Submitted to: International Journal of Systematic and Evolutionary Microbiology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/23/1998
Publication Date: N/A
Interpretive Summary: Our ability to identify and categorize life forms is much better today than it was just a few years ago. A new family of bacteria, Simkaniaceae, has recently been identified, and this study was conducted to characterize Simkaniaceae. Simkania belongs to an order of intracellular bacteria, Chlamydiales, because it grows only in the cells of animals. Simkania is associated with pneumonia in humans and bronchiolitis in infants. In this study, Simkania was found to have many genetic characteristics of chlamydiae. Simkania grew very slowly, compared to other chlamydiae. This new information will help us better understand this pathogenic group of bacteria and the role of Simkania in human disease.
Technical Abstract: Simkania negevensis, strain Z**T is the type species of Simkaniaceae, a recently identified family in the order Clamydiales. In the current study, growth, antigenic, and genomic characteristics of this intracellular bacterium were investigated and were compared to those of members of the family Chlamydiaceae. Growth of the organism, as assessed by infectivity assays, reached a plateau after 2-3 days, although by light microscopy, cytopathic effects increased for 12 or more days after infection. S. negevensis-infected cells were not recognized by either of two monoclonal antibodies specific for Chlamydiaceae LPS, and several specific Chlamydiaceae ompA primers were unable to PCR amplify a S. negevensis gene. Simkania had one copy of the ribosomal operon, and the 16S and 23S rRNA genes were linked. The genome length of S. negevensis was determined by PFGE to be 1.7 Mbp, and the G + C content was 42.5 mol %. These data, together with other published data, are consistent with the proposal that S. negevensis belongs to a distinct family in the order Chlamydiales.