Rapid Detection Of Tuberculosis Research Articles

Integration of Electrochemical Sensing and Machine Learning to Detect Tuberculosis via Methyl Nicotinate in Patient Breath.

Tuberculosis (TB) remains a significant global health issue; making early, accurate, and inexpensive point-of-care detection critical for effective treatment. This paper presents a clinical demonstration of an electrochemical sensor that detects methyl-nicotinate (MN), a volatile organic biomarker associated with active pulmonary tuberculosis. The sensor was initially tested on a patient cohort comprised of 57 adults in Kampala, Uganda, of whom 42 were microbiologically confirmed TB-positive and 15 TB-negative. The sensor employed a copper(II) liquid metal salt solution with a square wave voltammetry method tailored for MN detection using commercially available screen-printed electrodes. An exploratory machine learning analysis was performed using XGBOOST. Utilizing this approach, the sensor was 78% accurate with 71% sensitivity and 100% specificity. These initial results suggest the sensing methodology is effective in identifying TB from complex breath samples, providing a promising tool for non-invasive and rapid TB detection in clinical settings.

Rapid Detection of M. tuberculosis and Its Resistance to Rifampicin and Isoniazid with the mfloDx™ MDR-TB test.

Rapid detection of tuberculosis (TB) and its resistance are essential for the prompt initiation of correct drug therapy and for stopping the spread of drug-resistant TB. There is an urgent need for increased use of rapid diagnostic tests to control the threat of increased TB and multidrug-resistant TB (MDR-TB). EMPE Diagnostics has developed a multiplex molecular diagnostic platform called mfloDx™ by combining nucleotide-specific padlock probe-dependent rolling circle amplification with sensitive lateral flow biosensors, providing visual signals, similar to a COVID-19 test. The first test kit of this platform, mfloDx™ MDR-TB can identify Mycobacterium tuberculosis (MTB) complex and its clinically significant mutations in the rpoB and katG genes and in the inhA promotor contributing resistance to rifampicin (RIF) and isoniazid (INH), causing MDR-TB. We have evaluated the performance of the mfloDx™ MDR-TB test on 210 sputum samples (110 from suspected TB cases and 100 from TB-negative controls) received from a tertiary care center in India. The clinical sensitivity for detecting MTB compared to acid-fast microscopy and mycobacteria growth indicator tube (MGIT) cultures was 86.4% and 84.9%, respectively. All the 100 control samples were negative indicating excellent specificity. In smear-positive sputum samples, the mfloDx™ MDR-TB test showed a sensitivity of 92.5% and 86.4% against MGIT culture and Xpert MTB/RIF, respectively. The clinical sensitivity for the detection of RIF and INH resistance in comparison with MGIT drug susceptibility testing was 100% and 84.6%, respectively, while the clinical specificity was 100%. From the above evaluation, we find mfloDx™ MDR-TB to be a rapid and efficient test to detect TB and its multidrug resistance in 3 h at a low cost making it suitable for resource-limited laboratories.

Performance of clinical scoring and microscopic combinations for diagnosing pulmonary tuberculosis with the GenXpert criteria

Pulmonary tuberculosis is a prominent health issue in Indonesia, which ranks second in the world regarding the number of patients. Rapid tuberculosis detection is crucial for early treatment, a better prognosis, and a reduction in disease transmission; however, the availability of molecular rapid tests is limited. Cross-sectional design and retrospective analyses of pre-pandemic data from 723 patients with suspected pulmonary tuberculosis from 2017 to 2019 were conducted in this study. The study aimed to assess the performance of clinical scoring and microscopic examination in tuberculosis diagnosis at RSUD Sayang Cianjur. The effectiveness of sequential (two-stage) and simultaneous combinations of clinical scoring and sputum smear microscopic were investigated. Performance assessments consisted of 2x2 tables, calculation according to Gordis, and Receiver Operator Characteristic (ROC) analysis, with GenXpert results as the gold standard. The results showed lower performance of the individually performed scoring system, with clinical scoring having a sensitivity of 34.44% and a specificity of 97.15%. Microscopic Acid Fast Bacteria (AFB) had a sensitivity of 70.20% and a specificity of 98.57%. The net sensitivity of the sequential combination was 28.48%, and the specificity was 99.05%. The net sensitivity of the simultaneous combination was 77.15%, and the specificity was 95.72%. The area under the curve from the sequential diagnostic method was 0.728, and the area under the curve of the simultaneous diagnostic was 0.884. The sequential and simultaneous combinations of clinical scoring and the AFB microscopy improved the test performance. The simultaneous combination performed slightly better than the sequential combination.

