Tool For Diagnosis Of Tuberculosis Research Articles

Use of uncoated magnetic beads to capture Mycobacterium smegmatis and Mycobacterium avium paratuberculosis prior detection by mycobacteriophage D29 and real-time-PCR

Uncoated tosyl-activated magnetic beads were evaluated to capture Mycobacterium smegmatis and Mycobacterium avium subspecies paratuberculosis (MAP) from spiked feces, milk, and urine. Centrifugation and uncoated magnetic beads recovered more than 99% and 93%, respectively, of 1.68 × 107 CFU/mL, 1.68 × 106 CFU/mL and 1.68 × 105 CFU/mL M. smegmatis cells resuspended in phosphate buffer saline. The use of magnetic beads was more efficient to concentrate cells from 1.68 × 104 CFU/mL of M. smegmatis than centrifugation. Likewise, the F57-qPCR detection of MAP cells was different whether they were recovered by beads or centrifugation; cycle threshold (Ct) was lower (p < 0.05) for the detection of MAP cells recovered by beads than centrifugation, indicative of greater recovery. Magnetic separation of MAP cells from milk, urine, and feces specimens was demonstrated by detection of F57 and IS900 sequences. Beads captured no less than 109 CFU/mL from feces and no less than 104 CFU/mL from milk and urine suspensions. In another detection strategy, M. smegmatis coupled to magnetic beads were infected by mycobacteriophage D29. Plaque forming units were observed after 24 h of incubation from urine samples containing 2 × 105 and 2 × 103 CFU/mL M. smegmatis. The results of this study provide a promising tool for diagnosis of tuberculosis and Johne's disease.

Comparative Study of CBNAAT with Sputum Microscopy by Led Microscopy &amp; Liquid Culture in Sputum Samples of Presumptive Pulmonary Tuberculosis

Tuberculosis is a communicable disease &amp; a leading cause of death from a single infectious agent (ranking above HIV /AIDS). Early diagnosis is important for early patient management and successful treatment. The present study was a prospective observational study done on 84 suspected Pulmonary Tuberculosis patients visiting Government Chest disease and TB hospital Warangal during the time period of December 2017 to July 2019 &amp; were evaluated with different microbiological tests for further confirmation of pulmonary tuberculosis .Considering liquid culture as the gold standard tool for diagnosis of Tuberculosis, sensitivity , specificity, PPV, NPV of CBNAAT were 78.4%, 60.6%, 75%, 65% respectively and sensitivity, specificity, PPV, NPV of AFB smear were 80%, 47.5%, 39%, 85% respectively in the present study.

Transcriptomic Profiles of Confirmed Pediatric Tuberculosis Patients and Household Contacts Identifies Active Tuberculosis, Infection, and Treatment Response Among Indian Children.

Gene expression profiling is emerging as a tool for tuberculosis diagnosis and treatment response monitoring, but limited data specific to Indian children and incident tuberculosis infection (TBI) exist. Sixteen pediatric Indian tuberculosis cases were age- and sex-matched to 32 tuberculosis-exposed controls (13 developed incident TBI without subsequent active tuberculosis). Longitudinal samples were collected for ribonucleic acid sequencing. Differential expression analysis generated gene lists that identify tuberculosis diagnosis and tuberculosis treatment response. Data were compared with published gene lists. Population-specific risk score thresholds were calculated. Seventy-one genes identified tuberculosis diagnosis and 25 treatment response. Within-group expression was partially explained by age, sex, and incident TBI. Transient changes in gene expression were identified after both infection and treatment. Application of 27 published gene lists to our data found variable performance for tuberculosis diagnosis (sensitivity 0.38-1.00, specificity 0.48-0.93) and treatment response (sensitivity 0.70-0.80, specificity 0.40-0.80). Our gene lists found similarly variable performance when applied to published datasets for diagnosis (sensitivity 0.56-0.85, specificity 0.50-0.85) and treatment response (sensitivity 0.49- 0.86, specificity 0.50-0.84). Gene expression profiles among Indian children with confirmed tuberculosis were distinct from adult-derived gene lists, highlighting the importance of including distinct populations in differential gene expression models.

