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

Ml Martins,A Jatobá,Gf Fezer,Jlp Mouriño,P Garcia,Fn Vieira,Bc Silva,Cc Buglione Neto

doi:10.1590/s1519-69842010000100028

Ml Martins, A Jatobá + Show 6 more

Open Access

https://doi.org/10.1590/s1519-69842010000100028

Copy DOI

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 thiosulphate 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 x 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.

Highlights

The sea horse Hippocampus reidi is native to the Brazilian littoral (Dias and Rosa, 2003), and found fixed on mangrove vegetation, algae, Coelenterata and Bryozoa (Rosa et al, 2007)
Bacterial strains were isolated from an outbreak of sea horses reared at the Aquaculture Department, Federal University of Santa Catarina (UFSC) and the experimental infection occurred at the Research Laboratory of Aquatic Organisms Health, UFSC
Plates were incubated for 24 hours at 30 °C and the colonies were isolated on tryptone soy agar (TSA) to obtain a pure culture for identification with the API 20E (Biomeriux®) kit

Summary

Introduction

The sea horse Hippocampus reidi is native to the Brazilian littoral (Dias and Rosa, 2003), and found fixed on mangrove vegetation, algae, Coelenterata and Bryozoa (Rosa et al, 2007). They can be found near the surface (Rosa et al, 2002) up to 55 m depth (Lourie et al, 1999), distributed along the Atlantic coast from Rio de Janeiro to the Gulf of Mexico (Rosa et al, 2002). According to Monteiro-Neto et al (2003) and Rosa et al (2005, 2006), Brazil is one of the most important exporters of H. reidi

Objectives

Methods

Results