scholarly journals Detection of Mycobacterium tuberculosisComplex in Sputum Specimens by the Automated Roche Cobas Amplicor Mycobacterium Tuberculosis Test

1998 ◽  
Vol 36 (4) ◽  
pp. 975-978 ◽  
Author(s):  
Iiris Rajalahti ◽  
Pauli Vuorinen ◽  
Markku M. Nieminen ◽  
Ari Miettinen
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Liquid Culture ◽  
Nucleic Acid Amplification ◽  
Pcr Assay ◽  
Predictive Values ◽  
Tube Culture ◽  
Active Pulmonary Tuberculosis ◽  
Amplification Method ◽  
Culture Positive ◽  
Roche Cobas

Three hundred twenty-four sputum specimens from 151 patients with suspected active pulmonary tuberculosis were tested for the presence of the Mycobacterium tuberculosis complex with auramine fluorochrome stain and automated PCR assay (Roche Cobas Amplicor Mycobacterium Tuberculosis Test [MTB]). The results were compared with those of the conventional Löwenstein-Jensen tube culture and the BACTEC radiometer liquid culture. A total of 76 specimens from 32 patients were culture positive for M. tuberculosis. In addition, 37 specimens from 15 patients were smear and culture positive for other Mycobacterium species but negative by the present nucleic acid amplification method and thus were not included in the comparison. Compared with culture, the sensitivities, specificities, and positive and negative predictive values for acid-fast smear were 67, 98, 93, and 91% and those for the Cobas Amplicor MTB were 83, 99, 97, and 95%, respectively. When three consecutive sputum specimens per patient could be obtained, the sensitivity of the Cobas Amplicor MTB improved to 91%, whereas the sensitivity of the acid-fast smear remained unchanged.

scholarly journals Rapid Diagnosis of Pulmonary Tuberculosis with the LCx Mycobacterium tuberculosis Assay and Comparison with Conventional Diagnostic Techniques

1998 ◽  
Vol 36 (10) ◽  
pp. 3046-3047 ◽  
Author(s):  
Peter Rohner ◽  
Esther I. M. Jahn ◽  
Beatrice Ninet ◽  
Concetta Ionati ◽  
Rainer Weber ◽  
...  
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Direct Detection ◽  
Diagnostic Techniques ◽  
Nucleic Acid Amplification Test ◽  
Nucleic Acid Amplification ◽  
Predictive Values ◽  
Amplification Assay ◽  
Sensitivity Specificity ◽  
Culture Positive ◽  
Respiratory Specimens

The LCx MTB amplification assay is a nucleic acid amplification test intended for the direct detection ofMycobacterium tuberculosis complex in respiratory specimens. We evaluated its performance on 2,001 consecutive respiratory specimens; 78 were culture positive for M. tuberculosis. Sensitivity, specificity, and positive and negative predictive values of this assay for all specimens compared to culture results were 88.5, 97.7, 60.5, and 99.5%, respectively. When referred to resolved clinical diagnosis of active tuberculosis, these values improved to 90.2, 98.4, 72.8, and 99.5%, respectively.

scholarly journals Development of an in-house loop-mediated isothermal amplification (LAMP) assay for detection of Mycobacterium tuberculosis and evaluation in sputum samples of Nepalese patients

2008 ◽  
Vol 57 (4) ◽  
pp. 439-443 ◽  
Author(s):  
Basu Dev Pandey ◽  
Ajay Poudel ◽  
Tomoko Yoda ◽  
Aki Tamaru ◽  
Naozumi Oda ◽  
...  
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Lamp Assay ◽  
High Sensitivity ◽  
Isothermal Amplification ◽  
Nucleic Acid Amplification ◽  
Lamp Method ◽  
Rrna Gene ◽  
Predictive Values ◽  
Loop Mediated Isothermal Amplification ◽  
System A

A number of nucleic acid amplification assays (NAAs) have been employed to detect tubercle bacilli in clinical specimens for tuberculosis (TB) diagnosis. Among these, loop-mediated isothermal amplification (LAMP) is an NAA possessing superior isothermal reaction characteristics. In the present study, a set of six specific primers targeting the Mycobacterium tuberculosis 16S rRNA gene with high sensitivity was selected and a LAMP system (MTB-LAMP) was developed. Using this system, a total of 200 sputum samples from Nepalese patients were investigated. The sensitivity of MTB-LAMP in culture-positive samples was 100 % (96/96), and the specificity in culture-negative samples was 94.2 % (98/104, 95 % confidence interval 90.5–97.9 %). The positive and negative predictive values of MTB-LAMP were 94.1 and 100 %, respectively. These results indicate that this MTB-LAMP method may prove to be a powerful tool for the early diagnosis of TB.

