title: The great escape:Pseudomonasbreaks out of the lung.
abstract: The Gram-negative bacteriumPseudomonas aeruginosais a major cause of hospital-acquired infections and the focus of much attention due to its resistance to many conventional antibiotics. It harbors a wide range of disease-promoting virulence factors, including a type III secretion system. Here we review our recent study of ExoS, one of the effector proteins exported by this type III secretion system. Using a mouse model of pneumonia, we showed that the ADP-ribosyltransferase (ADPRT) activity of ExoS caused formation of "fields of cell injection" (FOCI) in the lungs. These FOCI represented ExoS-injected clusters of type I pneumocytes that became compromised, leading to disruption of the pulmonary-vascular barrier and subsequent bacterial dissemination from the lungs to the bloodstream. We discuss the potential mechanisms by which these processes occur as well as the novel techniques used to study ExoS functionin vivo.
authors.affiliation: Department of Microbiology/Immunology, Northwestern University, Feinberg School of Medicine, Chicago Illinois, USA.
authors.forename: Angelica
authors.initials: A
authors.lastname: Zhang
authors.affiliation: Department of Microbiology/Immunology, Northwestern University, Feinberg School of Medicine, Chicago Illinois, USA.
authors.forename: Stephanie M
authors.initials: SM
authors.lastname: Rangel
authors.affiliation: Department of Microbiology/Immunology, Northwestern University, Feinberg School of Medicine, Chicago Illinois, USA; Department of Medicine, Northwestern University, Feinberg School of Medicine, Chicago Illinois, USA.
authors.forename: Alan R
authors.initials: AR
authors.lastname: Hauser
keywords: ExoS; Pseudomonas aeruginosa; dissemination; pneumonia