Screening antibiofilm and quorum-quenching activity of Actinomycetes isolates against aquatic pathogens

Abstract

Background: Indonesia aquatic industry continually experience the same challenges, namely bacterial outbreaks which result in economic losses and could also endanger food security of Indonesia. This condition is exacerbated by the increasing prevalence of resistance of pathogenic bacteria to various antibiotics. The formation of biofilms structure is one important aspect in the emergence of the nature of resistance in several bacteria. In this case, the formation of this structure is regulated by communication system owned by bacteria, namely the quorum sensing system. Therefore, many researchers are now using this approach through this system to both inhibit and destroy the structure of biofilms, hoping to reduce the prevalence of bacterial resistance to various antibiotics. In this study, we attempted to screen and characterize bioactive compounds isolated from isolates of Actinomycetes which perform antibiofilm and quorum quenching (anti-quorum sensing) activity against aquatic pathogen. Methods and materials: Actinomycetes isolates were grown in yeast malt extract agar +1% calcium carbonate as their differential media. In this study, screening of bioactive compound of Actinomycetes isolates were performed by using liquid-liquid extraction. In addition in this study, we also performed antibiofilm activity assay in two different categories based on its mechanisms (inhibition and destruction activity) against biofilm structure forming by Vibrio harveyi, Aeromonosa hydrophila, and Streptococcus agalactiae ATCC 27956. We also characterized bioactive compounds of these isolates which showed quorum quenching activity. Results: We found sixteen isolates of Actinomycetes which showed quorum quenching activity, based on the characterization of quorum quenching activity we found that there were several isolates, such as 16PM and 18PM which showed protein as its major quorum quenching activity. In addition, these isolates were screened for their antibiofilm activity against biofilm structure forming by Vibrio harveyi, Aeromonas hydrophila, and Streptococcus agalactiae. We found that SW03 isolates showed inhibition activity against biofilm structure of V. harveyi for up to 77%, whereas 12AC isolates showed destruction activity against biofilm structure of V. harveyi for up to 59%. Conclusion: This study revealed antibiofilm and quorum quenching activity Actinomycetes isolates potentially to be applied in the prevention and treatment of infectious disease in aquatic environment.