Emergence of multi drug resistant (MDR) and extensively drug resistant (XDR) Mycobacterium tuberculosis poses a serious threat to TB control as the available treatment options are less effective in these cases. Therefore, new strategies are required for identification of new drugs and drug targets. The M. tuberculosis dihydrodipicolinate synthase is a putative drug target with no potent inhibitor. Here in this study, we have used a comprehensive computational approach to identify small molecule inhibitors and validated them in vitro. As similar structures tend to have similar functions, therefore 3 approaches, namely, (a) known inhibitor-based approach, (b) substrate analogues, (c) product analogues were used for compound screening from various chemical libraries. The fourth approach we have taken is fragment library screening.In vitro studies revealed that β-hydroxypyruvic acid tartronic acid are inhibitors of Mtb-rDapA with maximum inhibition 48% and 51% at 500µM concentrations respectively. We have also observed that β-hydroxypyruvic acid is a time dependent inhibitor of Mtb-rDapA. Further, thermal shift assays showed that β-hydroxypyruvic acid interacts with Mtb-rDapA and the thermal stability of Mtb-rDapA shifted by 3˚C. Among the product analogues of Mtb-DapA, dipicolinic acid showed to bind to Mtb-rDapB shifting thermal stability of Mtb-rDapB by 0.5˚C in binding. Additionally, we have designed a new approach by combining substrate and product analogues to achieve better inhibitions. In vitro assays validated that this combination approach increased maximum inhibition up to 100%. We envision that these compounds would serve as potent leads for tuberculosis drug discovery.

Antimicrobial resistance (AMR) is one of the top 10 threats affecting global health. AMR defeats the effective prevention and treatment of infections caused by microbial pathogens including bacteria, parasites, viruses and fungi (WHO). Microbial pathogens have natural tendency to evolve and mutate over time resulting in AMR strains. The set of genes involved in antibiotic resistance also termed as “antibiotic resistance genes” (ARGs) spread through species by lateral gene transfer thereby causing global dissemination. While this biological mechanism is prevalent in the spread of AMR, human methods also augment through various mechanisms such as over prescription, incomplete treatment, environmental waste etc. A considerable portion of scientific community is engrossed in AMR related work trying to discover novel therapeutic solutions for tackling resistant pathogens. Comprehensive inspection of the literature shows that diverse therapeutic strategies have evolved over recent years. Collectively, these therapeutic strategies include novel small molecules, newly identified antimicrobial peptides, bacteriophages, phytochemicals, nanocomposites, novel phototherapy against bacteria, fungi and virus. In this work we have developed a comprehensive knowledgebase by collecting alternative antimicrobial therapeutic strategies from literature data. We have used subjective approach for datamining new strategies resulting in broad coverage of entities and subsequently add objective data like entity name, potency, safety information etc. The extracted data was organized KOMBAT (Knowledgebase Of Microbes’ Battling Agents for Therapeutics). A lot of these data are tested against AMR pathogens. We envision that this database will be noteworthy for developing future therapeutics against resistant pathogens. The database can be accessed through http://kombat.igib.res.in/.