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Staphylococcus aureus seroproteomes discriminate ruminant isolates causing mild or severe mastitis

Caroline Le Maréchal123, Julien Jardin12, Gwenaël Jan12, Sergine Even12, Coralie Pulido3, Jean-Michel Guibert3, David Hernandez4, Patrice François4, Jacques Schrenzel4, Dieter Demon5, Evelyne Meyer5, Nadia Berkova12, Richard Thiéry3, Eric Vautor36 and Yves Le Loir12*

Author Affiliations

1 INRA, UMR1253 Science et Technologie du Lait et de l'Œuf, F-35042 Rennes, France

2 AGROCAMPUS OUEST, UMR1253 Science et Technologie du Lait et de l'Œuf, F-35042 Rennes, France

3 ANSES, Laboratoire de Sophia-Antipolis, Unité pathologie des ruminants, F-06902 Sophia-Antipolis, France

4 Genomic Research Laboratory, Service of Infectious Diseases; University of Geneva Hospitals (HUG), CH-1211 Geneva 14, Switzerland

5 Ghent University, Faculty of Veterinary Medicine, Merelbeke, Belgium

6 LVD06, F606902 Sophia-Antipolis, France

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Veterinary Research 2011, 42:35  doi:10.1186/1297-9716-42-35

Published: 15 February 2011

Abstract

Staphylococcus aureus is a major cause of mastitis in ruminants. In ewe mastitis, symptoms range from subclinical to gangrenous mastitis. S. aureus factors or host-factors contributing to the different outcomes are not completely elucidated. In this study, experimental mastitis was induced on primiparous ewes using two S. aureus strains, isolated from gangrenous (strain O11) or subclinical (strain O46) mastitis. Strains induced drastically distinct clinical symptoms when tested in ewe and mice experimental mastitis. Notably, they reproduced mild (O46) or severe (O11) mastitis in ewes. Ewe sera were used to identify staphylococcal immunoreactive proteins commonly or differentially produced during infections of variable severity and to define core and accessory seroproteomes. Such SERological Proteome Analysis (SERPA) allowed the identification of 89 immunoreactive proteins, of which only 52 (58.4%) were previously identified as immunogenic proteins in other staphylococcal infections. Among the 89 proteins identified, 74 appear to constitute the core seroproteome. Among the 15 remaining proteins defining the accessory seroproteome, 12 were specific for strain O11, 3 were specific for O46. Distribution of one protein specific for each mastitis severity was investigated in ten other strains isolated from subclinical or clinical mastitis. We report here for the first time the identification of staphylococcal immunogenic proteins common or specific to S. aureus strains responsible for mild or severe mastitis. These findings open avenues in S. aureus mastitis studies as some of these proteins, expressed in vivo, are likely to account for the success of S. aureus as a pathogen of the ruminant mammary gland.