Diagnostic accuracy of tests for tuberculous pericarditis: A network meta-analysis.

Tuberculous pericarditis (TBP) is a relatively uncommon but potentially fatal extrapulmonary manifestation of tuberculosis. Despite its severity, there is no universally accepted gold standard diagnostic test for TBP currently. The objective of this study is to compare the diagnostic accuracy of the most commonly used tests in terms of specificity, sensitivity, negative predictive value (NPV), and positive predictive value (PPV), and provide a summary of their diagnostic accuracies. A comprehensive literature review was performed using Scopus, MEDLINE, and Cochrane central register of controlled trials, encompassing studies published from start to April 2022. Studies that compared Interferon Gamma Release Assay (IGRA), Xpert MTB/RIF, Adenosine Deaminase levels (ADA), and Smear Microscopy (SM) were included in the analysis. Bayesian random-effects model was used for statistical analysis and mean and standard deviation (SD) with 95% confidence intervals were calculated using the absolute risk (AR) and odds ratio (OR). Rank probability and heterogeneity were determined using risk difference and Cochran Q test, respectively. Sensitivity and specificity were evaluated using true negative, true positive, false positive, and false negative rates. Area under the receiver operating characteristic (AUROC) was calculated for mean and standard error. A total of seven studies comprising 16 arms and 618 patients were included in the analysis. IGRA exhibited the highest mean (SD) sensitivity of 0.934 (0.049), with a high rank probability of 87.5% for being the best diagnostic test, and the AUROC was found to be 94.8 (0.36). On the other hand, SM demonstrated the highest mean (SD) specificity of 0.999 (0.011), with a rank probability of 99.5%, but a leave-one-out analysis excluding SM studies revealed that Xpert MTB/RIF ranked highest for specificity, with a mean (SD) of 0.962 (0.064). The diagnostic tests compared in our study exhibited similar high NPV, while ADA was found to have the lowest PPV among the evaluated methods. Further research, including comparative studies, should be conducted using a standardized cutoff value for both ADA levels and IGRA to mitigate the risk of threshold effect and minimize bias and heterogeneity in data analysis.

Evaluation of new haematology analyser, XN-31, for malaria detection in blood donors: A single-centre study from India.

BACKGROUND AND OBJECTIVES: Malaria continues to be a significant public health concern in India, with several regions experiencing endemicity and sporadic outbreaks. The prevalence of malaria in blood donors, in India, varies between 0.02% and 0.07%. Common techniques to screen for malaria, in blood donors and patients, include microscopic smear examination and rapid diagnostic tests (RDTs) based on antigen detection. The aim of this study was to evaluate a new fully automated analyser, XN-31, for malaria detection, as compared with current practice of using RDT. MATERIALS AND METHODS: Cross-sectional analytical study was conducted to evaluate clinical sensitivity and specificity of new automated analyser XN-31 among blood donors' samples and clinical samples (patients with suspicion of malaria) from outpatient clinic collected over between July 2021 and October 2022. No additional sample was drawn from blood donor or patient. All blood donors and patients' samples were processed by malaria rapid diagnostic test, thick-smear microscopy (MIC) and the haematology analyser XN-31. Any donor blood unit incriminated for malaria was discarded. Laboratory diagnosis using MIC was considered the 'gold standard' in the present study. Clinical sensitivity and specificity of XN-31 were compared with the gold standard. RESULTS: Fife thousand and five donor samples and 82 diagnostic samples were evaluated. While the clinical sensitivity and specificity for donor samples were 100%, they were 96.3% and 100% for diagnostic samples. CONCLUSION: Automated haematology analysers represent a promising solution, as they can deliver speedy and sensitive donor malaria screening assessments. This method also has the potential to be used for pre-transfusion malaria screening along with haemoglobin estimation.

Automatic bright-field smear microscopy for diagnosis of pulmonary tuberculosis.

