Comparative Evaluation of Two Commercial Assays for Direct Detection of Mycobacterium tuberculosis in Respiratory Specimens

1998 ◽  
Vol 17 (3) ◽  
pp. 151-157 ◽  
Author(s):  
F. Gamboa ◽  
J. M. Manterola ◽  
J. Lonca ◽  
L. Matas ◽  
P. J. Cardona ◽  
...  
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Comparative Evaluation ◽  
Direct Detection ◽  
Respiratory Specimens

scholarly journals Direct Detection of Pyrazinamide Resistance in Mycobacterium tuberculosis by Use of pncA PCR Sequencing

2019 ◽  
Vol 57 (8) ◽  
Author(s):  
Kingsley King-Gee Tam ◽  
Kenneth Siu-Sing Leung ◽  
Gilman Kit-Hang Siu ◽  
Kwok-Chiu Chang ◽  
Samson Sai-Yin Wong ◽  
...  
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Direct Detection ◽  
Drug Susceptibility ◽  
Multidrug Resistant ◽  
Activity Data ◽  
Content Type ◽  
Treatment Regimens ◽  
Mdr Tb ◽  
Resistant Strains ◽  
Respiratory Specimens

ABSTRACT An in-house-developed pncA sequencing assay for analysis of pyrazinamide (PZA) resistance was evaluated using 162 archived Mycobacterium tuberculosis complex (MTBC) isolates with phenotypic PZA susceptibility profiles that were well defined by analysis of Bactec MGIT 960 PZA kit and PZase activity data. Preliminary results showed 100% concordance between pncA sequencing and phenotypic PZA drug susceptibility test (DST) results among archived isolates. Also, 637 respiratory specimens were prospectively collected, and 158 were reported as MTBC positive by the Abbott Realtime MTB assay (96.3% sensitivity [95% confidence interval {CI}: 92.2% to 98.7%]; 100% specificity [95% CI: 99.2% to 100.0%]). Genotypic and phenotypic PZA resistance profiles of these 158 MTBC-positive specimens were analyzed by pncA sequencing and Bactec MGIT 960 PZA kit, respectively. For analysis of PZA resistance, pncA sequencing detected pncA mutations in 5/5 (100%) phenotypic PZA-resistant respiratory specimens within 4 working days. No pncA mutations were detected among PZA-susceptible specimens. Combining archived isolates with prospective specimens, 27 were identified as phenotypic PZA resistant with pncA mutation. Among these 27 samples, 6/27 (22.2%) phenotypic PZA-resistant strains carried novel pncA mutations without rpsA and panD mutations. These included 5 with mutations (a deletion [Del] at 383T [Del383T], Del 380 to 390, insertion of A [A Ins] at position 127, A Ins at position 407, and G Ins at position 508) in pncA structural genes and 1 with a mutation (T-12C) at the pncA promoter region. All six of these strains had no or reduced PZase activities, indicating that the novel mutations might confer PZA resistance. Additionally, 25/27 phenotypic PZA-resistant strains were confirmed multidrug-resistant tuberculosis (MDR-TB) strains. As PZA is commonly used in MDR-TB treatment regimens, direct pncA sequencing will rapidly detect PZA resistance and facilitate judicious use of PZA in treating PZA-susceptible MDR-TB.

Evaluation of the upgraded amplified mycobacterium tuberculosis direct test (gen-probe) for direct detection of mycobacterium tuberculosis in respiratory and non-respiratory specimens

2001 ◽  
Vol 41 (1-2) ◽  
pp. 51-56 ◽  
Author(s):  
Luis Alcalá ◽  
Marı́a Jesús Ruiz-Serrano ◽  
Susana Hernangómez ◽  
Mercedes Marı́n ◽  
Darı́o Garcı́a de Viedma ◽  
...  
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Direct Detection ◽  
Direct Test ◽  
Respiratory Specimens

scholarly journals Clinical Evaluation of the BDProbeTec ET System for Rapid Detection of Mycobacterium tuberculosis

