ABSTRACT
OBJECTIVE/BACKGROUND: Lack of rapid and accurate diagnostic testing is a critical obstacle to global tuberculosis (TB) control. Sensitivity of sputum smear microscopy (SSM) is not optimal; however, it remains the most prevalent tool for TB confirmation in poor countries. As a part of passive case finding of TB detection, this study was conducted to determine the clinical performance of PURE TB-LAMP assay using liquid culture medium as the gold standard. METHODS: Centre Antituberculeux de Yopougon is one of the 17 intermediate Tuberculosis centers in Côte d'Ivoire. A standardized questionnaire was submitted to patients with signs and symptoms consistent with tuberculosis by a trained caregiver. After obtaining signed consent forms, sputum samples were collected according to National TB Control Programme guidelines (spot-morning). SSM after Ziehl-Neelsen staining and TB-LAMP assay were blindly performed on the first sample. Samples transported to Institut Pasteur de Côte d'Ivoire were decontaminated according to the N-acetyl-L-Cystein method. In Mycobacteria Growth Indicator Tube (MGIT), 500mL of pellets were inoculated and incubated in the MGIT 960 system. MPT64 antigen was detected in positive cultures. RESULTS: Of the 500 patients enrolled, 469 (232men and 239 women) patients were included. The mean ages of men and women were 36.9 (15-86) and 37.3 (15-37.3) years, respectively. There were 56 (12.2%) HIV-infected patients, including 14 women. Clinical isolates of M. tuberculosis complex were detected for 157 (33.5%) patients. Compared with culturing, the overall sensitivity and specificity of SSM were 86% (95% confidence interval [CI]=81-91) and 96% (95% CI=94-98), respectively. The overall sensitivity and specificity for TB-LAMP was 92% (95% CI=0.88-0.96) and 94% (95% CI=0.91-0.97), respectively. Positive likelihood ratios for TB-LAMP and SSM were 15.3 and 21.5, respectively, and negative likelihood ratios for TB-LAMP and SSM were 0.09 and 0.15, respectively. Among the 469 patients, active tuberculosis was detected using TB-LAMP assay and SSM in 162 (34.5%) and 147 (31.3%) patients, respectively. CONCLUSION: For accurate diagnostic of pulmonary TB, TB-LAMP could be used as a tool of the first intention.
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[This corrects the article on p. 166 in vol. 4, PMID: 25215193.].
ABSTRACT
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 Gene-Xpert 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.
ABSTRACT
UNLABELLED: 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. CONCLUSION: 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.