In recent decades, many studies have been published on the use of automatic smear microscopy for diagnosing pulmonary tuberculosis (TB). Most of them deal with a preliminary step of the diagnosis, the bacilli detection, whereas sputum smear microscopy for diagnosis of pulmonary TB comprises detecting and reporting the number of bacilli found in at least 100 microscopic fields, according to the 5 grading scales (negative, scanty, 1+, 2+ and 3+) endorsed by the World Health Organization (WHO). Pulmonary TB diagnosis in bright-field smear microscopy, however, depends upon the attention of a trained and motivated technician, while the automated TB diagnosis requires little or no interpretation by a technician. As far as we know, this work proposes the first automatic method for pulmonary TB diagnosis in bright-field smear microscopy, according to the WHO recommendations. The proposed method comprises a semantic segmentation step, using a deep neural network, followed by a filtering step aiming to reduce the number of false positives (false bacilli): color and shape filtering. In semantic segmentation, different configurations of encoders are evaluated, using depth-wise separable convolution layers and channel attention mechanism. The proposed method was evaluated with a large, robust, and annotated image dataset designed for this purpose, consisting of 250 testing sets, 50 sets for each of the 5 TB diagnostic classes. The following performance metrics were obtained for automatic pulmonary TB diagnosis by smear microscopy: mean precision of 0.894, mean recall of 0.896, and mean F1-score of 0.895.

Molecular and haematological investigations on Anaplasma ovis infection in goats in Ahvaz, Iran: Insights into infection rate, haemolytic effect and breed influences.

BACKGROUND: Anaplasma ovis (A. ovis) is the predominant causative agent of anaplasmosis in goats and sheep in most tropical and subtropical regions of the world. However, there is considerable variation in reported infection rates, breed susceptibility, and controversial findings regarding the haemolytic effects of A. ovis infection in goats. OBJECTIVES: Thus, we investigated the molecular and haematological aspects of A. ovis infection in goats from Ahvaz city. METHODS: One hundred and fifty apparently healthy goats (74 blacks and 76 Najdi goats) were randomly sampled from six flocks in the Ahvaz suburb during ticks' activity season. Haematological evaluation, smear microscopic (SM) examination and PCR assay were performed to assess A. ovis infection. Additionally, the percentage of parasitemia was determined from blood smears. RESULTS: SM examination revealed that 25.7% of the goats displayed erythrocyte Anaplasma-like inclusion bodies. PCR analysis indicated that 54% of the goats were positive for A. ovis infection (44.6% of blacks and 63.2% of Najdi goats). No significant difference in haematological values was observed between healthy and infected goats based on PCR testing. However, a significant difference in haematological indices was observed between the group with parasitemia level of 0.01-0.02% (SM and PCR positive) compared to the healthy goats (SM and PCR negative), particularly concerning Hb, PCV and RBC count (p < 0.01). CONCLUSIONS: When the parasitemia exceeds 0.01%, A. ovis infection may disrupt haematological parameters in infected goats. The high prevalence of A. ovis infection (54%) among the studied goats underscores the importance of giving special attention to implementing necessary measures for disease control in the Ahvaz suburb.

Usefulness of smear microscopy for therapeutic decision-making in patients with infectious keratitis.

PURPOSE: To determine the usefulness of smears in the diagnosis of infectious keratitis by comparing smears and 2 different culture methods. STUDY DESIGN: Retrospective, observational study. METHODS: The foci of 73 patients diagnosed with infectious keratitis at Hiroshima University Hospital between July 2011 and September 2015 were abraded, and smear microscopy and culturing were performed. The microorganism detection rates and other parameters were compared. RESULTS: Microorganisms were detected in 47 of 73 specimens. Microorganisms were identified in 32 of 69 cases cultured on plain medium (detection rate, 46.4%) compared with 22 of 61 cases cultured on swab transport medium (detection rate, 36.1%). There was no significant difference in the microbial detection rate between the plain medium method and the swab transport medium method (P = 0.23). Smear microscopy and culture findings were concordant in 21 (28.8%) cases, and different microorganisms were detected in 9 cases. In 17 cases, the culture was negative, despite the presence of microorganisms on smear microscopy, and in 7 cases, the culture was positive, despite the absence of microorganisms on smear microscopy. The positivity rate of microbial detection was significantly higher when no antimicrobial agents had been administered previously (odds ratio 7.50, P = 0.017). CONCLUSION: Smear microscopy of abrasions from lesions is useful for the initiation of treatment for infectious keratitis. However, culture studies should be conducted at the same time to confirm antimicrobial sensitivity. If possible, smear microscopy should be performed before the initiation of antimicrobial therapy.

Evaluation of BACTEC MGIT 960 system for recovery of Nocardia from clinical specimens.