TO ANALYZE THE TB-PCR POSITIVITY RATE USING REAL-TIME PCR FOR EARLY DETECTION OF TUBERCULOSIS

Objective: Tuberculosis is one of the leading causes of death worldwide. It is present in all the countries and among all age groups and also seen in both the genders. In investigating the early stage, identification, and rapid detection of tuberculosis, the PCR method (polymerase chain reaction) is one of the fast, safest, and reproducible new approaches. It covers all advantages such as the use of closed systems, reduced risk of carryover contamination, improved sensitivity and reproducibility, reduced turnaround time wide dynamic range of target detection, and feasibility for quantitation making it easy and reliable for the early detection of Mycobacterium tuberculosis. Methods: All samples used for the study are confirmed by conventional microscopic observation using acid-fast staining using ZN STAIN. The pulmonary sputum samples are obtained from clinical and radiological evidence of tuberculosis and these samples are selected for DNA extraction. Discussion: As per the statistical analysis using SPSS 22 version, it is found that the TB positivity rate (is 29.75%). Out of 119 positive patients (Male: 60.5% and Female: 39.5%). The average and standard deviation for CT values are 23.6 and 2.9, respectively. The 95% confidence interval of CT values for specimens is (22.7, 24.5). Average and standard deviation for CT values are equal in male patients and female patients. Age group-wise average and standard deviation for CT values are nearly equal. Results: The percentage of 3+ AFB positive grades having CT values between 20 and 24 is more than all other combinations of AFB positive grades and CT values. The average and standard deviation for CT values are 23.6 and 2.9, respectively. The 95% confidence interval of CT values for specimens is (22.7, 24.5). The average and standard deviation for CT values are equal in male patients and female patients. Conclusion: A significant improvement in specificity with high accuracy was achieved by a real-time PCR assay. Real-time PCR tests prove both a high degree of sensitivity in the upper respiratory sputum samples and for the early detection of the TB infection. The MTB real-time PCR test suitably identified the majority of the AFB positive and bacterial culture confirms TB.

Prevalence of Tuberculosis, Rifampicin Resistant Tuberculosis and Associated Risk Factors in Presumptive Tuberculosis Patients Attending Some Hospitals in Kaduna, Nigeria

The accurate diagnosis of tuberculosis (TB), detection of drug‐resistant TB and knowledge of the associated risk factors can reduce transmission of TB in the community. Therefore this study was carried out to determine the prevalence of Mycobaterium tuberculosis(MTB) and its resistance to Rifampicin using GeneXpert in presumptive tuberculosis patients attending some hospitals in Kaduna, Nigeria. A total of 198 sputum samples were collected and screened from participants who had been administered questionnaires using Ziehl Neelsen Acid Fast Bacilli (ZN AFB) method and GeneXpert molecular technique. Data obtained showed that using the Zn AFB staining technique, MTB was seen in 65 sputum test results but with the GeneXpert technique, MTB was further detected in 15 sputum sample, bringing the total to 80, thus confirming that GeneXpert was more sensitive in detecting TB compared to the ZN AFB method. The overall prevalence of TB and Rifampicin resistant TB (RRTB) was 40.4% and 1.25% respectively. A higher prevalence rate was reported among male subjects (47.2%), age group 31‐40 years (50.9%), HIV positive subjects (54.5%), those that smoke cigarettes (72.2%) and those that has previous contact with someone living with TB infection (82.4%). Assay for statistical significance showed that independent variables that were significantly associated with the rate of occurrence of TB (p<0.05 at 95% C.I) were Age, Gender, HIV Status, smoking behaviour and previous contact with someone having TB. The only RRTB case detected was a male who has had a previous contact with someone living with TB infection. This study indicates a low burden of rifampicin resistant tuberculosis among the participants. It is thus concluded that rapid detection of TB and Rifampicin resistant strains using GeneXpert and other molecular techniques for TB diagnosis in clinical settings is key to early access to the right therapy; it will also improve treatment outcomes and decrease transmission rates.

