Anaemia of chronic disease among pulmonary tuberculosis patients is associated with inflammatory marker at the start of intensive phase.

Background: Tuberculosis (TB) disrupts iron balance through systemic inflammation. Pulmonary tuberculosis (PTB) is linked to diverse anaemia types, necessitating intricate haematological and biochemical assessments for diagnosis. This study aims to describe the prevalence of anaemia of chronic disease (ACD), iron deficiency anaemia (IDA) among PTB patients and factors associated with these types of anaemia. Methods: A cross-sectional analysis was conducted from community-based cohort study involving sputum-positive PTB patients from 2018 to 2020 in urban Puducherry. Participants were enrolled from 10 primary health centres within 2 weeks of initiating anti-tubercular treatment (ATT). Blood samples were collected for assessing haematological and biochemical parameters. The sTfR/log ferritin ratio was used to distinguish between ACD and IDA. Data were captured using Epicollect5 and analysed using STATA V14. Result: Of the 176 PTB patients included, 63.07% (111/176) had anaemia, with ACD being the predominant type (84.6%, 94/111). The C-reactive protein (CRP) levels were higher among the anaemic group [40.77 (16.66-58.51) mg/dl vs 24.65 (14.23-47.26) mg/dl] and higher among the ACD as compared to IDA [46.9 (22.3-61.2) vs 20.8 (13.0-39.1) mg/dl]. Undernourished [adjusted prevalence ratio (APR) =3.43; confidence interval (CI): 1.21-9.69] and patients having low risk of dependence on tobacco [APR = 1.52; CI: 1.10-2.11] had higher risk of ACD. Female patients had higher risk of IDA [APR = 4.95, P < 0.01]. Conclusion: The largest proportion of the PTB participants with anaemia had ACD. Acute-phase reactant and inflammatory marker are increased among newly diagnosed new sputum smear-positive (NSP) PTB participants at the start of ATT. Addressing inflammation is needed for combating anaemia in PTB patients.

The prevalence of pulmonary and extrapulmonary tuberculosis in forensic autopsies in a teaching hospital in South India.

Introduction: An autopsy is a valuable tool for finding the cause of death, exploring the clinical diagnosis, documenting unexpected findings, and resolving diagnostic questions. However, this may subject the forensic pathologist and other workers to a wide variety of blood-borne and aerosolized pathogens. Tuberculosis (TB) is the most common cause of illness and death, resulting in infection transmission in the autopsy room. Our objective in this study was to estimate the prevalence of pulmonary and extrapulmonary tuberculosis among forensic autopsies in a tertiary care hospital in South India. Material and Methods: We identified positive TB cases from acid-fast bacteria staining and culture (Mycobacterium Growth Indicator Tube and Lowenstein-Jensen medium) out of 380 autopsy cases. Results: The prevalence of tuberculosis was 2.4% (n = 9), among which 2.1% of cases were positive for only pulmonary tuberculosis (n = 8), and 0.3% of cases had both pulmonary and extrapulmonary involvement (n = 1). In the bivariate analysis of TB cases, sex, occupation, family history of TB, habit of smoking, BCG vaccine scar, period of hospital stay, and cause of death were potentially significant. Conclusion: The prevalence of TB in forensic autopsy cases were similar to forensic autopsy-based studies, and it was less as compared to the prevalence of TB in the general population.

Prevalence and factors associated with inappropriate continuation of stress ulcer prophylaxis at discharge.

Stress ulcer prophylaxis is started in the critical care unit to decrease the risk of upper gastrointestinal ulcers in critically ill persons and to decrease mortality caused by stress ulcer complications. Unfortunately, the drugs are often continued after recovery through discharge, paving the way for unnecessary polypharmacy. STUDY DESIGN: We conducted a retrospective cross-sectional study including patients admitted to the adult critical care unit and started on the stress ulcer prophylaxis with a proton pump inhibitor (PPI) or histamine receptor 2 blocker (H2 blocker) with an aim to determine the prevalence of inappropriate continuation at discharge and associated factors. RESULT: 3200 people were initiated on stress ulcer prophylaxis, and the medication was continued in 1666 patients upon discharge. Indication for long-term use was not found in 744 of 1666, with a 44% prevalence of inappropriate continuation. A statistically significant association was found with the following risk factors: discharge disposition (home vs other medical facilities, p=0.002), overall length of stay (more than 10 days vs less than or equal to 10 days, p<0.0001), mechanical ventilator use (p<0.001), number of days on a mechanical ventilator (more than 2 days vs less than or equal to 2 days, p<0.001) and class of stress ulcer prophylaxis drug used (H2 blocker vs PPI, p<0.001). CONCLUSION: The prevalence of inappropriate continuation was found to be higher than prior studies. Given the risk of unnecessary medication intake and the associated healthcare cost, a web-based quality improvement initiative is being considered.