Gene Xpert MTB/RIF Assay as A New Tool for Tuberculosis Diagnosis and Detection of Rifampin Resistance

Background: Mycobacterium tuberculosis (MTB) is one of the top ten causes of death and the leading cause of a single infectious agent (above HIV/AIDS) Worldwide. Each year millions of people continue to fall sick with TB. Aim: To evaluate the MTB/RIF assay for rapid diagnosis and detection of rifampin resistance of tuberculosis in both positive and negative smears-as well as pulmonary and non-pulmonary clinical specimens. Patients and Methods: A prospective study was conducted on 50 patients (37 pulmonary, 13 extrapulmonary) patients attending the Outpatient Clinic and inpatients of Chest Department, Benha University Hospital, Egypt. Pulmonary samples were analyzed by (Sputum smear exam. by Ziehl Neelsen (ZN) stain, culture on Lowenstein-Jensen(LJ)media, and assessment of rifampin sensitivity). Extrapulmonary samples were analyzed by reference methods (pathological diagnosis) and by GeneXpert. Results: pulmonary patients’ smears were 32 (86.5%) positive and 5 (13.5%) negative. Culture on LJrevealed rifampin sensitivity in 33/37 (89.1%) and rifampin-resistant in 4/37 (10.9%), GeneXpert was positive in 32(86.5%) and negative in 5 (13.5%), rifampin assay was sensitive in 33 (89.1%) and resistant in 4(10.9%). All extrapulmonary patients, (n=13) were positive on GeneXpert and sensitive for rifampin. Conclusion: GeneXpert could be considered as a leading way to early diagnosis, treatment, and prevention of transmission of tuberculosis which could reduce TB- associated morbidity and mortality.

GeneXpert: A New Tool for Diagnosis of Tuberculosis

Abstract not available&#x0D; Journal of Armed Forces Medical College Bangladesh Vol.13(2) 2017: 1-2

A study of efficacy of phage amplification technique in diagnosis of pulmonary and extra-pulmonary tuberculosis

Background: Tuberculosis (TB) is a leading infectious disease in India. Diagnosis of TB has always been a problem due to slow rate of growth of Mycobacterium tuberculosis. In this study, author had compared the conventional tools for diagnosis of TB with the new Fast Plaque TBTM.Methods: The study was conducted at Dr. ML Chest Hospital, Department of Tuberculosis and Respiratory Diseases, G.S.V.M. Medical College, Kanpur. Specimens were collected after taking informed consent from patients attending outpatient and indoor patients admitted in the hospital. Study consisted of cases having suspected tuberculous exudation both pulmonary and extra pulmonary.Results: Most of the patients in this study were between 21-40years of age. Most of them were male (78%). Most of the patients came from urban areas and middle socioeconomic strata. Among them 68% were smokers and 32% were non-smokers. Comparison of phage assay with clinical evidence of disease has been done and results were sensitivity 85.7%, specificity 100%, PPV 100%, NPV 84.6% found.Conclusions: Delay in diagnosis resulting in further delay to initiate drug therapy. In these circumstances the rapid detection of mycobacteria by phage amplification technique could lead to earlier institution of antitubercular treatment.

Evaluation of XpertMTB/Rif performance for diagnosis of tuberculosis among HIV positive patients in northern Tanzania

Background: Diagnosis of tuberculosis (TB) in patients co-infected with HIV poses an important challenge since they are usually smear negative for pulmonary TB. The reason for this is the low sensitivity and specificity of microscopy as the standard diagnostic method . This study aimed to evaluate the performance of the XpertMTB/Rif tool for TB diagnosis among TB-HIV co-infected patients in order to characterize TB features in HIV co-infections. The study assessed the sensitivity, specificity and positive and negative predictive values of XpertMTB/Rif for TB detection in symptomatic and asymptomatic patients. Methods: This was a cross-sectional analytical study involving 69 patients as study participants. Demographic, clinical, laboratory and radiological data were collected. The performance of the XpertMTB/RIF and microscopy using LJ culture as a gold standard were determined and compared. Results: XpertMTB/Rif had a higher sensitivity (100%), specificity (100%), PPV (79.2%) and NPV (98.9%) as compared to microscopy. There was a strong correlation between XpertMTB/Rif, LJ culture and Microscopy in terms of their sensitivity and specificity. Conclusion: While using TB symptoms screening tool alone in HIV infected individuals may result into overtreatment, relying on microscopy alone has the potential of TB under-diagnosing, miss-diagnosing and delayed treatment. Our results show XpertMTB/Rif to be highly sensitive and specific to detect all culture positive TB cases among HIV patients. We recommend the adoption of XpertMTB/Rif as an early TB diagnosis tool among HIV patients for early detection of TB among HIV patients.

Diagnostic Value of Serum Adenosine Deaminase (ADA) Level for Pulmonary Tuberculosis.

