We conducted an evaluation study on the GenoType MTBDRplus assay's ability to detect mutations conferring resistance to rifampin and isoniazid directly from sputum taken from 120 smear positive pulmonary patients from tuberculosis (TB) centers in Cote d'Ivoire.The sputum was decontaminated by N-acetyl-l-cysteine (NALC) and comparatively analyzed with the MTBDRplus assay version 2.0 and the mycobacterial growth indicator tube (MGIT) 960 automated drug susceptibility testing (MGIT-DST). The GeneXpert Mycobacterium tuberculosis (MTB)/rifampicin (RIF) assay was performed for 21 sputa with absence of hybridization for at least one rpoB wild-type probes. Four and seven, respectively, discordant and concordant results were also analyzed.The mutations in the rpoB gene were 21 (17.5%), 20 (16.7%), 7 (5.8%), and 10 (8.3%), respectively, for D516V, H526Y, H526D, and S531L. S315T mutation in katG gene associated or not with mutation in promoter of inhA was detected in 76 (63.3%) of the sputum. Compared to MGIT-DST, the sensitivity and specificity of the MTBDRplus for rifampin resistance detection were 100% (75-100%) and 73.2% (61.3-84%), respectively. For isoniazid resistance detection, the sensitivity and specificity were, respectively, 95% (90-99) and 95.1% (88.5-100%).Interpretation of 16 sputa without hybridization of rpoB wild-type probe 8 compared to those obtained with MGIT-DST and GeneXpert MTB/RIF was discordant and concordant, respectively, for 11 and 5.

Drug-resistant tuberculosis is an important health problem in Côte d'Ivoire. Patients of category I treatment are based on 2RHZE/4RH regimen. For the patients of category II, the 2RHZES/1RHZE/5HRE regimen is systematically initiated. Study objective was to describe the susceptibility profile to Rifampin and Isoniazid among previously treated patients who are eligible for retreatment and who had received the 2RHZES/1RHZE/5HRE regimen in Côte d'Ivoire with a molecular method in 2012. Two sputum samples were collected to each patient recruited in the reference regional centres for tuberculosis. Sputum samples were decontaminated by NALC method. The DNA extraction was realized with 500 µl of decontaminated sputum sample with smear-positive. MTBDRplus assay version 1.0 was performed according to the manufacturer's instruction. An internal quality control program with positive and negative controls was implemented for interpretation of results. A total of 278 patients were enrolled, 148 (53.2%) were recurrent TB cases, 118 (42.5%) failure cases, and 12 (4.3%) defaulters. From sputum of previously treated patients, mutli-drug resistant tuberculosis was diagnosed for 60 (69.8%, 95% IC, 60%-80%) treated with the 2RHZE/4RH regimen, 24 (75%, 95% IC, 60%-90%) with the 2RHZES/1RHZE/5HRE regimen, 60 (41%, 95% IC, 33%-49%) recurrent TB cases, and 4 (33.3%) defaulters. The comparison of resistance rates to Rifampin estimated from sputum samples in the categories of treatment failures and the recurrence TB cases showed a statistically significant difference. In Côte d'Ivoire, genotype ® MTBDRplus assay has permitted to estimate the prevalence of MDR-TB in categories of previously treated patients for tuberculosis.

Use of a rapid method to detect drug-resistance in recurrent TB cases has permitted to identify patients eligible for first-line drugs or not.