Transcriptomic and proteomic analyses of Mycobacterium tuberculosis strains isolated from tuberculous meningitis patients.

Background: Tuberculous meningitis (TBM) is caused by the dissemination of Mycobacterium tuberculosis (MTB) from the primary site of infection to the central nervous system. However, the bacterial factors associated with the pathogenesis of TBM remain unclear. This study employed transcriptomic and proteomic methods to comprehensively analyze the changes in genes and proteins and their associated pathways in MTB strains isolated from cerebrospinal fluid (CSF) of TBM and sputum of pulmonary TB (PTB) cases. Methodology: Five MTB strains were subjected to OMICs (transcriptomic and proteomic) analysis. Among five MTB strains, two were isolated from CSF and sputum samples of the same patient with PTB and TBM infections, one from the sputum of a different PTB patient, and a strain obtained from the CSF of another TBM patient. H37Rv was used as a reference strain. The reliability of transcriptomic results was validated by real time polymerase chain reaction with selected genes from 100 MTB isolates (CSF, 50 and sputum, 50). Results: The transcriptomic study revealed that overlapping differentially expressed genes of MTB strains isolated from TBM patients showed featured enrichment in benzoate degradation, lysine degradation, tryptophan metabolism, fatty acid degradation, ATP binding cassette transporters, microbial metabolism in diverse environments, biosynthesis of antibiotics, and metabolic pathways. Eleven genes were upregulated, and four were downregulated in MTB strains isolated from TBM compared to PTB. From proteomic analysis, we identified three candidate proteins belonging to plasminogen binding proteins (PBP) (enolase, dnaK, and isocitrate lyase 1) that were significantly upregulated in MTB strains isolated from TBM. Conclusion: Overall, the transcriptomic and proteomic analyses provided an important base for understanding the unique feature of TBM pathogenesis. To the best of our knowledge, this is the first report highlighting the importance of PBPs on TBM pathogenesis.

Predictors of Change in the Anemia Status Among Pulmonary Tuberculosis Patients Following Anti-tuberculosis Treatment in Puducherry, India.

Background Pulmonary tuberculosis (PTB) is commonly associated with reversible peripheral blood abnormalities. The evolution of tuberculosis (TB)-associated anemia with anti-tuberculosis treatment (ATT) has not been well elucidated. This study aimed to compare the hematological profiles at the start and end of the ATT among new sputum smear-positive (NSP) PTB patients in Puducherry, India. Methods A prospective cohort study was conducted in the 10 urban primary health centers of Puducherry from 2017 to 2020. All the NSP PTB participants aged ≥18 years registered under the National Tuberculosis Elimination Program (NTEP) were contacted within two weeks of the start of the ATT. All eligible participants were enrolled, and they were followed up till the end of ATT (180 days). Hematological profiles and anthropometric measurements were compared at the start and end of the ATT. Binomial logistic regression analysis was used to assess the predictors of changes in the anemia status at the start and end of the ATT. Results Out of 176 NSP PTB participants, 145 were followed up after treatment. Initially, 63% (111/176) patients had anemia, which decreased to 44% (64/145) by the end of treatment. The risk factors for a negative change in hemoglobin levels were female gender, below poverty level, underweight, and reduced iron intake. The adjusted risk ratios (ARRs) were 1.53 (1.24-1.88), 1.18 (1.01-1.38), 1.29 (1.02-1.64), and 1.26 (1.05-1.51),respectively. Conclusion ATT may lead to the resolution of TB-associated anemia. Moreover, female gender, possession of a red ration card, being underweight, and reduced iron intake were identified as risk factors for negative changes in hemoglobin levels during treatment.

Active Case Finding for Tuberculosis among Health Care Workers in a Teaching Hospital, Puducherry, India.

