Use of rapid molecular test for multidrug-resistant tuberculosis detection among relapse cases in Cote d'Ivoire

Tuberculosis is explicitly recognized as a major global public health problem. In Côte d'Ivoire, relapse cases represent 66.5% of patients eligible for retreatment according to the National Tuberculosis Control Program. This study objective was to detect multidrug-resistance tuberculosis among relapse cases. Patients were recruited in tuberculosis centers in routine. A standardized questioning was administrated. Two sputum samples were collected and transported at Institut Pasteur. Sputum samples were decontaminated by NALC method. The DNA extraction was realized with 500μl of decontaminated sputum sample with smear-positive. MTBDRplus assay version 2.0 was performed according to the manufacturer's instruction. An internal quality control program with positive and negative controls was implemented for interpretation of results. In total 146 relapse cases with smear positive were studied. Out of selected patients, 130 had received the 2RHZE/4RH regimen and 16, the 2RHZES/1RHZE/5HRE. In group of relapse cases previously treated with 2RHZE/4RH regimen, 40 (31.3%, IC95%: [0.23; 0.39]) had punctual mutations at codon 526 in rpoB gene. Although, in patients under treated with 2RHZES/1RHZE/5HRE, a mutation in rpoB gene was identified in 12 of 16 sputum samples. Thirteen mutations conferring a resistance to Isoniazid were observed of which 9 in katG gene and 4 in katG and promoter region of inhA gene. The comparison (Chi-square with Yates correction) of resistance rates to Rifampin estimated showed a statistically significant difference.

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.