Real-time PCR detection of Moritella viscosa, the likely causal agent of winter-ulcer in Atlantic salmon Salmo salar and rainbow trout Oncorhynchus mykiss.
We report the development of a real-time PCR protocol for specific detection of Moritella viscosa. This bacterium is considered to be the main aetiological agent in development of winter-ulcer, a disease severely affecting salmonid aquaculture in Norway. From a newly elaborated draft version of the genome of M. viscosa, the tonB gene sequence was selected as a suitable basis for the development of the real-time PCR assay. The real-time PCR demonstrated the presence of M. viscosa DNA sequences in 88.1% of samples collected from 35 outbreaks of winter-ulcer in Norwegian fish farms. In contrast, standard culturing on blood agar identified M. viscosa in only 39.7% of fish. While the culturing method revealed a similar prevalence (26 to 27%) of M. viscosa in kidney and ulcer samples, substantially more ulcer (81.5%) than kidney (49.7%) samples were shown positive by real-time PCR.
Grove
S
S
National Veterinary Institute, PO Box 8156 Dep, 0033 Oslo, Norway. soren.grove@vetinst.no
Reitan
L J
LJ
Lunder
T
T
Colquhoun
D
D
D000818:Animals; D001431:Bacteriological Techniques; D005393:Fish Diseases / Q000382:microbiology*; D016905:Gram-Negative Bacterial Infections / Q000382:microbiology / Q000662:veterinary*; D034221:Moritella / Q000302:isolation & purification*; D017686:Oncorhynchus mykiss; D016133:Polymerase Chain Reaction / Q000662:veterinary*; D020317:Salmo salar; D012680:Sensitivity and Specificity