Growth and airborne transmission of cell-sorted life cycle stages of Pneumocystis carinii.
Pneumocystis organisms are airborne opportunistic pathogens that cannot be continuously grown in culture. Consequently, the follow-up of Pneumocystis stage-to-stage differentiation, the sequence of their multiplication processes as well as formal identification of the transmitted form have remained elusive. The successful high-speed cell sorting of trophic and cystic forms is paving the way for the elucidation of the complex Pneumocystis life cycle. The growth of each sorted Pneumocystis stage population was followed up independently both in nude rats and in vitro. In addition, by setting up a novel nude rat model, we attempted to delineate which cystic and/or trophic forms can be naturally aerially transmitted from host to host. The results showed that in axenic culture, cystic forms can differentiate into trophic forms, whereas trophic forms are unable to evolve into cystic forms. In contrast, nude rats inoculated with pure trophic forms are able to produce cystic forms and vice versa. Transmission experiments indicated that 12 h of contact between seeder and recipient nude rats was sufficient for cystic forms to be aerially transmitted. In conclusion, trophic- to cystic-form transition is a key step in the proliferation of Pneumocystis microfungi because the cystic forms (but not the trophic forms) can be transmitted by aerial route from host to host.
Biology and Diversity of Emerging Eukaryotic Pathogens (BDEEP), Center for Infection and Immunity of Lille (CIIL), INSERM U1019, CNRS UMR 8204, EA-4547, Univ Lille Nord de France, Institut Pasteur de Lille, Lille, France ; Japan Collection of Microorganisms, RIKEN BioResource Center, Koyadai, Tsukuba, Ibaraki, Japan.
Anna
A
Martinez
Marie C M
MC
Halliez
El Moukhtar
el M
Aliouat
Magali
M
Chabé
Annie
A
Standaert-Vitse
Emilie
E
Fréalle
Nausicaa
N
Gantois
Muriel
M
Pottier
Anthony
A
Pinon
Eduardo
E
Dei-Cas
Cécile-Marie
CM
Aliouat-Denis
D000391:Air Microbiology; D000818:Animals; D016720:Pneumocystis Infections / Q000382:microbiology / Q000635:transmission*; D045363:Pneumocystis carinii / Q000472:pathogenicity*; D051381:Rats; D011923:Rats, Nude