Isolation and characterization of Flavobacterium columnare (Bernardet et al. 2002) from four tropical fish species in Brazil

Abstract

Flavobacterium columnare is the causative agent of columnaris disease in freshwater fish, implicated in skin and gill disease, often causing high mortality. The aim of this study was the isolation and characterization of Flavobacterium columnare in tropical fish in Brazil. Piracanjuba (Brycon orbignyanus), pacu (Piaractus mesopotamicus), tambaqui (Colossoma macropomum) and cascudo (Hypostomus plecostomus) were examined for external lesions showing signs of colunmaris disease such as greyish white spots, especially on the head, dorsal part and caudal fin of the fish. The sampling comprised 50 samples representing four different fish species selected for study. Samples for culture were obtained by skin and kidney scrapes with a sterile cotton swabs of columnaris disease fish and streaked onto Carlson and Pacha (1968) artificial culture medium (broth and solid) which were used for isolation. The strains in the liquid medium were Gram negative, long, filamentous, exhibited flexing movements (gliding motility), contained a large number of long slender bacteria and gathered into 'columns'. Strains on the agar produced yellow-pale colonies, rather small, flat that had rhizoid edges. A total of four Flavobacterium columnare were isolated: 01 Brycon orbignyanus strain, 01 Piaractus mesopotamicus strain, 01 Colossoma macropomum strain, and 01 Hypostomus plecostomus strain. Biochemical characterization, with its absorption of Congo red dye, production of flexirubin-type pigments, H 2 S production and reduction of nitrates proved that the isolate could be classified as Flavobacterium columnare. Keywords

First identification of Flavobacterium columnare infection in farmed freshwater striped catfish Pangasianodon hypophthalmus

“…The mortality rates may vary due to virulence expression of the different bacterial strains as well as varied host response. This was also found in the present study but the differences observed in the mortality rate were not statistically evaluated, and further work is required to fully explore differences in virulence factors associated with Vietnamese F. columnare strains, where studies similar to those reported by Decostere et al (1999) Pilarski et al (2008) and Kunttu et al (2009). All yellow-pigmented isolates in the present study, whether originating from natural outbreaks or recovered from experimental challenge, were identified as F. colum nare using bacterial identification tests and confirmed using 16S rDNA PCR.…”

“…Ultimately, bacterial colonisation leads to tissue erosion (Wakabayashi 1993). Although the clinical signs are not pathognomonic for the disease, affected fish more commonly present with tail erosion, whitish spots on the body and greyish gills (Shotts & Starliper 1999, Pilarski et al 2008. F. columnare have been more commonly isolated from the external surfaces of affected animals (Foscarini 1989, Austin & Austin 1993, McElwain et al 2009).…”

Hematology and productive performance of nile tilapia (Oreochromis niloticus) naturally infected with Flavobacterium columnare

“…Thus, the infected fish presented weights and lengths that were significantly smaller than those of the healthy fish. It was therefore seen that the bacterium had a negative effect on the productive performance index, thereby reducing the growth and weight gain of the infected fish and causing low productivity and economic losses (28). The columnaris disease did not significantly influence the mean erythrocyte count, hematocrit percentage or hemoglobin rate in the tilapia, as can be seen in Table 2.…”

Difference in genes between a high virulence strain G4 and a low virulence strain G18 of Flavobacterium columnare by using suppression subtractive hybridization

“…Flavobacterium columnare , the causative agent of columnaris disease, is a significant pathogen of wild and cultured fish species because of its broad geographic distribution and its ability to infect a wide range of freshwater fish species (e.g. Anonymous 1975; Figueiredo, Klesius, Arias, Evans, Shoemaker, Pereira & Peixoto 2005; Pilarski, Rossini & Ceccarelli 2008). Fish infected with this bacterium often have necrotic skin and fins and gill lesions, with a high degree of mortality (Decostere, Haesebrouck & Devriese 1998).…”