Secretion of the toxin ExoU is a marker for highly virulent Pseudomonas aeruginosa isolates obtained from patients with hospital-acquired pneumonia.
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.
Schulert
Grant S
GS
Department of Microbiology/Immunology, Northwestern University, Chicago, Illinois 60611, USA.
Feltman
Heather
H
Rabin
Shira D P
SD
Martin
Ciara G
CG
Battle
Scott E
SE
Rello
Jordi
J
Hauser
Alan R
AR
D000818:Animals; D017209:Apoptosis; D001426:Bacterial Proteins / Q000633:toxicity*; D003428:Cross Infection / Q000382:microbiology*; D005964:Glucosyltransferases / Q000633:toxicity; D051379:Mice; D008807:Mice, Inbred BALB C; D018410:Pneumonia, Bacterial / Q000382:microbiology*; D011550:Pseudomonas aeruginosa / Q000472:pathogenicity*; D014774:Virulence
D001426:Bacterial Proteins; C111749:pseudomonas exoprotein A protein, Pseudomonas aeruginosa; C111504:ExoY protein, bacteria; D005964:Glucosyltransferases