Background: Health care workers (HCWs) are at risk of acquiring tuberculosis (TB) infection and disease due to occupational exposure. But there are no national guidelines on routine screening for TB (active case finding (ACF)) among HCWs and understand its implementation and feasibility. Methods: This study was conducted among HCWs in a teaching hospital in India. We used symptom screening to identify those with presumptive TB and were further evaluated for diagnosis of TB. Results: A total of 1,001 HCWs were screened over a period of 18 months. In our study, 51 (5.1%) HCWs were found to have presumptive TB and on further evaluation, 5 (0.5%) of these patients were diagnosed with active TB. The number needed to screen (NNS) for one active TB among the HCWs was 200. Alcohol use was significantly associated with both presumptive TB (P = 0.037) and active TB (P = 0.035) among HCWs, and exposure to active TB patients (P = 0.014) in the family and workplace and increased frequency of exposures (P = <0.001) were associated with presumptive TB. Conclusion: ACF for TB among HCWs had a good yield in our study. ACF utilizing routine national TB program guidelines is feasible to be implemented among HCWs to aid in the early diagnosis and treatment of TB in this high-risk group.

Quantitative Real-Time Polymerase Chain Reaction for Detection of Mycobacterium leprae DNA in Tissue Specimens from Patients with Leprosy.

In leprosy, early diagnosis is crucial to prevent transmission and onset of disabilities of the disease. The purpose of this study was to determine usefulness of quantitative real-time polymerase chain reaction (PCR) in clinically diagnosed cases of leprosy. Thirty-two leprosy cases were included. The real-time PCR was performed using commercial kit targeting Mycobacterium leprae-specific insertion sequence element. The slit skin smear was positive in two (22.2%) borderline tuberculoid (BT) patients, five (83.3%) borderline lepromatous (BL) patients, and seven (50%) lepromatous leprosy (LL). The positivity of quantitative real-time PCR in BT, BL, LL, and pure neuritic leprosy were 77.8%, 83.3%, 100%, and 33.3%, respectively. Using histopathology as the gold standard, sensitivity of quantitative real-time PCR was 93.1%, and specificity was 100%. The DNA load was higher in LL (3,854.29/106 cells), followed by BL (140.37/106 cells), and BT (2.69/106 cells). Because of the high sensitivity and specificity of real-time PCR, our study strongly suggests the use of real-time PCR as a diagnostic tool for leprosy.

Diagnostic performance of real time PCR for the detection of Mycobacterium tuberculosis in cerebrospinal fluid samples.

PURPOSE: We aimed this study to standardize real time - polymerase chain reaction (RT-PCR) for the detection of Mycobacterium tuberculosis (Mtb) in cerebrospinal fluid (CSF) samples and compare its diagnostic performance with GeneXpert (Xpert), Mycobacteria Growth Indicator Tube (MGIT) and Multiplex PCR (MPCR) for tuberculous meningitis (TBM). METHODOLOGY: A total of 217 CSF samples were obtained from patients with suspected TBM during the study period between January 2019 and December 2021. The optimal cycle threshold (CT) of RT-PCR was determined by comparing different gene targets of Mtb (IS6110, 16SrRNA, HSP65 and Ag85B). Sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) was determined for RT-PCR, Xpert, MGIT960 and MPCR. Diagnostic accuracy of these assays was compared by using clinical diagnosis as reference standard. RESULTS: IS6110RT-PCR was found to be highly sensitive as compared to other gene targets. Sensitivities of IS6110RT-PCR, MPCR, Xpert and MGIT against a reference standard of definite, probable and possible TBM were 36.7%, 21.1%, 16.7% and 6.7%, respectively; specificities were 97.6%, 100%, 100% and 100%, respectively. Xpert, RT-PCR, MPCR and MGIT960 detected 6.91% (n = 15), 5.99% (n = 13), 5.99% (n = 13) and 2.76% (n = 6) of definite TBM, respectively. RT-PCR detected 6.45% (n = 14) and 2.76% (n = 6) of possible TBM and probable TBM, respectively and MPCR detected 1.38% (n = 3) of possible and probable TBM each. CONCLUSION: IS6110RT-PCR is highly sensitive for primary screening of suspected TB cases, which may help clinicians to start appropriate patient's treatment with clinical suspicion of TBM.

