Genome sequencing of recent clinical Chlamydia trachomatis strains identifies loci associated with tissue tropism and regions of apparent recombination.

TitleGenome sequencing of recent clinical Chlamydia trachomatis strains identifies loci associated with tissue tropism and regions of apparent recombination.
Publication TypeJournal Article
Year of Publication2010
AuthorsJeffrey BM, Suchland RJ, Quinn KL, Davidson JR, Stamm WE, Rockey DD
JournalInfection and immunity
Volume78
Issue6
Pagination2544-53
Date Published2010 Jun
ISSN1098-5522
KeywordsAnal Canal, Cervix Uteri, Chlamydia trachomatis, DNA, Bacterial, Female, Genome, Bacterial, Humans, Lymphogranuloma Venereum, Male, Molecular Sequence Data, Polymorphism, Genetic, Recombination, Genetic, Sequence Analysis, DNA, Virulence Factors
Abstract

The human pathogen Chlamydia trachomatis exists as multiple serovariants that have distinct organotropisms for different tissue sites. Culture and epidemiologic data have demonstrated that serovar G is more prevalent, while serovar E is less prevalent, for rectal isolates from men having sex with men (MSM). The relative prevalence of these serovars is the opposite for isolates from female cervical infections. In contrast, the prevalence of serovar J isolates is approximately the same at the different tissue sites, and these isolates are the only C-class strains that are routinely cultured from MSM populations. These correlations led us to hypothesize that polymorphisms in open reading frame (ORF) sequences correlate with the different tissue tropisms of these serovars. To explore this possibility, we sequenced and compared the genomes of clinical anorectal and cervical isolates belonging to serovars E, G, and J and compared these genomes with each other, as well as with a set of previously sequenced genomes. We then used PCR- and restriction digestion-based genotyping assays performed with a large collection of recent clinical isolates to show that polymorphisms in ORFs CT144, CT154, and CT326 were highly associated with rectal tropism in serovar G isolates and that polymorphisms in CT869 and CT870 were associated with tissue tropism across all serovars tested. The genome sequences collected were also used to identify regions of likely recombination in recent clinical strains. This work demonstrated that whole-genome sequencing along with comparative genomics is an effective approach for discovering variable loci in Chlamydia spp. that are associated with clinical presentation.

Alternate JournalInfect. Immun.