Genotypic prevalence of apxIV in Actinobacillus pleuropneumoniae field isolates

A total of 90 Actinobacillus pleuropneumoniae field strains from pigs were serotyped by slide agglutination and analyzed for the presence of the apxlV gene by polymerase chain reaction. Of the 90 isolates serotyped, serotypes 2 (47 isolates) and 5 (25 isolates) were the most common, followed by serotype 6(10 isolates). Three isolates belonged to serotype 7, and 5 isolates could not be typed. All 90 A. pleuropneumoniae field isolates tested carried the apxIV gene. This gene is species specific rather than serotype specific. Therefore, the ApxlV toxin has potential value for use both in vaccines and in diagnostic tests.