Exploring the Potential Pathogenicity of Environmental Chlamydiae

Exploring the Potential Pathogenicity of Environmental Chlamydiae

Chlamydiae are pathogenic bacteria that cause many known human infections such as, trachoma, conjunctivitis, infant pneumonia, nongonococcal urethritis and female genitourinary disease. The discovery of new species of Chlamydiae in free-living amoebae has expanded diversity and has now opened the door for potential pathogenicity of those environmental Chlamydiae (1).

Introduction:

Chlamydiae are responsible for many human infections such as preventable blindness and sexually transmitted disease (2). These present –day pathogens only make up half the known Chlamydiae. The other half are environmental Chlamydiae founded through the discovery of endosymbionts in free living amoeba. Phylogenic research has revealed the divergence from each other about 700 million years ago (2).

All known species of Chlamydiae are obligate intracellular parasites that not only infect humans but other vertebrates as well. They generally have a two-stage life cycle starting with the infection of a host cell by an elementary body. After ingestion by the host cell, the elementary body stops the fusion of its endosome with lysosomes, which allows it to survive within the endosome. From there, the elementary body develops into a metabolically active reticulate body that replicates by binary fission (3).

All Chlamydiae require host cells to manufacture high energy adenosine triphosphate metabolites due to their limited anaerobic capabilities (4). In the case of pathogenic Chlamydiae, such as C. trachomatis, the host is a human cell where as in environmental Chlamydiae such as Parachlamydia acanthamoebae amoebae are the host.

P. acanthamoebae strain UWE25 is a symbiont that was analyzed and found to be about twice as large as the genomes of present day pathogenic species (Table 1 (2)).

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Comparing UWE25 to other present-day pathogenic species it is shown that 711 CDSs are shared...