The anti-biofilm effects of sponge (Callyspongia sp.) and two sea anemones (Zoanthus sansibaricus and Cerianthus lloydii) collected from the Persian Gulf

Background: Sponges and sea anemones do not have specialized defense organs. Instead, they rival harmful microorganisms by producing certain compounds. These compounds can also be useful against some human pathogens. This study aimed to investigate the antimicrobial effects of bioactive products from these marine animals. Methods: Two species of sea anemone (Zoanthus sansibaricus and Cerianthus lloydii) and one species of sponge (Callyspongia sp.) were collected at the Persian Gulf. The active metabolites of these two marine animals were extracted by methanol and dichloromethane solvents. The antimicrobial activity of each extract was performed against six human pathogenic bacteria including: Pseudomonas aeruginosa, Acinetobacter baumannii, Bacillus cereus, Klebsiella pneumoniae, Escherichia coli, and Staphylococcus aureus, using disk diffusion and agar well plate methods. The MIC and MBC were determined. The inhibitory effect of these extracts on biofilm formation was also studied. Results: The effect of sponge extracts against planktonic forms of bacteria showed that the most sensitive bacteria to Callyspongia sp. extracts were K. pneumoniae and S. aureus. However, C. lloydii did not have any inhibitory effect on K. pneumoniae. The results of this study confirmed that both sponge and sea anemones extracts had sufficient effects against biofilm formation of pathogenic bacteria.However, Callyspongia sp. extracts had the lowest inhibitory effect against biofilm formation of P. aeruginosa. The highest inhibitory effect was observed on biofilm formation of K. pneumoniae. Conclusion:The Callyspongia sp sponge extract (Dichloromethane: Methanol) has an excellent antimicrobial effect against six pathogenic bacteria in planktonic and biofilm forms. There was a direct correlation between the increase in the concentration of sea anemones extracts and the inhibitory effect of biofilm formation.