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SeeTB: A novel alternative to sputum smear microscopy to diagnose tuberculosis in high burden countries.

ABSTRACT: Microscopy-based tuberculosis (TB) diagnosis i.e. Ziehl-Neelsen screening still remains the primary diagnostic method in resource poor and high TB burden countries, however this method has poor sensitivity (~60%). Bringing three million TB patients who are left undiagnosed under the treatment has been a major focus as part of END-TB strategy across the world. We have developed a portable set-up called 'SeeTB' that converts a bright-field microscope into fluorescence microscope (FM) with minimal interventions. SeeTB, a total internal reflection-based fluorescence excitation system allows visualization of auramine-O stained bacilli efficiently with high signal-to-noise ratio. Along with the device, we have developed a sputum-processing reagent called 'CLR' that homogenizes and digests the viscous polymer matrix of sputum. We have compared the performance of SeeTB system in 237 clinical sputum samples along with FM, GeneXpert and liquid culture. In comparison with culture as gold standard, FM has sensitivity of 63.77% and SeeTB has improved sensitivity to 76.06%. In comparison with GeneXpert, FM has sensitivity of 73.91% while SeeTB has improved sensitivity to 85.51%. However, there is no significant change in the specificity between FM and SeeTB system. In short, SeeTB system offers the most realistic option for improved TB case identification in resource-limited settings.

SUBMITTER: Pandey V

PROVIDER: S-EPMC6851358 | biostudies-literature | 2019 Nov

REPOSITORIES: biostudies-literature

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SeeTB: A novel alternative to sputum smear microscopy to diagnose tuberculosis in high burden countries.

Pandey Vikas V Singh Pooja P Singh Saumya S Arora Naresh N Quadir Neha N Singh Saurabh S Das Ayan A Dudeja Mridu M Kapur Prem P Ehtesham Nasreen Zafar NZ Elangovan Ravikrishnan R Hasnain Seyed E SE

Scientific reports 20191112 1

Microscopy-based tuberculosis (TB) diagnosis i.e. Ziehl-Neelsen screening still remains the primary diagnostic method in resource poor and high TB burden countries, however this method has poor sensitivity (~60%). Bringing three million TB patients who are left undiagnosed under the treatment has been a major focus as part of END-TB strategy across the world. We have developed a portable set-up called 'SeeTB' that converts a bright-field microscope into fluorescence microscope (FM) with minimal ...[more]

PMID: 31719539

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Project description:IntroductionTajikistan has a laboratory network with three levels of tuberculosis (TB) laboratories. The external quality assessment (EQA) of sputum smear microscopy was implemented in 2007. The objective of this study was to evaluate the EQA system and identify potential performance improvement strategies in TB microscopic laboratories in Sughd, Tajikistan.MethodsThis is a cross-sectional study based on retrospective record review and secondary data analyses on Acid-Fast Bacilli (AFB) microscopy data and EQA reading results collected between the first quarter of 2011 and the fourth quarter of 2013. Descriptive analyses were conducted to examine the overview of microscopy laboratories activities, EQA results, and laboratory performance.ResultOf the 123,874 smears examined between 2011 and 2013, 11,522 (9.30%) were re-checked by the EQA system. The population TB screening rate rose from 0.46% in 2011 to 0.57% in 2013, and the case positivity rate decreased from 6.98% to 4.80%. The regional EQA results showed a reduction in high false-positive, high false-negative, and low false-negative errors. False-positive errors had decreased from 0.13% in 2011 to 0.07% in 2013, and false-negative errors from 0.91% in 2011 to 0.15% in 2013. Regional sensitivity of smear microscopy, when compared to re-checking controller, increased from 88.2% in 2011 to 97.2% in 2013. The regional specificity level remained relatively stable at above 99%.ConclusionOur study found that a decreasing trend of case positivity rate from 2011 to 2013 in Sughd, though the overall laboratory workload was on the rise. In addition, EQA results showed an overall error reduction and an improved sensitivity of smear microscopy in the region. The overview of microscopic laboratory activities and the actual evaluation of the EQA system on sputum smear microscopy complement each other in providing a better picture on the progress of TB laboratory strengthening. We recommend similar approaches to be adapted by future evaluations on TB microscopic laboratories, particularly among countries of high burden. Interactive training and feedback loops are crucial to improving TB surveillance in Tajikistan.

