In vitro haemolytic capacity of representative B. hyodysenteriae field strains. Isolates were grown to an OD600 of 0.250 ± 0.05 (A) and field strains JR11 and JR72 and type strain B78T were also grown to an OD600 of 0.550 ± 0.05 (B). Haemolysis is presented as the mean value of absorption at 450 nm after incubation of the red blood cell suspension with the supernatant of representative B. hyodysenteriae isolates. B. hyodysenteriae strain B78T served as positive control and B. innocens strain C336 was the negative control. Isolates with a significant difference in haemolytic capacity compared to B78T (p < 0.05 after Bonferroni correction) are indicated with an asterisk (*).