Antigenic characterization of Enterococcus strains pathogenic for turbot and their relationship with other Gram-positive bacteria

Abstract

We describe here the serological and antigenic characterization of a group of highly virulent Enterococcus strains that, since 1993, have caused heavy economic losses in turbot Scophthalmus maximus reared in northern and northwestern Spain. Reference Gram-positive strains and the corresponding polyclonal antisera raised against some species of lactic acid bacteria as well as Corynebacterium aquaticurn and Renibacterium salmoninarum were included. Agglutination assays demonstrated that regardless of the farm and year of isolation, all strains from turbot were serologically homogeneous. However, a number of cross-reactions occurred among the various groups of bacteria (malnly among Enterococcus, Carnobacterium and Lactobacillus species) Analysis of the surface proteins and western blot assays supported the antigenic homogeneity of the Enterococcus strains isolated from turbot because they all yielded an essentially identical protein pattern (major common bands were 40, 45, and 50 kDa) and reacted similarly with antisera raised against representative strains of this group (there were at least 7 common bands of 20, 25, 30, 40, 45, 57 and 80 kDa). This serological homogene~ty suggests that the development of vaccines to control enterococcosis in turbot should be feasible. Irrespective of the source of the polyclonal antisera employed, common immunoreactive proteins were present in all the Gram-positive bacilli and cocci tested. This, together with the cross-agglutination reactions noted among the various bacterial taxa tested, suggests that serological identification of the turbot Enterococcus using polyclonal antisera could be problematical.

Dormancy as a survival strategy of the fish pathogen Streptococcus parauberis in the marine environment

“…For this study, the isolate RA-99.1 of Streptococcus parauberis, recovered in 1993 from diseased turbot in our laboratory, was chosen as the representative strain since, as previously described (Toranzo et al , 1995, all the fish isolates show a high phenotypic and genetic homogeneity. Reference strain S. parauberis NCDO 2020, isolated from cattle in 1995, was included in all the experiments for comparative purposes.…”

“…Reference strain S. parauberis NCDO 2020, isolated from cattle in 1995, was included in all the experiments for comparative purposes. The phenotypic and serological characteristics of the isolates have been described elsewhere (Toranzo et al , 1995.…”

“…In 1993, there was an important epizootic outbreak of streptococcosis in turbot Scophthalmus maximus cultured in Galicia (NW Spain) that was initially thought to be caused by an Enterococcus specieslike bacterium . From 1993 to 1996, the disease was the main limiting factor of the turbot culture in Spain (Toranzo et al 1995, Romalde et al 1996. Characterization studies, including phenotypic, serological and genetical aspects, have been carried out showing a great homogeneity of the isolates regardless of their farm and year of isolation , Romalde et al 1999a.…”

Characterization of Drug Resistance in Streptococcus parauberis Isolated from Japanese Flounder

“…Doménech et al (1996) was the first to identify S. parauberis as a fish pathogen for the isolates from diseased turbot Scophthalmus maximus by analyzing the 16S rRNA gene. Another group reported that this pathogen caused high economic losses in turbot culture in Spain (Toranzo et al, 1995). Since then, streptococcicosis caused by S. parauberis had been limited to turbot and Japanese flounder Paralichthys olivaceus cultured in Spain and Korea, respectively (Toranzo et al, 2005;Baeck et al, 2006).…”

Lactococcus garvieae and Streptococcus iniae infections in rainbow trout Oncorhynchus mykiss:similar, but different diseases

“…Epidemic and sporadic diseases have been reported from different parts of the world, notably Japan (Kitao 1993), Singapore (Foo et al 1985). Australia (Carson et al 1993), Israel (Eldar et al 1995), Italy (Ghittino & Prearo 1992), Spain (Toranzo et al 1995, Domenech et al 1996, France (Michel et al 1997), South Africa (Braag & Broere 1986) and the United States (Perera et al 1994). Amended taxonomy reveals that at least 6 different species of Gram-positive cocci, including streptococci (Pier & Madin 1976, Domenech et al 1996, lactococci (Collins et al 1984, Williams et al 1990, Domenech et al 1993, Eldar et al 1996, and vagococci (Wallbanks et al 1990), are responsible for such conditions.…”