Insights on the virulence mechanisms of European Edwardsiella tarda strains isolated from turbot

• Published in: Frontiers in Marine Science
• Main Authors: Nuria Castro Iglesias, Carlos Jimenez Gonzalez
• Format: Article in Journal/Newspaper
• Language: English
• Published: Frontiers Media S.A. 2014
• Subjects: Edwardsiella tarda; Pathology; Quorum Sensing; Virulence Factors; vibrioferrin; chondroitinase; Science; Q; General. Including nature conservation; geographical distribution; QH1-199.5; Turbot
• Online Access: https://doi.org/10.3389/conf.fmars.2014.02.00110; https://doaj.org/article/80596034814641f581db066c7823e68d

Edwardsiella tarda is a common inhabitant of diverse ecological niches as well as a common guest of a high variety of animals including fish, reptiles, amphibians, chickens and other warm-blooded animals as humans. With regard to the aquatic environments, E. tarda has been described as the causative agent of infections in more than 20 fish species including some important fish species in aquaculture industry. Several potential pathogenic properties have been suggested to contribute to the infection process of E. tarda , which include adhesins, Type III and Type VI secretion system, and ability to survive and replicate in phagocytes, among others. Identification of these virulence-related genes is essential for understanding the pathogenesis of the species. Since E. tarda causes great losses in the Chinese aquaculture, great efforts have been recently devoted to study the pathogenicity mechanism of E. tarda in Asian countries. However, all these studies were conducted employing Asian isolates. Being E. tarda a pathogen of great economical concern in European turbot aquaculture and since the high intraspecific variability of E. tarda is well known, it becomes evident that additional pathogenicity studies conducted with non-Asiatic strains are needed. Enzymes such as chondroitinase are believed to play an important role in the pathogenicity of bacteria that cause infections (Tam et al ., 1982). Chondroitinase activity was proposed to be one virulence contributor in Edwardsiella spp. and mediates the cartilage degradation in the chronic “hole-in-the-head” lesion. In Gram-negative bacteria, the most intensively studied quorum sensing systems rely on the use of N-acylhomoserine lactones (AHLs), which production is common among marine and fish pathogenic Proteobacteria, controlling the expression of key virulence factors. In the case of E. tarda , strain NUF251 from diseased flounder had the ability to produce two kinds of AHL molecules. It is likely that the QS system of E. tarda controls the production of various ...