Quorum-sensing activity and related virulence factor expression in clinically pathogenic isolates of Pseudomonas aeruginosa.

Abstract : Respiratory isolates of Pseudomonas aeruginosa were collected from 58 critically-ill patients with ventilator-associated pneumonia. Expression of elastase and pyocyanin was assessed semi-quantitatively, while quorum-sensing activity was assessed by quantifying the levels of the autoinducers N-3-oxododecanoyl-L-homoserine lactone (C12-HSL) and N-butanoyl-L-homoserine lactone (C4-HSL). Correlations were sought between quorum-sensing activity and the expression of these two virulence factors, and all results were compared to those obtained with the laboratory reference strains PA103, a strain defective in quorum-sensing, and PAO1, a functional quorum-sensing strain. More than two-thirds of clinically pathogenic isolates had increased levels of elastase and/or pyocyanin, and high quorum-sensing activity, as assessed by autoinducer levels. However, a strong correlation between quorum-sensing activity and virulence factor production was revealed only for elastase and not for pyocyanin (C12-HSL/elastase, r = 0.7, p 2 x 10(-9); C4-HSL/elastase, r = 0.7, p 2 x 10(-9)). These data suggest that the pathogenicity of P. aeruginosa isolates from critically-ill patients with ventilator-associated pneumonia is caused, at least in part, by an increase in elastase production regulated by quorum-sensing, while increased pyocyanin production in these isolates may be regulated predominantly by mechanisms other than quorum-sensing.
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Clinical Microbiology and Infection, Wiley, 2008, 14 (4), pp.337-43. 〈10.1111/j.1469-0691.2007.01925.x〉
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Contributeur : Ghislaine Calvez <>
Soumis le : jeudi 8 novembre 2012 - 15:42:18
Dernière modification le : jeudi 17 juillet 2014 - 15:00:33

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Rozenn Le Berre, S. Nguyen, Emmanuel Nowak, E. Kipnis, M. Pierre, et al.. Quorum-sensing activity and related virulence factor expression in clinically pathogenic isolates of Pseudomonas aeruginosa.. Clinical Microbiology and Infection, Wiley, 2008, 14 (4), pp.337-43. 〈10.1111/j.1469-0691.2007.01925.x〉. 〈hal-00749907〉

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