Investigation article published in Applied and Environmental Microbiology

May 1^st, 2015

Haemophilus parasuis, the causative agent of Glässer`s disease, is one of the early colonizers of the nasal mucosa of piglets. It is prevalent in swine herds, and lesions associated with disease are fibrinous polyserositis and bronchopneumonia. Antibiotics are commonly used in disease control, and resistance to several antibiotics has been described in H. parasuis. Prediction of H. parasuis virulence is currently limited by our scarce understanding of its pathogenicity. Some genes have been associated with H. parasuis virulence, such as lsgB and group 1 vtaA, while biofilm growth has been associated to non-virulent strains. In this study, 86 H. parasuis nasal isolates from farms without disease for more than 10 years were obtained by sampling piglets at weaning. Isolates were studied by ERIC-PCR, presence of lsgB and group 1 vtaA, biofilm formation, inflammatory cell response, and resistance to antibiotics. As part of the diversity encountered, a novel 2,661-bp plasmid, named pJMA-1, bearing the blaROB-1 β-lactamase, was detected in 8 colonizing strains. pJMA-1 was shown to share a common backbone with other small plasmids described in Pasteurellaceae, to be 100% stable, and to have a lower biological cost than the previously described plasmid pB1000. pJMA-1 was also found in 9 H. parasuis nasal strains from a separate collection, but it was not detected in isolates from lesions of animals with Glässer`s disease, neither in nontypeable H. influenzae. Altogether, we show that commensal H. parasuis represents a reservoir of β-lactam resistance genes, which could be transferred to pathogens or other bacteria

Moleres J., Santos-Lopez A., Lazaro I., Labairu J., Prat C., Ardanuy C., Gonzalez-Zorn B., Aragon V. and Garmendia J.

Novel blaROB-1-Bearing Plasmid Conferring Resistance to B-Lactams in Haemophilus parasuis Isolates from Healthy Weaning Pigs

Novel blaROB-1-Bearing Plasmid Conferring Resistance to B-Lactams in Haemophilus parasuis Isolates from Healthy Weaning Pigs

	Consejo Superior de Investigaciones Científicas (CSIC).
	Universidad Pública de Navarra (UPNA).
	Departamento de Sanidad Animal. Facultad de Veterinaria. Universidad Complutense (UCM).
	Centro de Investigación Biomédica en Red de Enfermedades Respiratorias (CIBERES). Instituto de Salud Carlos III (ISCIII).
	Centre de Recerca en Sanitat Animal (CReSA). Universitat Autònoma de Barcelona (UAB).
	Instituto de Investigación y Tecnología Agroalimentarias (IRTA). Generalitat de Catalunya.
	Instituto Navarro de Tecnologías e Infraestructuras Agroalimentarias (INTIA).
	Hospital Universitari Germans Trias i Pujol. Generalitat de Catalunya.
	Hospital Universitari Bellvitge. Generalitat de Catalunya.
	Servicio de Zoonosis de Transmisión Alimentaria y Resistencia a Antimicrobianos (ZTA). Centro de Vigilancia Sanitaria Veterinaria (VISAVET). Universidad Complutense (UCM).