Nocardia spp. is an aerobic Gram-positive bacillus responsible for nocardiosis. Herein, we performed a retrospective study to evaluate the performance of BACTEC MGIT 960 system, in comparison with smear microscopy and blood agar plate (BAP) culture, to recover Nocardia from different clinical specimens. Furthermore, the inhibitory effect of antibiotics contained in MGIT 960 tube on Nocardia was also evaluated. The sensitivities for Nocardia recovery using smear microscopy, BAP culture, and MGIT 960 were 39.4% (54/137), 46.1% (99/215), and 81.3% (156/192), respectively. N. farcinica was the most detected species (60.4%, 136/225). In MGIT 960-recovered Nocardia strains, N. farcinica accounted for 76.9%. Furthermore, trimethoprim in MGIT 960 tube inhibited less N. farcinica growth than that of other Nocardia species, partially explaining why MGIT 960 recovered more N. farcinica from sputa. The current study demonstrated that MGIT 960 could recover Nocardia strains from heavily-contaminated samples if its components and antibiotics are redesigned.

Diagnosis of tuberculous pleural effusion in a tertiary care hospital of central India: The role of xpert Mycobacterium tuberculosis/rifampicin.

Background: In India, 15%-20% of tuberculosis (TB) cases are categorized as extra-pulmonary TB, and tuberculous pleural effusion (TPE) is the second-most common type after tuberculous lymphadenitis. However, the paucibacillary nature of TPE makes its diagnosis challenging. As a result, relying on empirical anti-TB treatment (ATT) based on clinical diagnosis becomes necessary for achieving the best possible diagnostic outcome. The study aims to determine the diagnostic utility of Xpert Mycobacterium tuberculosis/rifampicin (MTB/RIF) for the detection of TB in TPE in high incidence setting of Central India. Methods: The study enrolled 321 patients who had exudative pleural effusion detected through radiological testing and were suspected of having TB. The medical procedure of thoracentesis was conducted to collect the pleural fluid, which was then subjected to both the Ziehl-Neelsen staining and Xpert MTB/RIF test. The patients who showed improvement after receiving anti-tuberculosis treatment (ATT) were considered the composite reference standard. Results: The sensitivity of smear microscopy was found to be 10.19%, while that of the Xpert MTB/RIF method was 25.93% when compared to the composite reference standard. The accuracy of clinical diagnosis was measured using receiver operating characteristics based on clinical symptoms, and it was found to be 0.858 (area under the curve). Conclusions: The study shows that Xpert MTB/RIF has significant value in diagnosing TPE, despite its low sensitivity of 25.93%. Clinical diagnosis based on symptoms was relatively accurate, but relying on symptoms alone is not enough. Using multiple diagnostic tools, including Xpert MTB/RIF, is crucial for accurate diagnosis. Xpert MTB/RIF has excellent specificity and can detect RIF resistance. Its quick results make it useful in situations where a rapid diagnosis is necessary. While it should not be the only diagnostic tool, it has a valuable role in diagnosing TPE.

Asymptomatic malaria infection, associated factors and accuracy of diagnostic tests in a historically high transmission setting in Northern Uganda.

BACKGROUND: Asymptomatic malaria infections are important parasite reservoirs and could sustain transmission in the population, but they are often unreported. A community-based survey was conducted to investigate the prevalence and factors associated with asymptomatic malaria infections in a historically high transmission setting in northern Uganda. METHODS: Using a cross-sectional design, 288 children aged 2-15 years were enrolled and tested for the presence of malaria parasites using rapid diagnostic tests (RDTs) and blood smear microscopy between January to May 2022. Statistical analysis was performed using the exact binomial and Fisher's exact test with p ≤ 0.05 indicating significance. The logistic regression was used to explore factors associated with asymptomatic malaria infections. RESULTS: Overall, the prevalence of asymptomatic infection was 34.7% (95% CI 29.2-40.5) with the highest observed in children 5-10 years 45.9% (95% CI 35.0-57.0). Gweri village accounted for 39.1% (95% CI 27.6-51.6) of malaria infections. Median parasite density was 1500 parasites/µl of blood. Plasmodium falciparum was the dominant species (86%) followed by Plasmodium malariae (5%). Factors associated with asymptomatic malaria infection were sleeping under mosquito net (Adjusted Odds Ratio (aOR) 0.27; 95% CI 0.13-0.56), p = 0.001 and presence of village health teams (VHTs) (aOR 0.02; 95% CI 0.01-0.45), p = 0.001. Sensitivity and specificity were higher for the P. falciparum/pLDH RDTs compared to HRP2-only RDTs, 90% (95% CI 86.5-93.5) and 95.2% (95% CI 92.8-97.7), p = 0.001, respectively. CONCLUSION: Asymptomatic malaria infections were present in the study population and this varied with place and person in the different age groups. Plasmodium falciparum was the dominant parasite species however the presence of P. malariae and Plasmodium ovale was observed, which may have implication for the choice and deployment of diagnostic tools. Individuals who slept under mosquito net or had presence of functional VHTs were less likely to have asymptomatic malaria infection. P.f/pLDH RDTs performed better than the routinely used HRP2 RDTs. In view of these findings, investigation and reporting of asymptomatic malaria reservoirs through community surveys is recommended for accurate disease burden estimate and better targeting of control.

