ABSTRACT
OBJECTIVE: Spoligotyping is a valuable genotyping tool to study the genetic diversity and molecular epidemiology of Mycobacterium tuberculosis (M. tb). The aim of this study was to analyse different spoligotype patterns of M. tb strains isolated from patients with tuberculosis from different parts of India. MATERIALS AND METHODS: A total of 163 M. tb isolates were spoligotyped between January 2014 and January 2015. About 47% (n = 77) were from patients with extrapulmonary tuberculosis; of these, 10 were MDR, and seven were Pre-XDR. Of the 86 M. tb isolates from patients with pulmonary tuberculosis, 25 were MDR, and 25 were Pre-XDR. RESULTS: We found 61 spoligo patterns, 128 clusters in the spoligotype data base (spoldb4 data base) with spoligo international type (SIT) number and 35 true unique isolates. The most pre-dominant spoligotype was EAI lineage (56), followed by Beijing (28), CAS (20), T(9), U(7), X(3), H(3), BOVIS_1 BCG(1) and LAM(1). CONCLUSION: Although our study identified EAI, CAS and Beijing strain lineages as pre-dominant, we also found a large number of orphan strains (20%) in our study. Beijing strains were more significantly associated with MDR TB than CAS and EAI lineages. Further studies on large sample sizes would help to clearly describe the epidemiology of M. tb in India.
Subject(s)
Drug Resistance, Multiple, Bacterial , Genotype , Mycobacterium tuberculosis/genetics , Tuberculosis, Multidrug-Resistant/microbiology , Tuberculosis/microbiology , Bacterial Typing Techniques , Genetic Variation , Humans , India/epidemiology , Molecular Epidemiology , Tertiary Care Centers , Tuberculosis/epidemiology , Tuberculosis, Multidrug-Resistant/epidemiology , Tuberculosis, Pulmonary/microbiologyABSTRACT
OBJECTIVE: The Xpert MTB/Rif, with a detection limit of 131 CFU/ml, plays a valuable role in the diagnosis of extrapulmonary tuberculosis, both susceptible and resistant. This study aims at evaluating the Xpert MTB/Rif for the same, at a tertiary care centre in south India, assessing it against both culture and a composite gold standard (CGS). METHODS: We tested consecutive samples from patients suspected of extrapulmonary tuberculosis with Xpert MTB/Rif, evaluated its sensitivity and specificity against solid and/or liquid culture and CGS. An individual analysis of different sample types (tissue biopsies, fluids, pus, lymph node biopsies and CSF) given an adequate sample size, against both culture and CGS, was also performed. RESULTS: In total, 494 samples were analysed against culture. Compared to culture, the sensitivity of Xpert MTB/Rif was 89% (95% CI 0.81-0.94) and its specificity was 74% (95% CI 0.70-0.78). When Xpert MTB/Rif was compared to the CGS, pooled sensitivity was 62% (95% CI 0.56-0.67) and specificity was 100% (95% CI 0.91-1.00). CONCLUSION: This assay performs better than the currently available conventional laboratory methods. The rapidity with which results are obtained is an added advantage, and its integration into a routine diagnostic protocol must be considered.
Subject(s)
Real-Time Polymerase Chain Reaction , Tuberculosis/diagnosis , Automation, Laboratory , Drug Resistance, Bacterial/genetics , Humans , India , Microbial Sensitivity Tests/methods , Mycobacterium tuberculosis/drug effects , Mycobacterium tuberculosis/genetics , Real-Time Polymerase Chain Reaction/methods , Reproducibility of Results , Rifampin/therapeutic use , Sensitivity and Specificity , Sputum/microbiology , Tertiary Care CentersABSTRACT
BACKGROUND: Vitamin D has immunomodulatory effects that might aid clearance of mycobacterial infection. We aimed to assess whether vitamin D supplementation would reduce time to sputum culture conversion in patients with active tuberculosis. METHODS: We did this randomised, double-blind, placebo-controlled, superiority trial at 13 sites in India. Treatment-naive patients who were sputum-smear positive, HIV negative, and had pulmonary tuberculosis were randomly assigned (1:1), with centrally labelled, serially numbered bottles, to receive standard active tuberculosis treatment with either supplemental high-dose oral vitamin D3 (four doses of 2·5 mg at weeks 0, 2, 4, and 6) or placebo. Neither the patients nor the clinical and laboratory investigators and personnel were aware of treatment assignment. The primary efficacy outcome was time to sputum culture conversion. Analysis was by modified intention to treat. This trial is registered with ClinicalTrials.gov, number NCT00366470. FINDINGS: Between Jan 20, 2010, and Aug 23, 2011, we randomly assigned 247 participants to the vitamin D group (n=121) or the placebo group (n=126), of whom 211 participants (n=101 and n=110, respectively) were included in the primary efficacy analysis. Median time to culture conversion in the vitamin D group was 43·0 days (95% CI 33·3-52·8) versus 42·0 days (33·9-50·1) in the placebo group (log-rank p=0·95). Three (2%) patients died in the vitamin D group and one (1%) patient died in the placebo group; no death was considered attributable to the study intervention. No patients had hypercalcaemia. INTERPRETATION: Our findings show that vitamin D supplementation did not reduce time to sputum culture conversion. Further studies should investigate the role of vitamin D in prevention or reactivation of tuberculosis infection. FUNDING: Dalhousie University and Infectious Diseases Training and Research Centre.
