Research into chlamydial disease in koalas, led by
Dr. Adeeb Girjes
.

Dr Adeeb Girjes

Chlamydia

Chlamydiae are parasitic bacteria that grow in a variety of host cells. The intracellular development of these micro-organisms relies on high energy compounds from host cells for the completion of the unique life cycle. Nine species of Chlamydia have been described, including four major species; Chlamydia trachomatis (mainly infecting human beings), C. psittaci (mainly infecting birds), C. pecorum (mainly infecting sheep, cattle and perhaps koalas) and C. pnemoniae , which can infect humans, horses and maybe koalas.

Our research

Following our discovery of the two types of Chlamydia, designated as type I (generally associated with ocular disease) and type II (mainly associated with urogenital tract infection which causes infertility in koalas) that infect koalas, our research team is now planning to study in detail the types of Chlamydiathat infect kolas. Because of the similarity between koala type I strain and C. pneumoniae, some investigators have classified type I koala strain as a biovar of C. pneumoniae . Microbiological and molecular biological studies in our laboratory have revealed that the type-I strain of koala Chlamydiais not a member of C. pneumoniae, it is a new species that we now designate as C. koalae. We have found that this species is related, but not identical to C. pneumoniae and is sufficiently different to C. pneumoniae as to warrant classification as new species. We have also isolated genus-specific antigen genes coding for specific proteins (enzymes) involved in the biosynthesis of lipopolysaccharides (a major component of the chlamydial outer membrane). This compound plays an important role in the pathogenesis and manifestation of chlamydial infection.

Recent advances of our laboratory include

Isolation of koala immunoglobulin and preparation of rabbit anti-koala Ig.

Detection of chlamydial infection in koalas using four different methods developed in our laboratory;
        o     Gene probe
        o     Immunoscreening  -  blood samples or swab material.
        o     Tissue culture
        o     PCR ­we have developed primers to detect all chlamydial species including specific primers for koala type Chlamydia.

Our research is focussed on the following key areas:

    Studying the immune response in koalas to Chlamydia and other diseases.
    Using anti-sense technology to neutralise chlamydial infection in vitro and in vivo.
    Designing a DNA-binding drug to treat and inhibit chlamydial infection in vitro and in vivo.
    Studying the effect of two drugs (Baytril-50 & Azithromycin) on Chlamydia pneumoniae in culture.
    Studying the effect of two drugs (Baytril-50 & Azithromycin) on koala gut flora.
    Establishing a new koala cell line for in vitro study.

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