Serotyping of Pasteurella multocida isolated from swine lungs collected at slaughter

Abstract

To define the most prevalent serotypes and aid the preparation of more adequate vaccines, 222 P. multocida strains isolated from swine lungs at slaughter were serotyped. Capsular serotypes A and D were determined by the hyaluronidase sensitivity and acriflavin agglutination tests, respectively. Somatic antigens were determined by gel diffusion against standard antisera. Capsular serotype A was found in 97.3% of the strains and serotype D in the remaining 2.7%. The primary somatic antigen most commonly found was type 3 (86.0%). Type 5 was also very common (88.7%), but was usually a secondary antigen. The most common overall serotype was A:3(5) (39.2%). Other common serotypes were: A:3(4,5,12) (12.2%); A:3(4,5) (11.2%); A:3(5,12) (10.4%); A:3 (6.8%); and A:5 (6.8%). Type D strains had a similar distribution of serotypes, but with a higher prevalence of D:5 (33.3%) and D:3(5) (33.3%).