A comparative study of Conventional methods and GeneXpert Mycobacterium tuberculosis Rifampicin (MTB/RIF) assay for diagnosis of childhood pulmonary tuberculosis

2019 ◽  
Author(s):  
Allah Rakhia ◽  
Taj Muhammad Laghari ◽  
Muhammad Ayaz Mustufa ◽  
Yahya Noori ◽  
Rahila Bhutto ◽  
...  
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Predictive Value ◽  
Diagnostic Tests ◽  
Rapid Test ◽  
Clinical History ◽  
Smear Microscopy ◽  
Indicator Tube ◽  
Mdr Tb ◽  
Lowenstein Jensen ◽  
Early Case

Abstract Background Diagnosis of childhood TB (tuberculosis) is challenging because its symptoms resemble other diseases, very few (less than five) mycobacteria are capable of causing the disease and children do not or rarely expectorate. These peculiar attributes make childhood TB different from adult TB but it is still not being dealt differently from adult TB .Despite evidences from national, international data and WHO recommendation for use of Gene expert/TB/RIF assay, decision to start the treatment is based mostly on Chest X ray, tuberculin skin test, history of contact and clinical sign and symptoms .Therefore, we planned this study to find best available choices of diagnostic tests for early case detection of childhood TB particularly MDR TB Methods: This comparative analytical study of 15 months was done at PHRC, SRCCH, NICH and Provincial TB Lab Ojha Institute of chest diseases Karachi. Our study population comprised of 143 probable cases of pulmonary TB below the age of 15 years. After taking written consent from parent/guardian, a Performa was filled with contact no, address, clinical history, scoring chart and diagnostic tests suggested by attending clinician. ZN staining for smear microscopy GeneXpert Mycobacterium tuberculosis Rifampicin (Xpert MTB/RIF) assay, Culture on Lowenstein–Jensen (L.J) media and Mycobacterium Growth Indicator Tube (MGIT) was done for every sample according to standard operating procedures of WHO and results were entered and analyzed on SPSS statistical package for social sciences. Results Out of 143 samples 7 (5%) were positive for MTB via Xpert MTB/RIF assay while 3(2.09) were positive through AFB microscopy, LJ culture and MGIT. When compared with gold standard blood culture sensitivity and negative predictive value of Xpert MTB/RIF were 100% and 97.14% while specificity and positive predictive value were 97.14% and 43% respectively. Conclusion Xpert MTB/RIF is a rapid test that can aid in timely diagnosis of peds TB, facilitating the timely treatment. However, specificity and PPV need to be taken into account. Key words: AFB microscopy, LJ and MGIT, Xpert MTB/RIF, Peds TB.

scholarly journals Use of amplified Mycobacterium tuberculosis direct test in respiratory samples from HIV-infected patients in Brazil

2014 ◽  
Vol 40 (2) ◽  
pp. 148-154 ◽  
Author(s):  
Leonardo Bruno Paz Ferreira Barreto ◽  
Maria Cristina da Silva Lourenço ◽  
Valéria Cavalcanti Rolla ◽  
Valdiléia Gonçalves Veloso ◽  
Gisele Huf
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Predictive Value ◽  
Laboratory Diagnosis ◽  
Test Results ◽  
Tuberculosis Complex ◽  
Indicator Tube ◽  
Lowenstein Jensen ◽  
The Mean ◽  
Sensitivity Specificity ◽  
The City

