Differential production and secretion of potentially toxigenic extracellular proteins from hypervirulent Aeromonas hydrophila under biofilm and planktonic culture

Authors: BARGER, PRISCILLA - Auburn University; LILES, MARK - Auburn University; NEWTON, JOSEPH - Auburn University; Beck, Benjamin

Submitted to: BMC Microbiology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/7/2020
Publication Date: 1/6/2021
Citation: Barger, P., Liles, M., Newton, J., Beck, B.H. 2021. Differential production and secretion of potentially toxigenic extracellular proteins from hypervirulent Aeromonas hydrophila under biofilm and planktonic culture. BMC Microbiology. 21:8. https://doi.org/10.1186/s12866-020-02065-2.
DOI: https://doi.org/10.1186/s12866-020-02065-2

Interpretive Summary: Hypervirulent Aeromonas hydrophila (vAh) is an emerging pathogen in freshwater aquaculture that results in the loss of over 3 million pounds of marketable channel catfish, Ictalurus punctatus, and channel catfish hybrids each year from freshwater catfish production systems in Alabama, U.S.A. vAh isolates are clonal in nature and are genetically unique from, and significantly more virulent than, traditional A. hydrophila isolates from fish. Even with the increased virulence, natural infections cannot be reproduced in aquaria challenges making it difficult to determine modes of infection and the pathophysiology behind the devastating mortalities that are commonly observed. Despite the intimate connection between environmental adaptation and plastic response, the role of environmental adaption on vAh pathogenicity and virulence has not been previously explored. In this study, secreted proteins of vAh cultured as free-living planktonic cells and within a biofilm were compared to elucidate the role of biofilm growth on virulence.

Technical Abstract: Hypervirulent Aeromonas hydrophila (vAh) is an emerging pathogen in freshwater aquaculture that results in the loss of over 3 million pounds of marketable channel catfish, Ictalurus punctatus, and channel catfish hybrids each year from freshwater catfish production systems in Alabama, U.S.A. vAh isolates are clonal in nature and are genetically unique from, and significantly more virulent than, traditional A. hydrophila isolates from fish. Even with the increased virulence, natural infections cannot be reproduced in aquaria challenges making it difficult to determine modes of infection and the pathophysiology behind the devastating mortalities that are commonly observed. Despite the intimate connection between environmental adaptation and plastic response, the role of environmental adaption on vAh pathogenicity and virulence has not been previously explored. In this study, secreted proteins of vAh cultured as free-living planktonic cells and within a biofilm were compared to elucidate the role of biofilm growth on virulence.