Background:Diagnosis of tuberculosis (TB) is not always easy, thus employing methods with a short duration and acceptable sensitivity and specificity is necessary to diagnose TB.Objectives:The aim of this study was to investigate the diagnostic value of serum adenosine deaminase (ADA) level for diagnosis of pulmonary tuberculosis.Patients and Methods:A total of 160 sex and age-matched subjects were included in this study, and were divided to four groups; forty patients with pulmonary tuberculosis (PTB) diagnosed based on the national TB program (NTP), forty patients with non-tuberculosis bacterial pneumonia, forty patients with lung cancer and forty people who were healthy in every respect. Serum adenosine deaminase activity in patients of each group was measured by the Giusti and Galanti calorimetry method using a commercial kit (Diazyme, USA). The ANOVA analysis was used to compare groups for quantitative variables.Results:Mean serum ADA level in the PTB group was clearly higher than the mean serum ADA in the other three groups. Mean serum ADA was 26 IU/L in PTB patients, 19.48 IU/L in patients with pneumonia, 15.8 IU/L in patients with lung cancer, and 10.7 IU/L in the control group (P < 0.05). In regard to the cut off value of 26 IU/L for ADA in patients with PTB sensitivity and specificity was defined as 35% and 91%, respectively.Conclusions:Serum ADA activity with high specificity percentage may be a useful alternative test in restricted resource areas to rule out diagnosis of PTB. However, serum ADA activity is not a useful tool for TB diagnosis.

Increased IgG1, IFN-γ, TNF-α and IL-6 responses to Mycobacterium tuberculosis antigens in patients with Tuberculosis are lower after chemotherapy

Detection of specific antibodies may represent an additional tool in diagnosis of tuberculosis (TB). Herein, levels of serum IgG antibodies against early secreted antigenic target (ESAT-6), culture filtrate antigen-10 (CFP-10) and 16 kDa Mycobacterium tuberculosis antigens were measured in 33 active pulmonary TB patients (0M-TB), in 47 patients after 1-3 months of treatment (3M-TB) and in 22 patients who had completed 6 months of chemotherapy (6M-TB). The control group consisted of 38 BCG-vaccinated healthy controls (HC). In addition, IFN-gamma, tumor necrosis factor (TNF)-alpha, IL-6, IL-2, IL-4 and IL-10 production in PBMC cultures from 20 patients were measured following stimulation with the M. tuberculosis-specific fusion protein ESAT-6/CFP-10. Elevated levels of IgG against ESAT-6, CFP-10 and 16 kDa antigens were detected in 0M-TB and 3M-TB patients in comparison to the HC and 6M-TB groups. Receiver operating characteristic analysis indicated sensitivity of 85, 94 and 61% and specificity of 89, 87 and 89% for serum IgG against ESAT-6, CFP-10 and 16 kDa, respectively. A predominant IgG1 response to ESAT-6 and CFP-10 was observed in 0M-TB patients, together with ESAT-6/CFP-10-specific IFN-gamma, TNF-alpha and IL-6 that were produced at lower levels in the 6M-TB group. These data indicate that a T(h)1 phenotype against early phase Mtb antigens appears to be dominant in the peripheral blood of patients with active pulmonary TB that is reduced after chemotherapy. Taken together, ESAT-6/CFP-10 cytokine tests together with detecting IgG antibodies specific to ESAT-6 and CFP-10 may be the useful TB disease biomarkers in monitoring treatment success.

Characterization of temperate phage Che12 and construction of a new tool for diagnosis of tuberculosis

A temperate phage, Che12, able to infect Mycobacterium tuberculosis, was isolated from soil samples taken from tuberculosis sanatorium area in Chennai, India. The plaque morphology of this phage showed varying grades of turbidity on lawns of M. tuberculosis. The temperate nature of Che12 was established by super infection immunity. Phage integration into the host genomic DNA was confirmed by Southern hybridization using Che12 DNA as a probe. PCR amplification and sequencing of a part of the integrated phage genome in a M. tuberculosis lysogen also confirmed the temperate nature of Che12. The morphology of the phage particles was observed by electron microscopy, revealing similarities to other mycobacteriophages like L5, D29 and TM4. A luciferase reporter phage, phAETRC16, was constructed by cloning firefly luciferase gene into Che12. Infection of viable M. tuberculosis cells by phAETRC16 resulted in expression of luciferase leading to sustained light output. Che12, a true temperate phage infecting M. tuberculosis, is thus ideally suited for developing a diagnostic tool facilitating rapid diagnosis of M. tuberculosis.

Diagnostic Mycobacteriology: Current Challenges and Technologies

Tuberculosis (TB) has reemerged as a major public health problem worldwide. Although traditional acid-fast smears and cultures remain important tools for laboratory diagnosis of TB, these methods are not adequate to meet the challenges of the current crisis. In response to urgent needs for more rapid and sensitive diagnostic methods in mycobacteriology, several innovative procedures have been developed. Radiometric, molecular, biochemical, and chromatographic techniques have been introduced successfully in clinical laboratories, and others continue to be investigated. I review the newer technologies that provide laboratories with the tools necessary to achieve rapid detection, identification, and susceptibility testing of Mycobacterium tuberculosis .