Severe pneumonia due to Parachlamydia acanthamoebae following intranasal inoculation: a mice model

Article Article scientifique Article Severe pneumonia due to Parachlamydia acanthamoebae following intranasal inoculation: a mice model eng 2015 author Pilloux Ludovic author Casson Nicola 522620 author Sommer Kirsten author Klos Andreas author Stehle Jean-Christophe author Pusztaszeri Marc 640736 author Greub Gilbert Daniel 37836 755-760 10.1016/j.micinf.2015.08.007 26340890 1286-4579 Parachlamydia acanthamoebae is an obligate intracellular bacterium naturally infecting free-living amoebae. The role of this bacterium as an agent of pneumonia is suggested by sero-epidemiological studies and molecular surveys. Furthermore, P. acanthamoebae may escape macrophages microbicidal effectors. Recently, we demonstrated that intratracheal inoculation of P. acanthamoebae induced pneumonia in 100% of infected mice. However, the intratracheal route of infection is not the natural way of infection and we therefore developed an intranasal murine model. Mice inoculated with P. acanthamoebae by intranasal inoculation lost 18% of their weight up to 8 days post-inoculation. All mice presented histological signs of pneumonia at day 2, 4, 7, and 10 post-inoculation, whereas no control mice harboured signs of pneumonia. A 5-fold increase in bacterial load was observed from day 0 to day 4 post-inoculation. Lungs of inoculated mice were positive by Parachlamydia-specific immunohistochemistry 4 days post-inoculation, and P. acanthamoebae were localized within macrophages. Thus, we demonstrated that P. acanthamoebae induce a severe pneumonia in mice. This animal model (i) further supports the role of P. acanthamoebae as an agent of pneumonia, confirming the third Koch postulate, and (ii) identified alveolar macrophages as one of the initial cells where P. acanthamoebae is localized following infection. Dewey 616.07 137 Département de pathologie et immunologie 21F false 391 Métastases du foie 657 Microbes and infection 17 11-12 56042314-ef6e-4a83-bd0c-186c82e700f4 Article (Accepted version) Restricted Pusztaszeri M Microbes Infect 2015,17(11-12), 755-60.pdf 1773612 application/pdf restrictedAccess Faculté de médecine / Section de médecine fondamentale / Département de pathologie et immunologie

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Severe pneumonia due to Parachlamydia acanthamoebae following intranasal inoculation: a mice model	Microbes and infection			2015	504	0

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Casson, Nicola