Paradigm for diagnosing mycobacterial disease: direct detection and differentiation of Mycobacterium tuberculosis complex and non-tuberculous mycobacteria in clinical specimens using multiplex real-time PCR

2018 ◽  
Vol 71 (9) ◽  
pp. 774-780 ◽  
Author(s):  
Jeong-Uk Kim ◽  
Dae-Shick Ryu ◽  
Choong-Hwan Cha ◽  
Seon-Hee Park
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Real Time ◽  
Real Time Pcr ◽  
Predictive Value ◽  
Direct Detection ◽  
Positive Culture ◽  
Nucleic Acid Amplification ◽  
Mycobacterial Disease ◽  
Pcr Assay ◽  
Clinical Specimens

AimsMycobacterium tuberculosis and non-tuberculous mycobacteria (NTM) are clinically different, and the rapid detection and differentiation of M. tuberculosis complex (MTBC) and NTM is crucial for patient management and infection control. Given the slow growth of most pathogenic mycobacteria, nucleic acid amplification assays are excellent tools for direct identification of mycobacteria in clinical specimens. Recently, a multiplex real-time PCR assay was developed that can directly detect 20 mycobacterial species in clinical specimens. Here, we evaluated the diagnostic performance of the assay for diagnosing mycobacterial disease under routine laboratory conditions.MethodsA total of 3334 specimens collected from 1437 patients suspected of tuberculosis infection were subjected to acid-fast bacilli staining, conventional culture and the multiplex real-time PCR assay. To evaluate the sensitivity and specificity of the assay, the overall diagnosis of tuberculosis was defined by positive culture plus medical history, and the 2007 American Thoracic Society and Infectious Disease Society of America diagnostic criteria for NTM disease were applied.ResultsThe sensitivity, specificity, positive predictive value and negative predictive value were 87.5%, 99.6%, 96.1% and 98.5%, respectively, for the detection of MTBC isolates and 53.3%, 99.9%, 95.2%, and 98.9%, respectively, for detecting NTM isolates.ConclusionsThus, the assay can correctly differentiate between MTBC and NTM isolates in clinical specimens and would be a useful tool for the rapid differentiation of tuberculosis and NTM disease, despite its limited sensitivity for the diagnosis of NTM disease.

scholarly journals Multicenter Evaluation of the Abbott LCxMycobacterium tuberculosis Ligase Chain Reaction Assay

1999 ◽  
Vol 37 (10) ◽  
pp. 3102-3107 ◽  
Author(s):  
Richard Lumb ◽  
Kirsten Davies ◽  
David Dawson ◽  
Robert Gibb ◽  
Thomas Gottlieb ◽  
...  
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Grey Zone ◽  
Relative Operating Characteristic ◽  
Assay Sensitivity ◽  
Predictive Values ◽  
Sensitivity Specificity ◽  
The Relationship ◽  
Culture Positive ◽  
Respiratory Specimens ◽  
Australian Hospital

Four Australian hospital laboratories evaluated the performance of the Abbott LCx Mycobacterium tuberculosis assay with 2,347 specimens (2,083 respiratory and 264 nonrespiratory specimens) obtained from 1,411 patients. A total of 152 specimens (6.5%) were culture positive for Mycobacterium tuberculosis complex (MTBC); of these, 79 (52%) were smear positive. After resolution of discrepant data, the overall sensitivity, specificity, and positive and negative predictive values for the LCx assay were 69.7, 99.9, 99.1, and 97.7% respectively. For smear-positive respiratory specimens that were culture positive for MTBC, the values were 98.5, 100, 100, and 98.4%, respectively, while the values for smear-negative respiratory specimens were 41.5, 99.9, 96.4, and 98%, respectively. Relative operating characteristic curves were constructed to demonstrate the relationship between sensitivity and specificity for a range of possible cutoff values in the LCx assay. These graphs suggested that the assay sensitivity for respiratory samples could be increased from 70.2 to 78.6%, while the specificity would be reduced from 99.9 to 99.4% by inclusion of a grey zone (i.e., LCx assay values of between 0.2 and 0.99). An algorithm is presented for the handling of specimens with LCx assay values within this grey zone.