Development of prognostic scoring system for predicting 1-year mortality among pulmonary tuberculosis patients in South India.

BACKGROUND: Development of a prediction model using baseline characteristics of tuberculosis (TB) patients at the time of diagnosis will aid us in early identification of the high-risk groups and devise pertinent strategies accordingly. Hence, we did this study to develop a prognostic-scoring model for predicting the death among newly diagnosed drug sensitive pulmonary TB patients in South India. METHODS: We undertook a longitudinal analysis of cohort data under the Regional Prospective Observational Research for Tuberculosis India consortium. Multivariable cox regression using the stepwise backward elimination procedure was used to select variables for the model building and the nomogram-scoring system was developed with the final selected model. RESULTS: In total, 54 (4.6%) out of the 1181 patients had died during the 1-year follow-up period. The TB mortality rate was 0.20 per 1000 person-days. Eight variables (age, gender, functional limitation, anemia, leukopenia, thrombocytopenia, diabetes, neutrophil-lymphocyte ratio) were selected and a nomogram was built using these variables. The discriminatory power was 0.81 (95% confidence interval: 0.75-0.86) and this model was well-calibrated. Decision curve analysis showed that the model is beneficial at a threshold probability ~15-65%. CONCLUSIONS: This scoring system could help the clinicians and policy makers to devise targeted interventions and in turn reduce the TB mortality in India.

Corrigendum: Malnutrition leads to increased inflammation and expression of tuberculosis risk signatures in recently exposed household contacts of pulmonary tuberculosis.

[This corrects the article DOI: 10.3389/fimmu.2022.1011166.].

Malnutrition leads to increased inflammation and expression of tuberculosis risk signatures in recently exposed household contacts of pulmonary tuberculosis.

Background: Most individuals exposed to Mycobacterium tuberculosis (Mtb) develop latent tuberculosis infection (LTBI) and remain at risk for progressing to active tuberculosis disease (TB). Malnutrition is an important risk factor driving progression from LTBI to TB. However, the performance of blood-based TB risk signatures in malnourished individuals with LTBI remains unexplored. The aim of this study was to determine if malnourished and control individuals had differences in gene expression, immune pathways and TB risk signatures. Methods: We utilized data from 50 tuberculin skin test positive household contacts of persons with TB - 18 malnourished participants (body mass index [BMI] < 18.5 kg/m2) and 32 controls (individuals with BMI ≥ 18.5 kg/m2). Whole blood RNA-sequencing was conducted to identify differentially expressed genes (DEGs). Ingenuity Pathway Analysis was applied to the DEGs to identify top canonical pathways and gene regulators. Gene enrichment methods were then employed to score the performance of published gene signatures associated with progression from LTBI to TB. Results: Malnourished individuals had increased activation of inflammatory pathways, including pathways involved in neutrophil activation, T-cell activation and proinflammatory IL-1 and IL-6 cytokine signaling. Consistent with known association of inflammatory pathway activation with progression to TB disease, we found significantly increased expression of the RISK4 (area under the curve [AUC] = 0.734) and PREDICT29 (AUC = 0.736) progression signatures in malnourished individuals. Conclusion: Malnourished individuals display a peripheral immune response profile reflective of increased inflammation and a concomitant increased expression of risk signatures predicting progression to TB. With validation in prospective clinical cohorts, TB risk biomarkers have the potential to identify malnourished LTBI for targeted therapy.

Evaluation of Host Protein Biomarkers by ELISA From Whole Lysed Peripheral Blood for Development of Diagnostic Tests for Active Tuberculosis.