A Prospective Study On Utility Of Cbnaat In Enhancing Tb Case Detection In Pediatric Household Contacts Of Pulmonary Positive Tb Patients

Background: Burden of childhood TB is a very important measure of TB control in a community as it reflects recent transmission. CBNAAT assay is a rapid test which identifies both the presence of Mycobacterium tuberculosis and Rifampicin resistance associated with mutation of rpoB gene in a single test. Objectives: To evaluate the utility of CBNAAT in enhancing TB case detection in pediatric household contacts of pulmonary positive TB patients. Materials and Methods: It was an observational prospective study including 200 contacts from July 2019 to June 2020 on pediatric household contacts (0- 18 years) of diagnosed pulmonary positive TB patients. Result: Out of 200 pediatric contacts, 25 came out to be positive for tuberculosis by ZN staining and 67 were CBNAAT positive for tuberculosis which was found to be statistically significant. Out of 36 extra pulmonary tubercular cases, 26 (38.81%) were abdominal tuberculosis, 5 (7.46%) were CNS tuberculosis, 4 (5.97%) miliary and 1 (1.49%) of pleural etiology. Out of 67 CBNAAT positive contacts, 8(11.94%) were found to be resistant to Rifampicin. Conclusion: CBNAAT is an effective tool for rapid detection of tuberculosis and can revolutionise the scenario in prevention and management of tuberculosis which identifies both the presence of Mycobacterium Tuberculosis and Rifampicin resistance.

A cost\u2013benefit algorithm for rapid diagnosis of tuberculosis and rifampicin resistance detection during mass screening campaigns

BackgroundActive tuberculosis (TB) case finding is important as it helps detect pulmonary TB cases missed by the other active screening methods. It requires periodic mass screening in risk population groups such as prisoners and refugees. Unfortunately, in these risk population groups periodic mass screening can be challenging due to lengthy turnaround time (TAT), cost and implementation constraints. The aim of this study was to evaluate a diagnostic algorithm that can reduce the TAT and cost for TB and Rifampicin resistance (RR) detection. The algorithm involves testing with TB-LAMP followed by Xpert MTB/RIF for positive TB-LAMP cases to diagnose TB during mass campaigns in prisons and refugee camps.MethodsThe National Tuberculosis Control Program (NTCP) organized routine TB mass-screening campaigns in 34 prisons and 3 villages with refugees camps in Cameroon in 2019. TB LAMP was used for initial TB diagnosis and all TB-LAMP positive cases tested with the Xpert MTB/RIF assay to determine RR. TAT and cost benefits analysis of the combined use of TB-LAMP and Xpert MTB/RIF assays was determined and compared to the Xpert MTB/RIF assay when used only.ResultsA total of 4075 sputum samples were collected from TB presumptive, 3672 cases in 34 prisons and 403 samples in 3 villages. Of the 4,075 samples screened with TB-LAMP, 135 were TB positive (3.31%) and run on the Xpert MTB/RIF. Of the 135 positives cases, Xpert MTB/RIF revealed 3 were RR (2.22%). The use of TB-LAMP followed by testing with Xpert MTB/RIF for TB and RR detection reduced the TAT by 73.23% in prisons and 74.92% in villages. In addition to a reduced TAT, the two molecular tests used in synergy is cost benefit from year 2 onwards.ConclusionThis study demonstrates the advantages of a diagnostic algorithm based on an initial testing with TB-LAMP followed by testing with Xpert MTB/RIF for TB diagnosis. This approach improved early and rapid TB detection with an added advantage of providing RR status. The proposed algorithm is effective and less costly from the second year of implementation and should be used by TB control programs.

