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Comparison of koala LPCoLN and human strains of Chlamydia pneumoniae highlights extended genetic diversity in the species

Candice M Mitchell1, Kelley M Hovis2, Patrik M Bavoil2, Garry SA Myers3, Jose A Carrasco2 and Peter Timms1*

Author Affiliations

1 Institute of Health and Biomedical Innovation, Faculty of Science and Technology, Queensland University of Technology, Kelvin Grove, Queensland, 4059, Australia

2 Department of Microbial Pathogenesis, University of Maryland, Baltimore, Maryland 21201, USA

3 Institute for Genome Sciences, University of Maryland, Baltimore, Maryland 21201, USA

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BMC Genomics 2010, 11:442  doi:10.1186/1471-2164-11-442

Published: 21 July 2010



Chlamydia pneumoniae is a widespread pathogen causing upper and lower respiratory tract infections in addition to a range of other diseases in humans and animals. Previous whole genome analyses have focused on four essentially clonal (> 99% identity) C. pneumoniae human genomes (AR39, CWL029, J138 and TW183), providing relatively little insight into strain diversity and evolution of this species.


We performed individual gene-by-gene comparisons of the recently sequenced C. pneumoniae koala genome and four C. pneumoniae human genomes to identify species-specific genes, and more importantly, to gain an insight into the genetic diversity and evolution of the species. We selected genes dispersed throughout the chromosome, representing genes that were specific to C. pneumoniae, genes with a demonstrated role in chlamydial biology and/or pathogenicity (n = 49), genes encoding nucleotide salvage or amino acid biosynthesis proteins (n = 6), and extrachromosomal elements (9 plasmid and 2 bacteriophage genes).


We have identified strain-specific differences and targets for detection of C. pneumoniae isolates from both human and animal origin. Such characterisation is necessary for an improved understanding of disease transmission and intervention.