All isolates tested were oxidase negative, catalase positive, Gram
negative, short, rod shaped bacteria with facultative metabolism.
Most (23 of 25, 92%) of the recent (2005–2007) isolates from rainbow
trout and whitefish farms in the Archipelago Sea, as well as all of the
Danish reference isolates, were non-motile and Tween 80-negative,
and were thus considered to be biotype 2 (Table 1). Isolates from fresh
water farmed fish and from the Bothnian Bay were all motile and
Tween 80-positive, i.e. biotype 1.