<em>P. multocida</em> lipopolysaccharide outer core genetics and polymorphism: simultaneous expression of multiple LPS glycoforms that mimic the Globo series of vertebrate glycosphingolipids.  — ASN Events
  1. Schedule
  2. Symposium 6 - The Varied Roles of Bacterial Surface Structures: Biofilms and More
  3. P. multocida lipopolysaccharide outer core genetics and polymorphism: simultaneous expression of multiple LPS glycoforms that mimic the Globo series of vertebrate glycosphingolipids. 

P. multocida lipopolysaccharide outer core genetics and polymorphism: simultaneous expression of multiple LPS glycoforms that mimic the Globo series of vertebrate glycosphingolipids.  (#134)

Marina Harper 1 , Frank St Michael 2 , Marietta John 1 , Conny Turni 3 , Pat J Blackall 3 , Ben Adler 1 , Andrew D Cox 2 , John D Boyce 1
  1. Monash University, Clayton, VIC, Australia
  2. Institute for Biological Sciences, National Research Council, Ottawa, ON, Canada
  3. Queensland Alliance for Agriculture and Food Innovation, The University of Queensland, Brisbane, QLD, Australia

P. multocida is a Gram-negative capsulated bacterium that is the causative agent of a wide range of animal diseases, including bovine haemorrhagic septicaemia, atrophic rhinitis in pigs and fowl cholera, a serious disease of poultry which can present in both acute and chronic forms. Existing bacterin and live fowl cholera vaccines are believed to afford excellent homologous protection, that is protection against strains belonging to the same lipopolysaccharide (LPS) serovar, but heterologous protection is very limited. However, serovar-specific protection has never been objectively tested as knowledge of the exact LPS structures expressed by different strains has not been known until recently. Using this knowledge, we have shown that the current LPS serotyping system is inaccurate 66% of the time and we have replaced this typing system with an LPS multiplex PCR that groups the 16 serovar type strains into 8 genotypes based on their LPS outer core biosynthesis genes. The most common strains isolated from Australian poultry belong to serovars 3 and 4 and produce related but distinct LPS outer core structures despite sharing a common LPS outer core biosynthesis locus, L3. We show, using TargeTron® mutagenesis of genes within the L3 locus, that variation in the LPS structure is due to truncation of the full-length LPS, attributed to mutations within one of the six encoded glycosyltransferases. LPS structural and genetic analyses of over 20 field isolates belonging to genotype L3 reveal that a further four related, but distinct, LPS structures/glycoforms are produced by field isolates belonging to L3. Moreover, in some field isolates, multiple LPS glycoforms are simultaneously produced which mimic the Globo series of vertebrate glycosphingolipids. The existence of field isolates producing a wide range of LPS glycoforms, some producing all glycoforms simultaneously, raises significant questions about the ability of existing P. multocida vaccines to elicit strong cross-protection against even closely related strains.