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.

scholarly journals Simplified detection of Mycobacterium tuberculosis in sputum using smear microscopy and PCR with molecular beacons

2007 ◽  
Vol 56 (10) ◽  
pp. 1356-1362 ◽  
Author(s):  
Sagarika Haldar ◽  
Soumitesh Chakravorty ◽  
Manpreet Bhalla ◽  
Shyamasree De Majumdar ◽  
Jaya Sivaswami Tyagi
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Molecular Beacon ◽  
Cost Effective ◽  
Nucleic Acid Amplification ◽  
Smear Microscopy ◽  
Direct Smear ◽  
Effective Manner ◽  
Directly Observed Treatment ◽  
Smear Negative ◽  
Culture Positive

The prompt diagnosis of smear-negative cases is a prerequisite to controlling tuberculosis (TB). Several new laboratory approaches, including nucleic acid amplification (NAA), are being evaluated in various disease settings to meet this challenge. However, NAA needs simplification before it is widely accepted. Furthermore, a supporting smear result improves confidence in and reliability of PCR. In this context, an asymmetric devR PCR assay using two molecular beacon probes for visual or fluorimetric end-point detection of Mycobacterium tuberculosis was developed. The assays reproducibly detected 25 fg M. tuberculosis DNA versus 100 fg by conventional gel electrophoresis (henceforth referred to as gel assay). The devR and IS6110 PCR assays were blindly evaluated on sputum specimens obtained from a directly observed-treatment short-course centre. Universal sample processing (USP) smear microscopy and culture were used as a supportive test and the ‘gold’ standard, respectively. Among the 148 specimens analysed, 120 were M. tuberculosis culture-positive. Amongst the 122 direct smear-negative samples, 96 were culture-positive, of which 61 were detected by USP smear microscopy. All 35 USP smear-negative samples were positive by three or more PCR methods. devR PCR had a sensitivity of 92.5 % in the fluorimetric assay versus 86.7 % by visual inspection and 90.8 % by the gel method. IS6110 PCR performed at almost equivalent levels. devR visual and fluorimetric assays considered together yielded an increased sensitivity of 95 % without compromising on a specificity of 92.9 %. The results suggest that the USP smear test is useful for diagnosing direct smear-negative TB and judiciously restricting PCR testing to only smear-negative samples. When used together, these tests can provide rapid diagnosis of smear-negative TB in a cost-effective manner.

scholarly journals Reliability of Cobas Amplicor PCR test in detection of Mycobacterium tuberculosis in respiratory and nonorespiratory specimens

2009 ◽  
Vol 66 (12) ◽  
pp. 992-997
Author(s):  
Zorica Lepsanovic ◽  
Dejana Savic ◽  
Branka Tomanovic
Keyword(s):  
Mycobacterium Tuberculosis ◽  
High Sensitivity ◽  
High Specificity ◽  
Diagnostic Methods ◽  
Nucleic Acid Amplification ◽  
Culture Methods ◽  
Predictive Values ◽  
Polymerase Chain ◽  
Low Sensitivity ◽  
Sensitivity Specificity

Background/Aim. Traditional methods for detection of mycobacteria, such as microscopic examination for the presence of acid-fast bacilli and isolation of the organism by culture, have either a low sensitivity and/or specificity, or take weeks before a definite result is available. Molecular methods, especially those based on nucleic acid amplification, are rapid diagnostic methods which combine high sensitivity and high specificity. The aim of this study was to determine the usefulness of the Cobas Amplicor Mycobacterium tuberculosis polymerase chain reaction (CAPCR) assay in detecting the tuberculosis cause in respiratory and nonrespiratory specimens (compared to culture). Methods. Specimens were decontaminated by the N-acetyl-L-cystein- NaOH method. A 500 ?L aliquot of the processed specimen were used for inoculation of L?wenstein-Jensen (L-J) slants, a drop for acid-fast staining, and 100 ?L for PCR. The Cobas Amplicor PCR was performed according to the manufacturer's instructions. Results. A total of 110 respiratory and 355 nonrespiratory specimens were investigated. After resolving discrepancies by reviewing medical history, overall sensitivity, specificity, and positive and negative predictive values for CA-PCR assay compared to culture, were 83%, 100%, 100%, and 96.8%, respectively. In comparison, they were 50%, 99.7%, 87.5%, and 98%, respectively, for the nonrespiratory specimens. The inhibition rate was 2.8% for respiratory, and 7.6% for nonrespiratory specimens. Conclusion. CA-PCR is a reliable assay that enables specialists to start treatment promptly on a positive test result. Lower value for specificity in a group of nonrespiratory specimens is a consequence of an extremely small number of mycobacteria in some of them.

