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Vibriosis of sea-bass (Vibrio anguillarum)

Diagnosis

Aquarapid diagnostic kit: It is a self contained kit complete with reagents and necessary tubes and pipettes and can be applied on tissues of sick or suspected carrier fish, such as kidney, spleen or liver tissue, in order to detect the presence of the pathogen. It may be used in the field without the need of an equipped laboratory. Only the fish dissecting instruments are required (forceps, scissors, scalpel) in order to sample the tissues. It is the only available tool for mass screening of sea bass fry against asymptomatic carriers of vibriosis. Subsequent to performing the necessary steps, as described in the instructions' leaflet, the results are read on "test spoons" by means of colour change as seen below. Pink to red colouration shows the presence of the pathogen in the tissue sample at varying intensity. A pale yellow colour represents a negative result.

Mono-Aqua diagnostic kit: It comprises a kit complete with reagents and necessary cards in order to perform a quick (30 sec) sero-agglutination test on bacterial colonies that have been isolated on agar plates from the tissues of sick or suspect fish in the laboratory. Thus, it provides a fast and accurate identification of the pathogen bypassing the need to perform biochemical profiling. The kit's main novelty lies in the fact that it provides an additional "negative control antiserum", that is, an antiserum that reacts against bacteria with close antigenic properties with Vibrio anguillarum. Therefore, even when sero-agglutination occurs with the "positive antiserum" it should not happen when the bacterial colony is tried against the negative control antiserum, providing extra confidence for the result. A drop of the antiserum is placed on the dark field of the test card. A bacterial colony is taken from the agar plate with the loop and homogenised for 30 sec. with the antiserum. A positive agglutination is characterised by the formation of a multitude of small round agglutinates, whereas a negative test shows no agglutinate formation.

Biomerieux API 20E biochemical profile system: Most common profiles: 3047524, 3047526, 3247524, 3247526 Vibrio anguillarum most often presents the following results on the API 20E microtube test strip:
Abreviation of microtube substrate	Bacterial strain's biochemical attributes	Result	Triad code
OPNG: ADH: LDC: ODC: CIT: H2S: URE: TDA: IND: VP: GEL: GLU: MAN: INO: SOR: RHA: SAC: MEL: AMY: ARA: OX:	β-galactosidase production Arginine dihydrolase production Lysine decarboxylase production Ornithine decarboxylase production Citrate utilisation H2S production Urease production Tryptophane deaminase production Indole production Acetoin production Gelatinase production Acid from glucose Acid from mannitol Acid from inositol Acid from sorbitol Acid from rhamnose Acid from sucrose Acid from melibiose Acid from amygdalin Acid from arabinose Cytochrome oxidase production	+ + -- -- Variable -- -- -- + + + + + -- + -- + -- -- Variable +	3 0 or 2 4 7 5 2 4 or 6

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