Biologic and Serologic Relationships Between Page’s and Sawata’s Serotypes of Haemophilus paragallinarum

Biologic and serologic relationships between Page's serotypes A, B, and C and Sawata's serotypes 1 and 2 of Haemophilus paragallinarum were investigated. Of the 7 Page's serotype strains testes (which were biologically confirmed as H paragallinarum), serotype B strains Spross and 0222 (which produced a low-iridescent smooth-type colony) required V factor, but did not require chicken serum for growth. Serotype A strains 083, W, Georgia, and Germany and serotype C strain Modesto, as well as Sawata's serotype 1 strain 221 and serotype 2 strain H-18 (which produced a high-iridescent smooth-type colony) required V factor and chicken serum for growth. Strains 083, W, Georgia, and Germany of Page's serotype A and Modesto strain of serotype C, as well as strain 221 of Sawata's serotype 1 and H-18 of serotype 2, had a heat-labile, trypsin-sensitive L antigen. Because serotype A strains had serotype 1-specific antigen and common L antigen, which is shared by serotypes 1 and 2, these strains corresponded to Sawata's serotype 1. Serotype C strain Modesto, which had serotype 2-specific antigen and common L antigen, corresponded to serotype 2. However, serotype B strains Spross and 0222 lacked serotype B-specific L antigen, and were not typeable.