Phenotypic differences between Edwardsiella piscicida and Edwardsiella anguillarum isolates in Japan

Abstract

Objective Edwardsiella tarda has been regarded as the causative agent of edwardsiellosis in cultured marine and freshwater fish species in Japan. Our previous study genetically classified an E. tarda‐like isolate from diseased Olive Flounder Paralichthys olivaceus as E. piscicida and that from diseased Red Seabream Pagrus major as E. anguillarum. This study aimed to understand the phenotypic differences between E. piscicida and E. anguillarum. Methods Fourteen E. piscicida and seven E. anguillarum isolates were used in this study. The colonies of each isolate were grown on brain–heart infusion agar plates and then subjected to DNA extraction. The extracted DNA was amplified using PCR. carbohydrate fermentation of the isolates was examined using API 50 CH test kits. Moreover, the growth of the two species was examined in defined media. Also, free amino acids in Olive Flounder and Red Seabream sera were detected and quantified via high‐performance liquid chromatography–mass spectrometry. Statistical differences in the concentrations of free amino acids were analyzed using Welch's t‐tests. Result The API 50 CH test revealed that L‐arabinose and D‐mannitol were fermented by E. anguillarum isolates but not E. piscicida isolates. Furthermore, the growth of E. piscicida and E. anguillarum was reduced in the defined medium without methionine and iron sulfate. The growth of E. piscicida was reduced in the defined medium without phenylalanine, tyrosine, alanine, or nicotinic acid, whereas the growth of E. anguillarum was reduced in the defined medium without serine, cysteine, leucine, threonine, or isoleucine. Tyrosine and alanine were present in higher concentrations in the Olive Flounder serum, whereas threonine and isoleucine were present in higher concentrations in the Red Seabream serum, suggesting favorable growth conditions for E. piscicida and E. anguillarum. Conclusion This study characterizes a minimal defined medium that can be used for developing vaccines against E. piscicida and E. anguillarum.

Development of a real-time recombinase-aided amplification assay for rapid and sensitive detection of Edwardsiella piscicida

“…Similar to other invasive pathogens, E. piscicida exhibits a preference for infiltrating host cells as a means to evade immune system detection and facilitate replication within both phagocytes and nonphagocytes, thereby contributing to its pathogenicity ( Xie et al., 2014 ; Zhang et al., 2016 ). In recent years, increasing number of E. piscicida isolates have been obtained from aquacultural environment ( Ferrari et al., 2022 ; Kim et al., 2022 ; Sugiura et al., 2022 ). Consequently, the development of a prompt and highly sensitive diagnostic technique for E. piscicida is of utmost importance in the prevention of outbreaks.…”

“…Currently, the identification of E. piscicida primarily depends on conventional techniques, including culture, PCR, or immune-testing ( Swain et al., 2001 ; Hong et al., 2009 ; Castro et al., 2010 ; Ferrari et al., 2022 ; Sugiura et al., 2022 ). While cultures offer undeniable proof of infection, their lengthy incubation period renders them impractical for clinical diagnosis, except for antimicrobial susceptibility analysis ( Kim et al., 2022 ; Sugiura et al., 2022 ).…”

“…Currently, the identification of E. piscicida primarily depends on conventional techniques, including culture, PCR, or immune-testing ( Swain et al., 2001 ; Hong et al., 2009 ; Castro et al., 2010 ; Ferrari et al., 2022 ; Sugiura et al., 2022 ). While cultures offer undeniable proof of infection, their lengthy incubation period renders them impractical for clinical diagnosis, except for antimicrobial susceptibility analysis ( Kim et al., 2022 ; Sugiura et al., 2022 ). Various methods that rely on antibodies, such as enzyme-linked immunosorbent assay (ELISA), and quartz crystal microbalance (QCM) biosensor, have been developed for E. piscicida detection ( Swain et al., 2001 ; Hong et al., 2009 ).…”

Comparative genomics of Edwardsiella anguillarum and Edwardsiella piscicida isolated in Taiwan enables the identification of distinctive features and potential virulence factors using Oxford‐Nanopore MinION® sequencing

“…The bacteria can infect several cultured fish hosts, including cultured freshwater fish such as Japanese eel, tilapia, and cultured seawater fish such as milkfish, black seabream, and grouper, as recently reported in Taiwan (Rahmawaty et al, 2022). In other countries including South Korea, Japan, China, and Thailand, incidents of E. tarda infections have been reported in tilapia, Japanese eel, turbot, and flounder, respectively (Joh et al, 2011; Kim et al, 2014; Oh et al, 2020; Ota et al, 2011; Park et al, 2017; Sugiura et al, 2022).…”

Comparative pathogenicity and histopathological analysis of Edwardsiella anguillarum intraperitoneal infection in milkfish (Chanos chanos), Nile tilapia (Oreochromis niloticus) and Asian seabass (Lates calcarifer)

“…This bacterium is known to produce catalase, indole and H 2 S but does not produce oxidase (Sugiura et al, 2022). Recent research on the phenotypic and genotypic diversity of Edwardsiella tarda has led to the taxonomic separation of E. tarda into three distinct taxa: E. tarda, E. piscicida and E. anguillarum (Abayneh et al, 2013;Shao et al, 2015).…”