Antibacterial and Cytotoxic Effects of Bioactive Compounds from Halophilic Actinomycetes against Multi-Drug-Resistant Nosocomial Pathogens

A significant issue for global health is the rise of bacteria resistant to antibiotics.They diminish the therapeutic efficacy of the existing medications against nosocomial infections predominantly attributed to Pseudomonas aeruginosa and Klebsiella pneumoniae.The objective of this research was to assess the actinomycetes isolated from mangroves of Munroc Islands, Kollam, Kerala, India for their potential to produce components that inhibit pathogens of nosocomial infections.In the marsh ecosystem's water, two strains of saline actinomycetes were isolated.Utilizing physiological characteristics, biochemical processes, and 16S rDNA sequencing data, the isolates were identified as Nocardiopsis dassonvillei and Streptomyces daghestanicus.The isolated actinomycetes exhibited significant inhibitory effects against antibiotic-resistant P. aeruginosa and K. pneumoniae.During the exponential phase, the antibacterial molecule was successfully released in the starch casein medium at a pH of 7 and with 5-10% sodium chloride.The eluates obtained from the actinomycetes were subjected to determine antibacterial activity against multidrug-resistant bacteria.Cytotoxic activity of the elute was conducted against A549 lung cancer cell line using MTT assay.Further, the elutes obtained were characterized using LC-MS and NMR spectroscopy.The results showed that the pathogenic bacteria exhibited susceptibility across a range of 25-100 l per well from 1000 g/ml and the assessment of the elutes against A549 exhibited considerable cytotoxicity.LC-MS and NMR spectroscopy characterization indicated the presence of undecanedioic acid from N. dassonvillei and arachidonic acid (ARA) from S. daghestanicus.The study indicates that the halophilic actinomycetes have the potential to produce a broad-spectrum of antibacterial compounds effective against multidrug-resistant pathogens.