Detection of differentially culturable tubercle bacteria in sputum using mycobacterial culture filtrates

Rapid detection of tuberculosis (TB) infection is paramount to curb further transmission. The gold standard for this remains mycobacterial culture, however emerging evidence confirms the presence of differentially culturable tubercle bacteria (DCTB) in clinical specimens. These bacteria do not grow under standard culture conditions and require the presence of culture filtrate (CF), from axenic cultures of Mycobacterium tuberculosis (Mtb), to emerge. It has been hypothesized that molecules such as resuscitation promoting factors (Rpfs), fatty acids and cyclic-AMP (cAMP) present in CF are responsible for the growth stimulatory activity. Herein, we tested the ability of CF from the non-pathogenic bacterium Mycobacterium smegmatis (Msm) to stimulate the growth of DCTB, as this organism provides a more tractable source of CF. We also interrogated the role of Mtb Rpfs in stimulation of DCTB by creating recombinant strains of Msm that express Mtb rpf genes in various combinations. CF derived from this panel of strains was tested on sputum from individuals with drug susceptible TB prior to treatment. CF from wild type Msm did not enable detection of DCTB in a manner akin to Mtb CF preparations and whilst the addition of RpfABMtb and RpfABCDEMtb to an Msm mutant devoid of its native rpfs did improve detection of DCTB compared to the no CF control, it was not statistically different to the empty vector control. To further investigate the role of Rpfs, we compared the growth stimulatory activity of CF from Mtb, with and without Rpfs and found these to be equivalent. Next, we tested chemically diverse fatty acids and cAMP for growth stimulation and whilst some selective stimulatory effect was observed, this was not significantly higher than the media control and not comparable to CF. Together, these data indicate that the growth stimulatory effect observed with Mtb CF is most likely the result of a combination of factors. Future work aimed at identifying the nature of these growth stimulatory molecules may facilitate improvement of culture-based diagnostics for TB.

Impact of systematic early tuberculosis detection using Xpert MTB/RIF Ultra in children with severe pneumonia in high tuberculosis burden countries (TB-Speed pneumonia): a stepped wedge cluster randomized trial

BackgroundIn high tuberculosis (TB) burden settings, there is growing evidence that TB is common in children with pneumonia, the leading cause of death in children under 5 years worldwide. The current WHO standard of care (SOC) for young children with pneumonia considers a diagnosis of TB only if the child has a history of prolonged symptoms or fails to respond to antibiotic treatments. As a result, many children with TB-associated severe pneumonia are currently missed or diagnosed too late. We therefore propose a diagnostic trial to assess the impact on mortality of adding the systematic early detection of TB using Xpert MTB/RIF Ultra (Ultra) performed on nasopharyngeal aspirates (NPA) and stool samples to the WHO SOC for children with severe pneumonia, followed by immediate initiation of anti-TB treatment in children testing positive on any of the samples.MethodsTB-Speed Pneumonia is a pragmatic stepped-wedge cluster randomized controlled trial conducted in six countries with high TB incidence rate (Côte d’Ivoire, Cameroon, Uganda, Mozambique, Zambia and Cambodia). We will enrol 3780 children under 5 years presenting with WHO-defined severe pneumonia across 15 hospitals over 18 months. All hospitals will start managing children using the WHO SOC for severe pneumonia; one hospital will be randomly selected to switch to the intervention every 5 weeks. The intervention consists of the WHO SOC plus rapid TB detection on the day of admission using Ultra performed on 1 nasopharyngeal aspirate and 1 stool sample. All children will be followed for 3 months, with systematic trial visits at day 3, discharge, 2 weeks post-discharge, and week 12. The primary endpoint is all-cause mortality 12 weeks after inclusion. Qualitative and health economic evaluations are embedded in the trial.DiscussionIn addition to testing the main hypothesis that molecular detection and early treatment will reduce TB mortality in children, the strength of such pragmatic research is that it provides some evidence regarding the feasibility of the intervention as part of routine care. Should this intervention be successful, safe and well tolerated, it could be systematically implemented at district hospital level where children with severe pneumonia are referred.Trial registrationClinicalTrials.gov, NCT03831906. Registered 6 February 2019.

