Isolation and experimental infection with Vibrio alginolyticus in the sea horse, Hippocampus reidi Ginsburg, 1933 (Osteichthyes: Syngnathidae) in Brazil

Abstract

The aim of this study was to evaluate the pathogenicity of Vibrio alginolyticus isolated from an outbreak of sea horse Hippocampus reidi reared in the State of Santa Catarina, Brazil, by experimental infection. Sea horses with necrosis on the mouth epithelium were collected from aquaria at the Aquaculture Department, UFSC and the bacterium isolated from the mouth, liver, heart and blood in tiosulphate citrate bilesalt sucrose agar broth. The strains were identified by API 20E kit with 99.1% probability as Vibrio alginolyticus. Twelve adult sea horses (9.63 ± 2.42 g and 15.12 ± 0.87 cm) were distributed in six aquaria of 10 L capacity with aerated sea water. Fish from three aquaria were submitted to an immersion bath in a solution containing 1.0 × 10 7 CFU of V. alginolyticus/mL for 15 minutes. Fish from the other three aquaria received the same procedure without bacteria. Twenty four hours after this challenge, 100% mortality was observed in the animals infected with V. alginolyticus. No mortality was observed in non-infected fish. Hyperplasia, displacement and fusion of secondary lamellae of the gills; leukocyte infiltration and necrotic foci in the kidney; hyperplasia, sinusoidal deformation and necrotic foci in the liver were observed in histopathological analysis. The V. alginolyticus isolated in this study was pathogenic to H. reidi and constitutes an important sanitary problem to its culture.Keywords: experimental infection, vibriosis, histopathology. Isolamento e infecção experimental de Vibrio alginolyticus em cavalo-marinho,Hippocampus reidi Ginsburg, 1933 (Osteichthyes: Syngnathidae) no Brasil ResumoFoi avaliado por meio de infecção experimental a patogenicidade de Vibrio alginolyticus isolado de um surto de enfermidade em cavalo-marinho Hippocampus reidi cultivado no Estado de Santa Catarina, Brasil. Os peixes com necroses no epitélio bucal foram coletados em aquários do Departamento de Aquicultura, UFSC e as bactérias isoladas da boca, fígado, coração e sangue em meio Agar tiossulfato citrato bile sacarose. Os isolados foram identificados pelo kit API 20E como Vibrio alginolyticus com 99,1% de probabilidade. Doze peixes adultos (9,63 ± 2,42 g e 15,12 ± 0,87 cm) foram distribuídos em seis aquários de 10 L com água marinha e aeração. Peixes de três aquários foram submetidos a um banho de imersão por 15 minutos em uma solução contendo 1,0 × 10 7 UFC de V. alginolyticus/ mL. Nos outros três aquários realizou-se o mesmo procedimento sem a bactéria. Vinte e quatro horas após o desafio, 100% de mortalidade foi observada nos animais infectados com V. alginolyticus. Não houve mortalidade nos peixes não infectados. Nas análises histopatológicas, foi observado hiperplasia, deslocamento do epitélio e fusão das lamelas secundárias das brânquias; infiltração de leucócitos e necrose no rim; hiperplasia, deformação sinusoidal e necrose no fígado nos animais desafiados com V. alginolyticus. O V. alginolyticus isolado neste estudo foi patogênico para H. reidi, constituindo-se de um importante problema para seu...

A novel pathogenic bacteria (Vibrio fortis) causing enteritis in cultured seahorses, Hippocampus erectus Perry, 1810

“…Some other Vibrio species have been identified in seahorses, for example V. alginolyticus in H. reidi , H. guttulatus and H. hippocampus (Balcázar ; Martins et al . ), V. splendidus in H. guttulatus and H. hippocampus (Balcázar et al . ), V. harveyi in H. kuda (Alcaide et al .…”

Comparison of Intestinal Microbiota in Intestinal Tracts of the Wild and Cultured Seahorses, Hippocampus trimaculatus (Leach)

“…Other Vibrio such as Vibrio alginolyticus , Vibrio harveyi , Vibrio hippocampi sp. nov., V. parahemolyticus , and Vibrio splendidus have been found to be pathogens in Hippocampus guttulatus , Hippocampus hippocampus , H. kelloggi , H. kuda , and Hippocampus reidi (Alcaide et al ; Tendencia ; Yang et al ; Balcázar et al ; Martins et al ; Raj et al ). Together with the previous studies, this finding indicated that the intestinal bacteria of Vibrio , especially the V. parahaemolyticus strain CM12 may be the most important pathogen of intestinal diseases in the cultured seahorses H. trimaculatus .…”

A bacterial infection by Vibrio harveyi causing heavy reduction of cultured lined seahorse Hippocampus erectus

“…Vibriosis in seahorses has been previously reported, but all were involved in the experimental breeding or aquariums, and several Vibrio species including V. alginolyticus (Martins et al . ), V. splendidus (Balcazar et al . ) and V. fortis (Wang et al .…”