A tissue culture procedure for the isolation of chlamydia psittaci From koalas (phascolarctos cinereus)
by R. G. GRICE and A. S. BROWN*
Queensland Slate Health Department George St.. Brisbane, Australia 4000. and The Department of Veterinary Anatomy, University of Queensland, St. Lucia, Australia 4067
A tissue culture system used to isolate oculogenital strains of Chlamydia trachomatis from human specimens was adapted to screen koalas (Phascolarctos cinereus) for Chlamydia psittaci. The system employed an African green monkey kidney cell line designated BGM (Dahling, Berg and Berman, 1974) with centrifugation and cycloheximide to enhance infection and sensitivity of the cell sheets. Giemsa staining of the monolayers and reading under darkfield was adequate to detect intracytoplasmic inclusions. Isolates fulfil the criteria laid down for C. psittaci serotype 2. To overcome the effect of the cycloheximide on this serotype and successfully passage the organism, it was necessary to remove the anti-metabolite from the culture medium 24 h post-inoculation. The organism was recovered from diverse sites in live and dead animals. Swabs were taken from the conjunctival, nasal, rectal, penile urethral, vaginal, uterine, oviductular, bladder and urogenital sinus epithelia. A total of 630 swabs from 84 koalas yielded 85 positive swabs from 34 animals.