scholarly journals Clinical Evaluation of COBAS TaqMan PCR for the Detection ofMycobacterium tuberculosisandM. aviumComplex

2012 ◽  
Vol 2012 ◽  
pp. 1-5 ◽  
Author(s):  
Satoshi Ikegame ◽  
Yoritake Sakoda ◽  
Nao Fujino ◽  
Kazuhito Taguchi ◽  
Masayuki Kawasaki ◽  
...  
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Observational Study ◽  
Careful Consideration ◽  
Pcr Analysis ◽  
Test Results ◽  
Clinical Specimens ◽  
Cobas Taqman ◽  
Taqman Pcr ◽  
Smear Negative ◽  
Pcr Test

A retrospective observational study was performed to determine the sensitivity and limitation of PCR test for the detection ofMycobacterium tuberculosisandM. aviumcomplex. We obtained clinical specimens collected from the respiratory tract, culturedM. tuberculosisorM. aviumcomplex, and performed PCR analysis. A total of 299 samples (M. tuberculosis, 177;M. avium, 35;M. intracellulare, 87) were analyzed by COBAS TaqMan PCR from April 2007 to March 2011. The PCR positivity rates were 50–55%, 70–100%, 88–98%, and 100% in smear-negative, smear 1+, 2+, and 3+ groups, respectively. The PCR positivity of tuberculosis in smear 1+ was 80.6%, which was statistically significantly (P<0.001) lower than that of smear 2+ (97.3%). From January 2005 to March 2007, we collected an additional 138 samples (M. tuberculosis, 74;M. avium, 21; M. intracellulare, 43), which were analyzed by COBAS Amplicor PCR. The PCR positivity rates obtained using COBAS TaqMan PCR and COBAS Amplicor PCR were not significantly different. The sensitivity of PCR test for mycobacteria is not sufficient in case of smear 1+. Careful consideration must be given to the interpretation of negative PCR test results in smear 1+, because smear-positive tuberculosis is the criterion for isolation.

scholarly journals Evaluation of the Abbott RealTi m e MTB and RealTi m e MTB INH/RIF Assays for Direct Detection of Mycobacterium tuberculosis Complex and Resistance Markers in Respiratory and Extrapulmonary Specimens

2016 ◽  
Vol 54 (12) ◽  
pp. 3022-3027 ◽  
Author(s):  
Sabine Hofmann-Thiel ◽  
Nikolay Molodtsov ◽  
Uladzimir Antonenka ◽  
Harald Hoffmann
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Susceptibility Testing ◽  
Drug Susceptibility ◽  
Drug Susceptibility Testing ◽  
Nucleic Acid Amplification ◽  
Content Type ◽  
Clinical Specimens ◽  
Different Types ◽  
Resistance Markers ◽  
Smear Negative

The Abbott RealTi m e MTB (RT MTB) assay is a new automated nucleic acid amplification test for the detection of Mycobacterium tuberculosis complex (MTBC) in clinical specimens. In combination with the RealTi m e MTB INH/RIF (RT MTB INH/RIF) resistance assay, which can be applied to RT MTB-positive specimens as an add-on assay, the tests also indicate the genetic markers of resistance to isoniazid (INH) and rifampin (RIF). We aimed to evaluate the diagnostic sensitivity and specificity of RT MTB using different types of respiratory and extrapulmonary specimens and to compare performance characteristics directly with those of the FluoroType MTB assay. The resistance results obtained by RT MTB INH/RIF were compared to those from the GenoType MTBDR plus and from phenotypic drug susceptibility testing. A total of 715 clinical specimens were analyzed. Compared to culture, the overall sensitivity of RT MTB was 92.1%; the sensitivity rates for smear-positive and smear-negative samples were 100% and 76.2%, respectively. The sensitivities of smear-negative specimens were almost identical for respiratory (76.3%) and extrapulmonary (76%) specimens. Specificity rates were 100% and 95.8% for culture-negative specimens and those that grew nontuberculous mycobacteria, respectively. RT MTB INH/RIF was applied to 233 RT MTB-positive samples and identified resistance markers in 7.7% of samples. Agreement with phenotypic and genotypic drug susceptibility testing was 99.5%. In conclusion, RT MTB and RT MTB INH/RIF allow for the rapid and accurate diagnosis of tuberculosis (TB) in different types of specimens and reliably indicate resistance markers. The strengths of this system are the comparably high sensitivity with paucibacillary specimens, its ability to detect INH and RIF resistance, and its high-throughput capacities.

