Use of quantitative real-time PCR to monitor the shedding and treatment of chlamydiae in the koala (Phascolarctos cinereus)
Markey, B, Wan, C, Hanger, J, Phillips, C & Timms P 2007, Veterinary Microbiology, vol. 120, no. 1, pp. 334-342.
A quantitative real-time analysis revealed that antibiotic treatment for koalas with chlamydial infections caused chlamydiae to shed rapidly and in great numbers from both ocular and urogenital sites, with the majority of infections cleared after two weeks of treatment.
The polymerase chain reaction (PCR) assay is considered to be a reliable method for detecting chlamydiae in koalas. The purpose of this study was to use PCR analysis to quantify the chlamydiae shed in koalas treated for Chlamydia with antibiotics in order to determine the effects of the treatment in real-time. Koalas presented to a wildlife hospital were categorised according to their clinical symptoms of chlamydial infection: ophthalmic disease, urinary tract disease, or both. All koalas were treated with the antibiotic chloramphenicol at a dosage and via a route appropriate to their condition. Samples from various bodily sites were collected from each animal continuously for a period of eight to nine weeks during treatment, as well as a final sample taken two weeks after treatment had ended. In all but one koala, the antibiotic treatment was successful in combating the infection by the end of the second week of treatment, after which chlamydiae were no longer shedding. This result was the same for all groups with infections at different sites. As expected, the chlamydial copy number was consistently higher in the swab samples taken from clinically affected sites than from sites where no symptoms were exhibited. Furthermore, all chlamydial isolates were found to be Chlamydia pecorum, which is the most common chlamydial infection type in koalas.
Because the majority of infections were cleared following antibiotic treatment within only two weeks, the authors of this study suggest that the duration of treatment could be reduced from eight or nine weeks to only three weeks and still produce the desired results. Further research to investigate this possibility would be beneficial for the improvement of therapeutic regimes for treating chlamydial infection in koalas.
Summarised by Joanna Horsfall
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