title: Existence of two groups of Staphylococcus aureus strains isolated from bovine mastitis based on biofilm formation, intracellular survival, capsular profile and agr-typing.
abstract: Staphylococcus (S.) aureus is recognised worldwide as an important pathogen causing contagious acute and chronic bovine mastitis. Chronic mastitis account for a significant part of all bovine cases and represent an important economic problem for dairy producers. Several properties (biofilm formation, intracellular survival, capsular expression and group agr) are thought to be associated with this chronic status. In a previous study, we found the existence of two groups of strains based on the association of these features. The aim of the present work was to confirm on a large international and non-related collection of strains the existence of these clusters and to associate them with case history records. In addition, the genomes of eight strains were sequenced to study the genomic differences between strains of each cluster. The results confirmed the existence of both groups based on capsular typing, intracellular survival and agr-typing: strains cap8-positive, belonging to agr group II, showing a low invasion rate and strains cap5-positive, belonging to agr group I, showing a high invasion rate. None of the two clusters were associated with the chronic status of the cow. When comparing the genomes of strains belonging to both clusters, the genes specific to the group "cap5-agrI" would suggest that these strains are better adapted to live in hostile environment. The existence of these two groups is highly important as they may represent two clusters that are adapted differently to the host and/or the surrounding environment.
authors.affiliation: Bacteriology, Department of Infectious Diseases, Faculty of Veterinary Medicine and Institute for Fundamental and Applied Research in Animal Health (FARAH), University of Liège, Sart-Tilman, Bât. 43a, B-4000 Liège, Belgium; Environment & Public Health Research Group, School of Environment & Technology, University of Brighton, Cockcroft Building, Lewes Road, Brighton BN2 4GJ, United Kingdom. Electronic address: mbardiau@ulg.ac.be.
authors.forename: Marjorie
authors.initials: M
authors.lastname: Bardiau
authors.affiliation: Environment & Public Health Research Group, School of Environment & Technology, University of Brighton, Cockcroft Building, Lewes Road, Brighton BN2 4GJ, United Kingdom.
authors.forename: Jonathan
authors.initials: J
authors.lastname: Caplin
authors.affiliation: Biostatistics, Bioinformatics and Animal Selection, Department of Animal Production, Faculty of Veterinary Medicine, University of Liège, Sart-Tilman, Bât. 43a, B-4000 Liège, Belgium.
authors.forename: Johann
authors.initials: J
authors.lastname: Detilleux
authors.affiliation: Agroscope, Institute for Food Sciences IFS, Schwarzenburgstrasse 161, 3003 Berne, Switzerland.
authors.forename: Hans
authors.initials: H
authors.lastname: Graber
authors.affiliation: Università degli Studi di Milano, Department of Health, Animal Science and Food Safety, via Celoria 10, 20133 Milano, Italy; Cornell University, Animal Health Diagnostic Center, Quality Milk Production Services, 240 Farrier Road, Ithaca, NY 14853, USA.
authors.forename: Paolo
authors.initials: P
authors.lastname: Moroni
authors.affiliation: Quantitative Genetics Group, Department of Animal Production, Faculty of Veterinary Medicine, University of Liège, Sart-Tilman, Bât. 43a, B-4000 Liège, Belgium.
authors.forename: Bernard
authors.initials: B
authors.lastname: Taminiau
authors.affiliation: Bacteriology, Department of Infectious Diseases, Faculty of Veterinary Medicine and Institute for Fundamental and Applied Research in Animal Health (FARAH), University of Liège, Sart-Tilman, Bât. 43a, B-4000 Liège, Belgium.
authors.forename: Jacques G
authors.initials: JG
authors.lastname: Mainil
mesh_terms: D000818:Animals; D016667:Bacterial Capsules / Q000737:chemistry; D001426:Bacterial Proteins / Q000235:genetics; D015373:Bacterial Typing Techniques; D018441:Biofilms; D002417:Cattle; D005260:Female; D016680:Genome, Bacterial; D042541:Intracellular Space / Q000382:microbiology; D008414:Mastitis, Bovine / Q000382:microbiology*; D013045:Species Specificity; D013203:Staphylococcal Infections / Q000382:microbiology / Q000662:veterinary*; D013211:Staphylococcus aureus / Q000145:classification* / Q000235:genetics / Q000302:isolation & purification / Q000502:physiology*; D015534:Trans-Activators / Q000235:genetics; D037521:Virulence Factors / Q000235:genetics
chemical_list: C095698:Agr protein, Staphylococcus aureus; D001426:Bacterial Proteins; D015534:Trans-Activators; D037521:Virulence Factors
keywords: Biofilm; Bovine mastitis; Capsule; Intracellular survival; Persistence; Staphylococcus aureus