Copyright C 1993, American Society for Microbiology Serotype Identification of Actinobacillus pleuropneumoniae by Arbitrarily Primed Polymerase Chain Reactiont

Rapid and accurate determination of the Actinobacilus pleuropneumoniae serotype involved in a disease outbreak is important both in limiting the severity of an outbreak and for tracing the source of the infecting organism. This study describes the use of arbitrarily primed polymerase chain reaction (AP-PCR) as a rapid, precise, and genetically based procedure to identify A. pleuropneumoniae. AP-PCR amplification of bacterial genomic DNA results in specific DNA profiles, which can be used to differentiate currently recognized serotypes. This technique is especially useful for identifying previously nontypeable and serologically cross-reactive A. pleuropneumoniae field isolates. Consecutive passages of isolates on different media, freezing, and subsequent infection of pigs did not alter the AP-PCR genomic profile. We propose the use of M13 and T3-T7 oligodeoxynucleotide primers for diagnostic and epidemiological identification ofA. pleuropneumoniae by AP-PCR techniques. Actinobacillus pleuropneumoniae is the etiologic agent of contagious porcine pleuropneumonia, a severe and often fatal respiratory disease of pigs (13, 23, 29). Pigs that survive infection with one serotype ofA. pleuropneumoniae develop resistance to infection by any other serotype (15, 16), although surviving animals often become asymptomatic car-riers. Immunization reduces mortality and severity of the disease but routinely fails to prevent infection (15, 18). Immunized animals may become asymptomatic carriers of the organism (15), and, because of the serotype specificity of vaccination-induced immunity (15-18), these pigs can be infected by otherA. pleuropneumoniae serotypes from other asymptomatic carriers. Twelve serotypes of A. pleuropneumoniae biotype 1 (V-factor dependent) have been identified on the basis of immunologically unique capsular and lipopolysaccharide an