Biochemical properties and drug resistance of Aeromonas salmonicida in Finland

Hirvelä-Koski, Varpu; Koski, Perttu; Niiranen, H.

doi:10.3354/dao020191

Cited by 23 publications

(8 citation statements)

References 9 publications

(17 reference statements)

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“…Although Dalsgaard et al. (1998) and Austin & Austin (2007) reported that the majority of atypical A. salmonicida do not degrade aesculin, in our study, all isolates hydrolysed aesculin after 48 h, as also reported by other authors (Dalsgaard & Paulsen 1986; Hirvelä‐Koski, Koski & Niiranen 1994). In addition, our isolates showed divergences from the reference strains in amino acid utilization.…”

Section: Discussionsupporting

confidence: 88%

First description of atypical furunculosis in freshwater farmed Atlantic salmon, Salmo salar L., in Chile

Godoy¹,

Gherardelli²,

Heisinger³

et al. 2010

Journal of Fish Diseases

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We report the first isolation, identification and characterization of a group of Chilean strains of atypical Aeromonas salmonicida isolated from freshwater farmed Atlantic salmon, Salmo salar. Affected fish showed superficial ulcers and pale liver with or without petechial haemorrhages. Outbreaks of the disease occurred in two farms in the south of Chile about 2200 km apart. Five strains were isolated in pure culture and identified by serological assays and immunofluorescence tests as belonging to Aeromonas salmonicida. Although the bacterial isolates were phenotypically homogeneous, minor differences with the reference strain A. salmonicida subsp. salmonicida ATCC 33658 were noted. Three specific primer sets and partial 16S rRNA gene sequencing allowed the identification of the Chilean isolates as atypical A. salmonicida, with A. salmonicida subsp. achromogenes and A. salmonicida subsp. masoucida as their closest relatives (100% sequence similarity). Molecular typing indicated that the atypical isolates belong to two genetic groups that were associated with the geographical origin.

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Section: Discussionsupporting

confidence: 88%

First description of atypical furunculosis in freshwater farmed Atlantic salmon, Salmo salar L., in Chile

Godoy¹,

Gherardelli²,

Heisinger³

et al. 2010

Journal of Fish Diseases

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“…The Finnish AAS isolates from these fish species differ from the well‐characterized AAS causing disease in Atlantic salmon, Salmo salar L., in Iceland (Gudmundsdóttir 1997; Gudmundsdóttir, Hvanndal, Björnsdottir & Wagner 2003). The AAS isolates, phenotypically similar to isolates from Arctic charr and European grayling, have also been obtained from several other fish species in Finland (Hirvelä‐Koski, Koski & Niiranen 1994; Hänninen & Hirvelä‐Koski 1997, 1999).…”

Section: Introductionmentioning

confidence: 84%

Putative virulence factors of atypical Aeromonas salmonicida isolated from Arctic charr, Salvelinus alpinus (L.), and European grayling, Thymallus thymallus (L.)

Madetoja

Pylkkö²,

Pohjanvirta³

et al. 2003

Journal of Fish Diseases

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Atypical Aeromonas salmonicida (AAS) causes generalized lethal infections in farmed Arctic charr, Salvelinus alpinus (L.), and European grayling, Thymallus thymallus (L.), and is thus a serious threat for culture of these fish species. Virulence factors were studied among isolates of AAS from Arctic charr (n = 20), European grayling (n = 19) and other fish species (n = 20), of which 48 were of Finnish and 11 of Swedish origin. All isolates produced an A-layer. Extracellular products (ECP) of the AAS isolates did not produce detectable gelatinase and caseinase activity in test assays. Analysis of the same ECP preparations with substrate sodium dodecyl sulphate-polyacrylamide gel electrophoresis showed weak proteolytic activity, indicating the different sensitivity of the detection methods used. The ECP from AAS isolates showed low cytotoxic activity against cultured cells. However, the ECP did not induce mortality in challenged Arctic charr. The results suggest that toxic components, like ECP, secreted by the bacterium may not be the major virulence factor in AAS-infection in Arctic charr and European grayling, and hence the pathogenesis also differs from the pathogenesis of AAS-infection in Atlantic salmon, Salmo salar L.

