• Gianluigi Li Bassi, Montserrat Rigol, Joan-Daniel Marti, Lina Saucedo, Otavio T Ranzani, Ignasi Roca, Maria Cabanas, Laura Muñoz, Valeria Giunta, Nestor Luque, Mariano Rinaudo, Mariano Esperatti, Laia Fernandez-Barat, Miquel Ferrer, Jordi Vila, Jose Ramirez, and Antoni Torres.
• From the Department of Pulmonary and Critical Care Medicine, Thorax Institute, Hospital Clínic, Barcelona, Spain (G.L.B., M.R., J.-D.M., L.S., O.T.R., V.G., N.L., M.R., M.E., L.F.-B., M.F., A.T.); Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Barcelona, Spain (G.L.B., M.R., J.-D.M., I.R., L.M., L.F.-B., M.F., J.V., A.T.); Centro de Investigación Biomedica En Red- Enfermedades Respiratorias (CIBERES), Mallorca, Spain (G.L.B., M.R., O.T.R., V.G., M.R., M.E., L.F.-B., M.F., A.T.); Cardiology Department, Thorax Institute, Hospital Clínic, Barcelona, Spain (M.R.); Department of Clinical Microbiology, School of Medicine, and Barcelona Centre for International Health Research, (CRESIB, Hospital Clínic-Universitat de Barcelona), Barcelona, Spain (I.R., L.M., J.V.); Pathology Department, Hospital Clínic, Barcelona, Spain (M.C., J.R.); and University of Barcelona, Barcelona, Spain (J.V., J.R., A.T.).
• Anesthesiology. 2014 May 1;120(5):1205-15.

BackgroundAnimal models of ventilator-associated pneumonia (VAP) in primates, sheep, and pigs differ in the underlying pulmonary injury, etiology, bacterial inoculation methods, and time to onset. The most common ovine and porcine models do not reproduce the primary pathogenic mechanism of the disease, through the aspiration of oropharyngeal pathogens, or the most prevalent human etiology. Herein the authors characterize a novel porcine model of VAP due to aspiration of oropharyngeal secretions colonized by Pseudomonas aeruginosa.MethodsTen healthy pigs were intubated, positioned in anti-Trendelenburg, and mechanically ventilated for 72 h. Three animals did not receive bacterial challenge, whereas in seven animals, a P. aeruginosa suspension was instilled into the oropharynx. Tracheal aspirates were cultured and respiratory mechanics were recorded. On autopsy, lobar samples were obtained to corroborate VAP through microbiological and histological studies.ResultsIn animals not challenged, diverse bacterial colonization of the airways was found and monolobar VAP rarely developed. In animals with P. aeruginosa challenge, colonization of tracheal secretion increased up to 6.39 ± 0.34 log colony-forming unit (cfu)/ml (P < 0.001). VAP was confirmed in six of seven pigs, in 78% of the cases developed in the dependent lung segments (right medium and lower lobes, P = 0.032). The static respiratory system elastance worsened to 41.5 ± 5.8 cm H2O/l (P = 0.001).ConclusionsThe authors devised a VAP model caused by aspiration of oropharyngeal P. aeruginosa, a frequent causative pathogen of human VAP. The model also overcomes the practical and legislative limitations associated with the use of primates. The authors' model could be employed to study pathophysiologic mechanisms, as well as novel diagnostic/preventive strategies.

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