suis, C. felis, C. psittaci, C. caviae, and C. pecorum [3–5]. For the purpose of this research paper, we will refer to koala C. pecorum strains using this proposed nomenclature. While each

of these are responsible for a number of disease states in a wide range of animals (including humans), the prevalence and transmission this website of C. pneumoniae and C. pecorum throughout Australian koala populations has contributed to a significant decline in koala numbers and remain a critical threat to the koala’s continued survival [6–8]. C. pneumoniae and C. pecorum have been isolated from most koala populations investigated, with C. pecorum found to be the most widespread and pathogenic of the two species [7–10]. Notably, C. pecorum is also recognised as a pathogen and causative agent of polyarthritis and abortion in sheep and Androgen Receptor phosphorylation cattle [11]. In the koala, clinical manifestations of C. pecorum include ocular infection

leading to conjunctival scarring and blindness, respiratory tract infection, urinary tract infection causing incontinence, and genital tract infection potentially leading to infertility [6, 7, 12–14]. The latter disease signs have been implicated in lowered reproductive rates in wild koala populations in several parts of Australia, highlighting the need to understand this complex host-parasite relationship for the purpose of effective management and control strategies [8]. Questions remain about the evolutionary origin of C. pecorum in koalas, given its traditional role as a pathogen of sheep and cattle, and the modes of transmission within and between geographically isolated koala populations. In an attempt to understand these questions, Metabolism inhibitor Jackson et al., have previously BCKDHA performed fine-detailed epidemiological surveys of C. pecorum-infected koala populations, revealing that C. pecorum is genetically very diverse [7]. This analysis was performed on short variable domain IV (VDIV)

sequence fragments of the ompA gene, encoding the surface-exposed major outer membrane protein (MOMP) which is common to all members of the Chlamydiaceae [15]. There are currently eight ompA VDIV genotypes that have been identified, following several studies of geographically isolated koala populations in Australia [7, 8, 14, 16, 17]. While the majority of these genotypes are apparently confined to the koala host, several identical or near-identical sequences have been found in European sheep and cattle implying the possibility of cross-species transmission events between these hosts [7]. Questions, however, remain regarding the use of ompA as a single gene marker of chlamydial diversity. From a phylogenetic perspective, previous studies in other chlamydial species have demonstrated that ompA phylogenies are not congruent with the phylogeny of other gene targets, including other membrane proteins [18–20]. Similar observations have also been made for non-koala strains of C. pecorum [11, 21], indicating that C.