Sequencing of the genes responsible for the capsule production in Haemophilus parasuis

A study published in the Journal of Bacteriology, with the participation of Dr. Virginia Aragón (CReSA researcher), opens new possibilities in assisting the diagnosis and monitoring of Glässer’s disease.

A collaborative study between researchers of CReSA (Barcelona), the Department of Veterinary Medicine of the University of Cambridge (UK) and other European research groups has identified the DNA sequences of Haemophilus parasuis responsible for the bacterial capsule production.

H. parasuis is a member of the family Pasteurellaceae, which can be frequently found in the upper airways from healthy pigs. However it is better known as the etiologic agent of Glässer’s disease in pigs, a systemic disease characterized by fibronous polyserositis, that causes a high morbidity and mortality in piglets. H. parasuis can also produce pneumonia and sudden death. Glässer’s disease has achieved considerable importance during the last years and it is also known as one of the main causes for economic losses in the pig production.

Transmission electron micrograph of Haemophilus parasuis

Polysaccharides composing the capsule are potential virulence factors of this bacterium. H. parasuis strains are classified in 15 serovars that are differenced by several characteristics, including virulence. Sequences of the 15 reference strains have been identified and characterized and specific sequences among the genes encoding the capsule of each serovar have been detected in this study.

This finding is a first step towards understanding the basis of strain antigenic specificity and opens new possibilities for the developing of molecular serotyping systems, which could assist in the diagnosis and control of the disease.

The article has been published in: Howell KJ, Weinert LA, Luan SL, Peters SE, Chaudhuri RR, Harris D, Angen O, Aragon V, Parkhill J, Langford PR, Rycroft AN, Wren BW, Tucker AW, Maskell DJ; BRaDP1T Consortium. Gene content and diversity of the loci encoding biosynthesis of capsular polysaccharides of the 15 serovar reference strains of Haemophilus parasuis. J Bacteriol. 2013 Sep;195(18):4264-73.

Download the full paper:

To know more about this study:

Dra Virginia Aragón Fernández
Researcher of CReSA. Coordinator of the research line on bacterial respiratory infections.
Phone no.: +34 93 581 44 94
Fax: +34 93 581 44 90
Campus de la Universitat Autònoma de Barcelona, Edifici CReSA s/n
08193 Cerdanyola del Vallès (Bellaterra), Barcelona, Spain

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