2000 ◽  
Vol 38 (2) ◽  
pp. 863-865 ◽  
Author(s):  
John S. Bergmann ◽  
William E. Keating ◽  
Gail L. Woods
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Test Performance ◽  
Direct Detection ◽  
Distinct Advantage ◽  
Predictive Values ◽  
Number Of Patients ◽  
Smear Negative ◽  
Sensitivity Specificity ◽  
Culture Positive ◽  
Respiratory Specimens

The performance of the BDProbeTec ET system (BD Biosciences, Sparks, Md.) for direct detection of Mycobacterium tuberculosis complex (MTBC) in respiratory specimens was evaluated by comparing results to those of conventional mycobacterial culture performed with the BACTEC 460 TB system and Middlebrook 7H11 biplates. Patients known to have been on antituberculous therapy were excluded from the analysis. Of 600 evaluable specimens (4 specimens were excluded from the analysis due to failure of the internal amplification control [IAC]) from 332 patients, 57 grew mycobacteria; 16 were MTBC (from 12 patients), and 41 were nontuberculous mycobacteria. Of the 16 MTBC culture-positive specimens, 12 were smear positive and 4 were smear negative. BDProbeTec ET detected 14 of the 16 MTBC culture-positive specimens, resulting in initial overall sensitivity, specificity, and positive and negative predictive values of 87.5, 99.0, 70.0, and 99.7%, respectively. After resolution of discrepancies by review of medical records and retesting of samples yielding discordant MTBC culture and BDProbeTec ET results, the revised overall sensitivity, specificity, and positive and negative predictive values of the BDProbeTec ET were respectively 93.8, 99.8, 93.8, and 99.8% by specimen and 91.7, 99.7, 91.7, and 99.7% by patient. The BDProbeTec ET System offers the distinct advantage of including an IAC in the specimen well. These data suggest that the test performance is very good, especially for smear-positive samples. However, the number of patients with tuberculosis in our study, especially those with smear-negative disease, was small; therefore, additional studies are needed.

Evaluation of the Enhanced Amplified Mycobacterium Tuberculosis Direct Test for Direct Detection of Mycobacterium tuberculosis Complex in Respiratory Specimens

1999 ◽  
Vol 123 (11) ◽  
pp. 1101-1103 ◽  
Author(s):  
Michael B. Smith ◽  
John S. Bergmann ◽  
Michelle Onoroto ◽  
Greg Mathews ◽  
Gail L. Woods
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Nontuberculous Mycobacteria ◽  
Direct Detection ◽  
Direct Test ◽  
Tuberculosis Complex ◽  
Predictive Values ◽  
Smear Negative ◽  
Sensitivity Specificity ◽  
Culture Positive ◽  
Respiratory Specimens

Abstract Objective.—To evaluate the performance of the enhanced Mycobacterium Tuberculosis Direct Test (E-MTD), for the direct detection of M tuberculosis complex (MTBC) in respiratory specimens. Design.—Two hundred seventy-four respiratory specimens from 151 patients in respiratory isolation were tested with the E-MTD, and the results were compared with the results of mycobacterial smear, culture, and the earlier form of the test, MTD-1. Results.—Forty-one specimens were culture positive for mycobacteria (20 MTBC and 21 nontuberculous mycobacteria), 23 of which were smear positive (16 MTBC, 7 nontuberculous mycobacteria). Twenty-four specimens were positive by E-MTD, and 21 were positive by MTD-1. Of the 20 MTBC culture-positive specimens, 19 were positive by the E-MTD and 19 were positive by the MTD-1. The remaining specimens were MTBC negative by all methods. After resolution of discrepancies, the sensitivity, specificity, and positive and negative predictive values were 95.2%, 100%, 100%, 99.6% for the MTD-1 and 95.2%, 98.8%, 87.0%, and 99.6%, for the E-MTD. For the E-MTD smear-positive and smear-negative specimens, these same values were 93.8%, 100%, 100%, and 87.5% and 100%, 98.8%, 62.5%, and 100%, respectively. Conclusion.—The results suggest that the E-MTD is a reliable method for the direct detection of MTBC in smear-positive respiratory specimens.

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