Tuberculosis (TB) remains a significant global health crisis and the number one cause of death for an infectious disease. The health consequences in high-burden countries are significant. Barriers to TB control and eradication are in part caused by difficulties in diagnosis. Improvements in diagnosis are required for organisations like the World Health Organisation (WHO) to meet their ambitious target of reducing the incidence of TB by 50% by the year 2025, which has become hard to reach due to the COVID-19 pandemic. Development of new tests for TB are key priorities of the WHO, as defined in their 2014 report for target product profiles (TPPs). Rapid triage and biomarker-based confirmatory tests would greatly enhance the diagnostic capability for identifying and diagnosing TB-infected individuals. Protein-based test methods e.g. lateral flow devices (LFDs) have a significant advantage over other technologies with regard to assay turnaround time (minutes as opposed to hours) field-ability, ease of use by relatively untrained staff and without the need for supporting laboratory infrastructure. Here we evaluate the diagnostic performance of nine biomarkers from our previously published biomarker qPCR validation study; CALCOCO2, CD274, CD52, GBP1, IFIT3, IFITM3, SAMD9L, SNX10 and TMEM49, as protein targets assayed by ELISA. This preliminary evaluation study was conducted to quantify the level of biomarker protein expression across latent, extra-pulmonary or pulmonary TB groups and negative controls, collected across the UK and India, in whole lysed blood samples (WLB). We also investigated associative correlations between the biomarkers and assessed their suitability for ongoing diagnostic test development, using receiver operating characteristic/area under the curve (ROC) analyses, singly and in panel combinations. The top performing single biomarkers for pulmonary TB versus controls were CALCOCO2, SAMD9L, GBP1, IFITM3, IFIT3 and SNX10. TMEM49 was also significantly differentially expressed but downregulated in TB groups. CD52 expression was not highly differentially expressed across most of the groups but may provide additional patient stratification information and some limited use for incipient latent TB infection. These show therefore great potential for diagnostic test development either in minimal configuration panels for rapid triage or more complex formulations to capture the diversity of disease presentations.

Development and Validation of a Parsimonious Tuberculosis Gene Signature Using the digital NanoString nCounter Platform.

BACKGROUND: Blood-based biomarkers for diagnosing active tuberculosis (TB), monitoring treatment response, and predicting risk of progression to TB disease have been reported. However, validation of the biomarkers across multiple independent cohorts is scarce. A robust platform to validate TB biomarkers in different populations with clinical end points is essential to the development of a point-of-care clinical test. NanoString nCounter technology is an amplification-free digital detection platform that directly measures mRNA transcripts with high specificity. Here, we determined whether NanoString could serve as a platform for extensive validation of candidate TB biomarkers. METHODS: The NanoString platform was used for performance evaluation of existing TB gene signatures in a cohort in which signatures were previously evaluated on an RNA-seq dataset. A NanoString codeset that probes 107 genes comprising 12 TB signatures and 6 housekeeping genes (NS-TB107) was developed and applied to total RNA derived from whole blood samples of TB patients and individuals with latent TB infection (LTBI) from South India. The TBSignatureProfiler tool was used to score samples for each signature. An ensemble of machine learning algorithms was used to derive a parsimonious biomarker. RESULTS: Gene signatures present in NS-TB107 had statistically significant discriminative power for segregating TB from LTBI. Further analysis of the data yielded a NanoString 6-gene set (NANO6) that when tested on 10 published datasets was highly diagnostic for active TB. CONCLUSIONS: The NanoString nCounter system provides a robust platform for validating existing TB biomarkers and deriving a parsimonious gene signature with enhanced diagnostic performance.

Effect of Neutralization of Gastric Aspirate on culture yield of mycobacterium tuberculosis in children with pulmonary tuberculosis.

INTRODUCTION: Conventionally gastric aspirates are neutralized with sodium bicarbonate to improve the culture yield of MTB. However, only limited data is there to support this practice. The aim of this study was to compare the contamination rate, culture yield and time to detection of Mycobacterium tuberculosis (MTB) in neutralized and non-neutralized gastric aspirate samples and report the drug resistance. MATERIALS AND METHODS: A total of 336 neutralized and non-neutralized gastric aspirate samples were simultaneously cultured by both LJ culture and MGIT 960 to compare the difference in isolation rate, time to detection and contamination rate. First line drug susceptibility testing was performed using MGIT 960 SIRE kit. RESULTS: MTB was isolated from 8.6% (29/336) of GA samples by one or more of the culture methods. The isolation rate of MTB from neutralized and non-neutralized GA samples by combined LJ and MGIT 960 culture was 7.1% (24/336) and 6.8% (23/336), respectively. Both of them detected 18 MTB isolates in common. However, the neutralized and non-neutralized GA samples detected additional 6 and 5 MTB isolates, respectively. The mean time to detection of MTB were similar. In MGIT 960 culture, contamination rate of non-neutralized samples (17%) was significantly lower when compared to neutralized samples (21.1%) (P = 0.044). Drug susceptibility testing of MTB isolates revealed that, out of 26 isolates, 2 were resistant to ethambutol, one each was resistant to isoniazid and rifampicin. CONCLUSION: The findings of this study suggest that non-neutralized samples should be routinely processed in addition to the neutralized samples for optimum isolation of MTB from gastric aspirate samples.

