530
10–100 cells (equivalent to 2 × 10
3 to 2 × 10
4 cells/g of tissue) in turbot tissue per
PCR reaction was detailed by Powell and Loutit ( 1994a ) used a 310 base pair DNA
fragment as a probe for V. anguillarum. This system detected 100 (but not 10) ng of
purifi ed genomic DNA of most serogroups (not serogroup O7) of V. anguillarum
but did not react with other vibrios. Using the species specifi c. probe in combination
with membrane fi ltration, V. anguillarum could be detected in water (Powell and
Loutit 1994b ). In a parallel development, an oligonucleotide (VaV3) detected
150 ng by DNA:DNA slot blot hybridisation. The system did not cross react with
other species, and was capable of detecting 8 out of 10 serogroups of V. anguillarum
(Martínez-Picardo et al. 1994 ). Using the empA gene, which encodes a zinc metalloproteinase, Xiao et al. ( 2009 ) detected 3.3 × 10
2 CFU/ml of pure culture, and
4.1 × 10
2 in seeded turbot kidney homogenates. The rpoS gene, which is involved
with regulating stress, was incorporated into a PCR which led to the detection of
6 CFU/ml for cultures but was less sensitive when used with genomic DNA from
infected fl ounder (50 ng/g of tissue) and prawn (10 ng/g of tissue) (Kim et al. 2008 ).
González et al. ( 2004 ) used a multiplex PCR and DNA microarray, and achieved the
simultaneous and differential diagnosis of Aer. salmonicida, Ph. damselae subsp.
damselae, V. anguillarum, V. parahaemolyticus and V. vulnifi cus, with a minimum
detection limit of <20 fg per reaction, which equates to 4–5 bacterial cells. A multiplex PCR was developed for the simultaneous detection of Aer. salmonicida, Pis.
salmonis, Str. phocae and V. anguillarum . The detection limit using purifi ed total
bacterial DNA was 50 pg/μl (=3.69 × 10
5 CFU/ml). The limits of detection using
spiked tissues, i.e. kidney, liver, muscle or spleen, were 2.64 ± 0.54 × 10
7 CFU/g
(Tapia-Cammas et al. 2011 ).
Epizootiology
Vibriosis had gained considerable notoriety in mariculture, where it has become a
major limiting factor in the successful rearing of salmonids (Mahnken 1975 ). To
cite one example, in Denmark, the disease has resulted in cumulative losses of 30 %
among eel populations (Bruun and Heiberg 1935 ). This represents a signifi cant economic loss. An authoritative publication reported that vibriosis occurs in more than
14 countries, where it has ravaged approximately 48 species of marine fi sh. Vibriosis
appears to have been confi ned initially in European waters. North America escaped
the ravages of the disease until 1953 (Crosa et al. 1977 ). Its arrival in Japan in 1975
may have resulted from the importation from France of contaminated eels (Muroga
et al. 1976a , b ). Evidence is also accumulating that the disease may occur in freshwater conditions (Muroga 1975 ; Ghittino and Andruetto 1977 ). This suggests that
vibriosis is an extremely widespread problem. Consequently, the literature abounds
with reports of ‘new’ isolations and titbits of gossip, which slowly contribute to an
overall saga. However, it would appear that vibriosis is, in fact, a syndrome caused
by a multiplicity of vibrios (see Schiewe 1981 ). Here, emphasis will be placed on V.
anguillarum.
10 Vibrios
10–100 cells (equivalent to 2 × 10
3 to 2 × 10
4 cells/g of tissue) in turbot tissue per
PCR reaction was detailed by Powell and Loutit ( 1994a ) used a 310 base pair DNA
fragment as a probe for V. anguillarum. This system detected 100 (but not 10) ng of
purifi ed genomic DNA of most serogroups (not serogroup O7) of V. anguillarum
but did not react with other vibrios. Using the species specifi c. probe in combination
with membrane fi ltration, V. anguillarum could be detected in water (Powell and
Loutit 1994b ). In a parallel development, an oligonucleotide (VaV3) detected
150 ng by DNA:DNA slot blot hybridisation. The system did not cross react with
other species, and was capable of detecting 8 out of 10 serogroups of V. anguillarum
(Martínez-Picardo et al. 1994 ). Using the empA gene, which encodes a zinc metalloproteinase, Xiao et al. ( 2009 ) detected 3.3 × 10
2 CFU/ml of pure culture, and
4.1 × 10
2 in seeded turbot kidney homogenates. The rpoS gene, which is involved
with regulating stress, was incorporated into a PCR which led to the detection of
6 CFU/ml for cultures but was less sensitive when used with genomic DNA from
infected fl ounder (50 ng/g of tissue) and prawn (10 ng/g of tissue) (Kim et al. 2008 ).
González et al. ( 2004 ) used a multiplex PCR and DNA microarray, and achieved the
simultaneous and differential diagnosis of Aer. salmonicida, Ph. damselae subsp.
damselae, V. anguillarum, V. parahaemolyticus and V. vulnifi cus, with a minimum
detection limit of <20 fg per reaction, which equates to 4–5 bacterial cells. A multiplex PCR was developed for the simultaneous detection of Aer. salmonicida, Pis.
salmonis, Str. phocae and V. anguillarum . The detection limit using purifi ed total
bacterial DNA was 50 pg/μl (=3.69 × 10
5 CFU/ml). The limits of detection using
spiked tissues, i.e. kidney, liver, muscle or spleen, were 2.64 ± 0.54 × 10
7 CFU/g
(Tapia-Cammas et al. 2011 ).
Epizootiology
Vibriosis had gained considerable notoriety in mariculture, where it has become a
major limiting factor in the successful rearing of salmonids (Mahnken 1975 ). To
cite one example, in Denmark, the disease has resulted in cumulative losses of 30 %
among eel populations (Bruun and Heiberg 1935 ). This represents a signifi cant economic loss. An authoritative publication reported that vibriosis occurs in more than
14 countries, where it has ravaged approximately 48 species of marine fi sh. Vibriosis
appears to have been confi ned initially in European waters. North America escaped
the ravages of the disease until 1953 (Crosa et al. 1977 ). Its arrival in Japan in 1975
may have resulted from the importation from France of contaminated eels (Muroga
et al. 1976a , b ). Evidence is also accumulating that the disease may occur in freshwater conditions (Muroga 1975 ; Ghittino and Andruetto 1977 ). This suggests that
vibriosis is an extremely widespread problem. Consequently, the literature abounds
with reports of ‘new’ isolations and titbits of gossip, which slowly contribute to an
overall saga. However, it would appear that vibriosis is, in fact, a syndrome caused
by a multiplicity of vibrios (see Schiewe 1981 ). Here, emphasis will be placed on V.
anguillarum.
10 Vibrios