Strain discrimination of a novel serotype of Salmonella from harbour porpoises (Phocoena phocoena) by molecular techniques

The relatedness of 41 isolates of Salmonella of a novel serotype (antigenic formula 4,12:a:-) of serogroup B, obtained from harbour porpoises (Phocoen a phocoena) stranded at various sites around the coastline of Scotland, was assessed by two molecular typing methods. Ribotyping showed that these iso lates belonged to seven EcoRI (E) ribotypes and 11 PstI (P) ribotypes that were, in each case, distinct but closely related. Combined ribotyping data identified 15 different E/P ribotypes, the most common of which, E1/P1, was represented by 15 isolates from 14 animals stranded on both east and west coastlines. Strain discrimination achieved by E/P ribotyping was high (D=0. 84). IS200 profiling revealed only three different fingerprints and strain discrimination by this method alone was poor (D=0.39). When E/P ribotyping and IS200 profiling were used together, they revealed the existence of 17 d ifferent types among the 41 isolates which formed two distinct, but related , groups of Salmonella serotype 4,12:a:-. This information should prove hel pful in future studies examining the mode of transmission of this novel sal monella serotype and its association with disease in harbour porpoises. (C) 2000 Elsevier Science B.V. All rights reserved.