Mitchell, Gabriel; Séguin, David Lalonde; Asselin, Ann-Elise; Déziel, Éric ORCID: https://orcid.org/0000-0002-4609-0115; Cantin, André M.; Frost, Eric H.; Michaud, Sophie et Malouin, François
(2010).
Staphylococcus aureus sigma B-dependent emergence of small-colony variants and biofilm production following exposure to Pseudomonas aeruginosa 4-hydroxy-2-heptylquinoline-N-oxide
BMC Microbiology
, vol. 10
, nº 33.
pp. 1-15.
DOI: 10.1186/1471-2180-10-33.
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Résumé
BACKGROUND: Staphylococcus aureus and Pseudomonas aeruginosa are often found together in the airways of cystic fibrosis (CF) patients. It was previously shown that the P. aeruginosa exoproduct 4-hydroxy-2-heptylquinoline-N-oxide (HQNO) suppresses the growth of S. aureus and provokes the emergence of small-colony variants (SCVs). The presence of S. aureus SCVs as well as biofilms have both been associated with chronic infections in CF.
RESULTS: We demonstrated that HQNO stimulates S. aureus to form a biofilm in association with the formation of SCVs. The emergence of SCVs and biofilm production under HQNO exposure was shown to be dependent on the activity of the stress- and colonization-related alternative sigma factor B (SigB). Analysis of gene expression revealed that exposure of a prototypical S. aureus strain to HQNO activates SigB, which was leading to an increase in the expression of the fibronectin-binding protein A and the biofilm-associated sarA genes. Conversely, the quorum sensing accessory gene regulator (agr) system and the alpha-hemolysin gene were repressed by HQNO. Experiments using culture supernatants from P. aeruginosa PAO1 and a double chamber co-culture model confirmed that P. aeruginosa stimulates biofilm formation and activates SigB in a S. aureus strain isolated from a CF patient. Furthermore, the supernatant from P. aeruginosa mutants unable to produce HQNO induced the production of biofilms by S. aureus to a lesser extent than the wild-type strain only in a S. aureus SigB-functional background.
CONCLUSIONS: These results suggest that S. aureus responds to HQNO from P. aeruginosa by forming SCVs and biofilms through SigB activation, a phenomenon that may contribute to the establishment of chronic infections in CF patients.
Type de document: | Article |
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Mots-clés libres: | - |
Centre: | Centre INRS-Institut Armand Frappier |
Date de dépôt: | 09 juill. 2024 14:43 |
Dernière modification: | 09 juill. 2024 14:43 |
URI: | https://espace.inrs.ca/id/eprint/14975 |
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