Risk assessment of the aquatic bacterium Vibrio coralliilyticus

Vibrio coralliilyticus is a flagellated, Gram-negative, rod-shaped bacterium ubiquitously distributed in marine waters. This aquatic bacterium is facultatively anaerobic, chemoorganotrophic, and grows in the mesophilic temperature range at a NaCl content of 1–7%. In natural habitats, V. coralliilyticus causes lethal infections in a variety of organisms, including stony corals, unicellular algae, oyster larvae, and various mussels. Due to its high lethality, infections with V. coralliilyticus are of economic importance, particularly in mussel farms . Furthermore, an increase in V. coralliilyticus infections observed in recent years has been associated with increased coral mortality . In experimental infection studies, lethal infections with V. coralliilyticus have also been observed in fish (rainbow trout), brine shrimp, and fruit flies. V. coralliilyticus exhibits temperature-dependent virulence . Many of the bacterium's virulence-associated genes are only expressed at temperatures above 26 degrees Celsius. In TRBA 466 "Classification of Prokaryotes (Bacteria and Archaea)," V. coralliilyticus is assigned to risk group 1 with the index n (pathogen for non-vertebrates). In its current statement from April 2022, the ZKBS classifies V. coralliilyticus in risk group 2 according to Section 5 (1) of the Genetic Engineering Ordinance (GenTSV) in conjunction with the criteria in Annex 1 of the Genetic Engineering Ordinance (GenTSV) as donor and recipient organisms for genetic engineering work . The justification states that V. coralliilyticus is a pathogenic bacterium for mostly aquatic invertebrates. However, based on the findings from infection studies, it cannot be ruled out that its host range also extends to vertebrates. The current ZKBS statement on V. coralliilyticus can be accessed under the reference number 45241.0233 .