Chlamydia pecorum gastrointestinal tract infection associations with urogenital tract infections in the koala (Phascolarctos cinereus)

PLoS One. 2018 Nov 1;13(11):e0206471. doi: 10.1371/journal.pone.0206471. eCollection 2018.


Background: Chlamydia infects multiple sites within hosts, including the gastrointestinal tract (GIT). In certain hosts, gastrointestinal infection is linked to treatment avoidance and self-infection at disease susceptible sites. GIT C. pecorum has been detected in livestock and koalas, however GIT prevalence rates within the koala are yet to be established.

Methods: Paired conjunctival, urogenital and rectal samples from 33 koalas were screened for C. pecorum and C. pecorum plasmid using 16S rRNA and CDS5-specific quantitative PCR assays, respectively. Amplicon sequencing of 359 bp ompA fragment was used to identify site-specific genotypes.

Results: The overall C. pecorum prevalence collectively (healthy and clinically diseased koalas) was 51.5%, 57.6% and 42.4% in urogenital, conjunctival and gastrointestinal sites, respectively. Concurrent urogenital and rectal Chlamydia was identified in 14 koalas, with no cases of GIT only Chlamydia shedding. The ompA genotype G dominated the GIT positive samples, and genotypes A and E' were dominant in urogenital tract (UGT) positive samples. Increases in C. pecorum plasmid per C. pecorum load (detected by PCR) showed clustering in the clinically diseased koala group (as assessed by scatter plot analysis). There was also a low correlation between plasmid positivity and C. pecorum infected animals at any site, with a prevalence of 47% UGT, 36% rectum and 40% faecal pellet.

Conclusions: GIT C. pecorum PCR positivity suggests that koala GIT C. pecorum infections are common and occur regularly in animals with concurrent genital tract infections. GIT dominant genotypes were identified and do not appear to be related to plasmid positivity. Preliminary results indicated a possible association between C. pecorum plasmid load and clinical UGT disease.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Chlamydia / classification
  • Chlamydia / genetics
  • Chlamydia / isolation & purification
  • Chlamydia Infections / complications
  • Chlamydia Infections / epidemiology*
  • Chlamydia Infections / veterinary
  • Eye Infections, Bacterial / complications
  • Eye Infections, Bacterial / epidemiology
  • Eye Infections, Bacterial / veterinary
  • Female
  • Gastrointestinal Diseases / complications
  • Gastrointestinal Diseases / epidemiology*
  • Gastrointestinal Diseases / veterinary
  • Genotype
  • Male
  • Phascolarctidae / microbiology*
  • Plasmids / analysis
  • Prevalence
  • RNA, Ribosomal, 16S / analysis
  • Urinary Tract Infections / complications
  • Urinary Tract Infections / epidemiology*
  • Urinary Tract Infections / veterinary
  • Urogenital System / microbiology


  • RNA, Ribosomal, 16S

Grants and funding

This project was financially supported by Australian Research Council (ARC, Linkage Scheme) to PT and AP. This project was significantly supported by the Queensland Government (Department of Transport and Main Roads) and specifically the Moreton Bay Rail Link project team. JH, JL and AR were employed by Endeavour Veterinary Ecology (EVE). EVE provided support in the form of salaries for JH, JL and AR, but did not have any additional role in the study design, data collection and analysis, decision to publish, or preparation of the manuscript. The Australian Research Council also did not play a role in the study design, data collection and analysis, decision to publish, or preparation of the manuscript and only provided financial support in the form of authors' salaries and research materials.