Potential applications of lactic acid bacteria and bacteriocins in anti-mycobacterial therapy

Tuberculosis (TB) is a communicable disease caused by Mycobacterium tuberculosis (M. tuberculosis). WHO estimated that 10.4 million new (incident) TB cases worldwide in year 2016. The increased prevalence of drug resistant strains and side effects associated with the current anti-tubercular drugs make the treatment options more complicated. Hence, there are necessities to identify new drug candidates to fight against various sub-populations of M. tuberculosis with less or no toxicity/side effects and shorter treatment duration. Bacteriocins produced by lactic acid bacteria (LAB) attract attention of researchers because of its 'Generally recognized as safe' status. LAB and its bacteriocins possess an effective antimicrobial activity against various bacteria and fungi. Interestingly bacteriocins such as nisin and lacticin 3147 have shown antimycobacterial activity in vitro. As probiotics, LAB plays a vital role in promoting various health benefits including ability to modulate immune response against various infectious diseases. LAB and its metabolic products activate immune system and thereby limiting the M. tuberculosis pathogenesis. The protein and peptide engineering techniques paved the ways to obtain hybrid bacteriocin derivatives from the known peptide sequence of existing bacteriocin. In this review, we focus on the antimycobacterial property and immunomodulatory role of LAB and its metabolic products. Techniques for large scale synthesis of potential bacteriocin with multifunctional activity and enhanced stability are also discussed.

Luciferase reporter phage phAE85 for rapid detection of rifampicin resistance in clinical isolates of Mycobacterium tuberculosis

OBJECTIVE@#To evaluate luciferase reporter phage (LRP) phAE85 in rapid detection of rifampicin resistance in a region where TB is endemic.@*METHODS@#One hundred and ninety primary isolates on Lowenstein-Jensen medium were tested. Middlebrook 7H9 complete medium with and without rifampicin at 2 μg/mL was inoculated with standard inoculum from suspensions of the clinical isolate. After incubation for 72 h, LRP was added. Following 4 h of further incubation, light output from both control and test was measured as relative light units. Strains exhibiting a reduction of less than 50% relative light units in the drug containing vial compared to control were classified as resistant. Results were compared with the conventional minimum inhibitory concentration method (MIC) of drug susceptibility testing.@*RESULTS@#The two methods showed high level of agreement of 97% (CI 0.94, 0.99) and P value was 0.000 1. The sensitivity and specificity of LRP assay for detection of rifampicin resistance were 91% (CI 0.75, 0.98) and 99% (CI 0.95, 1.00) respectively. Time to detection of resistance by LRP assay was 3 d in comparison with 28 d by the minimum inhibitory concentration method.@*CONCLUSIONS@#LRP assay with phAE85 is 99% specific, 91% sensitive and is highly reproducible. Thus the assay offers a simple procedure for drug sensitivity testing, within the scope of semi-automation.

Newer diagnostic tools in tuberculosis.

Tuberculosis (TB) is a global health problem. Multi Drug Resistant TB (MDR-TB) and Extensively Drug Resistant TB (XDR-TB) cause high mortality. There are obstacles to the diagnosis of TB due to lack of accurate, cost effective and rapid diagnostic tools. The delay in diagnostic process is an unresolved bottleneck impeding access to treatment. Presently available diagnostic tools for TB except some liquid culture and molecular tests take long time. TB culture and drug susceptibility test (DST) need specialized laboratory setup and are also very expensive. The New Diagnostics Working Group (NDWG) on TB is supporting development of new tools and also provides information to World Health Organization (WHO) for endorsement. Globally, TB control programmes need rapid and accurate diagnostic tools, which are to be implemented in peripheral health centers as well. In this review, we describe development of newer diagnostic tools, their endorsement status and usage in TB diagnosis.

Effect of bacteriophage lysin on lysogens

<p><b>OBJECTIVE</b>To study the effect of phage lysin on the growth of lysogens.</p><p><b>METHODS</b>Sputum specimens processed by modified Petroff's method were respectively treated with phagebiotics in combination with lysin and lysin alone. The specimens were incubated at 37 °C for 4 days. At the end of day 1, 2, 3 and day 4, the specimens were streaked on blood agar plates and incubated at 37 °C for 18-24 hours. The growth of normal flora observed after day 1 was considered as lysogens.</p><p><b>RESULTS</b>Sputum specimens treated with phagebiotics-lysin showed the growth of lysogens. When specimens treated with lysin alone, lysogen formation was avoided and normal flora was controlled.</p><p><b>CONCLUSIONS</b>Lysin may have no effect on the growth of lysogens.</p>

Effect of bacteriophage lysin on lysogens

Objective: To study the effect of phage lysin on the growth of lysogens. Methods: Sputum specimens processed by modified Petroff's method were respectively treated with phagebiotics in combination with lysin and lysin alone. The specimens were incubated at 37℃ for 4 days. At the end of day 1, 2, 3 and day 4, the specimens were streaked on blood agar plates and incubated at 37℃ for 18-24 hours. The growth of normal flora observed after day 1 was considered as lysogens.Results:When specimens treated with lysin alone, lysogen formation was avoided and normal flora was controlled. Conclusions: Lysin may have no effect on the growth of lysogens. Sputum specimens treated with phagebiotics-lysin showed the growth of lysogens.