Tuberculosis-Learning the Impact of Nutrition (TB LION): protocol for an interventional study to decrease TB risk in household contacts.

BACKGROUND: Comorbidities such as undernutrition and parasitic infections are widespread in India and other tuberculosis (TB)-endemic countries. This study examines how these conditions as well as food supplementation and parasite treatment might alter immune responses to Mycobacterium tuberculosis (Mtb) infection and risk of progression to TB disease. METHODS: This is a 5-year prospective clinical trial at Jawaharlal Institute of Post Graduate Medical Education and Research in Puducherry, Tamil Nadu, India. We aim to enroll 760 household contacts (HHC) of adults with active TB in order to identify 120 who are followed prospectively for 2 years: Thirty QuantiFERON-TB Gold Plus (QFT-Plus) positive HHCs ≥ 18 years of age in four proposed groups: (1) undernourished (body mass index [BMI] < 18.5 kg/m2); (2) participants with a BMI ≥ 18.5 kg/m2 who have a parasitic infection (3) undernourished participants with a parasitic infection and (4) controls-participants with BMI ≥ 18.5 kg/m2 and without parasitic infection. We assess immune response at baseline and after food supplementation (for participants with BMI < 18.5 kg/m2) and parasite treatment (for participants with parasites). Detailed nutritional assessments, anthropometry, and parasite testing through polymerase chain reaction (PCR) and microscopy are performed. In addition, at serial time points, these samples will be further analyzed using flow cytometry and whole blood transcriptomics to elucidate the immune mechanisms involved in disease progression. CONCLUSIONS: This study will help determine whether undernutrition and parasite infection are associated with gene signatures that predict risk of TB and whether providing nutritional supplementation and/or treating parasitic infections improves immune response towards this infection. This study transcends individual level care and presents the opportunity to benefit the population at large by analyzing factors that affect disease progression potentially reducing the overall burden of people who progress to TB disease. Trial registration ClinicalTrials.gov; NCT03598842; Registered on July 26, 2018; https://clinicaltrials.gov/ct2/show/NCT03598842.

Pulmonary cryptosporidiosis in a case of adenocarcinoma of stomach: A rare case report.

Cryptosporidium species are commonly known to cause chronic intractable diarrhea in patients suffering from human immunodeficiency virus (HIV)-acquired immunodeficiency syndrome, however extra-intestinal presentations have been rarely reported. Hereby, we report a rare case of isolated pulmonary cryptosporidiosis in a 75-year-old HIV-negative patient with metastatic carcinoma of the stomach who was managed conservatively with hemostatic radiotherapy for palliative care. The patient had presented with cough with expectoration for 2 months. Sputum microscopic examination was suggestive of pulmonary cryptosporidiosis. There was no evidence of intestinal cryptosporidiosis. Therapy for pulmonary cryptosporidiosis was started with tablet nitazoxanide. The patient succumbed to the disease few days later following discharge. Although rare, patients with disseminated gastrointestinal malignancy can potentially have isolated pulmonary cryptosporidiosis.

Evaluation of real time polymerase chain reaction targeting mpb64 gene for diagnosis of extrapulmonary tuberculosis.

