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- Seth-Smith, Helena M. B., et al.
(author)
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Ongoing evolution of Chlamydia trachomatis lymphogranuloma venereum : exploring the genomic diversity of circulating strains
- 2021
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In: Microbial Genomics. - : Microbiology Society. - 2057-5858. ; 7:6
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Journal article (peer-reviewed)abstract
- Lymphogranuloma venereum (LGV), the invasive infection of the sexually transmissible infection (STI) Chlamydia trachomatis, is caused by strains from the LGV biovar, most commonly represented by ompA- genotypes L2b and L2. We investigated the diversity in LGV samples across an international collection over seven years using typing and genome sequencing. LGV- positive samples (n=321) from eight countries collected between 2011 and 2017 (Spain n=97, Netherlands n=67, Switzerland n=64, Australia n=53, Sweden n=37, Hungary n=31, Czechia n=30, Slovenia n=10) were genotyped for pmpH and ompA variants. All were found to contain the 9 bp insertion in the pmpH gene, previously associated with ompA- genotype L2b. However, analysis of the ompA gene shows ompA- genotype L2b (n=83), ompA- genotype L2 (n=180) and several variants of these (n=52; 12 variant types), as well as other/mixed ompA-genotypes (n=6). To elucidate the genomic diversity, whole genome sequencing (WGS) was performed from selected samples using SureSelect target enrichment, resulting in 42 genomes, covering a diversity of ompA- genotypes and representing most of the countries sampled. A phylogeny of these data clearly shows that these ompA- genotypes derive from an ompA- genotype L2b ancestor, carrying up to eight SNPs per isolate. SNPs within ompA are overrep-resented among genomic changes in these samples, each of which results in an amino acid change in the variable domains of OmpA (major outer membrane protein, MOMP). A reversion to ompA- genotype L2 with the L2b genomic backbone is commonly seen. The wide diversity of ompA- genotypes found in these recent LGV samples indicates that this gene is under immunological selection. Our results suggest that the ompA- genotype L2b genomic backbone is the dominant strain circulating and evolving particularly in men who have sex with men (MSM) populations.
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