| 1. |
- van Bergen, Jan E. A. M., et al.
(författare)
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Where to go to in chlamydia control? : From infection control towards infectious disease control
- 2021
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Ingår i: Sexually Transmitted Infections. - : BMJ Publishing Group Ltd. - 1368-4973 .- 1472-3263. ; 97:7, s. 501-506
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Forskningsöversikt (refereegranskat)abstract
- Objectives: The clinical and public health relevance of widespread case finding by testing for asymptomatic chlamydia infections is under debate. We wanted to explore future directions for chlamydia control and generate insights that might guide for evidence-based strategies. In particular, we wanted to know the extent to which we should pursue testing for asymptomatic infections at both genital and extragenital sites.Methods: We synthesised findings from published literature and from discussions among national and international chlamydia experts during an invitational workshop. We described changing perceptions in chlamydia control to inform the development of recommendations for future avenues for chlamydia control in the Netherlands.Results: Despite implementing a range of interventions to control chlamydia, there is no practice-based evidence that population prevalence can be reduced by screening programmes or widespread opportunistic testing. There is limited evidence about the beneficial effect of testing on pelvic inflammatory disease prevention. The risk of tubal factor infertility resulting from chlamydia infection is low and evidence on the preventable fraction remains uncertain. Overdiagnosis and overtreatment with antibiotics for self-limiting and non-viable infections have contributed to antimicrobial resistance in other pathogens and may affect oral, anal and genital microbiota. These changing insights could affect the outcome of previous cost-effectiveness analysis.Conclusion: The balance between benefits and harms of widespread testing to detect asymptomatic chlamydia infections is changing. The opinion of our expert group deviates from the existing paradigm of 'test and treat' and suggests that future strategies should reduce, rather than expand, the role of widespread testing for asymptomatic chlamydia infections.
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| 2. |
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| 3. |
- Christerson, Linus, et al.
(författare)
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Chlamydia trachomatis Strains Show Specific Clustering for Men Who Have Sex with Men Compared to Heterosexual Populations in Sweden, the Netherlands, and the United States
- 2012
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Ingår i: Journal of Clinical Microbiology. - 0095-1137 .- 1098-660X. ; 50:11, s. 3548-3555
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Tidskriftsartikel (refereegranskat)abstract
- High-resolution genotyping of Chlamydia trachomatis improves the characterization of strains infecting different patient groups and sexual networks. In this study, multilocus sequence typing (MLST) and ompA sequence determination were used for an analysis of C. trachomatis strains from 203 men who have sex with men (MSM) from Sweden, the Netherlands, and the United States. The results obtained were compared with data from 153 heterosexual women from Sweden and the Netherlands. The overlap in MLST/ompA profiles between MSM from Sweden and the Netherlands was 68%, while the overlap between heterosexual populations from these countries was only 18%. The distribution of genotypes in MSM from the United States was less similar to that in MSM from the European countries, with 45% and 46% overlaps for MSM in Sweden and the Netherlands, respectively. Minimum-spanning-tree analysis of MLST/ompA sequence types identified two large clusters that contained almost exclusively samples from MSM and comprised 74% of all MSM samples. Three other clusters were predominated by samples from women but also contained MSM specimens. Of 19 detected variants of the MLST target CT144, three variants were highly associated with MSM. Our study supports the hypotheses of both tissue tropism as well as epidemiological network structures as explanations for the linkage between specific genetic variants and sexual orientation.
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| 4. |
- Christerson, Linus, et al.
(författare)
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Typing of Lymphogranuloma Venereum Chlamydia trachomatis Strains
- 2010
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Ingår i: Emerging Infectious Diseases. - : Centers for Disease Control and Prevention (CDC). - 1080-6040 .- 1080-6059. ; 16:11, s. 1777-1779
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Tidskriftsartikel (refereegranskat)abstract
- We analyzed by multilocus sequence typing 77 lymphogranuloma venereum Chlamydia trachomatis strains from men who have sex with men in Europe and the United States. Specimens from an outbreak in 2003 in Europe were monoclonal. In contrast, several strains were in the United States in the 1980s, including a variant from Europe.