Project description:In Zimbabwe, sputum smear microscopy (SSM) is the routinely used TB diagnostic tool in hospitalised HIV-infected patients. However, SSM has poor sensitivity in HIV-infected patients. We compared performance of urine lipoarabinomannan strip test (LAM) and SSM among hospitalized HIV-infected patients with suspected TB.Hospitalized HIV-infected patients with suspected TB were randomized to LAM plus SSM or SSM alone groups as part of a larger multi-country parent study. Here we present a comparison of LAM versus SSM performance from the Zimbabwe study site. LAM analyses (grade 2 cut-off) were conducted using (i) a microbiological reference standard (MRS; culture positivity for M.tb and designated definite TB) and (ii) a composite reference standard (CRS; definite TB plus probable TB i.e. patients with clinical TB excluded from the culture negative group). CRS constituted the primary analysis.82/457 (18%) of the patients randomized to the LAM group were M.tuberculosis culture positive. Using CRS, sensitivity (%, 95% CI) of LAM was significantly higher than SSM [49.2 (42.1-56.4) versus 29.4(23.2-36.3); p?<?0.001]. Specificity and PPV were 98.1%, and 95.8%, respectively. By contrast, using MRS, LAM sensitivity was similar to SSM and specificity was significantly lower, however, the combined sensitivity of LAM and SSM was significantly higher than that of SSM alone, p?=?0.009. Using CRS, LAM sensitivity (%, CI) was CD4 count dependent [60.6(50.7-69.8) at ?50 cells/?L; 40.0(22.7-59.4) at 51-100 cells/?L, and 32.8(21.0-46.3) at >100 cells/?L. The combined sensitivity of LAM and SSM was higher than SSM alone being highest at CD4 counts <50 cells/?L [67.6(57.9-76.3); p?=?<0.001]. Specificity of LAM or SSM alone, or of combined LAM and SSM was >97% in all the 3 CD4 strata.Among hospitalized HIV-infected patients with suspected TB, the sensitivity of LAM is significantly higher than that of SSM, especially at low CD4 counts. LAM and SSM are complimentary tests for diagnosis of TB in HIV-infected patients. We recommend a combination of LAM and SSM for TB diagnosis in HIV-infected patients with low CD4 counts in HIV/TB co-endemic countries, where alternative methods are unavailable.

Project description:BackgroundSputum smear conversion is a key indicator of treatment response and reduced infectivity among bacteriologically confirmed pulmonary tuberculosis (PTB) patients. This study aimed at estimating sputum smear conversion and identifying factors hindering sputum smear conversion among bacteriologically confirmed PTB cases in East Gojjam Zone, Northwest Ethiopia.MethodsA total of 282 bacteriologically confirmed PTB patients were followed for 22 weeks through weekly sputum smear examination. Due to the absence of sputum culture and rapid diagnostic services, sputum smear conversion evaluation was conducted microscopically using acid-fast-bacilli staining technique of sediments from a 5% sodium hypochlorite concentration technique. Data on socio-demographic, clinical profile and personal behavior variables were collected using a pretested interviewer-administered questionnaire. Various descriptive statistics including mean, median with interquartile range (IQR), and proportions were computed to describe study objectives. Factors of sputum smear conversion were identified by multivariable logistic regression analysis and statistical significance was determined at a p value < 0.05.ResultsOver half, 166 (59%) of bacteriologically confirmed PTB patients were males and 147 (52%) were rural dwellers. The mean age of respondents was 35 ± 5 SD years. About 88 (31.2%) of bacteriologically confirmed PTB patients had comorbidities, 102 (36.2%) faced stigma, and 54 (19%) history of cigarette smoking. The median sputum smear conversions during the intensive phase and 5th months of treatment follow up were 35 dyas (IQR: 21-56 days) and 53 days (IQR: 28-82 days), respectuvely. The majority, 85% (95% CI 76-93%) and 95% (95% CI 85-99%) of bacteriologically confirmed PTB patients underwent sputum smear conversion at the end of 2nd and 5th months of treatment, respectively. Poor knowledge on TB, being HIV positive, higher smear grading, having diabetes mellitus, undernutrition, cigarette smoking, facing societal stigma, and TB service delays were positively associated with the length of sputum smear conversion (p value < 0.05).ConclusionBased on this study, the median sputum smear conversion time was higher compared to TB program expectations and findings from former studies. The study also identified important factors associated with sputum smear conversion time. Improving health literacy of the community by revising the existing community awareness strategies is essential to enhance treatment adherence and lower infectiousness after treatment initiation.

