Two distinct forms of Chlamydia psittaci associated with disease and infertility in Phascolarctos cinereus (koala)

While several diseases associated with Chlamydia psittaci infection have been reported in Phascolarctos cinereus (koala), it is still unclear whether one or more chlamydial strains are responsible. In this study, we provide evidence, obtained by restriction enzyme and gene probe analysis, that two quite distinct strains of C. psittaci infect koalas; one strain was isolated from the conjunctivae, and the other was isolated from the urogenital tract and the rectum. A gene probe, pFEN207, containing the coding sequence for an enzyme involved in the biosynthesis of the chlamydial genus-specific lipopolysaccharide antigen, and a separate probe, pCPML-4N, prepared from a DNA fragment of a koala-infecting strain of C. psittaci, were used to determine the patterns of hybridization in the koala-infecting strains; these patterns were found to be quite distinct from those observed with C. psittaci isolates from other animals. We also demonstrated by hybridization analysis with an avian strain plasmid that all three koala urogenital isolates contain a plasmid and that there is no evidence for the presence of a homologous plasmid in any of the ocular isolates.