Fluorescein Diacetate Vital staining for detecting viability of acid-fast bacilli in sputum of pulmonary tuberculosis patients.

OBJECTIVE: To compare the performance of the Fluorescein diacetate (FDA) vital staining method with Ziehl-Neelsen staining method in detecting the viability of acid-fast bacilli using MGIT culture as "reference standard". METHODS: This was a single centre prospective observational study conducted from October 2015 to November 2016. Microbiologically confirmed ZN-Smear positive (3+) sputum specimens were obtained from 30 pulmonary tuberculosis patients taking anti-tuberculosis treatment at DOTS centre of NITRD, New Delhi. Patients were made available to collect the first baseline sputum sample before commencing treatment, and an early morning sputum sample was collected as per RNTCP guidelines. After starting treatment, sputum specimens were collected weekly in the first month and thereafter twice-weekly until 18th week. All sputum specimens from patients receiving anti-tuberculosis treatment were examined using Ziehl-Neelsen (ZN) smear microscopy, FDA vital staining, and MGIT culture. RESULT: Out of 360 follow up sputum specimens collected from 30 adult microbiologically confirmed ZN- Smear (3+) pulmonary tuberculosis patients, 146 were ZN-positive and 130 FDA-positive. Of 130 FDA-positive sputum samples, mycobacteria tuberculosis (MTB) growth was found in 116 sputum samples, of which 116 sputum specimens were positive for FDA. Additionally, 14 culture-negative specimens were FDA positive. No FDA-negative sputum samples were positive for MGIT culture. Among ZN positive specimens, FDA had 100% sensitivity and 85.3% specificity with an accuracy of 96.58% for the detection of viable mycobacteria. Among ZN negative sputum specimens, FDA had comparatively high specificity (95.7%). Using positive MGIT culture as a reference for viability, negative predictive value (NPV) and positive predictive value (PPV) from FDA vital staining method were found to be 100 and 89% respectively. CONCLUSION: FDA staining is a simple and rapid tool for identifying viable MTB bacilli. Because of its excellent NPV and encouraging specificity, FDA staining is useful to identify patients with non-viable bacilli (FDA negative) among retreatment cases at diagnosis and patients on anti-tuberculosis treatment for both drug-sensitive and drug-resistant tuberculosis for follow up for the response of treatment.

Evaluation of a novel sputum processing ReaSLR methodology for improving sensitivity of smear microscopy in clinical samples.

Background: Early case detection is a crucial step in the control of tuberculosis (TB). Sputum smear microscopy is the primary method of TB diagnosis in developing countries. The modified Petroff's method using sodium hydroxide at concentrations ranging between 2% and 4% to digest the specimen is widely used in developing countries. A novel ReaSLR (ReaMetrix's Sputum Liquefying Reagent) methodology has been proposed as a simple, easy, low-cost, and better alternative to conventional methods for sputum processing. This study was undertaken to evaluate the performance of the ReaSLR method of sputum processing in comparison with that of the modified Petroff's method. Methods: Early-morning sputum samples were collected. After preparing a direct smear, each sample was divided into two equal halves and processed by both the methods, i.e., modified Petroff's method and ReaSLR method. Direct smears were graded according to Revised National Tuberculosis Control Program grading, and smears prepared after processing by the two different methods were graded according to Center for Disease Control and Prevention grading. Smear microscopy results were compared taking culture results of samples processed by the modified Petroff's method as the gold standard. Results: The rate of smear positivity with the modified Petroff's method (22.22%) was found to be higher than that with direct smear microscopy (13.56%; p = 0.0002) and the ReaSLR method (17.32%; p = 0.04). The modified Petroff's method was found to be 26.76% more sensitive than direct microscopy and 15.59% more sensitive than the ReaSLR method. Conclusion: The ReaSLR method was not superior to the modified Petroff's method for smear microscopy. Although this method was more sensitive than the direct method in smear microscopy, the modified Petroff's method performed much better than the ReaSLR method.

