[Identification of Pasteurella serotypes by indirect hemagglutination]

The indirect haemagglutination test was used for serological type identification of Pasteurella strains. The Pasteurella multocida strains were tested by parallel application of antigen production methods (common method plus hyaluronidase treatment). Thirty-nine (72.2 per cent) of 54 Pasteurella multocida strains, which had been obtained from cattle and swine, were serologically tested by the common technique of antigen production, their types being identified, while 42 (77.7 per cent) were tested and typed by means of hyaluronidase treatment. Depolimerisation of hyaluronic acid by means of hyaluronidase increased the agglutinability of eight strains (14.8 per cent) which could thus be identified by types. Serological identification of 47 (87.1 per cent) Pasteurella multocida strains was achieved by parallel use of the two antigen production methods. Identification was not possible of two strains. Cross-reaction was recorded from five strains. Most of the Pasteurella multocida strains isolated from cattle were A serotype (54 per cent), while those of swine were B strains (50 per cent). Thirty-six of 40 serologically tested Pasteurella haemolytica strains were serotypes A1, A2, T3, T4, A5, and A6, and most of these were A5 and T4.