scholarly journals Investigation of suspected laboratory cross-contamination: interpretation of single smear-negative, positive cultures for Mycobacterium tuberculosis

2006 ◽  
Vol 12 (10) ◽  
pp. 1042-1045 ◽  
Author(s):  
V.J. Cook ◽  
G. Stark ◽  
D.L. Roscoe ◽  
A. Kwong ◽  
R.K. Elwood
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Cross Contamination ◽  
Smear Negative

Detection of Mycobacterium tuberculosis in smear negative sputum by PCR

2012 ◽  
Vol 6 (2) ◽  
pp. 2-6 ◽  
Author(s):  
Mohammad Jobayer ◽  
SM Shamsuzzaman ◽  
Kazi Zulfiquer Mamun
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Pulmonary Tuberculosis ◽  
Accurate Method ◽  
Major Health Problem ◽  
Major Health ◽  
Tuberculosis Patients ◽  
Diagnostic Potential ◽  
Total Death ◽  
Smear Negative ◽  
Negative Sputum

Pulmonary tuberculosis is a major health problem in Bangladesh that is responsible for about 7% of total death in a year. This study was conducted to isolate and identify Mycobacterium tuberculosis from sputum and to evaluate the efficacy of PCR as a modern diagnostic tool, for diagnosis of pulmonary tuberculosis, especially in the smear negative cases. One hundred and fifty suspected pulmonary TB patients (male/ female: 97/53) were included in this study. Single morning sputum was collected from each patient and diagnostic potential of PCR was compared with staining and culture. Twenty five (16.7%) sputum were positive by ZN stained smear. Among 125 smear negative samples, 13 (10.4%) yielded growth in culture in LJ media and 21 (16.8%) samples were positive by PCR. The sensitivity and specificity of PCR in smear negative cases was 100% and 92.9% respectively. Mean detection time in PCR was 24 hours. PCR detected M. tuberculosis in 21 smear negative and 9 culture negative samples. For diagnosis of tuberculosis in smear negative cases, PCR directly from sputum was a very sensitive and accurate method. In conclusion, PCR may be done, especially in clinically suspected pulmonary tuberculosis patients who remain negative by conventional methods.DOI: http://dx.doi.org/10.3329/bjmm.v6i2.19368 Bangladesh J Med Microbiol 2012; 06(02): 2-6

scholarly journals Comparison of Proportion and Resistance Ratio Methods for Drug Susceptibility Testing of Mycobacterium tuberculosis Isolated from Patients Attending National Tuberculosis Centre, Nepal

2010 ◽  
Vol 5 (1) ◽  
pp. 13-20
Author(s):  
S Acharya ◽  
P Ghimire ◽  
DK Khadka ◽  
S Nepali
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Fluorescence Microscopy ◽  
Susceptibility Testing ◽  
Drug Susceptibility ◽  
Drug Susceptibility Testing ◽  
Resistance Ratio ◽  
National Tuberculosis ◽  
Smear Negative ◽  
Culture Positive ◽  
Good Agreement

Background: Tuberculosis (TB) is among the most serious infectious cause of global morbidity and mortality. Emergence of Multi-drug resistant tuberculosis (MDR-TB) is posing an increased threat to TB control programs. Drug susceptibility testing (DST) of Mycobacterium tuberculosis (M. tuberculosis) isolates is important for tackling such problems. Setting: National Tuberculosis Centre (NTC), Thimi, Bhaktapur, Nepal. Objectives: Comparative evaluation of two in vitro DST methods in determining susceptibility of M. tuberculosis isolates from patients attending NTC, to front-line anti-TB drugs: (Isoniazid-INH, Rifampicin-RFP, Streptomycin-SM, and Ethambutol-EMB). Methodology: This study was conducted from Sep 2006-Jun 2007. A total of 862 sputum samples (diagnosis or follow up cases) collected from patients (type of patients or their categories was not differentiated in this study) attending NTC bacteriology lab for sputum direct smear microscopy were analyzed using fluorescence microscopy. All smear positive samples, smear negative samples requested for culture were cultured. All culture positive samples confirmed as M. tuberculosis by biochemical tests were processed for DST by both proportion (PR) and resistance ratio (RR) methods. Results: Out of 862 sputum samples analyzed, 226 (26.2%) samples were positive for Acid Fast Bacilli (AFB) by fluorescence microscopy. Among 323 samples 226 smear positive samples and 97 smear negative samples requested for culture), 221 (68.4%) were culture positive, 92 (28.5%) were culture negative and 10 (3.1%) were contaminated. Out of 221 isolates of M. tuberculosis, 57.5% were resistant to one or more drugs by the PR method and 56.6% by the RR method. Similarly, MDR isolates were 29.9% and 29% by PR and RR methods respectively. On correlation analysis using Mc Nemar Chi-square test, no significant difference between the two tests were observed (p>0.05). The results showed high agreement between both methods and agreement rates to INH, RFP, SM and EMB were 93.2%, 93.7%, 93.2% and 94.1% respectively. Similarly, the agreement rates between both methods using kappa analysis showed kappa (k) value of 0.86, 0.85, 0.86 and 0.84 for INH, RFP, SM and EMB respectively, which is believed to be good agreement between both methods (k=0.80 to 1.00: Very good agreement). Conclusion: In conclusion, this study showed that both the Proportion and Resistance ratio methods are equally good for determining drug susceptibility of M. tuberculosis. Keywords: Mycobacterium tuberculosis; Drug Susceptibility Testing; Proportion Method; Resistance Ratio Method. DOI: 10.3126/saarctb.v5i1.3078 SAARC J. Tuber. Lung Dis. HIV/AIDS 2008 Vol.5(1) 13-20

