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ABSTRACT: Staphylococcus aureus is a major pathogen responsible for mastitis in dairy herds. S. aureus mastitis is difficult to treat and prone to recurrence despite antibiotic treatment. S. aureus ability to invade bovine mammary epithelial cells (bMEC) is evoked to explain this chronicity. One sustainable alternative to treat or prevent mastitis is the use of lactic acid bacteria (LAB) as mammary probiotics. In this study, we tested the ability of Lactobacillus casei strains to prevent invasion of bMEC by two S. aureus bovine strains, RF122 and Newbould305, which reproducibly induce acute and moderate mastitis, respectively. L. casei strains affected adhesion and/or internalization of S. aureus in a strain-dependent manner. Interestingly, L. casei CIRM-BIA 667 reduced S. aureus Newbould305 and RF122 internalization by 60% to 80%, and this inhibition was confirmed for two other L. casei strains, including one isolated from bovine teat canal. The protective effect occurred without affecting bMEC morphology and viability. Once internalized, the fate of S. aureus was not affected by L. casei. It should be noted that L. casei was internalized at a low rate but survived in bMEC cells with a better efficiency than that of S. aureus RF122. Inhibition of S. aureus adhesion was maintained with heat-killed L. casei, whereas contact between live L. casei and S. aureus or bMEC was required to prevent S. aureus internalization. This first study of the antagonism of LAB towards S. aureus in a mammary context opens avenues for the development of novel control strategies against this major pathogen.
Applied and environmental microbiology 11/2012; · 3.69 Impact Factor
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Damien Bouchard,
Vincent Peton,
Sintia Almeida,
Caroline Le Maréchal,
Anderson Miyoshi,
Vasco Azevedo, Nadia Berkova,
Lucie Rault,
Patrice François,
Jacques Schrenzel,
Sergine Even,
David Hernandez,
Yves Le Loir
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ABSTRACT: Staphylococcus aureus is a major etiological agent of mastitis in ruminants. We report here the genome sequence of bovine strain Newbould 305, isolated in the 1950s in a case of bovine mastitis and now used as a model strain able to reproducibly induce chronic mastitis in cows.
Journal of bacteriology 11/2012; 194(22):6292-3. · 3.94 Impact Factor
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Nubia Seyffert,
Caroline Le Maréchal,
Julien Jardin,
John A McCulloch,
Fabio R Rosado,
Anderson Miyoshi,
Sergine Even,
Gwenaël Jan, Nadia Berkova,
Eric Vautor,
Richard Thiéry,
Vasco Azevedo,
Yves Le Loir
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ABSTRACT: Staphylococcus aureus is an opportunistic pathogen in dairy ruminants where it is found in healthy carriage and can be a major cause of mastitis. A better knowledge of the host-pathogen interactions is needed to tackle this serious animal health problem. This study aimed at identifying S. aureus proteins differentially expressed by S. aureus in nasal colonization versus mastitis. Serological proteome analysis (SERPA) was used to examine protein samples prepared from culture supernatants of S. aureus strains originally isolated from gangrenous mastitis and nasal carriage (O11) or subclinical mastitis (O46) and to compare patterns of immune-reactive proteins. These staphylococcal proteins were revealed by sera obtained from ewes suffering from S. aureus mastitis and by sera obtained from healthy nulliparous ewes (i.e. no lactation and no mastitis or other symptoms) that were nasally colonized by S. aureus. Altogether 49 staphylococcal immune-reactive proteins were identified in this study. Patterns of proteins revealed by sera from infected- or healthy carrier- animals were comparable and analysis singled out one immune-reactive protein, N-acetylmuramyl-L-alanine amidase, which was recognized by each of the 6 sera from infected animals, when tested individually, and not by the sera of healthy carriers. This is the first study that compares the S. aureus seroproteome in colonization versus mastitis context in ruminants. These results open avenues for studies aiming at a better understanding of the balance between infection and commensal lifestyle in this opportunistic pathogen and at new prevention strategies.
Veterinary Microbiology 01/2012; 157(3-4):439-47. · 3.33 Impact Factor
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ABSTRACT: Staphylococcus aureus is a major etiological agent of mastitis in ruminants. We report here the genome sequences of two ovine strains that were isolated from gangrenous (strain O11) and subclinical (strain O46) ewe mastitis. Both strains belong to the same clonal complex. Despite this close genotypic relationship, the two isolates were shown to reproducibly induce highly divergent types of infections, either severe (O11) or mild (O46) mastitis, in an experimental ewe model.
Journal of bacteriology 03/2011; 193(9):2353-4. · 3.94 Impact Factor
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Caroline Le Maréchal,
Julien Jardin,
Gwenaël Jan,
Sergine Even,
Coralie Pulido,
Jean-Michel Guibert,
David Hernandez,
Patrice François,
Jacques Schrenzel,
Dieter Demon,
Evelyne Meyer, Nadia Berkova,
Richard Thiéry,
Eric Vautor,
Yves Le Loir
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ABSTRACT: 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.
Veterinary Research 02/2011; 42(1):35. · 4.06 Impact Factor
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Caroline Le Maréchal,
Nubia Seyffert,
Julien Jardin,
David Hernandez,
Gwenaël Jan,
Lucie Rault,
Vasco Azevedo,
Patrice François,
Jacques Schrenzel,
Maarten van de Guchte,
Sergine Even, Nadia Berkova,
Richard Thiéry,
J Ross Fitzgerald,
Eric Vautor,
Yves Le Loir
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ABSTRACT: S. aureus is one of the main pathogens involved in ruminant mastitis worldwide. The severity of staphylococcal infection is highly variable, ranging from subclinical to gangrenous mastitis. This work represents an in-depth characterization of S. aureus mastitis isolates to identify bacterial factors involved in severity of mastitis infection.
We employed genomic, transcriptomic and proteomic approaches to comprehensively compare two clonally related S. aureus strains that reproducibly induce severe (strain O11) and milder (strain O46) mastitis in ewes. Variation in the content of mobile genetic elements, iron acquisition and metabolism, transcriptional regulation and exoprotein production was observed. In particular, O11 produced relatively high levels of exoproteins, including toxins and proteases known to be important in virulence. A characteristic we observed in other S. aureus strains isolated from clinical mastitis cases.
Our data are consistent with a dose-dependant role of some staphylococcal factors in the hypervirulence of strains isolated from severe mastitis. Mobile genetic elements, transcriptional regulators, exoproteins and iron acquisition pathways constitute good targets for further research to define the underlying mechanisms of mastitis severity.
PLoS ONE 01/2011; 6(11):e27354. · 4.09 Impact Factor
