Gene content and diversity of the Loci encoding biosynthesis of capsular polysaccharides of the fifteen serovar reference strains of Haemophilus parasuis

Howell, K J; Weinert, L A; Luan, S L; Peters, S E; Chaudhuri, R R; Harris, D; Angen, Ø; Aragon, V; Parkhill, J; Langford, P R; Rycroft, A N; Wren, B W; Tucker, A W; Maskell, D J

Abstract

Haemophilus parasuis is the causative agent of Glässer's disease, a systemic disease of pigs, and is also associated with pneumonia. H. parasuis can be classified into 15 different serovars. Here we report, from the 15 serotyping reference strains, the DNA sequences of the loci containing genes for the biosynthesis of the group 1 capsular polysaccharides, which are potential virulence factors of this bacterium. We contend that these loci contain genes for polysaccharide capsule structures, and not a lipopolysaccharide O antigen, supported by the fact that they contain genes such as wza, wzb, and wzc, which are associated with the export of polysaccharide capsules in the current capsule classification system. A conserved region at the 3′ end of the locus, containing the wza, ptp, wzs, and iscR genes, is consistent with the characteristic export region 1 of the model group 1 capsule locus. A potential serovar-specific region (region 2) has been found by comparing the predicted coding sequences (CDSs) in all 15 loci for synteny and homology. The region is unique to each reference strain with the exception of those in serovars 5 and 12, which are identical in terms of gene content. The identification and characterization of this locus among the 15 serovars is the first step in understanding the genetic, molecular, and structural bases of serovar specificity in this poorly studied but important pathogen and opens up the possibility of developing an improved molecular serotyping system, which would greatly assist diagnosis and control of Glässer's disease.

Citation

Howell, K. J., Weinert, L. A., Luan, S. L., Peters, S. E., Chaudhuri, R. R., Harris, D., …Maskell, D. J. (in press). Gene content and diversity of the Loci encoding biosynthesis of capsular polysaccharides of the fifteen serovar reference strains of Haemophilus parasuis. Journal of Bacteriology, 195(18), 4264-4273. https://doi.org/10.1128/JB.00471-13

• Journal Article Type: Article
• Acceptance Date: Jul 14, 2013
• Deposit Date: Nov 11, 2014
• Journal: Journal of Bacteriology
• Print ISSN: 0021-9193
• Publisher: American Society for Microbiology
• Peer Reviewed: Peer Reviewed
• Volume: 195
• Issue: 18
• Pages: 4264-4273
• DOI: https://doi.org/10.1128/JB.00471-13
• Public URL: https://rvc-repository.worktribe.com/output/1409072
• Additional Information: Corporate Creators : Barcelona, Cambridge, Imperial College London, LSHTM, Norwegian Vet Instit, Wellcome Trust Sanger Institute