OBJECTIVE: To compare the accuracy of the amplified Mycobacterium tuberculosis direct (AMTD) test with reference methods for the laboratory diagnosis of tuberculosis in HIV-infected patients. METHODS: This was a study of diagnostic accuracy comparing AMTD test results with those obtained by culture on Löwenstein-Jensen (LJ) medium and by the BACTEC Mycobacteria Growth Indicator Tube 960 (BACTEC MGIT 960) system in respiratory samples analyzed at the Bioassay and Bacteriology Laboratory of the Oswaldo Cruz Foundation Evandro Chagas Clinical Research Institute in the city of Rio de Janeiro, Brazil. RESULTS: We analyzed respiratory samples collected from 118 patients, of whom 88 (74.4%) were male. The mean age was 36.6 ± 10.6 years. Using the AMTD test, the BACTEC MGIT 960 system, and LJ culture, we identified M. tuberculosis complex in 31.0%, 29.7%, and 27.1% of the samples, respectively. In comparison with LJ culture, the AMTD test had a sensitivity, specificity, positive predictive value, and negative predictive value of 87.5%, 89.4%, 75.7%, and 95.0%, respectively, for LJ culture, whereas, in comparison with the BACTEC MGIT 960 system, it showed values of 88.6%, 92.4%, 83.8%, and 94.8%, respectively. CONCLUSIONS: The AMTD test showed good sensitivity and specificity in the population studied, enabling the laboratory detection of M. tuberculosis complex in paucibacillary respiratory specimens.

scholarly journals Performance of Xpert® MTB/RIF among tuberculosis outpatients in Lilongwe, Malawi

2017 ◽  
Vol 6 (2) ◽  
Author(s):  
Tarsizio Chikaonda ◽  
Nelson Nguluwe ◽  
Brian Barnett ◽  
Runa H. Gokhale ◽  
Robert Krysiak ◽  
...  
Keyword(s):  
Predictive Value ◽  
Diagnostic Yield ◽  
Fluorescent Microscopy ◽  
Cross Reactivity ◽  
Smear Microscopy ◽  
Indicator Tube ◽  
Or Groups ◽  
Lowenstein Jensen ◽  
Culture Positive ◽  
Growth Indicator

Background: Xpert® MTB/RIF is a molecular test for the detection of Mycobacterium tuberculosis and rifampicin resistance. It is considered to be a great advance over smear microscopy and culture. However, there is very little information regarding the performance characteristics of Xpert MTB/RIF in Malawi.Objective: We aimed to evaluate the performance of Xpert MTB/RIF in a Malawian setting.Methods: Stored sputum pellets were processed on Xpert MTB/RIF between June 2012 andMay 2014. Results were compared to mycobacteria growth indicator tube and Löwenstein-Jensen cultures, LED fluorescent microscopy and GenoType® MTBDRplus assay. Rifampicinresistance was confirmed by DNA sequencing.Results: Of the 348 specimens with valid Xpert MTB/RIF results, 129/348 (37%) were smearpositive and 198/348 (57%) were culture-positive. Xpert MTB/RIF demonstrated a sensitivity of 93.8% (95% CI 89.4% – 96.8%) and specificity of 97.4% (95% CI 93.5% – 99.3%), with a positive predictive value of 97.8% (95% CI 94.6% – 99.4%) and a negative predictive value of 92.6% (95% CI 87.4% – 96.1%). Xpert MTB/RIF correctly identified 185/186 (99.5%) rifampicin sensitive and 2/2 (100%) rifampicin-resistant M. tuberculosis strains. Mutations were notdetected by sequencing in one isolate which was rifampicin resistant on Xpert MTB/RIF butsensitive on MTBDRplus. Four non-tuberculous mycobacteria grew from four smear-negativespecimens, namely, M. avium (n = 1) and M. intracellulare (n = 3). No cross-reactivity wasobserved with any of the non-tuberculous mycobacteria when using Xpert MTB/RIF.Conclusion: When fully implemented, Xpert MTB/RIF may have an impact on patient care inMalawi. The increased diagnostic yield of Xpert MTB/RIF over smear microscopy can increaselaboratory-confirmed tuberculosis detection and ensure that treatment is given to appropriateindividuals or groups.

scholarly journals Characterization of Drug-Resistant Lipid-Dependent Differentially Detectable Mycobacterium tuberculosis

2021 ◽  
Vol 10 (15) ◽  
pp. 3249
Author(s):  
Annelies W. Mesman ◽  
Seung-Hun Baek ◽  
Chuan-Chin Huang ◽  
Young-Mi Kim ◽  
Sang-Nae Cho ◽  
...  
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Culture Media ◽  
Multidrug Resistant ◽  
Culture Conditions ◽  
Sputum Smear ◽  
Smear Microscopy ◽  
Solid Culture ◽  
Lowenstein Jensen ◽  
Genetic Mechanisms ◽  
Lipid Resuscitation

