SPECIFIC DETECTION OF THE GENUS SERPULINA, S-HYODYSENTERIAE AND S-PILOSICOLI IN PORCINE INTESTINES BY FLUORESCENT RIBOSOMAL-RNA IN-SITU HYBRIDIZATION

A fluorescent-labelled in situ hybridization method targeting rRNA was devised to facilitate specific identification and diagnosis of diarrh oea and colitis in pigs caused by the genus Serpulina, as well as to d istinguish the species Serpulina hyodysenteriae and Serpulina pilosico li in formalin-fixed colon tissue sections. A genus-specific oligonucl eotide probe SER1410 targeting the five species of porcine Serpulina w as thus designed. Furthermore, species specific oligonucleotide probes (Hyo1210, Pilosi209 and Pilosi1405) were also designed to detect, ide ntify and differentiate S. hyodysenteriae and S. pilosicoli. These pro bes clearly demonstrated and possessed the desired specificity, when e valuated by whole cell hybridization on five reference strains and 20 isolates covering the five species of porcine Serpulina. Furthermore, the oligonucleotide probes were specific when used both, for the detec tion of Serpulina isolates at genus level as well as for specific dete ction of S. hyodysenteriae and S. pilosicoli in formalin-fixed colon t issue sections from pigs suffering from swine dysentery and porcine co lonic spirochaetosis, respectively. Tissue sections were also used fro m pigs without any intestinal disorders as controls for estimating the specificity of the probes. The probes developed in this study thus ha d the potential of specific identification and histological recognitio n obtained in the formalin-fixed tissue samples. (C) 1998 Academic Pre ss.