SDS-PAGE profiles of representative H. parasuis strains. Gradient SDS-PAGE gels of WCP lysates were stained with Coomassie Brilliant Blue R250. Reference strains A-O are described in Table 1. Reference strains were obtained between 1978 and 1990. Field strains 1–31 are described in Table 2. Field strains 1–24, 25–29, 30–31 were obtained in 2004, 1999, and 1984, respectively. Each lane was loaded with 10 μg of protein. Molecular weights (MW) are indicated in kilodaltons.