Cambios en el perfil electroforético sérico de Lutjanus analis (Cuvier, 1828) en respuesta a la infección aguda por Listonella (sin. Vibrio) anguillarum

The results of electrophoresis of the blood serum of Lutjanus analis in agarose gel from two groups of fishes: (a) fish exposed to live Listonella anguillarum diluted in 0.9% NaCl solution (saline) by intramuscular injection and (b) control specimens injected with the saline solution are provided. Differences in the serum protein profiles of the two groups of specimens were observed. The method here employed, seems to be useful in detecting potential markers for monitoring infection or inflammatory reactions in L. analis after acute infection by L. anguillarum and has the advantage to allow easy analysis of several samples in a short time.

In Vitro Antibacterial Potential of Salix babylonica Extract against Bacteria that Affect Oncorhynchus mykiss and Oreochromis spp.

Aquaculture development is limited by bacteria associated with several diseases; antibiotics are used for the treatment of these affections, but bacteria have developed resistance to these drugs. It is important to develop effective treatments that allow the production of antibiotic-free food. The aim of the present study is to evaluate the in vitro antibacterial effects of Salix babylonica hydro-alcoholic extract (SbHE) against Aeromonas hydrophila, Listonella anguillarum, Edwarsiella tarda, and Streptococcus iniae, bacteria that affect Oncorhynchus mykiss and Oreochromis spp. production. SbHE was obtained through the maceration technique. Reference strains were used and their sensitivity to antibiotics was determined. Minimal inhibitory concentration (MIC) and minimal bactericidal concentration (MBC) of SbHE were determined. Results showed that three of four evaluated bacteria were multidrug resistant, except S. iniae. SbHE showed antibacterial activity against all bacteria. Results indicate an MIC of 1.56 to 25 mg/mL and an MBC of 3.12 to 100 mg/mL. The greatest inhibitory activity occurred against L. anguillarum obtaining a MIC of 1.56 mg/mL and an MBC of 3.12 mg/mL. Results indicate that SbHE has bactericidal activity against A. hydrophila, L.anguilalurm, and S. iniae as well as bacteriostatic activity against E. tarda and could be an alternative treatment against these bacteria.

Clinical listonellosis in meagre (Argyrosomus regius) from recirculated aquaculture system in Turkey

Vibriosis caused byListonella anguillarumwas reported in several fish species from both fresh and saltwater conditions. This pathogen causes disease in rainbow trout, sea bass, and sea bream in Turkey, however, it has not been reported from meagre (Argyrosomus regius) before. Great loss of meagre was observed in the Recirculated Aquaculture System at the Faculty of Fisheries of Izmir Katip Celebi University, which had been transferred from a commercial hatchery for a nutrition experiment. Clinical signs of vibriosis were observed in infected fish, i.e. haemorrhage in the anal area and pectoral fins, mostly as tail ulcers. Petechial haemorrhages in the muscle, liver, peritoneal membranes and pyloric caeca were determined by necropsy. A Gram-negative, rod-shaped, motile bacterium was isolated, showing a positive reaction to oxidase, catalase and gelatin tests, and being sensitive to O/129. Biochemical identification tests and PCR amplifications identified the bacterium asListonella anguillarum. In slide agglutination test with antiL. anguillarumO1 (ATCC43305) serum, all isolates were positive. The isolated bacteria was resistant to oxytetracycline, sensitive to enrofloxacin, flumequine, phosphomycin, furozulidone, kanamycin and oxolinic acid. In this study, the isolated bacteria from meagre were determined asListonella anguillarumO1 with biochemical, moleculer identification and agglutination tests.

Antimicrobial resistance of Vibrio (Listonella) anguillarum isolatedfrom rainbow trouts (Oncorhynchus mykiss)

Vibrio (also known as Listonella) species are widely distributed in aquatic environments and are often mentioned as the aquatic equivalent of aeromonads. The aim of this study is to investigate the exposure of rainbow trouts with V. anguillarum, and determination of antimicrobial resistance of the isolated strains. A total of 100 rainbow trout (Oncorhynchus mykiss) samples were collected from various commercial fish hatcheries in the Aegean Region of Turkey in June 2013. Twelve V. anguillarum were isolated from 100 rainbow trout (Oncorhynchus mykiss) samples. V. anguillarum isolates were resistant to cloxacillin, ampicillin, sulfamethoxazol-trimethoprime and erythromycin in the ratio of 100 %. High levels of resistance are considered to be the result of random antibiotic therapies in aquaculture, hence the results of this study indicated that identification of etiological agent and the exact chemotherapy must be applied in order to prevent residual water contamination and resistant strains of V. anguillarum.