BACKGROUND: Paucibacillary nature of extrapulmonary tuberculosis (EPTB) has paved way for molecular methods increasingly being used for diagnosis. We undertook a study for evaluation of sensitivity and specificity of real-time polymerase chain reaction (RT-PCR) targeting mpb64 gene for diagnosis of EPTB. METHODS: A total of 152 clinical samples from suspected cases of EPTB were included in this study. All samples were extracted using spin column based commercial DNA extraction kit and were subjected to RT-PCR targeting mpb64 and IS6110. Smear and culture was also done for samples whenever quantity was sufficient. Cytology report was noted from hospital information system. Receiver operating characteristic (ROC) curve analysis was done for determining cut-off Ct value for mpb64 RT-PCR. Melt curve analysis was done for samples whose cycle threshold (Ct) value was more than 37. The sensitivity and specificity of the mpb64 RT-PCR was calculated using a composite gold standard i.e., positive for one or more of the following: microscopy (including fine needle aspiration cytology (FNAC), acid-fast bacilli positivity), culture and IS6110 RT-PCR. RESULTS: Out of the 152 samples, 72 (47.4%) were positive for tuberculosis by composite gold standard. Samples consisted of ascitic fluid (12), CSF (35), pus (23), lymph node aspirate (35), pleural fluid (37), synovial fluid (4), urine (1), pericardial fluid (1) and tissue bits (4). Microscopy (AFB smear including lymph node aspirate) was done for 124 samples of which 43 (34.7%) were positive. Culture results were available for 79 samples, 25 (31.6%) of which were positive and 42 (27.6%) of the 152 samples were positive by IS6110 PCR. Based on ROC and melt curve analysis, mpb64 RT-PCR was able to detect 38 (52.8%) of the 72 positive samples. In comparison to IS6110 RT PCR, 4 additional cases were detected by mpb64 RT-PCR. Compared to composite gold standard mpb64 showed overall sensitivity of 52.8%. CONCLUSION: The mpb64 RT-PCR is highly specific or MTB and can be used as a supplemental test for diagnosis of EPTB along with other diagnostic tests. However the overall sensitivity of mpb64 RT-PCR is too low to be used as an independent test for diagnosis of EPTB. Combining the results of IS6110 RT PCR and mpb64 RT PCR improved the overall sensitivity and hence mpb64 can be used as an additional target for diagnosis of EPTB.

Prevalence and speciation of non-tuberculous mycobacteria among pulmonary and extrapulmonary tuberculosis suspects in South India.

BACKGROUND AND OBJECTIVES: Non tuberculous mycobacteria (NTM) is an emerging opportunistic pathogen increasing globally and indistinguishable from tuberculosis (TB), which remains a challenge particularly in developing countries. This study aimed to identify the prevalence and diversity of NTM among both pulmonary TB (PTB) and extrpulmonary TB (EPTB) clinical isolates from south India. METHODOLOGY: A total of 7633 specimens from TB suspects (PTB, n = 4327 and EPTB, n = 3306) were collected during the study period (July 2018-March 2020) in a tertiary care hospital. The study specimens were subjected to Ziehl Neelsen (ZN) staining and Auramine phenol (AP) staining followed by Lowenstein-Jensen (LJ) and mycobacteria growth indicator tube (MGIT) culture. The MPT64 immunochromatographic test (ICT) was performed among mycobacterial cultures and ICT negative isolates were subjected to Line Probe Assay (LPA). In addition, 53 (PTB, 48 and EPTB, 5) NTM MGIT positive cultures were collected from Intermediate Reference Laboratory (IRL), Puducherry and subjected to LPA for speciation. RESULTS: Of the 7633 TB suspects, 0.6% were diagnosed as NTM diseases and 5.5% with Mycobacterium tuberculosis (MTBC). NTM infection was observed among 0.7% (31/4327) of PTB and 0.4% (14/3306) of EPTB. MTBC was detected among 6.1% (264/4327) of PTB and 4.6% (153/3306) of EPTB. Among 98 NTM cultures, 80.6% of isolates were recovered from PTB and 19.4% from EPTB specimens. Among pulmonary specimens, Mycobacterium intracellulare (26.6%), Mycobacterium abscessus (17.7%) and Mycobacterium kansasii (12.7%) were the most frequently detected species, while Mycobacterium intracellulare (21.1%), Mycobacterium scrofulaceum (15.8%) and Mycobacterium fortuitum (10.5%) were common in extrapulmonary specimens. CONCLUSION: The frequency of NTM infection among TB suspects was low at a South Indian tertiary care hospital. The most predominant NTM species isolated from both pulmonary and extrapulmonary specimens was M. intracellulare.

Prevalence and Time Trend of SARS-CoV-2 Infection in Puducherry, India, August-October 2020.

We conducted 3 population-based cross-sectional surveys, at 1-month intervals, to estimate the prevalence and time-trend of severe acute respiratory syndrome coronavirus 2 infection in Puducherry, India. Seropositivity rate increased from 4.9% to 34.5% over 2 months and was 20-fold higher than the number of diagnosed cases of infection.