Identification of Mycobacterium tuberculosis complex species using dual-tube multiplex real-time PCR and determination of their rifampicin and isoniazid resistance profiles: A 5-year study

Background :The identification of species of the Mycobacterium tuberculosis (M. tuberculosis) complex and their resistance profile to the main antibacillary drugs (Rifampicin and Isoniazid) causing tuberculosis could contribute to the tuberculosis control program in a specific geographical region and enrich the existing literature on tuberculosis worldwide. The objective of our study was to identify the MTBC species responsible for pulmonary and extra-pulmonary tuberculosis and to study their resistance profiles to rifampicin and isoniazid in our region. Methods : This is a retrospective study conducted at the bacteriology laboratory of the Mohammed V military training hospital, spread over a 5-year period from January 2017 to December 2021. Isolates were tested for MTBC species identification using dual -Tube Multiplex Real-Time PCR and for rifampicin and isoniazid resistance using the GenoType ® MTBDRplus Ver 2.0 test. Results : Molecular typing using multiplex real-time PCR showed the predominance of M. tuberculosis species in 97%, followed by M. africanum species in 14 isolates, M. microti in 7 isolates and M. bovis in 5 isolates. Non-tuberculous mycobacteria were detected in 6 isolates. For M. tuberculosis strains, the genotyping study showed that 98% of strains were sensitive to rifampicin and 97% were sensitive to isoniazid. Isolated resistance to rifampicin and isoniazid was 1.7% and 3% respectively. Rate of MDR was 5.1%. Conclusions: Knowledge of circulating strains of the Mycobacterium tuberculosis complex in a country or region helps to strengthen the tuberculosis control program and also to provide valuable information for a better understanding of this disease.