases (n = 100) and previously treated TB cases (n = 69), the MDR-TB prevalence was very high in previously TB-treated cases, 40.58% (28/69) compared to new TB cases, 13% (13/100). Of the 41 rifampin-resistant cases (or MDR-TB cases based on prediction) detected by Xpert MTB/RIF, a subset of 35 samples (randomly selected) were analyzed by the MTBDR Plus V2 test and revealed 5. 71% (2/35) mono-resistant to rifampicin, 14.28% (5/35) mono-resistant to isoniazid and 74.29% (26/35) multi-resistant (rifampicin + isoniazid). The main genes associated-mutations conferring drug resistance to rifampicin and isoniazid determined by the GenoType MTBDR Plus V2 on the subset strains (N = 35) were D516V (20%), S531L (20%), H526D (15.29%) in rpoB gene for rifampicin resistance and S315T1 (80%), T8C (14.29%) in katG and inhA genes for isoniazid resistance. These mutations are the main ones described and targeted by the Nucleic Acid Amplification Tests (Xpert MTB/RIF, GenoType MTBDR Plus V2, and others). Therefore, Xpert/MTB-RIF and MTBDR Plus tests are expected to be performant in Burkina Faso for the detection of resistance to rifampicin or rifampicin plus isoniazid, as the conferring resistance mutations circulating in this geographical area are mainly those covered by these tests.