scholarly journals Improving the Sensitivity of the Xpert MTB/RIF Assay on Sputum Pellets by Decreasing the Amount of Added Sample Reagent: a Laboratory and Clinical Evaluation

2015 ◽  
Vol 53 (4) ◽  
pp. 1258-1263 ◽  
Author(s):  
Nila J. Dharan ◽  
Danielle Amisano ◽  
Gerald Mboowa ◽  
Willy Ssengooba ◽  
Robert Blakemore ◽  
...  
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Limit Of Detection ◽  
Smear Microscopy ◽  
Content Type ◽  
Clinical Specimens ◽  
Test Sensitivity ◽  
Smear Negative ◽  
Almost All ◽  
Culture Positive ◽  
Xpert Assay

The Xpert MTB/RIF (Xpert) assay permits rapid near-patient detection ofMycobacterium tuberculosisin sputum; however, the test sensitivity remains suboptimal in paucibacillary specimens that are negative for acid-fast bacilli using smear microscopy. Xpert testing includes dilution with sample reagent, and when processed sputum pellets are tested, the recommended sample reagent/pellet ratio is 3:1. We evaluated whether a decreased sample reagent/pellet ratio of 2:1 increased Xpert sensitivity compared to the recommended 3:1. The limit of detection was determined by inoculating serial dilutions ofM. tuberculosisinto sputum samples, preparing sputum pellets, and testing each pellet by Xpert at both sample reagent ratios. Processed sputum pellets obtained fromM. tuberculosisculture-positive clinical specimens were also tested by Xpert at both ratios. Among spiked sputum pellets, the limit of detection was 1,478 CFU/ml (95% confidence interval [CI], 1,211 to 1,943) at a 3:1 ratio and decreased to 832 CFU/ml (95% CI, 671 to 1,134) at 2:1. The proportion of specimens in whichM. tuberculosiswas detected was greater at 2:1 than at 3:1 for almost all numbers of CFU/ml; this difference was most prominent at lower numbers of CFU/ml. Among 134 concentrated sputum pellets from the clinical study, the sensitivity of Xpert at 2:1 was greater than at 3:1 overall (80% versus 72%;P= 0.03) and for smear-negative specimens (67% versus 58%;P= 0.12). For Xpert testing of sputum pellets, using a lower sample reagent/pellet ratio increasedM. tuberculosisdetection, especially for paucibacillary specimens. Our study supports use of a 2:1 sample reagent/pellet dilution for Xpert testing of sputum pellets.

scholarly journals Comparison of recoveries of Mycobacterium tuberculosis using the automated BACTEC MGIT 960 System and Lowenstein – Jensen medium

2010 ◽  
Vol 9 (1) ◽  
pp. 44
Author(s):  
Mo. A.AL-Mazini, T. Bukeet, and A. Abdul Kareem
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Recovery Rates ◽  
Clinical Specimens ◽  
Indicator Tube ◽  
Lowenstein Jensen ◽  
Bactec System ◽  
Smear Negative ◽  
The Difference ◽  
Growth Indicator

We examined whether the BACTEC/ Mycobacteria Growth Indicator Tube (MGIT) System alone could supplant the use of a supplemental Lowenstein–Jensen (LJ) slant for routine recovery of M. tuberculosis from clinical specimens. A total of 392 specimens of sputum were included in the study, collected from 196 patients. Specimens were processed with standard N-acetyl- L- Cysteine (NALC-NaOH) method, then inoculated onto BACTEC MGIT 960 and onto LJ media. The recovery rates of M.tuberculosis were 100 % (256/256) with BACTEC MGIT 960 and 72.6%(186/256) with LJ. The rates of contamination for each of the system were 4.8%with BACTEC MGIT 960 and 5.3%with LJ. The TTD for M. tuberculosis was 11.3 days with BACTEC System and 30.8 days with LJ. The difference in TTD between smear positive and smear negative specimens for M.tuberculosis with BACTEC MGIT 960 was not statistically significant. This study shows that the BACTEC System demonstrates better sensitivity for the recovery of M. tuberculosis from clinical specimens.

scholarly journals Observational study of SARS-CoV-2 antibody immune response in a cohort of patients at a North Suburban Chicago, Illinois, in a physician’s practice