An estimated 15–20% of patients who are treated for pulmonary tuberculosis (TB) are culture-negative at the time of diagnosis. Recent work has focused on the existence of differentially detectable Mycobacterium tuberculosis (Mtb) bacilli that do not grow under routine solid culture conditions without the addition of supplementary stimuli. We identified a cohort of TB patients in Lima, Peru, in whom acid-fast bacilli could be detected by sputum smear microscopy, but from whom Mtb could not be grown in standard solid culture media. When we attempted to re-grow Mtb from the frozen sputum samples of these patients, we found that 10 out of 15 could be grown in a glycerol-poor/lipid-rich medium. These fell into the following two groups: a subset that could be regrown in glycerol after “lipid-resuscitation”, and a group that displayed a heritable glycerol-sensitive phenotype that were unable to grow in the presence of this carbon source. Notably, all of the glycerol-sensitive strains were found to be multidrug resistant. Although whole-genome sequencing of the lipid-resuscitated strains identified 20 unique mutations compared to closely related strains, no single genetic lesion could be associated with this phenotype. In summary, we found that lipid-based media effectively fostered the growth of Mtb from a series of sputum smear-positive samples that were not culturable in glycerol-based Lowenstein–Jensen or 7H9 media, which is consistent with Mtb’s known preference for non-glycolytic sources during infection. Analysis of the recovered strains demonstrated that both genetic and non-genetic mechanisms contribute to the observed differential capturability, and suggested that this phenotype may be associated with drug resistance.

scholarly journals XPERT MYCOBACTERIUM TUBERCULOSIS/RIFAMPICIN ASSAY: A BOON IN TUBERCULOSIS DIAGNOSTICS

2016 ◽  
Vol 9 (5) ◽  
pp. 225 ◽  
Author(s):  
Sevitha Bhat ◽  
Kavya Ramamurthy ◽  
Shalini Shenoy ◽  
Aseem Rangnekar
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Predictive Value ◽  
High Sensitivity ◽  
Mortality And Morbidity ◽  
Indicator Tube ◽  
Promising Tool ◽  
Causes Of Mortality ◽  
Conventional Microscopy ◽  
Tb Diagnostics ◽  
Sensitivity Specificity

ABSTRACTObjectives: Mycobacterium tuberculosis (MTB) remains one of the most significant causes of mortality and morbidity in developing countriesespecially India. India has the highest burden of TB, with an estimated incidence figure of 2.1 million cases out of the 9 million cases of TB globally.Diagnosis of TB relies on conventional microscopy and culture with drawbacks related to sensitivity, specificity, turn around time (TAT). The aim ofthis study was to evaluate the performance of Xpert MTB/rifampicin (RIF) assay (GX) for MTB detection in pulmonary and extrapulmonary clinicalsamples.Methods: A total of 209 clinical specimens (182: pulmonary and 27: extrapulmonary) were processed using auramine smear, culture by mycobacteriagrowth indicator tube and GenXpert.Results: The sensitivity of GenXpert was 62.63% for pulmonary and 55% for extrapulmonary samples. The sensitivity and specificity of GX were100% for the smear positive cases. The sensitivity, specificity, positive predictive value, and negative predictive value of the GX for smear negativecases were 67.8%, 97.5%, 90.4%, and 89.6%, respectively. RIF resistance was detected in 3.8% the samples.Conclusion: GenXpert, with short TAT, high sensitivity, specificity and less technical expertise required is a promising tool in TB diagnostics for thefuture.Keywords: GenXpert, Tuberculosis diagnosis, Molecular method, Rifampicin resistance.

scholarly journals Evaluation of Gene Xpert Mtb/Rif Assay for the Detection of Mycobacterium Tuberculosis in Sputum of Patients Suspected of Pulmonary Tuberculosis Visiting National Tuberculosis Centre, Thimi, Bhaktapur, Nepal

