Detection of Actinobacillus pleuropneumoniae by PCR on field strains from healthy and diseased pigs.
We investigated whether primers able to specifically amplify a 0.7-kb DNA fragment from the conserved cpx genes could be applied to analyze A. pleuropneumoniae field isolates. The specific cpx primers were tested on 120 strains of A. pleuropneumoniae and other NAD-dependent field isolates from healthy and diseased animals to analyze A. pleuropneumoniae isolates from pigs in Brazil. We found that PCR and hybridization were able to discriminate between isolates of A. pleuropneumoniae and other bacteria. The 0.7-kb cpx DNA fragments were amplified from all 63 A. pleuropneumoniae isolates from herds with clinical symptoms and were isolated from lesions of acute cases of swine pleuropneumonia, both serotypable and nonserotypable. The PCR was also applied to 57 field isolates obtained from animals of apparently healthy herds, and the amplified cpx product was present in four serotypable and only two out of eleven A. pleuropneumoniae nonserotypable isolates. All nonserotypable A. pleuropneumoniae isolates revealed the apxA amplification pattern compatible with previously known serotypes. Some nonserotypable isolates might represent a population of isolates that originally were serotypable but lost the ability to react with serotype-specific antisera or might belong to novel serotypes. The PCR method applied is highly sensitive for serotypable A. pleuropneumoniae strains and for nonserotypable strains isolated from acute cases of swine pleuropneumoniae in Brazil.
Centro de Biotecnologia, Universidade Federal do Rio Grande do Sul, Av Bento Gonçalves, 9500, Prédio 43421, CP 15005, CEP 91501-970, Porto Alegre, RS, Brazil.
Catia Silene
CS
Klein
Itamar Antônio
IA
Piffer
Sérgio
S
Ceroni da Silva
Augusto
A
Schrank
Maria Bernardete Burin
MB
Fávero
Irene Silveira
IS
Schrank
D000189:Actinobacillus Infections / Q000175:diagnosis / Q000382:microbiology / Q000662:veterinary*; D016977:Actinobacillus pleuropneumoniae / Q000235:genetics / Q000302:isolation & purification*; D000818:Animals; D015139:Blotting, Southern / Q000662:veterinary; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics; D011002:Pleuropneumonia, Contagious / Q000175:diagnosis / Q000382:microbiology*; D016133:Polymerase Chain Reaction / Q000379:methods / Q000662:veterinary; D012680:Sensitivity and Specificity; D017422:Sequence Analysis, DNA; D012703:Serotyping / Q000662:veterinary; D013552:Swine / Q000382:microbiology*; D013553:Swine Diseases
D004269:DNA, Bacterial