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In this work, we studied a disease outbreak that affected meagre (Argyrosomus regius) at a temperature of 14–15 °C, and that reached a mortality rate of 45% in one week. Moribund fish showed neither external nor internal signs of disease. However, a large number of bacteria, phenotypically similar and in pure culture, were recovered from the liver and kidney. A further phenotypic, genotypic and serological characterization of a selection of three isolates (a828, a834 and a842) allowed the identification of them as Vibrio tapetis. Phylogenetic analysis placed the isolates within the subspecies tapetis, being clearly differentiated from the subspecies britannicus and quintayensis. Nevertheless, all the isolates showed some phenotypic discrepancies with the type strain CECT 4600T; also, they proved to belong to a different O-serotype and genogroup (according to REP-PCR analysis) than the type strain. A virulence evaluation performed in sea bass (Dicentrarchus labrax) by intraperitoneal injection using isolate a828 in two different doses (1 × 105 and 3 × 108 cfu/fish) led to mean mortality rates of 30% and 60%, respectively, corroborating its potential to cause significant mortalities in fish. To our knowledge, this is the first evidence of pathogenic Vibrio tapetis isolates associated with disease outbreaks in meagre.

To date, the genus Psychrobacter consists of 37 recognized species isolated from different sources, however they are more frequently found in cold and other non-polar environments of low water activity. Some strains belonging to the genus have shown different enzymatic activities with potential applications in bioremediation or food industry. In the present study, the whole genome sequences of three Psychrobacter-like strains (C 20.9, Cmf 22.2 and Rd 27.2) isolated from reared clams in Galicia (Spain) are described. The sequenced genomes resulted in an assembly size of 3,143,782 bp for C 20.9 isolate, 3,168,467 bp for Cmf 22.2 isolate and 3,028,386 bp for Rd 27.2 isolate. Among the identified coding sequences of the genomes, mercury detoxification and biogeochemistry genes were found, as well as genes related to heavy metals and antibiotic resistance. Also virulence-related features were identified such as the siderophore vibrioferrin or an aerobactin-like siderophore. The phylogenetic analysis of the 16S rRNA gene suggested that these strains may represent novel species of the Psychrobacter genus. The genome sequences of the Psychrobacter sp. strains have been deposited at DDBJ/EMBL/GenBank under the accession numbers MRYA00000000 (Cmf 22.2), MRYB00000000 (Rd 27.2) and MRYC00000000 (C 20.9), and the sequences could be found at the site https://www.ncbi.nlm.nih.gov/bioproject/PRJNA353858.