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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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https://hal.univ-brest.fr/hal-00749907
Contributor : Ghislaine Calvez <>
Submitted on : Thursday, November 8, 2012 - 3:42:18 PM
Last modification on : Friday, January 3, 2020 - 12:36:03 AM

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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, Elsevier for the European Society of Clinical Microbiology and Infectious Diseases, 2008, 14 (4), pp.337-43. ⟨10.1111/j.1469-0691.2007.01925.x⟩. ⟨hal-00749907⟩

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