2020 ◽  
Vol 7 (3) ◽  
pp. 104-108
Author(s):  
Gerald Osher ◽  
Christopher C. Lamb ◽  
Yuliana Ibarra ◽  
Deborah Erickson-Samson
Keyword(s):  
Immune Response ◽  
Observational Study ◽  
Patient Population ◽  
Healthcare Professionals ◽  
Clinical Symptoms ◽  
Point Of Care ◽  
Test Results ◽  
Serological Testing ◽  
Past Infection ◽  
Pcr Test

Background: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has caused a global pandemic. The application of point of care serological testing can help determine past infection and assist healthcare workers assess patient risk. Method: An observational study of 114 subjects in North Suburban Chicago, Illinois, was performed using the Clungene® lateral flow immunoassay (LFI). Patients’ PCR test results and clinical symptoms were used to compare the seroconversion rate of this patient population with the surrounding community. Results: Excluding 1 aberrant result, there was 100% positive agreement (10) between PCR and antibody (IgG or IgM) test results. There were 7 patients who did not have a prior PCR test who were positive for IgG; 5 of the 7 had clinical symptoms consistent with possible exposure and 2 were asymptomatic. There was 1 person with a suspected exposure to an infected person who was IgM positive. Ninety-five asymptomatic patients were seronegative. The overall rate of 15.9% seroconversion (IgG or IgM) is consistent with other community-based testing results in the North Suburban Chicago, Illinois area. Conclusion: Rapid screening tests to identify antibody positive patients recovered from coronavirus disease-2019 can be a useful tool for healthcare professionals to determine or confirm past infection. Statement of novelty: Limited data is available on the use of point of care serological testing to assist healthcare professionals with the assessment of their patient population regarding past SARS-CoV-2 infectivity and seroconversion. The present study successfully investigated the use of a point of care antibody test in a physician’s office to determine which patients have developed antibodies, indicating an immune response to SARS-CoV-2, and to assist with decisions on whether patients should pursue normal social and workplace activities.

scholarly journals Comparison of the MB/BacT and BACTEC 460 TB Systems for Recovery of Mycobacteria from Various Clinical Specimens

1999 ◽  
Vol 37 (4) ◽  
pp. 1206-1209 ◽  
Author(s):  
Francesca Brunello ◽  
Flavio Favari ◽  
Roberta Fontana
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Nontuberculous Mycobacteria ◽  
Common Species ◽  
Individual Species ◽  
Mycobacterium Chelonae ◽  
Recovery Rates ◽  
Clinical Specimens ◽  
Lowenstein Jensen ◽  
Smear Negative ◽  
The Difference

A total of 1,830 specimens (75.7% respiratory and 24.3% nonrespiratory) were cultured in parallel with the MB/BacT and BACTEC 460 TB systems and on Lowenstein-Jensen (LJ) medium. Mycobacteria were identified from 173 (6.5%) specimens. The most common species recovered were Mycobacterium tuberculosis complex (65.9%),Mycobacterium avium complex (22.5%), andMycobacterium chelonae (9.2%). The recovery rates by individual systems were 96.5, 99.4, and 95.9% for MB/BacT, BACTEC 460 TB, and LJ medium, respectively, for all mycobacteria; the recovery rates were 99.1, 100, and 98.2%, respectively, for M. tuberculosis complex alone. The difference among the recovery rates for all mycobacteria and those for individual species was not significant. The BACTEC 460 TB system detected M. tuberculosis isolates more rapidly than the MB/BacT system (8 versus 11.8 days for smear-positive specimens [P < 0.01] and 18 versus 21 days for smear-negative specimens [P < 0.05]), whereas the MB/BacT system more rapidly detected the nontuberculous mycobacteria (17.1 versus 12.7 days [P < 0.01]). These results indicate that the nonradiometric MB/BacT system is a rapid, sensitive, and efficient method for the recovery ofM. tuberculosis and nontuberculous mycobacteria from both pulmonary and extrapulmonary clinical specimens.

scholarly journals Comparison of MB/BacT and BACTEC 460 TB Systems for Recovery of Mycobacteria in a Routine Diagnostic Laboratory

1999 ◽  
Vol 37 (11) ◽  
pp. 3711-3712 ◽  
Author(s):  
Andreas Roggenkamp ◽  
Mathias W. Hornef ◽  
Adelheid Masch ◽  
Bettina Aigner ◽  
Ingo B. Autenrieth ◽  
...  
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Routine Laboratory ◽  
Diagnostic Laboratory ◽  
Recovery Rates ◽  
Clinical Specimens ◽  
Smear Negative

