EVALUATION OF MICROAGGLUTINATION TEST FOR DIFFERENTIATION BETWEEN SERPULINA (TREPONEMA) HYODYSENTERIAE AND S-INNOCENS AND SEROTYPING OF S-HYODYSENTERIAE

Swine dysentery is a mucohemorrhagic diarrheal disease caused by the a naerobic spirochete Serpulina hyodysenteriae. At present, the serotypi ng is done by immunodiffusion testing with lipopolysaccharide (LPS) ex tract as antigen and rabbit hyperimmune sera produced against differen t serotypes of S. hyodysenteriae. Since the preparation of LPS is time -consuming and requires a large quantity of bacteria, it is desirable to use a serotyping method which does not require the extraction of LP S. In the present investigation, microagglutination was evaluated by u sing Both formalinized whole- and boiled cell suspensions as antigens and rabbit hyperimmune sera produced against formalinized whole-cell s uspensions of reference strains of S. hyodysenteriae and S. innocens B 256; Use of boiled cell suspension as antigen permitted the differenti ation between isolates of S. hyodysenteriae and S. innocens as well as serotyping of S. hyodysenteriae strains accurately. A total of 18 iso lates were identified as S. hyodysenteriae, and 3 isolates were identi fied as S. innocens. The microagglutination test was found specific, s ensitive, and easy Co perform; thus, it was judged suitable for routin e identification and serotyping of S. hyodysenteriae isolates.