Overall, hospital-acquired pneumonia (HAP) caused by Pseudomonas aeruginosa is associated with high attributable mortality. Although the intrinsic virulence of P. aeruginosa undoubtedly contributes to this phenomenon, it is unclear whether all strains share this property or whether only a subpopulation of strains are capable of causing such severe disease. In this study, the virulence of 35 P. aeruginosa isolates obtained from patients with HAP by use of a cytolytic cell-death assay, an apoptosis assay, and a mouse model of pneumonia. The virulence of individual isolates differed significantly from one to another in each of these assays. Increased virulence was associated with the secretion of ExoU, a toxin transported by the P. aeruginosa type III secretion system. Secretion of ExoS or ExoY, 2 other proteins transported by this system, was not consistently associated with increased virulence. Together, these findings suggest that secretion of ExoU is a marker for highly virulent strains of P. aeruginosa.
|Original language||English (US)|
|Number of pages||12|
|Journal||Journal of Infectious Diseases|
|State||Published - Dec 1 2003|
Bibliographical noteFunding Information:
Financial support: Schweppe Foundation (to A.R.H.); Northwestern Memorial Hospital (to A.R.H.); National Institutes of Health (grants AI46543 and AI01524 to A.R.H.); Distincio a la Recerca Universitaria (to J.R.); Comisio Interdepartamental de Ciencia i Tecnologia (grant SGR 2001/441 to J.R.).