Tween 80 Improves the Acid-Fast Bacilli Quantification in the Magnetic Nanoparticle-Based Colorimetric Biosensing Assay (NCBA).

Despite its reduced sensitivity, sputum smear microscopy (SSM) remains the main diagnostic test for detecting tuberculosis in many parts of the world. A new diagnostic technique, the magnetic nanoparticle-based colorimetric biosensing assay (NCBA) was optimized by evaluating different concentrations of glycan-functionalized magnetic nanoparticles (GMNP) and Tween 80 to improve the acid-fast bacilli (AFB) count. Comparative analysis was performed on 225 sputum smears: 30 with SSM, 107 with NCBA at different GMNP concentrations, and 88 with NCBA-Tween 80 at various concentrations and incubation times. AFB quantification was performed by adding the total number of AFB in all fields per smear and classified according to standard guidelines (scanty, 1+, 2+ and 3+). Smears by NCBA with low GMNP concentrations (≤1.5 mg/mL) showed higher AFB quantification compared to SSM. Cell enrichment of sputum samples by combining NCBA-GMNP, incubated with Tween 80 (5%) for three minutes, improved capture efficiency and increased AFB detection up to 445% over SSM. NCBA with Tween 80 offers the opportunity to improve TB diagnostics, mainly in paucibacillary cases. As this method provides biosafety with a simple and inexpensive methodology that obtains results in a short time, it might be considered as a point-of-care TB diagnostic method in regions where resources are limited.

Evaluating the accuracy and diagnostic value of CFW and a new fluorescent reagents, fluorescent brightener 85, for the diagnosis of vulvovaginal candidiasis.

BACKGROUND: Vulvovaginal candidiasis (VVC) is a common vaginitis in females. The commonly used diagnostic method, 10% potassium hydroxide (KOH) smear microscopy, makes it not very easy to recognize fungi. METHODS: Vaginal secretions were collected from clinically suspected VVC patients and divided into four groups and examined using KOH, CFW (Calcofluor White), FB 85(fluorescent brightener 85), and culture. The data were statistically analyzed. RESULTS: In total, 110 patients with suspected VVC were recruited. The positive rates of KOH, CFW, FB 85, and the culture method were 68.2%, 64.5%, 61.8%, and 77%, respectively. According to the McNemar test, there was no statistically significant difference between the KOH, CFW, and the FB 85 methods (p > 0.05). However, CFW had a shorter diagnosis time than the KOH method and had a statistically significant difference (p < 0.001). Moreover, CFW has the highest sensitivity, specificity, and accuracy. In morphological recognition, it was easier to recognize fungal structures with CFW and FB 85 than with the KOH. CONCLUSIONS: The fluorescent method is a good method for the diagnosis of VVC. And the fungi can be found more quickly. Similar to CFW, FB 85 is also a potential good fluorescent reagent for the diagnosis of VVC and has potential value for application in clinical fungal infection diseases.

Comparing rates of mycobacterial clearance in sputum smear-negative and smear-positive adults living with HIV.

BACKGROUND: Pulmonary tuberculosis (TB) in people living with HIV (PLH) frequently presents as sputum smear-negative. However, clinical trials of TB in adults often use smear-positive individuals to ensure measurable bacterial responses following initiation of treatment, thereby excluding HIV-infected patients from trials. METHODS: In this prospective case cohort study, 118 HIV-seropositive TB patients were assessed prior to initiation of standard four-drug TB therapy and at several time points through 35 days. Sputum bacillary load, as a marker of treatment response, was determined serially by: smear microscopy, Xpert MTB/RIF, liquid culture, and colony counts on agar medium. RESULTS: By all four measures, patients who were baseline smear-positive had higher bacterial loads than those presenting as smear-negative, until day 35. However, most smear-negative PLH had significant bacillary load at enrolment and their mycobacteria were cleared more rapidly than smear-positive patients. Smear-negative patients' decline in bacillary load, determined by colony counts, was linear to day 7 suggesting measurable bactericidal activity. Moreover, the decrease in bacterial counts was comparable to smear-positive individuals. Increasing cycle threshold values (Ct) on the Xpert assay in smear-positive patients to day 14 implied decreasing bacterial load. CONCLUSION: Our data suggest that smear-negative PLH can be included in clinical trials of novel treatment regimens as they contain sufficient viable bacteria, but allowances for late exclusions would have to be made in sample size estimations. We also show that increases in Ct in smear-positive patients to day 14 reflect treatment responses and the Xpert MTB/RIF assay could be used as biomarker for early treatment response.

