Molecular Detection of Resistance to Rifampin and Isoniazid among Patients Eligible for Retreatment Regimen in Côte d’Ivoire in 2012

Drug-resistant tuberculosis is an important health problem in Cote 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 Cote 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 Cote d’Ivoire, genotype? MTBDRplus assay has permitted to estimate the prevalence of MDR-TB in categories of previously treated patients for tuberculosis.

QBC ParaLens^(TM) LED fluorescent microscope attachment with QBC F.A.S.T.^(TM) AFB staining system

This study was designed to evaluate the QBC ParaLensTM LED fluorescent microscope attachment and the QBC F.A.S.T.TM AFB staining system for the detection of Acid Fast Bacilli in pathological samples in Abidjan, Cote d’Ivoire. A total of 50 patients were tested using direct smear specimens with both Ziehl-Neelsen (ZN) light microscopy and LED fluorescence microscopy with QBC F.A.S.T. AFB stain. The samples were also cultured and tested using an immunochromatograpic test for detection of antigen MPT 64 and the results were compared to direct examination. ZN light microscopy detected 20 positive cases and LED fluorescent microscopy with QBC F.A.S.T. AFB stain detected 21. The sensitivity and specificity of ZN light microscopy was determined to be 84.2% and 87.1% respectively. The sensitivity and specificity of LED fluorescent microscopy with QBC F.A.S.T. AFB stain was determined to be 94.7% and 90.3% respectively. Compared to ZN light microscopy, LED fluorescent microscopy with QBC F.A.S.T. AFB stain increased the sensitivity of direct examination without concentration by 10.5%.

GenoType MTBDRplus as a Complementary Tool for the Typing of Mycobacterium tuberculosis

The aim of this study was to investigate the usefulness of combining profiles obtained by using a line probe assay (LPA) originally intended to characterize the resistance of two major anti-tuberculosis drugs to the association of spoligotyping and MIRU-VNTR, in order to improve its discriminatory power. For this purpose, 74 strains of Mycobacterium tuberculosis belonging to the same cluster after spoligotyping were further typed by using the 24 loci MIRU/VNTR. These strains were then tested by the GenoType MTBDRplus, and profiles obtained were analyzed within previously obtained clusters. The combination of spoligotying and MIRU-VNTR led to the consolidation of 56 of them (75.7%) in 9 clusters. Most of the strains (54, 96.4%) were multidrug resistant (MDR). From the 9 initial clusters, the addition of GenoType MTBDRplus helped to define 26 profiles including 11 unique profiles, and 3 original clusters remained undifferentiated. Results obtained express the relevance of combining this method which improved quite significantly the discriminatory power in typing Mycobacterium tuberculosis.