TB Elimination Requires Discovery and Development of Transformational Agents

The World Health Organization (WHO) End Tuberculosis (TB) Strategy has set ambitious targets to reduce 2015 TB incidence and deaths by 80% and 90%, respectively, by the year 2030. Given the current rate of TB incidence decline (about 2% per year annually), reaching these targets will require new transformational tools and innovative ways to deliver them. In addition to improved tests for early and rapid detection of TB and universal drug-susceptibility testing, as well as novel vaccines for improved prevention, better, safer, shorter and more efficacious treatments for all forms of TB are needed. Only a handful of new drugs are currently in phase II or III clinical trials, and a few combination regimens are being tested, mainly for drug-resistant TB. In this article, capitalising on an increasingly rich medicine pipeline and taking advantage of new methodological designs with great potential, the main areas where progress is needed for a transformational improvement of treatment of all forms of TB are described.

Rapid detection of tuberculosis in remote Alaska

ABSTRACT In a remote region of western Alaska where tuberculosis (TB) incidence remains relatively high, a rapid molecular detection assay (Xpert MTB/RIF) was introduced four years ago with goal of improving the ability to diagnose active pulmonary tuberculosis (TB). Our aggressive testing programme was intended for all patients acutely evaluated for pulmonary TB at our regional hospital and multiple clinics over a large area. All 223 consecutive patients evaluated for active pulmonary TB were tested with Xpert MTB/RIF (Xpert) per our protocol of which 192 (86.1%) had at least one additional (paired) sputum sample collected for standard acid-fast bacilli (smear) microscopy and culture. Fourteen patients eventually became culture-positive for Mycobacterium tuberculosis (MTB), all but one having initially tested positive (MTB detected) by Xpert (sensitivity 92.9%). All remaining culture-negative individuals had tested negative (not detected) by Xpert (specificity 100%). By contrast, smear microscopy sensitivity and specificity was 64.3% and 98.9% respectively. This represents the addition of four active TB patients detected by Xpert over smear. In remote regions, the ability of Xpert to quickly and reliably detect TB while determine which patients are not contagious represents a huge healthcare savings as in most cases these patients will not require hospitalized isolation.

Multicenter evaluation of TB-SPRINT 59-Plex Beamedex\xae: accuracy and cost analysis

BackgroundMolecular tests can allow the rapid detection of tuberculosis (TB) and multidrug-resistant TB (MDR-TB). TB-SPRINT 59-Plex Beamedex® is a microbead-based assay developed for the simultaneous spoligotyping and detection of MDR-TB. The accuracy and cost evaluation of new assays and technologies are of great importance for their routine use in clinics and in research laboratories. The aim of this study was to evaluate the performance of TB-SPRINT at three laboratory research centers in Brazil and calculate its mean cost (MC) and activity-based costing (ABC).MethodsTB-SPRINT data were compared with the phenotypic and genotypic profiles obtained using Bactec™ MGIT™ 960 system and Genotype® MTBDRplus, respectively.ResultsCompared with MGIT, the accuracies of TB-SPRINT for the detection of rifampicin and isoniazid resistance ranged from 81 to 92% and 91.3 to 93.9%, respectively. Compared with MTBDRplus, the accuracies of TB-SPRINT for rifampicin and isoniazid were 99 and 94.2%, respectively. Moreover, the MC and ABC of TB-SPRINT were USD 127.78 and USD 109.94, respectively.ConclusionTB-SPRINT showed good results for isoniazid and rifampicin resistance detection, but still needs improvement to achieve In Vitro Diagnostics standards.