Harnessing Big Data to Optimize an Algorithm for Rapid Diagnosis of Pulmonary Tuberculosis in a Real-World Setting.

Background: The prompt diagnosis of pulmonary tuberculosis (PTB) remains a challenge in clinical practice. The present study aimed to optimize an algorithm for rapid diagnosis of PTB in a real-world setting. Methods: 28,171 adult inpatients suspected of having PTB in China were retrospectively analyzed. Bronchoalveolar lavage fluid (BALF) and/or sputum were used for acid-fast bacilli (AFB) smear, Xpert MTB/RIF (Xpert), and culture. A positive mycobacterial culture was used as the reference standard. Peripheral blood mononuclear cells (PBMC) were used for T-SPOT.TB. We analyzed specimen types' effect on these assays' performance, determined the number of smears for diagnosing PTB, and evaluated the ability of these assays performed alone, or in combination, to diagnose PTB and nontuberculous mycobacteria (NTM) infections. Results: Sputum and BALF showed moderate to substantial consistency when they were used for AFB smear or Xpert, with a higher positive detection rate by BALF. 3-4 smears had a higher sensitivity than 1-2 smears. Moreover, simultaneous combination of AFB and Xpert correctly identified 44/51 of AFB+/Xpert+ and 6/7 of AFB+/Xpert- cases as PTB and NTM, respectively. Lastly, when combined with AFB/Xpert sequentially, T-SPOT showed limited roles in patients that were either AFB+ or Xpert+. However, T-SPOTMDC (manufacturer-defined cut-off) showed a high negative predicative value (99.1%) and suboptimal sensitivity (74.4%), and TBAg/PHA (ratio of Mycobacterium tuberculosis-specific antigens to phytohaemagglutinin spot-forming cells, which is a modified method calculating T-SPOT.TB assay results) ≥0.3 demonstrated a high specificity (95.7%) and a relatively low sensitivity (16.3%) in AFB-/Xpert- patients. Conclusions: Concurrently performing AFB smear (at least 3 smears) and Xpert on sputum and/or BALF could aid in rapid diagnosis of PTB and NTM infections in a real-world high-burden setting. If available, BALF is preferred for both AFB smear and Xpert. Expanding this algorithm, PBMC T-SPOTMDC and TBAg/PHA ratios have a supplementary role for PTB diagnosis in AFB-/Xpert- patients (moderately ruling out PTB and ruling in PTB, respectively). Our findings may also inform policy makers' decisions regarding prevention and control of TB in a high burden setting.

Decline of Tuberculosis Burden in Vietnam Measured by Consecutive National Surveys, 2007-2017.

Vietnam, a high tuberculosis (TB) burden country, conducted national TB prevalence surveys in 2007 and 2017. In both surveys participants were screened by using a questionnaire and chest radiograph; sputum samples were then collected to test for Mycobacterium tuberculosis by smear microscopy and Löwenstein-Jensen culture. Culture-positive, smear-positive, and smear-negative TB cases were defined by laboratory results, and the prevalence of tuberculosis was compared between the 2 surveys. The results showed prevalence of culture-positive TB decreased by 37% (95% CI 11.5%-55.4%), from 199 (95% CI 160-248) cases/100,000 adults in 2007 to 125 (95% CI 98-159) cases/100,000 adults in 2017. Prevalence of smear-positive TB dropped by 53% (95% CI 27.0%-69.7%), from 99 (95% CI 78-125) cases/100,000 adults to 46 (95% CI 32-68) cases/100,000 adults; smear-negative TB showed no substantial decrease. Replacing microscopy with molecular methods for primary diagnostics might enhance diagnosis of pulmonary TB cases and further lower TB burden.

