Fine-tuned characterization of Staphylococcus aureus Newbould 305, a strain associated with mild and chronic mastitis in bovines

Abstract

S. aureus is a major aetiological agent of ruminant mastitis worldwide. The chronic nature of S. aureus mastitis makes it difficult to cure and prone to resurgence. In order to identify the bacterial factors involved in this chronicity, Newbould 305 (N305), a strain that can reproducibly induce mild and chronic mastitis in an experimental setting, was characterized in depth. We employed genomic and proteomic techniques combined with phenotype characterization, in order to comprehensively analyse N305. The results were compared with data obtained on S. aureus RF122, a strain representative of the major clone involved in severe bovine mastitis worldwide. Five mobile genetic elements were identified in the N305 genome as carrying virulence factors which correlated with phenotypic features such as cytotoxicity, mammary epithelial cell invasion or host-adaptation. In particular, the presence and characteristics of surface exposed proteins correlated well with the greater adhesion and internalization capacities of N305 in bovine mammary epithelial cells. N305 also displayed less diversity of toxin genes but secreted larger quantities of these toxins, associated with a higher cytotoxicity potential. Our data are consistent with the invasiveness and host-adaptation features which contribute to the chronicity of S. aureus mastitis. Mobile genetic elements, exoproteins and surface exposed proteins constitute good targets for further research to explore the underlying mechanisms related to mastitis chronicity.Electronic supplementary materialThe online version of this article (doi:10.1186/s13567-014-0106-7) contains supplementary material, which is available to authorized users.

Distinct phenotypic traits of Staphylococcus aureus are associated with persistent, contagious bovine intramammary infections

“…Several studies reported links between biofilm formation, CP expression and internalization capacity to chronicity in bovine IMI. However, these studies are based on well-established mastitis reference strains, such as RF122 and Newbould 305 26 , or on strains derived from different local or clonal (CC) origin 15 , 27 , while data from studies addressing differences of specific phenotypic and virulence traits of persistent strains in the context of within-herd prevalence are still lacking. To gain insights into the mechanism allowing S. aureus to spread and successfully persist within a herd, this study focuses on isolates collected over a 3-years period from a single dairy herd, which differed in their within-herd prevalence.…”

Genomic and transcriptomic comparison between Staphylococcus aureus strains associated with high and low within herd prevalence of intra-mammary infection

“…And more, the presence of protein variations for both groups of strains suggests a different affinity for fibronectin, necessary for the internalization of Staph. aureus into host cells [23]. …”

“…aureus strains. More recently, Peton and co-workers [23] described a fine-tuned characterization of Staph. aureus Newbond 305, a strain belonging to ST115 and associated to bovine mastitis, by genomic and proteomic comparison with the reference strain RF122.…”

Extracellular vesicles produced by human and animal Staphylococcus aureus strains share a highly conserved core proteome

“…Bovine strain RF122 was isolated from a case of clinical mastitis 61,62 . Bovine strain Newbould 305 (N305) was shown to reproducibly induce mild and chronic mastitis in bovines 63,64 . RF122 and N305 were kindly provided by Pr Ross J. Fitgerald (Edinburgh Infectious Diseases, Roslin Institute, University of Edinburgh, UK) and Dr Pascal Rainard (ISP, INRAE, Nouzilly France), respectively.…”