Affordable Access

Isolation of an atypical strain of Actinobacillus pleuropneumoniae serotype 1 with a truncated lipopolysaccharide outer core and no O-antigen.

Authors
  • Jacques, Mario
  • Labrie, Josée
  • St Michael, Frank
  • Cox, Andrew D
  • Paradis, Marie-Anne
  • Dick, C Paul
  • Klopfenstein, Christian
  • Broes, André
  • Fittipaldi, Nahuel
  • Gottschalk, Marcelo
Type
Published Article
Journal
Journal of clinical microbiology
Publication Date
Jul 01, 2005
Volume
43
Issue
7
Pages
3522–3525
Identifiers
PMID: 16000496
Source
Medline
License
Unknown

Abstract

A field isolate of Actinobacillus pleuropneumoniae, the causative agent of porcine fibrinohemorrhagic necrotizing pleuropneumonia, was sent to the diagnostic laboratory for serotyping. The isolate presented a clear reaction, with both polyclonal antibodies against serotype 1 and monoclonal antibodies against the capsular polysaccharide of serotype 1. It also exhibited a PCR profile of Apx toxins expected for serotype 1. The isolate, however, failed to react with monoclonal antibodies against the O-antigen of serotype 1 lipopolysaccharide (LPS), suggesting a rough phenotype. The lipid A-core region of the isolate migrated faster than the corresponding region of the serotype 1 reference strain S4074 by Tricine-sodium dodecyl sulfate-polyacrylamide gel electrophoresis, suggesting the presence of a truncated core. Sugar analysis and mass spectrometry analysis of the O-deacylated LPS from the field isolate were consistent with the absence of O-antigen and truncation of the outer core compared to the wild-type reference strain. Experimental infection of pigs confirmed the virulence of the isolate. This is the first report of an isolate of A. pleuropneumoniae serotype 1 with a truncated outer core and a rough LPS phenotype. Veterinary diagnostic laboratories should be vigilant, since infections caused by such an isolate will not be detected by serological tests based on LPS O-antigen.

Report this publication

Statistics

Seen <100 times