scholarly journals Evaluation of the COBAS AMPLICOR MTB test for the detection of Mycobacterium tuberculosis complex

2004 ◽  
Vol 10 (3) ◽  
pp. 329-335
Author(s):  
K. K. Abu Amero ◽  
M. A. Halablab
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Mycobacterium Tuberculosis Complex ◽  
Tuberculosis Complex ◽  
False Negatives ◽  
Predictive Values ◽  
Lowenstein Jensen ◽  
Polymerase Chain ◽  
Sensitivity Specificity ◽  
Culture Positive ◽  
Positive Results

Wevaluated the COBAS AMPLICOR polymerase chain reaction [PCR] based test for the detection of Mycobacterium tuberculosis complex in 866 respiratory and non-respiratory samples. Acid-fast staining and culture on Lowenstein-Jensen medium were also performed on all samples. Of the 866 samples tested, 87 [10.0%] were PCR-positive compared to 94 [10.9%] culture positive. There were no false positive results but 7 PCR-negative, culture-positive samples were, considered false negatives after reviewing medical records of patients. A PCR inhibitory rate of 2.0% [17/866] was observed in respiratory samples only. Sensitivity, specificity, and positive and negative predictive values for this test were 92.5%, 100%, 100% and 99.1% respectively. This test is a valuable diagnostic tool for today’s mycobacteriology laboratory

scholarly journals Comparison of Roche Cobas Amplicor Mycobacterium tuberculosis Assay with In-House PCR and Culture for Detection of M. tuberculosis

1998 ◽  
Vol 36 (7) ◽  
pp. 2023-2029 ◽  
Author(s):  
Bodo R. Eing ◽  
Andrea Becker ◽  
Arthur Sohns ◽  
Ronald Ringelmann
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Dna Extraction ◽  
Extraction Methods ◽  
Predictive Values ◽  
Three Samples ◽  
Smear Negative ◽  
Negative Sputum ◽  
Dna Extraction Methods ◽  
Sensitivity Specificity ◽  
Roche Cobas

The new Roche Cobas Amplicor Mycobacterium tuberculosisassay, which is a semiautomated version of the manually performed Roche Amplicor M. tuberculosis test, was compared to culture and an IS6110-based in-house PCR protocol. A total of 1,681 specimens from 833 patients, including specimen types other than sputum, were tested in parallel by both the in-house PCR and the Cobas Amplicor M. tuberculosis assay. After we resolved discrepant PCR results, the sensitivity, specificity, and positive and negative predictive values for the Cobas Amplicor M. tuberculosis assay were 66.33, 99.71, 94.36, and 97.66%, respectively. The corresponding values for the in-house PCR were 91.08, 99.85, 97.87, and 99.37%, respectively. For culture- and smear-positive specimens, the sensitivity of the Cobas AmplicorM. tuberculosis test was 96.42% (in-house PCR, 100%). If only smear-negative sputum specimens were considered, the Cobas Amplicor M. tuberculosis assay exhibited a sensitivity of 45.45% (in-house PCR, 63.63%) relative to that of culture. With a modified protocol for DNA extraction (washing of samples plus ultrasonication), both PCR methods performed better with gastric aspirates than with sputum samples (sensitivity of the Cobas AmplicorM. tuberculosis assay with smear-negative gastric aspirates, 70.00%; sensitivity of in-house PCR, 90.00%). With dithiothreitol being used for liquefaction of specimens in this study, the Cobas Amplicor M. tuberculosis assay exhibited an inhibition rate of 9.16%. In our view, the new Cobas Amplicor M. tuberculosis test (i) is well suited for typing of smear-positive specimens, (ii) may also be applied to gastric aspirates and other types of specimens if DNA extraction methods are modified appropriately, and (iii) exhibits a sensitivity with smear-negative sputum specimens which makes it recommendable that a minimum of three samples from the same patient be tested.

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