Molecular analysis of multidrug resistantMycobacterium tuberculosis isolates from Morocco

Abstract

Tuberculosis remains a global threat to public health. Considerable efforts have been made to combat this disease. However, the emergence of Mycobacterium tuberculosis (Mtb) strains resistant to the major anti-tuberculosis drugs especially multidrug resistant (MDR) strains poses a deadly threat to control programs. The present study aims to identify the most common mutations within multidrug-resistant M. tuberculosis Moroccan isolates in order to use them as molecular markers for early and rapid detection of multidrug resistant strains. For that, all M. tuberculosis isolates received during 2002-2003 in the National Reference Laboratory of Tuberculosis in Morocco were subject to drug susceptibility tests for rifampicin and isoniazid and to a PCR probe method to detect specific mutation. Sequencing was performed for all genotypic rifampicin resistant isolates and also for four genotypic isoniazid resistant isolates randomly selected. Out of 187 M. tuberculosis positive cultures, 46 (24.6%) were phenotypically resistant to both rifampicin and isoniazid. Nucleotide mutations in rpoB531, rpoB526, rpoB516, katG315 and inh-15 codons associated with resistance to rifampin (RIF) and isoniazid (INH) were found respectively in 37/46 (80.4%) and 43/46 (93.5%) isolates. Genotypic multi drug resistance was then confirmed in 74% (34/46) isolates. The mutations at codon 315 of katG gene and at codons 531, 526 and 516 of rpoB gene are frequently found in MDR isolates which confirm their strong implication in the development of multidrug resistant tuberculosis. We concluded that these mutations are useful as molecular markers for detection of multidrug resistant isolates but are not yet sufficient to fully predict M. tuberculosis multidrug resistance.

Molecular characterization of mutations associated with resistance to second-line tuberculosis drug among multidrug-resistant tuberculosis patients from high prevalence tuberculosis city in Morocco

“…Among the 703 recruited strains, 90 cases were MDR (12.8%), which is in agreement with previously reported data in Morocco [ 3 , 25 ]. DNA genotyping showed that mutations in RRDR region of rpoB gene and, in katG gene and inhA promoter region, are the main SNPs conferring resistance to RIF and INH, respectively, confirming previously reported data [ 21 – 23 ] and reaffirming the usefulness of rpoB , katG and inhA promoter mutations as predictive markers for MDR TB. Moreover, molecular analysis could be limited to rpoB516, rpoB526, rpoB531, katG315 and inhA− 15 mutations, due to their high sensitivity and spectificity, to detect MDR strains.…”

“…It is widely accepted that the knowledge of the Mycobacterium tuberculosis (MTB) resistance spectrum is important for the effective treatment of MDR- and XDR-TB. In Morocco, many studies have already investigated first line drug resistance prevalence and associated genetic mutations [ 21 – 24 ]. However, to our best knowledge, no study has explored the pre-XDR and XDR TB status in Morocco.…”

Molecular Approaches for Detection of the Multi-Drug Resistant Tuberculosis (MDR-TB) in Bangladesh

“…Early detection of MDR-TB is crucial both for the patient management and infection control in TB positive cases [38] . Increased prevalence of drug resistant tuberculosis in Bangladesh and other developing countries is a growing threat to tuberculosis control since a few drugs has so far been found to be effective against TB [3] , [4] , [8] , [38] , [39] , [40] , [41] , [42] , [43] . According to the WHO report in 2010, the estimated MDR-TB among the notified retreatment cases (n = 7795) was 2200 (28%) [44] .…”

Treatment Default amongst Patients with Tuberculosis in Urban Morocco: Predicting and Explaining Default and Post-Default Sputum Smear and Drug Susceptibility Results

“…Samples were cultured on Lowenstein-Jensen media at the regional TB laboratory or the National TB Reference Laboratory (LNRT). Drug susceptibility testing (DST) for isoniazid (H), rifampin (R), ethambutol (E) and streptomycin (S) was performed on all positive cultures at LNRT as previously described [16] . Culture data from one city did not meet quality control standards and were excluded from final analyses.…”