2017 ◽  
Vol 13 (1) ◽  
pp. 16-22
Author(s):  
Ashok Thapa ◽  
P Gurung ◽  
G R Ghimire
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Pulmonary Tuberculosis ◽  
Predictive Value ◽  
Sputum Sample ◽  
Culture Method ◽  
Smear Microscopy ◽  
National Tuberculosis ◽  
Standard Culture ◽  
Sensitivity Specificity ◽  
And Control

Introduction: Tuberculosis (TB) is one of the most deadly and common major infectious diseases in developing countries. Rapid and accurate diagnosis of tuberculosis is indispensable to adequately manage the disease and control its transmission. The objective of this study was to evaluate Gene Xpert MTB/RIF Assay for detection of M. tuberculosis in sputum of patients suspected of pulmonary tuberculosis and its comparison with traditional conventional methods.Methodology: A total of 138 patients sputum samples were collected and processed. Gene Xpert MTB/ RIF Assay, culture method and smear microscopy were performed under standard guideline inside biosafety cabinet class II. Data were reported, structured and analyzed using SPSS version 16.00. Study was carried out from June to November 2014.Results: Assay detected M. tuberculosis in 37 (26.81%) samples out of total 138. Of these 37, 10 and 3 were resistance and indeterminate to rifampicin respectively. Culture, Ziehl-Neelsen staining and Auramine staining were positive in 43 (31.16%), 18 (13.04%) and 24 (17.39%) samples respectively. Sensitivity, specificity, Positive predictive value and Negative predictive value of Assay were 76.74%, 95.79%, 89.19% and 90.09% respectively with reference to gold standard culture method.Conclusions: Assay was found rapid in direct detec tion of Mycobacterium tuberculosis in sputum sample and was also found more sensitive than both Ziehl-Neelsen staining and Auramine staining and especially showed good promise in diagnosis of smear negative specimens.SAARC J TUBER LUNG DIS HIV/AIDS, 2016; XIII(1), page: 16-22

scholarly journals Immunocytochemical Study of Rabbit-Polyclonal to Mycobacterium Tuberculosis, AB905: Improving Diagnostic of Tuberculous Lymphadenitis

2021 ◽  
Vol 21 (2) ◽  
pp. 95-101
Author(s):  
Humairah Medina Liza Lubis ◽  
Emni Purwoningsih ◽  
Ance Roslina ◽  
Muhammad Al Anas
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Predictive Value ◽  
Extrapulmonary Tuberculosis ◽  
Clinical History ◽  
Excisional Biopsy ◽  
Needle Aspiration ◽  
Cross Sectional Study ◽  
Tuberculous Lymphadenitis ◽  
Immunocytochemical Study ◽  
Cross Sectional

Tuberculous lymphadenitis (TBLN) is the most common form of extrapulmonary tuberculosis. However, the optimal diagnosis using Fine-Needle Aspiration Cytology (FNAC) or excisional biopsy is uncertain. This research aims to improve the diagnostic of TBLN with FNAC and immunocytochemistry (ICC) compared to the response to antituberculosis therapy. The cross-sectional study involved 43 patients with the criteria for TBLN diagnosis based on the appropriate clinical history of tuberculosis and indicative cytological results. Immunocytochemical examination employed rabbit-polyclonal to Mycobacterium tuberculosis (MTB) antibody (AB905). The MTB expression was found in 35 out of 43 cases (81%) that appropriate cytological features of the tuberculosis process. Meanwhile, eight out of 43 cases (19%) did not express MTB. Diagnostic tests for lesions with a positive cytologic appearance of TBLN and ICC were compared to the response to anti-tuberculosis therapy, revealing the sensitivity, specificity, positive predictive value, and negative predictive value of 95.2%, 75%, 95.2%, and 17%, respectively. Besides, Fisher's exact tests utilized to identify the relationship between two variables; p 0.05 was considered significant. This research found immunocytochemical study was a sensitive and specific tool for improving the diagnostic of TBLN.

scholarly journals Sensitivitas Metode Pemeriksaan Mikroskopis Fluorokrom dan Ziehl-Neelsen untuk Deteksi Mycobacterium tuberculosis pada Sputum