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“…The development of resistance to antibiotics among atypical strains has been observed by Hirvela-Koski et al (1994). who found resistance to sulfonamides.…”

Section: Controlmentioning

confidence: 94%

“…Wiklund et al (1992) bMcCarthy (1978, Bohm et al (1986). Olivier (1992) CAustin et al (1989) dPedersen et al (1994, Wiklund et al (1994), Wiklund & Dalsgaard (1995 'Dalsgaard & Fdulsen (1986), Hirvela-Koski et al (1994), Nakatsugatva (1994) McCarthy (1978), Bohm et al (1986) and Olivier (1992) classified the examined atypical strains as subspecies achromogenes and nova. Some important characteristics of these isolates were the same for all strains (Table 2), but subspecies nova seemed to be more fastidious and growth could require up to 5 d incubation at 22'C.…”

Section: Identification and Characterizationmentioning

confidence: 99%

Occurrence and significance of atypical Aeromonas salmonicida in non-salmonid and salmonid fish species:a review

Wıklund¹,

Dalsgaard²

1998

Dis. Aquat. Org.

198

167

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ABSTRACT. Bacterial strains of Aeromonas salmonicida included in the recognized subsp. achromogenes, subsp. masoucida, and subsp. smithia in addition to the large number of strains not included in any of the described subspecies are referred to as atypical A. salmonicida. The atypical strains form a very heterogeneous group w~t h respect to biochemical characteristics, growth conditions, and production of extracellular proteases. Consequently, the present taxonomy of the species A. salmonicida is rather ambiguous. Atypical A. salmonicida has been isolated from a wide range of cultivated and wild fish species, non-salmonids as well as salrnonids, inhabiting fresh water, brackish water and marine environments in northern and central Europe, South Africa. North America. Japan and Australia. In non-salmonid fish species, infections with atypical strains often manifest themselves as superficial skin ulcerations. The best known diseases associated with atypical A. salmonicida are carp Cypnnus carpio erythrodermatitis, goldfish Carassius auratus ulcer disease, and ulcer disease of flounder Platichthys flesus, but atypical strains are apparently involved in more disease outbreaks than previously suspected. Macroscopical and microscopical studies of ulcerated fish indicate internal organs are infrequently invaded by atypical A. salmonicida. This view is supported by the fact that atypical strains are ~rregularly isolated from visceral organs of ulcerated fish. High mortality caused by atypical A. salmonicida has been observed in populations of wild non-salmonids and farmed salmon~ds, although the association between the mortality in the wild fish stocks and atypical A. salmonicida has not always been properly assessed. In injection experiments the pathogenicity of the atypical strains examined showed large variation. An extracellular A-layer has been detected in different atypical strains, but virulence mechanisms different from those described for (typical) A. salmonicida subsp. salrnonicida, for example an extracellular metallo-protease and a different iron utilization mechanism, have been described. Limited information is available about the ecology, spread and surv~val of atypical strains in water. The commonly used therapeutic methods for the control of diseases in farmed fish caused by atypical A. salrnonicida are generally effective against the atypical strains. Resistance to different antibiotics and transferable plasmids encoding multiple drug resistance have been observed in atypical A. salmonicida. Studies aimed at producing a vaccine against atypical strains are in progress.

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Biochemical properties and drug resistance of Aeromonas salmonicida in Finland

Cited by 23 publications

References 9 publications

First description of atypical furunculosis in freshwater farmed Atlantic salmon, Salmo salar L., in Chile

First description of atypical furunculosis in freshwater farmed Atlantic salmon, Salmo salar L., in Chile

Putative virulence factors of atypical Aeromonas salmonicida isolated from Arctic charr, Salvelinus alpinus (L.), and European grayling, Thymallus thymallus (L.)

Occurrence and significance of atypical Aeromonas salmonicida in non-salmonid and salmonid fish species:a review

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