Molecular serotyping of clinical strains of Haemophilus (Glaesserella) parasuis brings new insights regarding Glässer’s disease outbreaks in Brazil
Julia Pires Espíndola,
Natalia Balbinott,
Letícia Trevisan Gressler,
Gustavo Machado,
Catia Silene Klein,
Raquel Rebelatto,
César Bernardo Gutiérrez Martín,
Luiz Carlos Kreutz,
Anthony Bernard Schryvers,
Rafael Frandoloso
Affiliations
Julia Pires Espíndola
Laboratory of Microbiology and Advanced Immunology, Faculty of Agronomy and Veterinary Medicine, University of Passo Fundo, Passo Fundo, Rio Grande do Sul, Brazil
Natalia Balbinott
Laboratory of Microbiology and Advanced Immunology, Faculty of Agronomy and Veterinary Medicine, University of Passo Fundo, Passo Fundo, Rio Grande do Sul, Brazil
Letícia Trevisan Gressler
Laboratory of Microbiology and Advanced Immunology, Faculty of Agronomy and Veterinary Medicine, University of Passo Fundo, Passo Fundo, Rio Grande do Sul, Brazil
Gustavo Machado
Department of Population Health and Pathobiology, College of Veterinary Medicine, North Carolina State University, Raleigh, NC, United States of America
Catia Silene Klein
Embrapa Suínos e Aves, Concórdia, Santa Catarina, Brazil
Raquel Rebelatto
Embrapa Suínos e Aves, Concórdia, Santa Catarina, Brazil
César Bernardo Gutiérrez Martín
Section of Microbiology and Immunology, Department of Animal Health, Faculty of Veterinary, University of León, León, Castilla y León, Spain
Luiz Carlos Kreutz
Laboratory of Microbiology and Advanced Immunology, Faculty of Agronomy and Veterinary Medicine, University of Passo Fundo, Passo Fundo, Rio Grande do Sul, Brazil
Anthony Bernard Schryvers
Department of Microbiology & Infectious Diseases, Faculty of Medicine, University of Calgary, Calgary, Alberta, Canada
Rafael Frandoloso
Laboratory of Microbiology and Advanced Immunology, Faculty of Agronomy and Veterinary Medicine, University of Passo Fundo, Passo Fundo, Rio Grande do Sul, Brazil
Glässer’s disease (GD) is an important infectious disease of swine caused by Haemophilus (Glaesserella) parasuis. Vaccination with inactivated whole cell vaccines is the major approach for prevention of H. parasuis infection worldwide, but the immunity induced is predominantly against the specific polysaccharide capsule. As a consequence, the available vaccines may not induce adequate protection against the field strains, when the capsules present in the vaccine strains are different from those in strains isolated from the farms. Therefore, it is crucial to map H. parasuis serovars associated with regional outbreaks so that appropriate bacterin vaccines can be developed and distributed for prevention of infection. In this study, 459 H. parasuis field strains isolated from different Glässer’s disease outbreaks that occurred in 10 different Brazilian States were analyzed for serotype using PCR-based approaches. Surprisingly, non-typeable (NT) strains were the second most prevalent group of field strains and along with serovars 4, 5 and 1 comprised more than 70% of the isolates. A PCR-based approach designed to amplify the entire polysaccharide capsule locus revealed 9 different band patterns in the NT strains, and 75% of the NT strains belonged to three clusters, suggesting that a number of new serovars are responsible for a substantial proportion of disease. These results indicate that commercially available vaccines in Brazil do not cover the most prevalent H. parasuis serovars associated with GD.
