In-vitro study on antimicrobial and anticancer activities of marine sponge Clathria frondifera associated bacteria

Microorganisms associated with marine sponges represent a rich source of bioactive compounds. In this study, an attempt was made to find out the antimicrobial and anticancer activity of symbiotic bacteria associated with marine sponge. A total of nine bacterial species were isolated from the marine sponge Clathria frondifera and they were screened for their antibacterial activity against clinical pathogens such as Staphylococcus aureus and Escherichia coli using agar overlay method. Among the nine isolates, two unidentified bacterial species GACSB 1 and GACSB 2 exhibited antibacterial activity against the clinical pathogen tested. Of them, GACSB 1 was pigmented bacterium exhibited moderate activity and GACSB 2 was non-pigmented bacterium exhibited significant activity. Of these two bacterial isolates pigment producer was identified as Pseudoalteromonas ruthenica MK568059 (GACSB 1) and non-pigment producer was identified as Pseudoalteromonas sp. MK568069 (GACSB 2) using 16s rRNA gene sequencing method. Furthermore, bacterial crude extract from Pseudoalteromonas sp was tested against multidrug-resistant (MDR) bacterial pathogens and Candida albicans by agar well diffusion method and anti-cancer activity against human ovarian teratocarcinoma cancer PA- 1 cell line. The extract showed moderate activity against MDR Acinetobacter baumannii and Non MDR Candida albicans when compared with other bacteria tested and also it showed moderate anticancer activity against ovarian cancer PA 1 cell line. This study concludes that the Pseudoalteromonas sp. isolated from Clathria frondifera would be a good source of natural bioactive compounds and this will leads to the discovery of new drug for crucial clinical ailments.