Culture conversion and six months interim outcomes in retreatment cases of pulmonary MDRTB - a six month interim analysis.

OBJECTIVE: To estimate the time to culture conversion and factors associated with failure to culture conversion, six-month interim outcomes and associated risk factors with poor interim outcomes in multi-drug resistant tuberculosis patients previously treated with second-line drugs. METHODS: The prospective clinical case series study was conducted from March 2016 to January 2017 at the Indus Hospital Tuberculosis Clinic and seven other sites that are part of the hospital's Programmatic Management of Drug Resistant Tuberculosis initiative. All bacteriologically confirmed multi-drug resistant tuberculosis retreatment patients were enrolled. Data was collected on age, gender, site of enrollment, detailed history of previous treatment with anti-tuberculosis drugs, medical history, history of first-line drugs, history of second-line drugs, treatment outcomes, baseline sputum smear microscopy and monthly follow-up sputum smear microscopy and culture results. Data was subjected to univariate and multiple logistic regression analyses, and risk factors for failure to culture conversion were assessed using Cox Proportional Hazards Model. RESULTS: Out of 266 patients, 143(53.8%) were males, the overall largest age group was 5-24 years 97(36.5%), and 250 (94%) patients had previous history of treatment with first-line drugs. Overall, 101(40.1%) patients experienced poor interim outcome. Poor interim outcomes were significantly associated with higher number of drugs on the regimen, (odds ratio: 1.27; 95% confidence interval: 1.03-1.58) and high sputum smear grading (odds ratio: 4.56; 95% confidence interval: 3.30-18.71). Besides, 186(70.3%) patients experienced culture conversion within the initial six months of treatment. CONCLUSIONS: The success rate of re-treatment of multi-drug resistant tuberculosis with conventional regimen was found to be unacceptably low.

Evaluation of the Xpert MTB/RIF test accuracy for diagnosis of tuberculosis in areas with a moderate tuberculosis burden.

The Xpert MTB/RIF assay (Xpert) is a molecular assay used for direct detection of Mycobacterium tuberculosis (MTB) in clinical specimens. In this study, we aimed to assess the accuracy of the Xpert assay for the diagnosis of tuberculosis (TB) in TB suspected patients from the northern region of Iran. The obtained results were compared with the culture method. The sputum specimens were examined using the Xpert assay, smear microscopy, and solid culture media as a reference diagnostic tool. Among 293 presumptive TB cases, 92 (31.4%) were positive according to the culture method. The Xpert method detected 88 (95.7%) cases that were positive according to the culture method, compared with 78 (84.8%) positive cases according to smear microscopy. The overall sensitivity and specificity of the Xpert method for TB diagnosis were 95.7% and 99%, respectively. Also, the sensitivity and specificity for smear microscopy were 84.8% and 97.5%, respectively. The Xpert assay showed high overall sensitivity and specificity; thus, it can be effectively used for the early and accurate diagnosis of MTB in TB endemic areas. In addition, the agreement between semi-quantitative results of Xpert and smear microscopy assays could be helpful in evaluating transmission potential in TB patients.

Evaluation of 'TBDetect' sputum microscopy kit for improved detection of Mycobacterium tuberculosis: a multi-centric validation study.

OBJECTIVES: The present study aimed to evaluate the performance of the 'TBDetect' kit-based bio-safe fluorescent microscopy filter (BioFM-Filter) microscopy in comparison with direct smear microscopy and culture for the detection of pulmonary tuberculosis (TB) in a multi-centric setting in India. METHODS: The TBDetect kit enables sputum concentration through filtration using the BioFM-Filter for improved and bio-safe smear microscopy. We evaluated the performance of the TBDetect kit in a six-site multi-centric validation study on sputum collected from 2086 presumptive TB patients. RESULTS: The combined positivity of TBDetect microscopy performed on these sputum samples was 20% (n = 417/2086) vs 16.1% of light-emitting diode fluorescence microscopy (LED-FM, n = 337/2086) and 16% of Ziehl Neelsen (ZN) smear microscopy (n = 333/2086). The increment in positivity of TBDetect over both LED-FM and ZN smears was significant (p < 0.001). The overall sensitivity of TBDetect for six sites was ~55% (202/367, 95% confidence interval (CI): 50, 60%) vs 52% (191/367, 95% CI: 47, 57%) for LED-FM (p 0.14) and 50.9% (187/367, 95% CI: 46, 56%) for ZN smear (p < 0.05), using Mycobacterium Growth Indicator Tube culture (MGIT, n = 1949, culture positive, n = 367) as the reference standard. A bio-safety evaluation at six sites confirmed efficient sputum disinfection by TBDetect; 99.95% samples (1873/1874) were sterile after 42 days of incubation. Scientists and technicians at the study sites indicated the ease of use and convenience of TBDetect microscopy during feedback. CONCLUSIONS: TBDetect added value to the smear microscopy test due to its improved performance, convenience and user safety. These findings indicate that equipment-free TBDetect technology has the potential to improve TB diagnosis in basic laboratory settings by leveraging on the existing nationwide network of designated microscopy centres and primary healthcare centres.

