Evaluation of the Performance of Nitrate Reductase Assay for Rapid Drug-susceptibility Testing of Mycobacterium tuberculosis in North India

The objective of the study was to evaluate the performance of nitrate reductase assay (NRA) as a rapid, reliable and inexpensive method for drug-susceptibility testing (DST) of Mycobacterium tuberculosis against first-line antitubercular drugs, such as rifampicin (RIF), isoniazid (INH), streptomycin (STR), and ethambutol (EMB). In total, 286 isolates were subjected to test by proportion method (PM) and NRA. By comparing the results of NRA with those of the gold standard PM, sensitivities and specificities were 98.4%, 97%, 88.5%, and 94.2% and 100%, 100%, 94%, and 99% for RIF, INH, STR, and EMB respectively. The positive predictive values were 100%, 100%, 95%, and 98% for RIF, INH, STR, and EMB respectively. The negative values were 99%, 98%, 87%, and 96% for RIF, INH, STR, and EMB respectively. The median time of obtaining results was shorter using NRA (10 days) compared to PM (28 days). An excellent agreement was observed between the two phenotypic tests with the κ values of 0.98, 0.97, 0.81, and 0.93 for RIF, INH, STR, and EMB respectively. The results demonstrated that NRA is suitable for the early determination of INH and RIF resistance and has the potential to be a useful tool for rapid drug-sensitivity test of M. tuberculosis in resource-constrained settings

Dark secrets behind the shimmer of contact lens: the Indian scenario

<p>Abstract</p> <p>Background</p> <p>We studied the bacteriological profile of soft contact lens and its accessories among the asymptomatic subjects and monitored the compliance level with the lens use and its cleaning protocol.</p> <p>Findings</p> <p>A total of 115 (104 daily wear and 11 extended wear) subjects using contact lens were studied. Data regarding the duration of use and frequency and method of cleaning were recorded. Contact lens, lens cases, preserving solutions and tips of solution bottles were the samples collected. The isolates were identified on the basis of their phenotypic characters. Samples from 24 subjects (21 daily wear and 3 extended wear) were found contaminated. Of the 24 contaminated cases, 23 showed medium adherence to the cleaning protocol. Contamination rate was higher among the 56 daily wear lens users who used same lens for 2 years and more, than the 48 users who used their lenses for less than 2 years. Lens case contamination was found in all the 24 cases. The bacteria isolated were <it>Citrobacter freundii, Escherichia coli</it>, <it>Klebsiella pneumoniae, Pseudomonas aeruginosa</it>, <it>Staphylococcus epidermidis </it>and <it>Streptococcus pneumoniae</it>. In extended wear lens users, there was no change in microbial flora on repeating the cultures on day 7 and 14.</p> <p>Conclusion</p> <p>Non-compliance with contact lens use may lead to invitation of microbial flora. The accumulation of these bacteria may act as a precursor to biofilm formation, thus colonizing the lens accessories as well. The bacteria isolated in this study were similar to the ones causing microbial keratitis thus, predisposing the otherwise asymptomatic subjects to permanent visual damage.</p

Evaluation of the Performance of Nitrate Reductase Assay for Rapid Drug-susceptibility Testing of Mycobacterium tuberculosis in North India

The objective of the study was to evaluate the performance of nitrate reductase assay (NRA) as a rapid, reliable and inexpensive method for drug-susceptibility testing (DST) of Mycobacterium tuberculosis against firstline antitubercular drugs, such as rifampicin (RIF), isoniazid (INH), streptomycin (STR), and ethambutol (EMB). In total, 286 isolates were subjected to test by proportion method (PM) and NRA. By comparing the results of NRA with those of the gold standard PM, sensitivities and specificities were 98.4%, 97%, 88.5%, and 94.2% and 100%, 100%, 94%, and 99% for RIF, INH, STR, and EMB respectively. The positive predictive values were 100%, 100%, 95%, and 98% for RIF, INH, STR, and EMB respectively. The negative values were 99%, 98%, 87%, and 96% for RIF, INH, STR, and EMB respectively. The median time of obtaining results was shorter using NRA (10 days) compared to PM (28 days). An excellent agreement was observed between the two phenotypic tests with the \u3ba values of 0.98, 0.97, 0.81, and 0.93 for RIF, INH, STR, and EMB respectively. The results demonstrated that NRA is suitable for the early determination of INH and RIF resistance and has the potential to be a useful tool for rapid drug-sensitivity test of M. tuberculosis in resource-constrained settings

Aeruginosins from a <i>Microcystis</i> sp. Bloom Material Collected in Varanasi, India

Two novel biologically active short peptides, aeruginosins IN608 and IN652, were isolated from the cyanobacterium <i>Microcystis</i> sp. strain BHU006, which was collected from Durgakund water reservoir in Varanasi, India. Aeruginosins IN608 and IN652 are linear modified peptides containing four building blocks, one of which is the arogenate-derived modified amino acid 2-carboxy-6-hydroxyoctahydroindole. Aeruginosin IN608 and aeruginosin IN652 inhibit the activity of the proteolytic enzyme trypsin with IC₅₀’s of 4.3 and 4.1 μM, respectively