Ahmed Ben Hadj Hassine1,2,3*, Manel Marzouk3, Jamal Saad1, Jalel Boukadida3 and Michel Drancourt1
1Institutes Hospital University Méditerranée Infection, Marseille, France 2Faculty of Pharmacy of Monastir, University of Monastir, Tunisia 3Laboratory of Microbiology and Immunology, UR12SP34, University Hospital Farhat Hatched Sousse, Tunisia
*Corresponding author: benhadjhassine.ahmed@yahoo.fr
Tuberculosis remains one of the leading causes of morbidity and mortality in Arab Maghreb. In this large and diverse geographic region, the dynamic of tuberculosis is contrasted among the different countries. In Tunisia, tuberculosis mortality is decreasing, but its incidence has risen almost one and a half times between 2002 and 2016. To contribute to the knowledge of tuberculosis epidemiology in Center Tunisia, we performed a characterization of Mycobacterium tuberculosis complex mycobacteria isolated over 7 years to depict the dynamics of pulmonary tuberculosis in the region of Sousse and to establish molecular epidemiology. We investigated all the Ziehl-Neelsen-positive isolates made from respiratory tract specimens and related clinical specimens submitted for the routine diagnosis of pulmonary tuberculosis in one university and tertiary care center, Center Tunisia. After heat-inactivation, isolates were identified using rpoB gene sequencing first and quantitative real-time PCR (qRT-PCR) of the internal transcribed spacer (ITS) to confirm the identification of mycobacteria as members of the M. tuberculosis complex. Then, identification at the species level within the M. tuberculosis complex was ensured by PCR-sequencing of the Exact Tandem Repeat D. Finally, the M. tuberculosis Beijing family was identified by using qRT-PCR in the isolates identified as M. tuberculosis sensu strict, which were further genotyped using RD deletion region system to detect lineages. Among 298 M. tuberculosis complex isolates, 294 isolates were identified as M. tuberculosis sensu stricto and four isolates as Mycobacterium bovis BCG. The prevalence of M. tuberculosis in Beijing families steadily increased from 9.52% in 2014 up to 23.33% in 2016. M. tuberculosis was identified as the agent primarily involved in pulmonary tuberculosis and a correlation between the increasing prevalence of Beijing family isolates and increasing incidence of pulmonary tuberculosis was detected.