Atypical characteristics of the salmonid pathogen Aeromonas salmonicida.

Incubation of Aeromonas salmonicida at supra-optimal temperatures, i.e. 30-37 degrees C, resulted in the expression of motility by polar flagella, and changes in sugar fermentation patterns, e.g. loss of acid production from mannitol, loss of the ability to degrade complex molecules (aesculin, DNA, elastin and gelatin), and an increase in antibiotic resistance (notably co-trimoxazole). Motility was enhanced in cultures grown in brain heart infusion broth supplemented with 18% (w/v) Ficoll.