Monitoring and assessment of the therapeutic impact of metabolites extracted from sponge-associated bacteria screened from Gulf of Mannar, southeast coast of India.

The present study aimed to assess and monitor the therapeutic potential of antimicrobial metabolites from marine sponge-associated bacteria collected from the southeast coast of India against multidrug-resistant clinical bacterial isolates. Five sponge samples were collected and the metabolite-producing bacteria were screened from the Gulf of Mannar, India, and their antibacterial potential was studied against drug-resistant clinical bacterial isolates obtained from the hospitals. The two metabolite-producing bacteria (IS1 and IS2) were characterized by standard microbiology protocols and 16S rRNA sequencing. The antibacterial metabolites were characterized by liquid chromatography mass spectrometry (LCMS) analysis. The study suggested that marine sponges such as Spheciospongia spp., Haliclona spp., Mycale spp., Tedania spp., and SS-01 were associated with 30 ± 2, 26 ± 2, 23 ± 3, 21 ± 2, and 20 ± 2% of antibacterial metabolite-producing bacteria, respectively. The LCMS analysis of metabolites extracted from IS1 (4,6-dimethyl-2-pyrimidinamine; 4,5-dimethyl-2-propylsilyl-1H-imidazole) and IS2 (caproyl amide, 2-imidazoline) associated with Spheciospongia spp. exhibited significant antibacterial properties against drug-resistant bacteria. IS1 showed antimicrobial potential against the clinical isolates of Proteus spp., and IS2 showed antibacterial potential against isolates of both Proteus mirabilis and Salmonella typhi. IS1 and IS2 were identified by 16S rRNA sequencing and designated as Klebsiella spp. DSCE-bt01 and Pseudomonas spp. DSCE-bt02, respectively. The current study concluded that the assessment and monitoring of novel isolates from sponge-associated bacteria from marine coastal areas probably offer latest breakthrough in curtailing the global antimicrobial resistance and the study of such ecosystems adds value addition to the searching of novel bioactive compounds from terrestrial ecosystems.