Generation and Evaluation of a Glaesserella (Haemophilus) parasuis Capsular Mutant [Bacterial Infections]

Glaesserella (Haemophilus) parasuis is a commensal bacterium of the upper respiratory tract in pigs and also the causative agent of Glässer’s disease, which causes significant morbidity and mortality in pigs worldwide. Isolates are characterized into 15 serovars by their capsular polysaccharide, which has shown a correlation with isolate pathogenicity. To investigate the role the capsule plays in G. parasuis virulence and host interaction, a capsule mutant of the serovar 5 strain HS069 was generated (HS069cap) through allelic exchange following natural transformation. HS069cap was unable to cause signs of systemic disease during a pig challenge study and had increased sensitivity to complement killing and phagocytosis by alveolar macrophages. Compared with the parent strain, HS069cap produced more robust biofilm and adhered equivalently to 3D4/31 cells; however, it was unable to persistently colonize the nasal cavity of inoculated pigs, with all pigs clearing HS069cap by 5 days postchallenge. Our results indicate the importance of the capsular polysaccharide to G. parasuis virulence as well as nasal colonization in pigs.

Source: Infection and Immunity - April 19, 2020 Category: Infectious Diseases Authors: Eberle, K. C., Hau, S. J., Luan, S.-L., Weinert, L. A., Stasko, J. A., Wang, J., Peters, S. E., Langford, P. R., Rycroft, A. N., Wren, B. W., Maskell, D. J., Tucker, A. W., Brockmeier, S. L., on behalf of the BRaDP1T Consortium Tags: Bacterial Infections Source Type: research