Experimental platform utilising melting curve technology for detection of mutations in Mycobacterium tuberculosis isolates

Tuberculosis (TB) remains one of the most deadly infections with approximately a quarter of cases not being identified and/or treated mainly due to a lack of resources. Rapid detection of TB or drug-resistant TB enables timely adequate treatment and is a cornerstone of effective TB management. We evaluated the analytical performance of a single-tube assay for multidrug-resistant TB (MDR-TB) on an experimental platform utilising RT-PCR and melting curve analysis that could potentially be operated as a point-of-care (PoC) test in resource-constrained settings with a high burden of TB. Firstly, we developed and evaluated the prototype MDR-TB assay using specimens extracted from well-characterised TB isolates with a variety of distinct rifampicin and isoniazid resistance conferring mutations and nontuberculous Mycobacteria (NTM) strains. Secondly, we validated the experimental platform using 98 clinical sputum samples from pulmonary TB patients collected in high MDR-TB settings. The sensitivity of the platform for TB detection in clinical specimens was 75% for smear-negative and 92.6% for smear-positive sputum samples. The sensitivity of detection for rifampicin and isoniazid resistance was 88.9 and 96.0% and specificity was 87.5 and 100%, respectively. Observed limitations in sensitivity and specificity could be resolved by adjusting the sample preparation methodology and melting curve recognition algorithm. Overall technology could be considered a promising PoC methodology especially in resource-constrained settings based on its combined accuracy, convenience, simplicity, speed, and cost characteristics.

Comparison of Gene Xpert MTB/RIF Assays with Conventional Standard Proportion Method for Determination of Drug Susceptibility In Multidrug Resistant TB Suspects

Background: Tuberculosis (TB) is a contagious disease and multidrug resistant tuberculosis is an emerging global issue. Rapid detection of such type of tuberculosis is necessary for timely control of the disease. GeneXpert test has already been implemented by World Health Organization to diagnose the infection on urgent basis. Objectives: This study was designed to apply GeneXpert MTB/RIF assays for the detection of rifampicin resistant tuberculosis and validation of assays by comparing with conventional standard drug proportion method. Additionally, to explore whether the assay can be utilized in treatment of Multidrug Resistant TB Settings: This study was undertaken in Pakistan Health Research Council TB Research Centre in collaboration with Department of Pulmonology, King Edward Medical University, Mayo Hospital, Lahore. Methods: Sputum samples from 125 patients were collected from confirmed pulmonary TB patients who were not responding to standard regimen of first line anti-tubercular treatment. Smears were stained by Ziehl-Neelsen method. All specimens were processed for culture and drug sensitivity by drug proportion method using Lowenstein Jensen medium as well as GeneXpert MTB/RIF assay. Results: A total of 125 subjects were registered in present study including 64 (51.2%) males and 61 (48.8%) females of age 15 years and above with mean age of 36.9±14.99. Sensitivity and specificity of the assay was observed as 92.1% and 93.5%, respectively. Association of rifampicin resistant by MTB/RIF assay and isoniazid resistance was found to be 88.1% and an agreement rate of rifampicin resistance by GeneXpert MTB/ RIF assay with isoniazid resistance was 81.25%. A total of 56 (44.8%) cases were found to be multidrug resistant patients and an agreement rate of 92.9% (52/56) was demonstrated in multidrug resistant patients which was found to be rifampicin resistant by GeneXpert in present study. Conclusion: GeneXpert MTB/RIF assay shown high sensitivity (96.7%) and specificity (98.6%). This most modern and latest technique, particularly in smear negative patients, helps rapid detection of TB and rifampicin resistance, which facilitates prompt diagnosis of multidrug resistant TB. These results propose that effective treatment can be initiated at an early stage, which will greatly help in reducing multidrug resistant TB.

