Identification of Bacterial Pathogens in Biofilms of Recirculating Aquaculture Systems

Abstract

Abstract Biofilms are capable of forming on all aquaculture system components, incorporating the various microflora present in the water. Pathogenic bacteria released from the biofilms are potentially capable of causing recurring diseases. Seven recirculating freshwater and two recirculating saltwater facilities were sampled, with eight different types of materials tested. Pathogenic bacteria were identified using standard bacteriological methods and commercial kits. The most significant human pathogens were Bacillus cereus, Shigella spp. and Vibrio spp. The major piscine pathogens of concern were Photobacterium damsela, Vibrio spp., and Aeromonas hydrophila. The most significant variation in biofilm pathogen occurrence was observed between facilities and not between construction materials. This study implicates biofilms as another reservoir for pathogenic bacteria in recirculating aquaculture systems.