title: Murine model of pneumonia caused by Parachlamydia acanthamoebae.
abstract: The role of Parachlamydia acanthamoebae as an agent of pneumonia is suggested by sero-epidemiological studies, molecular surveys and by the permissivity of macrophages, lung fibroblasts and pneumocytes to this obligate intracellular bacteria. We thus developed a murine model of pneumonia due to Parachlamydia. Mice were inoculated intratracheally with Parachlamydia acanthamoebae. Pneumonia-associated mortality was of 50% 5 days post-inoculation. Lungs histopathology was characterized by purulent and interstitial pneumonia. The presence of Parachlamydia in the lesions was demonstrated by PCR, immunohistochemistry and electron microscopy. Moreover, living Parachlamydia could be recovered from the lungs of infected mice using amoebal co-culture. All control mice inoculated with heat-inactivated bacteria were free of symptoms and survived. Thus, we demonstrated that Parachlamydia induce a severe pneumonia in mice. This animal model, which confirms the third and fourth Koch postulates, may be suitable to test in vivo efficient therapeutic regimens against Parachlamydia.
authors.affiliation: Center for Research on Intracellular Bacteria (CRIB), Institute of Microbiology, University Hospital Center, University of Lausanne, Lausanne, Switzerland.
authors.forename: Nicola
authors.initials: N
authors.lastname: Casson
authors.forename: José Manuel
authors.initials: JM
authors.lastname: Entenza
authors.forename: Nicole
authors.initials: N
authors.lastname: Borel
authors.forename: Andreas
authors.initials: A
authors.lastname: Pospischil
authors.forename: Gilbert
authors.initials: G
authors.lastname: Greub
mesh_terms: D000818:Animals; D002695:Chlamydiales / Q000472:pathogenicity* / Q000502:physiology; D004195:Disease Models, Animal; D008168:Lung / Q000382:microbiology / Q000473:pathology*; D051379:Mice; D008854:Microscopy, Electron; D008954:Models, Biological; D011014:Pneumonia / Q000382:microbiology* / Q000503:physiopathology