2019 ◽  
Vol 1 (2) ◽  
pp. 56
Author(s):  
BETTY SURYAWATI ◽  
LELI SAPTAWATI ◽  
ASTARI FEBYANE PUTRI ◽  
JATU APHRIDASARI
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Early Detection ◽  
Pulmonary Tuberculosis ◽  
Sensitivity And Specificity ◽  
Smear Microscopy ◽  
Microbiology Laboratory ◽  
Fluorochrome Staining ◽  
Primary Screening ◽  
Lowenstein Jensen ◽  
Tuberculosis Diagnosis

<p class="AbstractNormal"><em>Background: Detection of fast acid bacteria (FAB) using smear microscopy is used as a primary screening for tuberculosis diagnosis. Previous studies have shown that fluorochrome </em>(<em>Auroamine-rhodamine</em>) <em>staining showed better sensitivity compared to Ziehl-Neelsen (ZN) method in the detection of FAB in sputum. However this method has not been recommended for routine use including in Indonesia. This study aimed to evaluate the sensitivity and specificity of fluorochrome compared to ZN to detect FAB in patient’s sputum.</em><em></em></p><p class="AbstractNormal"><em>Methods: </em><em>This study analyzed 60 sputum samples from patients with tuberculosis and suspected pulmonary tuberculosis. Samples were obtained consecutively from microbiology laboratory</em><em> Moewardi Hospital, Indonesia. Each sample was examined using ZN and fluorochrome staining and cultured in Lowenstein-Jensen (LJ) medium.</em><em> Data were analyzed using sensitivity and spesificity tests.</em></p><p class="AbstractNormal"><em>Results: ZN staining detected FAB in 12 samples (10%), while fluorochrome detected FAB in 17 samples (28%). The sensitivity and specificity of ZN staining were 70% and 90% while these for fluorochrome were 90% and 84%. </em><em></em></p><p class="AbstractNormal"><em>Conclusions: The sensitivity of fluorochrome staining is better compared to ZN staining. This method can be recommended for early detection of tuberculosis.</em><em></em></p><p class="AbstractNormal"><em> </em></p>

scholarly journals Evaluation of a Rapid Differentiation Test for Mycobacterium Tuberculosis from other Mycobacteria by Selective Inhibition with p-nitrobenzoic Acid using MGIT 960

2010 ◽  
Vol 2 (02) ◽  
pp. 089-092 ◽  
Author(s):  
Babita Sharma ◽  
Nita Pal ◽  
Bharti Malhotra ◽  
Leela Vyas
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Selective Inhibition ◽  
Clinical Samples ◽  
Biochemical Tests ◽  
Mycobacterium Tuberculosis H37rv ◽  
Nitrobenzoic Acid ◽  
Indicator Tube ◽  
Heat Stable ◽  
Lowenstein Jensen ◽  
Differentiation Test

ABSTRACTTuberculosis is caused by Mycobacterium tuberculosis (M.tb) as well as Non-tubercular mycobacterium (NTM) with similar clinical presentation. Infections due to NTM are reported to have increased in the past few years. Growth of M.tb is inhibited by p-Nitrobenzoic acid (PNB), whereas, NTM are resistant. One hundred and nine isolates from various clinical samples were identified up to species level by their growth rate, pigmentation, and a battery of biochemical tests, including niacin accumulation, nitrate reduction, and heat-stable catalase (68°C) reactions. Para-nitrobenzoic acid (PNB) inhibition test was performed to differentiate between M.tb and NTM. PNB was added to the Lowenstein-Jensen (LJ) medium and BACTECTM MIGIT (Mycobacteria Growth Indicator Tube)960 medium to a final concentration of 500 μg/ml. All the M.tb isolates, including Mycobacterium tuberculosis H37Rv (standard strain), were inhibited by PNB on both LJ and MGIT 960. Of the NTM isolates, all were resistant to PNB on MGIT 960 and on LJ PNB, except one isolate of Mycobacterium marinum that was resistant to MGIT 960 PNB, but was susceptible to LJ PNB. The reporting time for M.tb ranged from 4–11 days (median 5.9 days) by MGIT 960 and for NTM it was 2–10 days with an average of 4.5 days. This study was carried out to establish the accuracy and efficiency of MGIT 960 PNB and to differentiate between M.tb and NTM.

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