Coastal environments are increasingly recognised as reservoirs of known antibiotic resistance genes (ARGs), but are less frequently identified as sources of novel ARGs. Here, we investigated class A β‐lactamases circulating in European coastal environments used for oyster farming. We examined their diversity, function, and the ecological factors associated with their geographic distribution and environmental dynamics. A high d...

Summary A major debate in evolutionary biology is whether virulence is maintained as an adaptive trait and/or evolves to non‐virulence. In the environment, virulence traits of non‐obligatory parasites are subjected to diverse selective pressures and trade‐offs. Here, we focus on a population of Vibrio splendidus that displays moderate virulence for oysters. A MARTX (Multifunctional‐autoprocessing repeats‐in‐toxin) and a type‐s...

Summary Pacific oyster mortality syndrome affects juveniles of Crassostrea gigas oysters and threatens the sustainability of commercial and natural stocks of this species. Vibrio crassostreae ( V . crassostreae ) has been repeatedly isolated from diseased animals, and the majority of the strains have been demonstrated to be virulent for oysters. In this study, we showed that oyster farms exhibited a high prevalence of a virule...

Summary Oyster diseases caused by pathogenic vibrios pose a major challenge to the sustainability of oyster farming. In F rance, since 2012 a disease affecting specifically adult oysters has been associated with the presence of V ibrio aestuarianus. Here, by combining genome comparison, phylogenetic analyses and high‐throughput infections of strains isolated before or during the recent outbreaks, we show that virulent strains...

Summary Vibrioses are the predominant bacterial infections in marine shrimp farms. Vibrio nigripulchritudo is an emerging pathogen of the cultured shrimp Litopenaeus stylirostris in New Caledonia and other regions in the Indo‐Pacific. The molecular determinants of V. nigripulchritudo pathogenicity are unknown; however, molecular epidemiological studies have revealed that recent pathogenic V. nigripulchritudo isolates from New...