title: Parachlamydiaceae: potential emerging pathogens.
abstract: Parachlamydiaceae, which naturally infect amoebae, form a sister taxon to the Chlamydiaceae on the basis of the Chlamydia-like cycle of replication and 80% to 90% homology of ribosomal RNA genes. Because intra-amoebal growth could increase the virulence of some intracellular bacteria, Parachlamydiaceae may be pathogenic. Arguments supporting a pathogenic role are that Chlamydia pneumoniae, a well-recognized agent of pneumonia, was shown to infect free-living amoebae and that another member of the Chlamydiales, Simkania negevensis, which has 88% homology with Parachlamydia acanthamoebae, has caused pneumonia in adults and acute bronchiolitis in infants. The recent identification of a 16S rRNA gene sequence of a Parachlamydiaceae from bronchoalveolar lavage is additional evidence supporting potential for pathogenicity.
authors.affiliation: Unité des Rickettsies, Université de la Méditerranée, Marseille, France.
authors.forename: Gilbert
authors.initials: G
authors.lastname: Greub
authors.forename: Didier
authors.initials: D
authors.lastname: Raoult
mesh_terms: D000048:Acanthamoeba / Q000382:microbiology / Q000648:ultrastructure; D000818:Animals; D002695:Chlamydiales / Q000254:growth & development* / Q000472:pathogenicity / Q000648:ultrastructure; D017714:Community-Acquired Infections / Q000382:microbiology*; D006801:Humans; D010802:Phylogeny; D014871:Water Microbiology; D014881:Water Supply