Use of Spoligotype Analysis to Detect Laboratory Cross-Contamination

2000 ◽  
Vol 21 (8) ◽  
pp. 525-527 ◽  
Author(s):  
Beth Nivin ◽  
Jeffrey Driscoll ◽  
Tom Glaser ◽  
Pablo Bifani ◽  
Sonal Munsiff
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Dna Fingerprinting ◽  
False Positive ◽  
Cross Contamination

Spoligotype analysis identified false-positive isolates ofMycobacterium tuberculosiscaused by laboratory cross-contamination. Spoligotyping is faster, is less expensive than DNA fingerprinting, and can be used with a variety of media. Patients were reevaluated and had medications discontinued as a result of this investigation. Months of unnecessary patient follow-up and treatment were avoided.

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 Endobronchial tuberculosis: histopathological subsets and microbiological results

2012 ◽  
Vol 7 ◽  
Author(s):  
Sevket Ozkaya ◽  
Salih Bilgin ◽  
Serhat Findik ◽  
Hayriye Çete Kök ◽  
Canan Yuksel ◽  
...  
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Lavage Fluid ◽  
Tracheobronchial Tree ◽  
Sputum Smear ◽  
Tuberculous Infection ◽  
Bronchial Lavage ◽  
Culture Positivity ◽  
Endobronchial Tuberculosis ◽  
Smear Negative ◽  
Histopathological Evidence

Background: Endobronchial tuberculosis (EBTB) is defined as a tuberculous infection of the tracheobronchial tree with microbial and histopathological evidence, with or without parenchymal involvement. Bronchoscopic appearances of EBTB have been divided into seven subtypes: actively caseating, edematous-hyperemic, fibrostenotic, tumorous, granular, ulcerative, and nonspecific bronchitic. However, information for establishing a definite microbiological diagnosis in each of these categories is lacking. We aimed to present bronchoscopic appearances and percentages for the EBTB subtypes and to compare bronchoscopic appearances with microbiological positivity in bronchial lavage fluid. Methods: From 2003 to 2009, 23 biopsy-proven EBTB patients were enrolled in the study. Diagnosis of EBTB was histopathologically confirmed in all patients. Results: The commonest subtype was the edematous-hyperemic type (34.7%); other subtypes in order of occurrence were: tumorous (21.7%), granular (17.3%), actively caseating (17.3%), fibrostenotic (4.3%), and nonspecific bronchitic (4.3%). Although all patients were sputum-smear-negative for acid-fast bacilli (AFB), 26% of patients were smear-positive for AFB in the bronchial lavage fluid. The bronchial lavage fluid grew Mycobacterium tuberculosis in 39.1% of all patients. The bronchial lavage smear positivity for AFB in the bronchial lavage fluid was 75%, 25%, 20%, 12.5%, 0%, and 0% for the granular, actively caseating, tumorous, edematous-hyperemic, fibrostenotic, and nonspecific bronchitic subtypes of EBTB, respectively. Culture positivity for Mycobacterium tuberculosis in bronchial lavage fluid was 75%, 50%, 40%, 25%, 0%, and 0%, respectively. Conclusion: The commonest subtype of EBTB was the edematous-hyperemic subtype. The granular type had the highest smear positivity and culture positivity for Mycobacterium tuberculosis in bronchial lavage fluid. Bronchoscopy should be performed in all patients suspected to have EBTB.

scholarly journals Clonal Complexity in Mycobacterium tuberculosis Can Hamper Diagnostic Procedures

2017 ◽  
Vol 55 (5) ◽  
pp. 1388-1395 ◽  
Author(s):  
Laura Pérez-Lago ◽  
Marta Herranz ◽  
Yurena Navarro ◽  
María Jesús Ruiz Serrano ◽  
Pilar Miralles ◽  
...  
Keyword(s):  
Mycobacterium Tuberculosis ◽  
High Risk ◽  
Mixed Infection ◽  
Diagnostic Procedures ◽  
Hiv Positive ◽  
Mixed Infections ◽  
Cross Contamination ◽  
Content Type ◽  
High Burden ◽  
Susceptibility Patterns

ABSTRACT Clonal complexity is increasingly accepted in Mycobacterium tuberculosis infection, including mixed infections by ≥2 strains, which usually occur in settings with a high burden of tuberculosis and/or a high risk of overexposure to infected patients. Mixed infections can hamper diagnostic procedures; obtaining an accurate antibiogram is difficult when the susceptibility patterns of the strains differ. Here, we show how mixed infections can also prove challenging for other diagnostic procedures, even outside settings where mixed infections are traditionally expected. We show how an unnoticed mixed infection in an HIV-positive patient diagnosed in Madrid, Spain, with differences in the representativeness of the coinfecting strains in different sputum samples, markedly complicated the resolution of a laboratory cross-contamination false positivity alert.

