Edwardsiella piscicida, a pathogenic bacterium newly detected in spotted sea bass Lateolabrax maculatus in China

The pathway of Edwardsiella piscicida infecting Lateolabrax maculatus via the immersion bath

“…Since spotted sea bass has been intensively cultured in China, numerous diseases resulting in significant financial losses have been paid attention to. Subsequently, various bacterial pathogens causing disease outbreaks have been identified and well‐described (Han et al, 2017; Hu et al, 2022; Wang et al, 2021). Because no immersion challenge with E. piscicida has been reported previously for spotted sea bass.…”

“…Edwardsiella piscicida strain 18BJ136, isolated from the diseased spotted sea bass during a bacterial outbreak at a farm in Guangdong province of China was utilized in this study, which was demonstrated fatal to spotted sea bass by intraperitoneal injection challenge (Hu et al, 2022). Strain 18BJ136 was cultured on brain‐heart infusion (BHI) agar and incubated at 28°C for 24 h. The single colony was then inoculated into 3 mL BHI broth and incubated in the shaker at 180 rpm at 28°C for 10 h. Then it was diluted into 1:100 in BHI broth and incubated in the shaker at 180 rpm at 28°C for 10 h. The bacteria were harvested through centrifugation at 6000 × g for 10 min at 4°C.…”

“…Total RNA from the tissues was extracted and quantified, as described previously (Hu et al, 2022). Quantitative real‐time PCR (qPCR) was performed for the synthesis of cDNA.…”

“…Edwardsiella piscicida can cause high mortality with nonspecific clinical symptoms such as skin ulceration and internal organ swell, congestion and focal necrosis. Our former study reported the isolation of E. piscicida from spotted sea bass ( Lateolabrax maculatus ) for the first time and confirmed its pathogenicity through intraperitoneal injection (Hu et al, 2022). Research shows that immersion infection is hard to succeed without additional stress, such as skin abrasion (Darwish et al, 2000; Plumb & Hanson, 2010).…”

“…Spotted sea bass is one of the delicious edible fish consumption commodities in China, which has an important economic value. However, its farming industry is hampered by multiple bacteria diseases (Han et al, 2017; Hu et al, 2022; Wang et al, 2021). The purpose of this study was to establish an immersion infection model of E. piscicida and to analyse its pathogenicity under different environmental conditions, so as to lay a foundation for elucidating the infection mechanism of this pathogen.…”