Investigation of antibacterial potential of Actinomycetales isolated from hot springs in India through a combined analysis involving in vitro and computational methods

Abstract

Actinobacteria emerge as significant producers of bioactive compounds. These compounds exhibit diverse beneficial properties, such as antioxidative, anti-inflammatory, anticancer, antimicrobial, and antiviral attributes. Hot springs, with their high temperatures and unique geochemical conditions, serve as fascinating ecosystems harboring diverse microbial life. In these environments, actinomycetes thrive, utilizing the available organic matter and nutrients. The extreme conditions, characterized by high temperatures and pH levels, likely exert selective pressure, favoring the survival of resilient microorganisms like actinomycetes. This study specifically identified Actinomycetales bacterium spp. (Genbank ID: OP863023), isolated from Rajgir hot spring, as a noteworthy producer of a brown pigment at 43 °C. This isolated strain is known to produce various metabolites identified through GC–MS analysis. Following ADME/T screening of all the metabolites, Diethyl Phthalate (DEP) stands out among those produced by the Actinomycetales bacterium species. The isolated strain demonstrated in vitro antibacterial activity, inhibiting Listeria monocytogenes MTCC1143 with a 10-mm zone of inhibition, while the reference Ampicillin disc showed a 15 mm inhibition zone. In the in silico analysis targeting the Internalin A protein of L. monocytogenes, the Actinomycetales-produced compound DEP displayed an inhibition potential of − 5.4 kcal/Mol, while the reference drug Ampicillin exhibited a higher inhibition potential of − 7.4 kcal/Mol. These findings suggest that the isolated actionobacteria holds promise for antibacterial applications, particularly against L. monocytogenes.