Diagnostic luciferase reporter phage assay for active and non-replicating persistors to detect tubercle bacilli from sputum samples

Diagnosis of latent tuberculosis infection is a myth for want of a simple, direct tool. Simulation of hypoxic environment was done to create a novel hypothetical model for persistence using processed sputum samples. The adaptation of tubercle bacilli to hypoxic environment seems to be influenced by pre-existing clinical status of the patients at the time of sputum collection, resulting in varied growth pattern. Bacilli from 36 samples did not get adapted to latency of which 15 samples were from patients in whom the disease was well established and the tubercle bacilli in them probably did not experience any stress whatsoever. Similarly, 10 of the 37 samples showing the presence of cultivable cells in both aerobic and anaerobic conditions were from patients who had relapsed. The bacilli in these samples had been probably experiencing stress and thus were ready to adapt to the hypoxic environment. Diagnostic luciferase reporter phage assay for non-replicating persistors (DLRPA-NRP) identified 30 additional positives which failed to grow on Lowenstein– Jensen medium. Presence of viable bacilli in these samples was confirmed by reverse transcriptase-PCR (RT-PCR) for 16S rRNA indicating either the improved sensitivity of the assay to detect actively growing bacilli or its ability to detect non-replicating persistors. The utility of LRP assay to detect both dormant and active tubercle bacilli was explored in this work and was optimized using lysis inhibition to diagnose tuberculosis with rapidity, improved sensitivity and specificity. DLRPA-NRP, a rapid growth based assay is thus developed to detect both dormant and actively growing tubercle bacilli

Dodecanoic acid & palmitic acid disarms rifampicin resistance by putatively targeting mycobacterial efflux pump Rv1218c

Background & objectives: Drug-resistant tuberculosis (TB) jeopardizes the treatment process with poor outcomes. Efflux pumps (EPs) belonging to the ABC transporter family in Mycobacterium tuberculosis confer resistance to rifampicin (RMP) besides genetic mutations thus serving as a target for a potential adjunct therapeutic inhibitory molecule. Rv1218c is one such pump that was previously reported to be active in multidrug-resistant TB clinical isolates

Phage lysin as a substitute for antibiotics to detect Mycobacterium tuberculosis from sputum samples with the BACTEC MGIT 960 system

AbstractPhage lysin was evaluated as a substitute for antibiotics in sputum samples processed by a modified Petroff's method for the detection of Mycobacterium tuberculosis with the MGIT 960 system. One hundred and fifty sputum samples were processed, inoculated onto two slopes of Lowenstein–Jensen medium, and divided in to two aliquots of 0.5 mL each. One aliquot was added to 7 mL of MGIT medium containing polymyxin B, amphotericin B, nalidixic acid, trimethoprim and azlocillin (PANTA) (MGIT-PANTA) and the other was added to 7 mL of MGIT medium containing 0.8 mL of lysin (MGIT-Lysin). The samples were randomized and incubated at 37°C in the MGIT 960 system. The sensitivity and specificity of MGIT-Lysin were 97% and 88%, respectively, as compared with MGIT-PANTA. The average times to detection with MGIT-Lysin and MGIT-PANTA were 9.3 and 8.6 days, respectively. The rate of contamination with MGIT-PANTA and MGIT-Lysin were 16% and 7.3%, respectively. Phage lysin can be substituted for antibiotics in processed sputum samples for the detection of M. tuberculosis

A mannose-conjugated multi-layered polymeric nanocarrier system for controlled and targeted release on alveolar macrophages

To improve the performance of drug delivery systems in macrophages, targeted ligand-conjugated polymeric carriers have been realized to be vital for targeted, sustainable and controlled drug release with remarkable biocompatibility and bioavailability.</p

Correction: A mannose-conjugated multi-layered polymeric nanocarrier system for controlled and targeted release on alveolar macrophages

Correction for ‘A mannose-conjugated multi-layered polymeric nanocarrier system for controlled and targeted release on alveolar macrophages’ by Rajendran Amarnath Praphakar et al., Polym. Chem., 2018, DOI: 10.1039/c7py02000g.</p