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Disruption of the sigS gene attenuates the local innate immune response to Staphylococcus aureus in a mouse mastitis model
- Source :
- Veterinary Microbiology, Veterinary Microbiology, Elsevier, 2016, 186, pp.44-51. ⟨10.1016/j.vetmic.2016.02.014⟩, www.journals.elsevier.com/veterinary-microbiology/
- Publication Year :
- 2016
- Publisher :
- Elsevier BV, 2016.
-
Abstract
- Staphylococcus aureus (S. aureus) is a major pathogen involved in ruminant mastitis and present worldwide. Clinical signs of S. aureus mastitis vary considerably and are largely dependent on strain-specific factors. A comparison of two S. aureus strains that reproducibly induced either severe (O11) or mild (O46) mastitis in ewes revealed that the transcriptional regulator sigS was mutated in O46 (Le Maréchal et al., 2011. PLoS One. 6 (11) e27354. doi:10.1371/journal.pone.0027354). In the present paper, we analysed the sigS sequence in 18 other S. aureus strains isolated from goat or ewe mastitis and found a 4-bp deletion similar to that of the O46 sigS gene in three strains associated with subclinical ewe mastitis. This sigS gene was disrupted in strain O11 (O11ΔsigS), so our aim was to investigate its involvement in the severity of infections in the context of mastitis. The wild type (wt) and mutant strains were then characterized in vitro to determine the involvement of sigS in the response S. aureus under various stress conditions, and assess its influence on the cytotoxicity of the pathogen, its invasive capacity and biofilm formation. The strains were compared in vivo in an experimental mouse mastitis model in which clinical signs and cytokine production were evaluated at 24 h post-infection. While no significant differences in the effect on bacterial growth between O11 and O11ΔsigS were observed either in vitro or in vivo, a significantly weaker in vivo production of interleukin (IL)-1α, IL-1β, and Tumor Necrosis Factor (TNF)-α was measured in the mammary glands infected with the mutant strain, suggesting that infection with O11ΔsigS induced an attenuated local innate immune response. These results suggest an impact of sigS disruption on S. aureus pathogenesis in a ruminant mastitis context. This disruption is probably involved in, and may partly explain, the milder symptoms previously observed in S. aureus O46-induced mastitis in ewes.
- Subjects :
- 0301 basic medicine
modèle animal
Mastitis
medicine.disease_cause
virulence factor
Mice
[SDV.IDA]Life Sciences [q-bio]/Food engineering
animal modèle
immunologie
Pathogen
santé animale
Goats
General Medicine
Staphylococcal Infections
3. Good health
facteur de virulence
[SDV.MP]Life Sciences [q-bio]/Microbiology and Parasitology
Staphylococcus aureus
Female
réponse inflammatoire
staphylococcus aureus
réponse immunitaire
030106 microbiology
Virulence
Context (language use)
éléments de régulation transcriptionnelle
Biology
Microbiology
03 medical and health sciences
Mammary Glands, Animal
Immune system
Bacterial Proteins
Immunity
s factor
medicine
Animals
Sheep
Innate immune system
animal health
General Veterinary
animal model
medicine.disease
Immunity, Innate
mammite
virulence
Disease Models, Animal
Immunology
[SDV.AEN]Life Sciences [q-bio]/Food and Nutrition
Gene Deletion
Subjects
Details
- ISSN :
- 03781135
- Volume :
- 186
- Database :
- OpenAIRE
- Journal :
- Veterinary Microbiology
- Accession number :
- edsair.doi.dedup.....f369b69d688cd98bd6060fbc100fe631