Comparative evaluation of three immunochromatographic identification tests for culture confirmation of Mycobacterium tuberculosis complex

Abstract

BackgroundThe rapid identification of acid-fast bacilli recovered from patient specimens as Mycobacterium tuberculosis complex (MTC) is critically important for accurate diagnosis and treatment. A thin-layer immunochromatographic (TLC) assay using anti-MPB64 or anti-MPT64 monoclonal antibodies was developed to discriminate between MTC and non-tuberculosis mycobacteria (NTM). Capilia TB-Neo, which is the improved version of Capilia TB, is recently developed and needs to be evaluated.MethodsCapilia TB-Neo was evaluated by using reference strains including 96 Mycobacterium species (4 MTC and 92 NTM) and 3 other bacterial genera, and clinical isolates (500 MTC and 90 NTM isolates). M. tuberculosis isolates tested negative by Capilia TB-Neo were sequenced for mpt64 gene.ResultsCapilia TB-Neo showed 100% agreement to a subset of reference strains. Non-specific reaction to M. marinum was not observed. The sensitivity and specificity of Capilia TB-Neo to the clinical isolates were 99.4% (99.6% for M. tuberculosis, excluding M. bovis BCG) for clinical MTC isolates and 100% for NTM isolates tested, respectively. Two M. tuberculosis isolates tested negative by Capilia TB-Neo: one harbored a 63-bp deletion in the mpt64 gene and the other possessed a 3,659-bp deletion from Rv1977 to Rv1981c, a region including the entire mpt64 gene.ConclusionsCapilia TB-Neo is a simple, rapid and highly sensitive test for identifying MTC, and showed better specificity than Capilia TB. However, Capilia TB-Neo still showed false-negative results with mpt64 mutations. The limitation should be recognized for clinical use.

Extra pulmonary tuberculosis: Rapid identification of Mycobacterium tuberculosis grown in Mycobacterium growth indicator tube 960 and Lowenstein-Jensen media, employing Standard diagnostics Bioline Mycobacterium tuberculosis protein 64 antigen detection kit

“…Several reports from different countries recorded specifi city of nearly 100% and sensitivity ranging from 95% to 100% for the rapid MPT64 antigen detection kits in comparison to conventional methods for identifying MTB. [2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19] We have experienced 100% sensitivity and specifi city of this particular kit in comparison to conventional techniques. Our local strains are thus recognised by SD Bioline kit of Korean origin.…”

“…Our local strains are thus recognised by SD Bioline kit of Korean origin. [5,[10][11][12][13][14][15][16][17] In India, SD Bioline kit has been validated by fi ve different researchers: [5,[10][11][12][13] Maurya et al, [5] from Lucknow reported 99.1% sensitivity and 100% specifi city. Kannade et al, [11] from Bombay (Mumbai) examined 165 isolates (125 MTB; 30 NTM; 10 Non-Mycobacterial species) and observed sensitivity of 99.19% and 100% values for specifi city, positive predictive value (PPV) and negative predictive value (NPV).…”

Validation of nanodiamond-extracted CFP-10 antigen as a biomarker in clinical isolates of Mycobacterium tuberculosis complex in broth culture media

“…The sensitivity and specificity of the BD MGIT TBc Identification test were 97.3% and 100%, respectively [27]. Capilia TB-Neo, which is the improved version of Capilia TB, was recently developed and showed a sensitivity and specificity of 99.4% and 100%, respectively [28]. The SD Bioline TB Ag MPT64 rapid test showed a sensitivity of 99.19% and a specificity of 100% [29].…”

Immunochromatographic Detection of MPB64 Secreted from Active BCG by Heating: Toward Same-Day Diagnosis of Tuberculosis

“…The antibodies used were the same as those in the Capilia TB-Neo assay [10]. The detection sensitivity was much higher than that of the Capilia TB-Neo assay, whose limit of detection (LOD) is reported to be 1.2 × 10 6 CFU/ml (values for the present method are shown in Table 1) [9].…”

“…To detect MPB64 protein, we manufactured an immunochromatographic assay based on the Capilia TB-Neo assay (TAUNS, Shizuoka, Japan) [10]. Briefly, the main modification was changing the colloidal particles from gold colloid to platinum–gold colloid.…”