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 apxIV gene by polymerase chain reaction. Of the 90 isolates serotyped, serotypes 2 (47 isolates) and 5 (25 isolates) were the most common, followed by sero type 6 (10 isolates). Three isolates belonged to serotype 7, and 5 isolates could not be typed. All 90 A. pleuropneumoniae field isolates tested carri ed the apxIV gene. This gene is species specific rather than serotype speci fic. Therefore, the ApxIV toxin has potential value for use both in vaccine s and in diagnostic tests.