Characterization of Bacillus altitudinis (BSP-01) and Bacillus thuringiensis (BSP-06) Symbiont Associated with Stylissa massa Marine Sponge for Antimicrobial Agent and Multidrug Resistance Properties

     The problem of antibiotic resistance has driven research to seek for new antibiotics, including those derived from the sea. Bacteria highly resistant to antibiotics include Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli). Sponges have the potential to produce active compounds as raw materials for drugs. The main constraint in the final development of the potential of sponges is the issue of supply. Excessive use of sponges to search for new bioactive substances can lead to less conservative actions that may harm the ecological system of marine biota. An alternative approach is to explore the symbiotic bacteria of sponges to discover new antibiotic agents. The research aimed to screen and identify symbiotic bacteria in sponges as antibacterial agents. The study was conducted from September 2022 to September 2023 in the Oceanography Laboratory. The analyzed sponge samples belong to the Stylissa massa species. Based on the research, potential symbiotic bacterial isolates from Stylissa massa sponges were identified as BSP-01 and BSP-06. BSP-01 showed antibacterial activity in preliminary tests against Staphylococcus aureus strain MDR and Escherichia coli strain MDR with inhibition zones of 4.74 and 4.02mm against S. aureus strain MDR and E. coli strain MDR, respectively. BSP-06 exhibited inhibition zones of 5.82mm against S. aureus strain MDR and 4.6mm against E. coli strain MDR. Molecular identification revealed that the potential symbiotic bacteria from Stylissa massa sponges were Bacillus altitudinis (BSP-01) and Bacillus thuringiensis (BSP-06). Further research is needed to characterize the active compounds in the potential symbiotic bacteria to develop natural products that the community can utilize.