Project description:BACKGROUND:Xpert® MTB/RIF (Xpert) has high sensitivity for diagnosing tuberculosis (TB) compared to sputum-smear microscopy (smear) and can reduce time-to-diagnosis, time-to-treatment and potentially unfavorable patient-level treatment outcome. METHODS:People living with HIV (PLHIV) initiating antiretroviral therapy at 22 HIV clinics were enrolled and underwent systematic screening for TB (August 2012-November 2014). GeneXpert instruments were deployed following a stepped-wedge design at 13 centers from October 2012-June 2013. Treatment outcomes classified as an unfavorable outcome (died, treatment failure or loss-to-follow-up) or favorable outcome (cured and treatment completed). To determine outcome, smear was performed at month 5 or 6. Empiric treatment was defined as initiating treatment without/before receiving TB-positive results. Adjusting for intra-facility correlation, we compared patient-level treatment outcomes between patients screened using smear (smear arm)- and Xpert-based algorithms (Xpert arm). RESULTS:Among 6041 patients enrolled (smear arm, 1816; Xpert arm, 4225), 256 (199 per 2985 and 57 per 1582 person-years of follow-up in Xpert and smear arms, respectively; adjusted incidence rate ratio, 9.07; 95% confidence interval [CI]: 4.70-17.48; p?<?0.001) received TB diagnosis and were treated. TB treatment outcomes were available for 203 patients (79.3%; Xpert, 157; smear, 46). Unfavorable outcomes were reported for 21.7% (10/46) in the smear and 13.4% (21/157) in Xpert arm (adjusted hazard ratio, 1.40; 95% CI: 0.75-2.26; p?=?0.268). Compared to smear, in Xpert arm median days from sputum collection to TB treatment was 6?days (interquartile range [IQR] 2-17 versus 22?days [IQR] 3-51), p?=?0.005; patients with available sputum test result had microbiologically confirmed TB in 59.0% (102/173) versus 41.9% (18/43), adjusted Odds Ratio [aOR], 2.00, 95% CI: 1.01-3.96, p?=?0.048). In smear arm empiric treatment was 68.4% (39/57) versus 48.7% (97/199), aOR, 2.28, 95% CI: 1.24-4.20, p?=?0.011), compared to Xpert arm. CONCLUSIONS:TB treatment outcomes were similar between the smear and Xpert arms. However, compared to the smear arm, more patients in the Xpert arm received a TB diagnosis, had a microbiologically confirmed TB, and had a shorter time-to-treatment, and had a lower empiric treatment. Further research is recommended to identify potential gaps in the Botswana health system and similar settings. TRIAL REGISTRATION:ClinicalTrials.gov Identifier: NCT02538952. Retrospectively registered on 2 September 2015.

Project description:Both vitamin D deficiency and genetic variants in the vitamin D receptor (VDR) have been reported to associate with delayed response to intensive-phase therapy for pulmonary tuberculosis. Studies investigating the influence of genetic variants in vitamin D binding protein (DBP) and vitamin D 25-hydroxylase (CYP2R1) on vitamin D status and response to antituberculous therapy are lacking.We conducted a longitudinal study in 260 patients initiating treatment for smear-positive pulmonary tuberculosis in Lahore, Pakistan. Vitamin D status and genotypes for polymorphisms in VDR (rs2228570, rs731236, rs1544410), DBP (rs7041, rs4588) and CYP2R1 (rs2060793, rs10500804, rs10766197) were determined at baseline. Sputum smear microscopy was performed at 2, 4, 6 and 8 weeks, and time to sputum smear conversion was estimated for each participant. Analyses were conducted to determine demographic, clinical and genetic determinants of baseline vitamin D status and time to sputum smear conversion.Profound vitamin D deficiency (serum 25[OH]D < 25 nmol/L) was highly prevalent at TB diagnosis (present in 54 % of patients), and was independently associated with female vs. male sex (adjusted OR 2.60, 95 % CI 1.50 to 4.52, P = 0.001), recruitment in October to March inclusive (adjusted OR 1.75, 95 % CI 1.00 to 3.04, P = 0.047) and bilateral vs. unilateral disease (adjusted OR 1.89, 95 % CI 1.49 to 4.52 P = 0.025). Profound vitamin D deficiency was also independently associated with impaired response to antituberculous therapy (median time to sputum smear conversion 22.5 vs. 7.5 days for patients with serum 25[OH]D < 25 nmol/L vs. ? 25 nmol/L, respectively; aHR 4.36, 95 % CI 3.25 to 6.65, P < 0.001). No polymorphisms in VDR, CYP2R1 and DBP studied associated with either baseline vitamin D status or time to sputum smear conversion.Profound vitamin D deficiency is very common among TB patients in Lahore, Pakistan, and is independently associated with significantly delayed sputum smear conversion. Polymorphisms in VDR, CYP2R1 and DBP did not associate with baseline vitamin D status or response to intensive-phase treatment in this patient group.

Dataset Information

SeeTB: A novel alternative to sputum smear microscopy to diagnose tuberculosis in high burden countries.

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SeeTB: A novel alternative to sputum smear microscopy to diagnose tuberculosis in high burden countries.

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