Monitoring the Starvation–Survival Response of Edwardsiella piscicida and E. tarda in Freshwater Microcosms, at Various Temperatures

Abstract

Edwardsiella piscicida is an important fish pathogen responsible for economic losses in global aquaculture, and E. tarda is also a human zoonotic pathogen. In this study, the survival of E. piscicida and E. tarda strains kept in filtered and sterilized lake water microcosms was investigated during a 20-week period at 7 °C, 15 °C and 25 °C, as well as its pathogenicity retention during a starvation period. E. tarda V43.2 stayed culturable for 6 weeks at 7 °C, 9 weeks at 25 °C and 12 weeks at 15 °C. Both E. piscicida strains (V12.1 and V57.2) stayed culturable even longer, for at least 12 weeks at 7 °C, 15 °C and 25 °C under the same starvation conditions. After Edwardsiella cells entered into the VBNC state, some became shorter and ”rounded up,” but others aggregated and retained a short rod shape. Aggregates of Edwardsiella cells were common throughout the VBNC period, and a well-formed biofilm was observed for all tested strains at the end of the experiment. The growth capacity of VBNC cells was restored by cultivating microcosm water samples in LB broth at 28 °C. Resuscitated E. piscicida cells were as virulent for the European eel as the controls. Natural waters can be a reservoir for Edwardsiella, and its underestimation in environmental samples poses a risk to public health and aquaculture.

Bacteriostasis of nisin against planktonic and biofilm bacteria: Its mechanism and application

“…Although the pathogenicity of Legionella pneumophila reduced after entering VBNC state by heat treatment, the VBNC cells could still infect amoebae (Cervero‐Arago et al., 2019). Under starvation at 7°C, Esteve and Alcaide (2022) found that Edwardsiella piscicida V12.1, E. piscicida V57.2, and E. tarda V43.2 could enter the VBNC state at 14, 15, and 7 weeks, respectively. Among them, VBNC cells of E. piscicida V12.1 and E. piscicida V57.2 could still resuscitate after entering the VBNC state for 2 weeks, and the number of the resuscitated cells reached 0.7×10 6 CFU/g of fish.…”

Edwardsiella tarda Causing Septicemia in a Wild Crested Ibis (Nipponia nippon)

“…It includes five species: Edwardsiella hoshinae , Edwardsiella tarda , Edwardsiella ichtaluri , Edwardsiella piscicida , and Edwardsiella anguillarum (Miniero Davies et al 2018; da Costa et al 2022; Ziarati et al 2022). These bacteria are commonly known as disease agents in aquaculture and are associated with the systemic disease edwardsiellosis (Esteve and Alcaide 2022). Edwardsiella tarda , an opportunistic and zoonotic pathogen, has a broad host range, infecting birds, mammals, reptiles, fish, and humans (White et al 1973; Reichley et al 2017; Buján et al 2018).…”