Programmatic Impact of Implementing GeneXpert MTB/ RIF Assay for the Detection of Mycobacterium Tuberculosis in Respiratory Specimens from Pulmonary Tuberculosis Suspected Patients in Resource Limited Laboratory Settings of Eastern Nepal

Background:In Nepal, introduction of GeneXpert MTB/RIF assay (Xpert assay) as an initial confirmation test for tuberculosis (TB) has been considered to have impact as a significant decrease in number of clinically diagnosed pulmonary tuberculosis (PTB) cases than previous years. This study aims to find out the distribution profile of suspected tuberculosis cases according to patients age, gender, treatment history and HIV status as well as to evaluate the utility of the Xpert assay over conventional acid-fast bacilli (AFB) staining method for the proper diagnosis of M. Tuberculosis in respiratory specimens from the tuberculosis (TB) suspected patient samples. Methods:The prospective cross-sectional analytical study was conducted in National Anti-Tuberculosis Center (NATA) center- Biratnagar and Primary Healthcare Center (PHC) - Manglabare, Morang District, of eastern Nepal from January 2014 to August 2014. Laboratory investigation was done by conventional AFB staining followed by Xpert assay. Results:A total of 1549 sputum samples were initially analyzed. AFB staining resulted in 1441 AFB smear negative samples and 88 AFB smear positive samples, whereas 20 samples were directly processed for Xpert assay. The male: female smear positive ratio was 2.8:1 and was higher among age groups (21-40) years. Tuberculosis among HIV patients was found 22.22%. Xpert assay demonstrates that out of 1441 smear negative AFB cases, 258 were found to have TB positive, whereas out of 88 smears positive AFB cases 12 were found to have TB negative. The sensitivity of the Xpert assay in patients classified as AFB smear positive was found 85.4% and the specificity in smear negative patients was 81%. Conclusion:The study concluded that implementation of Gene Xpert MTB/RIF assay is a helpful tool for early and rapid detection of tuberculosis with greater sensitivity and specificity over traditional AFB staining techniques.

Detection of multidrug-resistant tuberculosis from stored DNA Samples: A multicenter study.

In low-income countries, rapid detection of tuberculosis (TB) drug resistance is often restricted by the difficulties of transporting and storing sputum samples from remote health centers to the reference laboratories where molecular tests are available. The aim of this study was to evaluate the performance of four transport and storage systems for molecular detection of rifampicin (RIF) and isoniazid (INH) resistance. This was a multicenter study. Molecular detection of RIF and INH resistance was performed directly from smear-positive TB sputa spotted on a slide, FTA card, GenoCard, and ethanol using the Genotype MTBDRplus assay. The performance of the DNA extraction method from each storage support to detect drug resistance was assessed by calculating their sensitivity and specificity compared to the phenotypic method. From all sites, the overall sensitivity and specificity for RIF-resistance detection was 88% and 85%, respectively, for slides, 86% and 92%, respectively, for GenoCard, 87% and 89%, respectively, for FTA card, and 88% and 92%, respectively, for ethanol. For INH-resistance detection, the overall sensitivity and specificity was 82% and 90%, respectively, for slides, 85% and 96%, respectively, for GenoCard, 86% and 92%, respectively, for FTA card, and 86% and 94%, respectively, for ethanol. Smear slides and filter cards showed to be very useful tools to facilitate DNA extraction from sputum samples with the potential to accelerate the detection of drug resistance in remote areas.

Lateral flow urine lipoarabinomannan assay for detecting active tuberculosis in HIV-positive adults.

Lateral flow urine lipoarabinomannan assay for detecting active tuberculosis in HIV-positive adults.

