Infectious Pancreatic Necrosis Virus (IPNV) - Fróðskaparsetur Føroya

During our work, we observed that sample 6C (a sample from fjord C) was lacking
haemolysis on blood agar, but was positive both on OCLA and in AccuProbe. Then we plated
the sample on RAPID'L.mono plate, where L. monocytogenes should form blue colonies.
However, the bacteria formed white colonies (Figure 3). We therefore sequenced PCR
products from the six virulence genes, but the sequences were consistent with L.
monocytogenes.
When all the samples were sequenced, and we combined all the genes from the same samples,
they were aligned using ClustalX and genetic distance was shown graphically using
TreeView. The only gene fragment that we did not manage to amplify by PCR was inlA for
sample 5A. So we did two TreeWiew images one using all the genes, were we had to exclude
sample 5A (Figure 4) and one using all the samples but excluded gene inlA (Figure 5). Two
old swab samples from 2009 (from the same processing plant) were included for comparison.
The greater the horizontal distance between two samples is in the tree, the greater is the
genetic difference between the samples.
Figure 3: RAPID'L.mono TM plates. Left plate
showing sample 6C with white colonies and
right plate with blue colonies, as they should
be if they are L. monocytogenes.
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