Temperature-dependent alterations in the proteome of emerging fish pathogen edwardsiella piscicida

Authors: JACOBSEN, KIM - University Of California, Davis; GRIFFIN, MATT - Mississippi State University; PHINNEY, BRETT - University Of California, Davis; SALEMI, MICHELLE - University Of California, Davis; YAZDI, ZEINAB - University Of California, Davis; BALAMI, SUJITA - Mississippi State University; Older, Caitlin; SOTO, ESTEBAN - University Of California, Davis

Submitted to: Journal of Fish Diseases
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/22/2024
Publication Date: 9/20/2024
Citation: Jacobsen, K.L., Griffin, M.J., Phinney, B.S., Salemi, M., Yazdi, Z., Balami, S., Older, C.E., Soto, E. 2024. Temperature-dependent alterations in the proteome of emerging fish pathogen edwardsiella piscicida. Journal of Fish Diseases. e14017. https://doi.org/10.1111/jfd.14017.
DOI: https://doi.org/10.1111/jfd.14017

Interpretive Summary: Edwardsiella piscicida is an emerging bacterial pathogen and causes edwardsiellosis, a bacterial infection, in cultured and wild fish species globally. The increased frequency of outbreaks of this pathogen pose not only a threat to the aquaculture industry but also a possible public health risk. Thus, understanding the role of temperature on the virulence of this emerging pathogen is essential for comprehending the pathogenesis of piscine edwardsiellosis in the context of current warming trends associated with climate change, as well as providing insight into its zoonotic potential. In this study, scientists at the University of California Davis, in collaboration with scientists at Mississippi State University and the National Warmwater Aquaculture Center in Stoneville, MS, evaluated the effect of temperature on the growth and proteins synthesized by multiple E. piscicida isolates. Isolates were grown at three temperatures reflective of conditions for cool (17°C) and warm (27°C) water aquaculture, and mammalian physiologic temperatures (37°C). Significant temperature-dependent alterations in bacterial growth patterns and production of crucial virulence proteins by E. piscicida was observed. Although further studies utilizing infection models are warranted, the data presented here suggests possible temperature-associated alterations in the virulence and pathogenicity of E. piscicida.

Technical Abstract: Edwardsiella piscicida is an emerging bacterial pathogen and the aetiological agent of edwardsiellosis among cultured and wild fish species globally. The increased frequency of outbreaks of this Gram-negative, facultative intracellular pathogen pose not only a threat to the aquaculture industry but also a possible foodborne/waterborne public health risk due to the ill-defined zoonotic potential. Thus, understanding the role of temperature on the virulence of this emerging pathogen is essential for comprehending the pathogenesis of piscine edwardsiellosis in the context of current warming trends associated with climate change, as well as providing insight into its zoonotic potential. In this study, significant temperature-dependent alterations in bacterial growth patterns were observed, with bacterial isolates grown at 17°C displaying higher peak growth sizes, extended lag times, and slower maximal growth rates than isolates grown at 27or 37°C. When E. piscicida isolates were grown at 37°C compared to 27 and 17°C, mass spectrometry analysis of the E. piscicida proteome revealed significant downregulation of crucial virulence proteins, such as Type VI secretion system proteins and flagellar proteins. Although in vivo models of infection are warranted, this in vitro data suggests possible temperature-associated alterations in the virulence and pathogenic potential of E. piscicida in poikilotherms and homeotherms.