Application of Gene Xpert Mycobacterium tuberculosis DNA and resistance to rifampicin assay in the rapid detection of tuberculosis in children

To detect Mycobacterium tuberculosis (MTB) and rifampin resistance of the clinical specimens in children by Xpert MTB DNA and resistance to rifampicin(MTB/RIF) detection system, and evaluate the application value of this method in children with tuberculosis. Data of 109 children cases of clinically suspected tuberculosis were collected (including 46 gastric lavage aspirate, 19 sputum, 10 fine needle aspiration biopsy, 4 pus, 14 cerebrospinal fluid, 11 Serous membrance fluid, 1 marrow, 3 stool, 1 urine specimens)between April 2014 and March 2015. All specimens were detected by smear fluorescence staining microscopy, MGIT 960 BACTEC liquid culture, Xpert MTB/RIF assay and T-SPOT.TB test respectively. The sensitivity and specificity of Xpert MTB/RIF assay were analyzed in those clinical specimens. The sensitivity and specificity of the Xpert MTB/RIF assay for MTB detection in childhood tuberculosis clinical specimen were 28.6% and 87.5%. The sensitivity of 65 pulmonary tuberculosis(46 gastric lavage aspirate, 19 sputum) which included gastric lavage aspirates and sputum was 33.3% and 57.1%, the specificity of the two was 100.0%. In 44 extrapulmonary tuberculosis, the sensitivity of the pus and the puncture fluid was higher and approached 100.0%. The detection rate of the cerebrospinal fluid and serous cavity effusion was very low. The sensitivity was 100.0% in smear-positive and culture-positive samples and only 30.8% to 50.0% in smear-negative and culture-positive samples. The sensitivity and specificity of Xpert MTB/RIF assay to detect rifampin resistance were 100.0%. In clinical samples, the sensitivity of Xpert MTB/RIF assay was higher than that of smear fluorescence staining microscopy, but the difference was not statistically significant (χ(2)=0, P>0.05). The result was equivalent to that of MGIT 960 BACTEC liquid culture (28.6% vs. 27.3%, χ(2)=2.50, P>0.05), and far below that of T-SPOT.TB(28.6% vs 59.7%, χ(2)=13.92, P<0.05). Xpert MTB/RIF assay did not show obvious advantage in childhood tuberculosis, especially in serous cavity effusion and cerebrospinal fluid, but the advantages of detecting tuberculosis rapidly and resistance to rifampin can provide help for the clinical diagnosis and treatment in childrenhood tuberculosis.

Utility of GenoType MTBDRplus assay in rapid diagnosis of multidrug resistant tuberculosis at a tertiary care centre in India

Purpose: Molecular methods which allow rapid detection of tuberculosis as well as drug resistance directly from clinical samples have become the most popular diagnostic methodology with the emergence of multidrug resistant tuberculosis. The aim of the present study was to evaluate the performance of a line probe assay, GenoType MTBDRplus for the rapid detection of Mycobacterium tuberculosis and mutations causing rifampicin and INH resistance directly in smear positive pulmonary specimens and also in M. tuberculosis isolates grown from various clinical specimens. Materials and Methods: The MTBDRplus assay was done directly on 37 smear positive pulmonary specimens and also on 69 M. tuberculosis isolates obtained by rapid automated culture using Bact/Alert 3D. The results were compared with phenotypic drug susceptibility testing (1% proportion method) using Bact/Alert 3D. Results: The sensitivity and specificity for detection of resistance to rifampicin was 100% and 97.3%, and to INH was 91.9% and 98.4%, respectively, in comparison with the phenotypic drug susceptibility testing. Conclusion: MTBDRplus assay had good sensitivity and specificity with turn around time of less than 48 hours. It may be a useful tool for rapid detection of multidrug resistant tuberculosis at a tertiary care centre.

Rapid detection of tuberculosis

Rapid detection of tuberculosis