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Poster De Conférence Année : 2012

Molecular and phenotypic comparison of two Staphylococcus aureus strains associated to severe or mild mastitis in cows

Résumé

Staphylococcus aureus is an opportunistic pathogen in humans and warm-blooded animals. In milk production, it is a main cause of mastitis in dairy ruminants, which induces huge economical loss. In this work, S. aureus strains RF122 and Newbould305, responsible for severe or mild mastitis, were compared at the genome scale. Whole Genome PCR Scanning and Comparative Genome Hybridization showed that RF122 (ST151) was closely related to ovine strains whereas Newbould305 (ST115) co-clustered with bovine isolates (J.Bact. 2008. 190(19):6302). The goal of this work was to identify staphylococcal factors explaining the differences of clinical signs and mastitis acuteness observed during infections with these strains. We compared the two strains, in silico and in vitro, at the genome, proteome and phenotype levels. The genome of S. aureus Newbould305 was sequencedusing an Illumina Genome Analyzer. A total of 2752 coding sequences were detected and Newbould305 sequence was compared to that of RF122, which is publicly available. The overall Newbould305 genome shares high similarity with that of RF122. A majority of genes (n= 1819) were common to both strains. Proteome analysis of supernatant, cell wall and total cell fractions was carried out in conditions mimicking the mastitis context and results lead to an additional characterization at the phenotype level. Efficiency of adhesion and internalisation of both strains were tested and compared in vitro on bovine mammary epithelial cells (MAC-T). The values for adhesion and internalization showed significantly higher rates for Newbould305 with differences of up to 1 order of magnitude in adhesion and 1.5 orders of magnitude for internalization. However, once internalized, intracellular survival appeared identical for both strains. This work provides targets for further investigations, especially to determine whether the differences observed at these initial steps of infection are indeed critical for the development and severity of cow mastitis.
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Dates et versions

hal-01209665 , version 1 (02-10-2015)

Identifiants

  • HAL Id : hal-01209665 , version 1
  • PRODINRA : 265081

Citer

Vincent Péton, Damien Bouchard, Sintia Almeida da Silva, Julien Jardin, Caroline Le Maréchal, et al.. Molecular and phenotypic comparison of two Staphylococcus aureus strains associated to severe or mild mastitis in cows. 15th International Symposium on Staphylococci and Staphylococcal Infections (ISSSI), Aug 2012, Lyon, France. 2012. ⟨hal-01209665⟩
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