bacteria phylogenetically related or commonly occurring
in the aquatic environment (Table 1). Speciesspecific
amplicons of the predicted sizes were observed
for all isolates of F. columnare (504 bp), E.
ictaluri (407 bp) and aerolysin-positive strains of A.
hydrophila (209 bp) (Fig. 1). Amplification of the target
DNA sequences of all 3 bacterial species yielded comparable
band intensities. With the exception of A.
salmonicida subsp. salmonicida, which produced a
209 bp amplification product with the primers specific
for the aerolysin gene, all other bacteria (other than the
3 targeted bacterial species) were found to be negative
by m-PCR (Fig. 1). An amplification product using the
set of universal bacterial primers as a positive control
confirmed the presence of amplifiable bacterial DNA
in the m-PCR negative samples.