Clinical comparison of five anti-chlamydial antibiotics in koalas (Phascolarctos cinereus).

Publisher: Public Library of Science Country of Publication: United States NLM ID: 101285081 Publication Model: eCollection Cited Medium: Internet ISSN: 1932-6203 (Electronic) Linking ISSN: 19326203 NLM ISO Abbreviation: PLoS One Subsets: MEDLINE

Original Publication: San Francisco, CA : Public Library of Science

Anti-Bacterial Agents/*pharmacology ; Chlamydia/*drug effects ; Chlamydia Infections/*drug therapy ; Phascolarctidae/*microbiology; Animals ; Australia ; Azithromycin/pharmacology ; Chlamydia Infections/microbiology ; Chlamydia Infections/pathology ; Chloramphenicol/pharmacology ; Doxycycline/pharmacology ; Enrofloxacin/pharmacology ; Female ; Male ; Thiamphenicol/analogs & derivatives ; Thiamphenicol/pharmacology

Chlamydiosis is the most significant infectious disease of koalas (Phascolarctos cinereus). It is primarily a systemic sexually transmitted disease caused by Chlamydia pecorum and was responsible for 46% of the 2348 koala admissions to Australia Zoo Wildlife Hospital between 2013 and 2017. Treatment of chlamydiosis in koalas is complicated by three major factors. Firstly, koalas rely on bacterial fermentation of their high fibre diet making antibiotic therapy a risk. Secondly, they possess efficient metabolic pathways for the excretion of plant toxins and potentially of therapeutic agents. Thirdly, wild koalas, often present to rehabilitation facilities with chronic and severe disease. Traditional anti-chlamydial antibiotics used in other species may cause fatal dysbiosis in koalas or be excreted before they can be effective. We compared five anti-chlamydial antibiotics, azithromycin, chloramphenicol, doxycycline, enrofloxacin and florfenicol, which were used to treat 86 wild koalas with chlamydiosis presented to Australia Zoo Wildlife Hospital under consistent conditions of nutrition, housing, husbandry and climate. Response to treatment was assessed by recovery from clinical signs, and clearance of detectable Chlamydia via quantitative PCR. Doxycycline was the most effective anti-chlamydial antibiotic of the five, producing a 97% cure rate, followed by chloramphenicol (81%), enrofloxacin (75%), florfenicol (66%) and azithromycin (25%). The long-acting injectable preparation of doxycycline was well tolerated by koalas when administered via the subcutaneous route, and the weekly dosing requirement is a major advantage when treating wild animals. These findings indicate that doxycycline is the current drug of choice for the treatment of chlamydiosis in koalas, with chloramphenicol being the best alternative.
Competing Interests: The authors have declared that no competing interests exist.

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0 (Anti-Bacterial Agents)
3DX3XEK1BN (Enrofloxacin)
66974FR9Q1 (Chloramphenicol)
83905-01-5 (Azithromycin)
9J97307Y1H (florfenicol)
FLQ7571NPM (Thiamphenicol)
N12000U13O (Doxycycline)

Date Created: 20200731 Date Completed: 20200924 Latest Revision: 20200924

20240829

PMC7392309

10.1371/journal.pone.0236758

32730301