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.

Diagnosis of tuberculosis by nanoparticle-based immuno-PCR assay based on mycobacterial MPT64 and CFP-10 detection

Nanomedicine ◽  
2020 ◽  
Vol 15 (26) ◽  
pp. 2609-2624
Author(s):  
Bhawna Dahiya ◽  
Tulika Prasad ◽  
Vishwajeet Singh ◽  
Anish Khan ◽  
Ekta Kamra ◽  
...  
Keyword(s):  
Gold Nanoparticles ◽  
Mycobacterium Tuberculosis ◽  
Diagnostic Accuracy ◽  
Magnetic Beads ◽  
Pcr Assay ◽  
Pulmonary Tb ◽  
Functionalized Gold Nanoparticles ◽  
Bodily Fluids ◽  
Smear Negative ◽  
Improved Technology

Aim: To improve the diagnostic accuracy of immuno-PCR (I-PCR) in tuberculosis (TB) patients by using functionalized gold nanoparticles (AuNPs) coupled with detection antibodies and oligonucleotides, and magnetic beads (MBs) conjugated with capture antibodies in the liquid phase. Materials & methods: MB-coupled AuNP-based I-PCR (MB-AuNP-I-PCR) assay was designed to detect a cocktail of Mycobacterium tuberculosis MPT64 and CFP-10 proteins in bodily fluids of TB patients. Results: The sensitivities of 89.3 (n = 94) and 78.1% (n = 73) were observed in pulmonary TB and extrapulmonary TB patients, respectively, with specificities of 97.9–98.3%. Notably, the sensitivities attained by MB-AuNP-I-PCR in smear-negative pulmonary TB and extrapulmonary TB patients were significantly higher (p < 0.05–0.001) than Magneto-ELISA and GeneXpert assay. Conclusion: The improved technology, as well as enhanced diagnostic accuracy of MB-AuNP-I-PCR, may lead to development of an attractive diagnostic kit.

scholarly journals Serodiagnostic Potential of Culture Filtrate Antigens of Mycobacterium tuberculosis

2000 ◽  
Vol 7 (4) ◽  
pp. 662-668 ◽  
Author(s):  
K. M. Samanich ◽  
M. A. Keen ◽  
V. D. Vissa ◽  
J. D. Harder ◽  
J. S. Spencer ◽  
...  
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Culture Filtrate ◽  
Bacterial Load ◽  
Enzyme Linked Immunosorbent Assay ◽  
E Coli ◽  
Immunodeficiency Virus ◽  
Antigen Profile ◽  
Smear Negative ◽  
Humoral Responses ◽  
Hiv Negative

ABSTRACT Our studies of the humoral responses of tuberculosis (TB) patients have defined the repertoire of culture filtrate antigens ofMycobacterium tuberculosis that are recognized by antibodies from cavitary and noncavitary TB patients and demonstrated that the profile of antigens recognized changes with disease progression (K. Samanich et al., J. Infect. Dis. 178:1534–1538, 1998). We have identified several antigens with strong serodiagnostic potential. In the present study we have evaluated the reactivity of cohorts of human immunodeficiency virus (HIV)-negative, smear-positive; HIV-negative, smear-negative; and HIV-infected TB patients, with three of the candidate antigens, an 88-kDa protein, antigen (Ag) 85C, and MPT32, and compared the reactivity of the same patient cohort with the 38-kDa antigen and Ag 85A. We have also compared the reactivity of native Ag 85C and MPT32 with their recombinant counterparts. The evaluation of the reactivity was done by a modified enzyme-linked immunosorbent assay described earlier (S. Laal et al., Clin. Diag. Lab. Immunol. 4:49–56, 1997), in which all sera are preadsorbed againstEscherichia coli lysates to reduce the levels of cross-reactive antibodies. Our results demonstrate that (i) antigens identified on the basis of their reactivity with TB patients' sera provide high sensitivities for serodiagnosis, (ii) recombinant Ag 85C and MPT32, expressed in E. coli, show reduced reactivity with human TB sera, and (iii) of the panel of antigens tested, the 88-kDa protein is the most promising candidate for serodiagnosis of TB in HIV-infected individuals. Moreover, these results reaffirm that both the extent of the disease and the bacterial load may play a role in determining the antigen profile recognized by antibodies.

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