Comparative genomics of the Pasteurella multocida toxin

Abstract

Pasteurella multocida is a zoonotic pathogen whose genetic heterogeneity is well known. 
 Five serogroups and 16 serotypes of P. multocida have been recognized thus far based on capsular polysaccharide typing and lipopolysaccharide typing, respectively. Progressive atrophic rhinitis in domestic pigs is caused by P. multocida strains containing toxA, which encodes a heat-labile toxin. In this study, by comparative analyses of the genomes of many strains, it has been shown that toxA is sparsely distributed in P. multocida. Furthermore, full-length homologs of P. multocida toxA were found only in two other bacterial species. It has also been shown that toxA is usually associated with a prophage. Among the toxA-containing prophages that were compared, an operon putatively encoding a type II restriction-modification system was present only in strains LFB3, HN01, and HN06. These results indicate that the selection and maintenance of the heat-labile toxin and the type II restriction-modification system are evolutionarily less favorable among P. multocida strains. Phylogenetic analysis using the alignment- and parameter-free method CVTree3 showed that deduced proteome sequences can be used as effectively as whole/core genome single nucleotide polymorphisms to group P. multocida strains in relation to their serotypes and/or genotypes.

CXCL8 Knockout: A Key to Resisting Pasteurella multocida Toxin-Induced Cytotoxicity

“…PMT, a 146 kDa heat-labile toxin, is only secreted by some serogroups A and D toxigenic strains encoded by the toxA gene [9]. This protein belongs to the skin necrosis toxin family and is one of the intracellularly acting, multipartite A-B toxins.…”