Associations between properties linked with persistence in a collection of Staphylococcus aureus isolates from bovine mastitis.
Staphylococcus aureus is recognized worldwide as a pathogen causing many serious diseases in humans and animals, and is one of the most important etiological agents of clinical and subclinical bovine mastitis. The aim of the present study was to investigate and correlate properties, that may be associated with persistent mastitis, of S. aureus strains isolated from milk of cows suffering from mastitis: (i) expression of capsular antigens (CP5 or CP8) by specific ELISA; (ii) intracellular survival by invasion of MAC-T cells; and (iii) biofilm production by spectrophotometry analysis after growth in TSBglc. The results showed that (i) the proportion of strains expressing capsular antigen was higher in cap8- than in cap5-positive isolates; (ii) a correlation was observed between the capsular profile and the intracellular survival as well as the biofilm production; and (iii) the capsular profile, biofilm production and intracellular survival were associated with only two agr-groups. Statistical and clustering analysis allowed us to establish different profiles that could be associated with in vivo persistence. Indeed, isolates belonging to agr group II, expressing the capsular antigen CP8 and showing low intracellular survival are probably better adapted to an extracellular niche. Conversely, isolates belonging to agr group I that do not express any capsular antigen (CP5 or CP8) but show high intracellular survival are probably better adapted to an intracellular niche.
Bacteriology, Department of Infectious Diseases, Faculty of Veterinary Medicine, University of Liège, Sart-Tilman, Bât. 43a, B-4000 Liège, Belgium. Electronic address: mbardiau@ulg.ac.be.
Marjorie
M
Bardiau
Quantitative Genetics Group, Department of Animal Production, Faculty of Veterinary Medicine, University of Liège, Sart-Tilman, Bât. 43a, B-4000 Liège, Belgium.
Johann
J
Detilleux
Biostatistics, Bioinformatics and Animal Selection, Department of Animal Production, Faculty of Veterinary Medicine, University of Liège, Sart-Tilman, Bât. 43a, B-4000 Liège, Belgium.
Frédéric
F
Farnir
Bacteriology, Department of Infectious Diseases, Faculty of Veterinary Medicine, University of Liège, Sart-Tilman, Bât. 43a, B-4000 Liège, Belgium.
Jacques G
JG
Mainil
Bacteriology, Department of Infectious Diseases, Faculty of Veterinary Medicine, University of Liège, Sart-Tilman, Bât. 43a, B-4000 Liège, Belgium.
Isabelle
I
Ote
D000818:Animals; D000942:Antigens, Bacterial / Q000032:analysis; D016667:Bacterial Capsules / Q000145:classification / Q000235:genetics / Q000276:immunology; D015373:Bacterial Typing Techniques; D018441:Biofilms / Q000254:growth & development; D002417:Cattle; D002460:Cell Line; D016521:Electrophoresis, Gel, Pulsed-Field; D004847:Epithelial Cells / Q000382:microbiology; D005260:Female; D008321:Mammary Glands, Animal / Q000166:cytology / Q000382:microbiology; D008414:Mastitis, Bovine / Q000382:microbiology*; D008892:Milk / Q000382:microbiology; D012703:Serotyping; D013203:Staphylococcal Infections / Q000382:microbiology / Q000662:veterinary*; D013211:Staphylococcus aureus / Q000145:classification / Q000276:immunology / Q000302:isolation & purification / Q000502:physiology*
D000942:Antigens, Bacterial
Biofilm; Bovine mastitis; Capsule; Intracellular survival; Persistence; S. aureus