MB/BacT, BACTEC 460 TB, and Löwenstein-Jensen (LJ) medium were evaluated in parallel for recovery of mycobacteria from 3,700 continuous clinical specimens in a routine laboratory. Mycobacteria were identified from 123 (3.3%) specimens. The recovery rates for all mycobacteria by the different systems were 91.0, 73.0, and 53.6% for BACTEC 460 TB, MB/BacT, and LJ medium, respectively. The recovery rates for Mycobacterium tuberculosis complex were 97.1, 80.2, and 67.6%, respectively. The lack of sensitivity of the MB/BacT system was more pronounced with smear-negative specimens and resulted in a failure to detect three patients with infectious tuberculosis.

scholarly journals Positive RT-PCR Test Results in 420 Patients Recovered From COVID-19 in Wuhan: An Observational Study

2020 ◽  
Vol 11 ◽  
Author(s):  
Shaobin He ◽  
Jiaxing Tian ◽  
Xiaodong Li ◽  
Yana Zhou ◽  
Mingzhong Xiao ◽  
...  
Keyword(s):  
Observational Study ◽  
Test Results ◽  
Rt Pcr ◽  
Pcr Test

scholarly journals No Evidence of Re-infection or Person-to-Person Transmission in Cured COVID-19 Patients in Guangzhou, a Retrospective Observational Study

2020 ◽  
Vol 7 ◽  
Author(s):  
Gang Xu ◽  
Feng Liu ◽  
Min Ye ◽  
Jun Zhao ◽  
Qing Li ◽  
...  
Keyword(s):  
Observational Study ◽  
Disease Onset ◽  
Antibody Test ◽  
Retrospective Observational Study ◽  
Antibody Detection ◽  
Test Results ◽  
Pcr Assay ◽  
Negative Results ◽  
Pcr Test

Objectives: To clarify the clinical characteristics of cured patients with coronavirus disease (COVID-19), and to clarify the re-infection and person-to-person transmission in the cured.Methods: A total of 187 cured COVID-19 patients with antibody test were followed up every 2 weeks in this retrospective observational study. Assessment for general condition, symptoms, epidemiological contact history, polymerase chain reaction (PCR) assay, and antibody tests were performed and recorded. Information from Guangzhou CDC was also screened.Results: There were 33 (17.6%) patients with negative results for IgG and 35 (18.7%) patients with positive results for IgM. The average days of antibody detection from disease onset were 53.0. PCR assay was positive in 10 (5.3%) patients during the follow-up. Neither IgG nor IgM results showed a relationship with PCR test results (all P &gt; 0.05). Neither re-infection nor person-to-person transmission was found in the cured patients. Factors associated with appearance of antibody comprised hospitalization days (OR: 1.06, 95%CI: 1.02–1.11, P = 0.006) and antibiotics treatment (OR: 3.50, 95%CI: 1.40–8.77, P = 0.007).Conclusions: In our study, no evidence of person-to-person transmission was found in cured COVID-19 patients. There seemed to be no re-infection in the cured COVID-19 patients in Guangzhou. These finding suggest that the cured do not cause the spread of disease. Additionally, neither IgG nor IgM can be used to replace the PCR test in cured patients.

scholarly journals Use of Transrenal DNA for the Diagnosis of Extrapulmonary Tuberculosis in Children: a Case of Tubercular Otitis Media

2014 ◽  
Vol 53 (1) ◽  
pp. 336-338 ◽  
Author(s):  
Roberta Petrucci ◽  
Giulia Lombardi ◽  
Ilaria Corsini ◽  
Francesca Visciotti ◽  
Antonio Pirodda ◽  
...  
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Otitis Media ◽  
Extrapulmonary Tuberculosis ◽  
Smear Microscopy ◽  
Test Results ◽  
Content Type ◽  
Dna Test ◽  
Smear Negative ◽  
Tuberculosis In Children

The diagnosis of tuberculosis (TB) is difficult in children, especially for smear-negative pulmonary and extrapulmonary TB, which are common at this age. We report an 11-year-old girl with TB otitis media with negative smear microscopy and Xpert MTB/RIF but positiveMycobacterium tuberculosis-specific transrenal DNA (Tr-MTB-DNA) test results and culture forM. tuberculosis.

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