Diagnostic Accuracy of Sputum Microscopy in Comparison With GeneXpert in Pulmonary Tuberculosis.

Background Tuberculosis (TB) is a major health problem. In Pakistan, the diagnosis of pulmonary tuberculosis mainly relies on acid-fast bacilli (AFB) smear microscopy and Xpert® MTB/RIF assay (Cepheid Inc., Sunnyvale, CA) - a nucleic acid amplification test - where available. There is a wide variation in the reported sensitivity of Ziehl-Neelsen (ZN) smear microscopy across previous studies. This study aimed to determine the accuracy of sputum ZN smear microscopy in diagnosing pulmonary tuberculosis as compared with the sputum GeneXpert (Xpert MTB/RIF assay) as the reference test. Materials and methods This is a retrospective cross-sectional study conducted in the outpatient department of the Pakistan Institute of Medical Sciences. This study included 326 patients, aged 12 years and above, who had their sputum samples tested for ZN smear microscopy and GeneXpert during the period January to June 2019. Patients' demographic details, sputum ZN smear microscopy, and GeneXpert test results were collected for data analysis. A case of pulmonary tuberculosis was defined as a patient with positive sputum GeneXpert test result. Results Out of the 326 patients, GeneXpert detected MTB deoxyribonucleic acid (DNA) in 50 patients and ZN smear microscopy detected AFB in 30 patients. There was a marginal male predominance among GeneXpert positive cases. Adolescents were the least affected age group. The sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy of ZN smear microscopy were 60%, 100%, 100%, 93.24%, and 93.87%, respectively. The positive likelihood ratio was infinite whereas the negative likelihood ratio was 0.4. The area under curve (AUC) for ZN smear microscopy was 0.800 and receiver operating characteristic (ROC) curve analysis revealed a diagonal straight line closer to the left upper corner. Conclusion Sputum ZN smear microscopy is a highly specific but moderately sensitive test for the diagnosis of pulmonary tuberculosis. This study recommends the sputum GeneXpert MTB/RIF test to avoid a missed diagnosis of smear-negative pulmonary TB.

Metagenomic Next-Generation Sequencing versus Traditional Pathogen Detection in the Diagnosis of Peripheral Pulmonary Infectious Lesions.

PURPOSE: The aim of this study was to evaluate the value of metagenomic next-generation sequencing (mNGS) in peripheral pulmonary infection management by comparing the diagnostic yield of mNGS and traditional pathogen detection methods on interventional specimens obtained by bronchoscopy. PATIENTS AND METHODS: This study enrolled patients suspected with pulmonary infection who were admitted to Tianjin Medical University General Hospital from June 2018 to August 2019. Specimens were obtained from bronchoscopy for mNGS analysis and traditional pathogen detection (including bronchoalveolar lavage fluid microbial culture, smear microscopy, and lung biopsy histopathology), and the diagnostic yields were compared between mNGS and traditional methods to evaluate the diagnostic value of mNGS in peripheral pulmonary infection diagnosis. RESULTS: In this study, by comparing mNGS with traditional pathogen detection, the results indicated that, first, mNGS identified at least one microbial species in almost 89% of the patients with pulmonary infection; second, mNGS detected microbes related to human diseases in 94.49% of samples from pulmonary infection patients who had received negative results from traditional pathogen detection; third, the accuracy and sensitivity of mNGS are higher than those of traditional pathogen detection; and, finally, mNGS could simultaneously detect and identify a large variety of pathogens. CONCLUSION: Metagenomic NGS analysis provided fast and precise pathogen detection and identification, contributing to prompt and accurate treatment of peripheral pulmonary infection.