Vibrios in hatchery cultures of the razor clam, Solen marginatus (Pulteney)

Abstract

Hatchery culture of the razor clam, Solen marginatus (Pulteney), has recently been developed in Galicia (NW Spain). However, recurrent episodes of mortalities of larval and post-larval cultures have been recorded during the course of various studies. The disease signs were similar to those described for other bivalve species in outbreaks caused by bacteria of the genus Vibrio. In this article, we present the results of microbiological monitoring of two batches of razor clams with different survival rates. All fermentative isolates were identified as members of the Splendidus clade within the genus Vibrio. Some of these isolates, identified as Vibrio splendidus-like, were clearly associated with the batch suffering mortalities, indicating their possible role as pathogens. Similar strains were found in the broodstock, suggesting vertical transmission of these bacteria. This is the first study of the microbiota associated with hatchery culture of S. marginatus, and the results will provide useful information for the optimization of a protocol for hatchery culture of this bivalve species.

Microbial Diseases of Bivalve Mollusks: Infections, Immunology and Antimicrobial Defense

“…), Pseudomonas and Aeromonas [22,23,24,25]. These bacteria are responsible for bacillary necrosis in a wide range of species of bivalve larvae [26].…”

Mortality event involving larvae of the carpet shell clam Ruditapes decussatus in a hatchery: isolation of the pathogen Vibrio tubiashii subsp. europaeus

“…Genetic characterization of isolates was performed by sequencing of the 16S rRNA gene as previously described (Prado et al . ). The Instagene kit (Bio‐Rad) was used to extract and purify DNA from pure isolates cultured for 24 h at 24 ± 1 °C on MA.…”

“…The TCBS isolates were phenotypically characterized (Prado et al . ) by tests for cell morphology and motility, oxidase, catalase, Gram reaction, growth in TCBS, glucose oxidation–fermentation in ZOF, amino acid decarboxylation in Moeller's medium, nitrate reduction, indole production and methyl‐red tests. The extracellular enzyme activities were examined using starch, aesculin, gelatine and Tween‐80.…”

New Insights into Pathogenic Vibrios Affecting Bivalves in Hatcheries: Present and Future Prospects

“…In hatcheries, antimicrobial agents have routinely been applied to water to treat and prevent disease, particularly during the first stages of bivalve development (Prado et al, 2014a; Dubert et al, 2016c). Therefore, antimicrobial agents as florfenicol, erythromycin, oxolinic acid and specially chloramphenicol are used in bivalve hatcheries to prevent the vibriosis and to improve the survival rates of larvae and juveniles (Lodeiros et al, 1987; Nicolas et al, 1996; Uriarte et al, 2001; Torkildsen et al, 2005; Campa-Córdova et al, 2006; Miranda et al, 2014; Dubert et al, 2016c).…”

“…Special attention should be focused on seawater, the common nexus among different compartments, which is generally renewed in larval and spat tanks every 2 days after filtration and UV-sterilization. In addition, and due to their filter feeding nature, bivalves act as a bacterial reservoir, including vibrios, and can release them to the seawater even after every renewal (Prado et al, 2014a). Broodstock, phytoplankton or seawater are key players in the Vibrio dissemination within the hatchery, especially to larval and spat cultures (Beaz-Hidalgo et al, 2010; Prado et al, 2014a; Romalde et al, 2014; Dubert et al, 2015, 2016a; Holbach et al, 2015).…”