Imane Chaoui
Science and Nuclear Techniques (CNESTEN)
France
Title: The possible occurrence of Extensively Drug-Resistant Tuberculosis within Multidrug-Resistant Mycobacterium tuberculosis isolates from Morocco: retrospective study
Biography
Biography: Imane Chaoui
Abstract
Background: The emergence of extensively drug-resistant tuberculosis (XDR-TB) has raised public Heath concern for global control of TB. Although molecular characterization of drug resistance-associated mutations in multidrug-resistant isolates in Morocco has been made, mutations in XDR isolates and their genotypes have not been reported previously. Resistance to second line antituberculosis drugs (SLDs) Is mainly due to mutations in specific genes: gyrA and gyrB for resistance to fluoroquinolones (FQs), rrs, eis and tlyA for resistance to injectable drugs (kanamycin (KAN), amikacin (AMK), and capreomycin (CAP). Methods: A laboratory collection of 90 MTB isolates already characterized as MDR and 60 susceptible isolates randomly selected were enrolled in this retrospective study. The mutation profiles associated with resistance to SLDs: FQs and injectable drugs were assessed by DNA sequencing. Target sequences for four genes were examined: gyrA and gyrB (FQs), and rrs (KAN, AMK, and CAP) and tlyA (CAP). All samples had their fingerprint already established by spoligotyping. Results: Molecular analysis showed that 26.7% of MDR isolates are pre-XDR strains and harbored mutations in gyrA gene. The Most prevalent mutations involved in FQ resistance was Asp94Gly (50%). None of the isolates harbored mutations neither in gyrB nor in rrs genes. The sensitivity for the detection of FQs resistance by DNA sequencing could not be evaluated because of the lack of the information regarding DST for SLDs. All pre-XDR strains belong to LAM Lineage (LAM4 and LAM9) raising the possible emergence of a specific clone. Conclusion: The results of this préliminaire study highlight the need for rapid detection of mutations associated with resistance to SLDs in order to adjust timely the treatment and to interrupt the propagation of virtually untreatable form of the diseuse. Keywords: Morocco, Mycobacterium tuberculosis, extremely drug resistant, gyrA, gyrB, rrs, tlyA, sequencing