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| 5. |
- Harris, Simon R., et al.
(författare)
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Whole-genome analysis of diverse Chlamydia trachomatis strains identifies phylogenetic relationships masked by current clinical typing
- 2012
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Ingår i: Nature Genetics. - : Nature Publishing Group. - 1061-4036 .- 1546-1718. ; 44:4, s. 413-419
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Tidskriftsartikel (refereegranskat)abstract
- Chlamydia trachomatis is responsible for both trachoma and sexually transmitted infections, causing substantial morbidity and economic cost globally. Despite this, our knowledge of its population and evolutionary genetics is limited. Here we present a detailed phylogeny based on whole-genome sequencing of representative strains of C. trachomatis from both trachoma and lymphogranuloma venereum (LGV) biovars from temporally and geographically diverse sources. Our analysis shows that predicting phylogenetic structure using ompA, which is traditionally used to classify Chlamydia, is misleading because extensive recombination in this region masks any true relationships present. We show that in many instances, ompA is a chimera that can be exchanged in part or as a whole both within and between biovars. We also provide evidence for exchange of, and recombination within, the cryptic plasmid, which is another key diagnostic target. We used our phylogenetic framework to show how genetic exchange has manifested itself in ocular, urogenital and LGV C. trachomatis strains, including the epidemic LGV serotype L2b.
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| 6. |
- Seth-Smith, Helena M. B., et al.
(författare)
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Ongoing evolution of Chlamydia trachomatis lymphogranuloma venereum : exploring the genomic diversity of circulating strains
- 2021
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Ingår i: Microbial Genomics. - : Microbiology Society. - 2057-5858. ; 7:6
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Tidskriftsartikel (refereegranskat)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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| 7. |
- Van Den Heuvel, Lambertus, et al.
(författare)
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Genetic predisposition to infection in a case of atypical hemolytic uremic syndrome
- 2018
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Ingår i: Journal of Human Genetics. - : Springer Science and Business Media LLC. - 1434-5161 .- 1435-232X. ; 63:1, s. 93-96
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Tidskriftsartikel (refereegranskat)abstract
- Most cases of hemolytic uremic syndrome (HUS) are caused by infection with enterohemorrhagic Escherichia coli (EHEC). Genetic defects causing uncontrolled complement activation are associated with the more severe atypical HUS (aHUS). Non-EHEC infections can trigger the disease, however, complement defects predisposing to such infections have not yet been studied. We describe a 2-month-old patient infected with different Gram-negative bacterial species resulting in aHUS. Serum analysis revealed slow complement activation kinetics. Rare variant R229C was found in complement inhibitor vitronectin. Recombinant mutated vitronectin showed enhanced complement inhibition in vitro and may have been a predisposing factor for infection. Our work indicates that genetic changes in aHUS can not only result in uncontrolled complement activation but also increase vulnerability to infections contributing to aHUS.
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| 8. |
- Hadfield, James, et al.
(författare)
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Comprehensive global genome dynamics of Chlamydia trachomatis show ancient diversification followed by contemporary mixing and recent lineage expansion
- 2017
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Ingår i: Genome Research. - : Cold Spring Harbor Laboratory Press. - 1088-9051 .- 1549-5469. ; 27:7, s. 1220-1229
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Tidskriftsartikel (refereegranskat)abstract
- Chlamydia trachomatis is the world's most prevalent bacterial sexually transmitted infection and leading infectious cause of blindness, yet it is one of the least understood human pathogens, in part due to the difficulties of in vitro culturing and the lack of available tools for genetic manipulation. Genome sequencing has reinvigorated this field, shedding light on the contemporary history of this pathogen. Here, we analyze 563 full genomes, 455 of which are novel, to show that the history of the species comprises two phases, and conclude that the currently circulating lineages are the result of evolution in different genomic ecotypes. Temporal analysis indicates these lineages have recently expanded in the space of thousands of years, rather than the millions of years as previously thought, a finding that dramatically changes our understanding of this pathogen's history. Finally, at a time when almost every pathogen is becoming increasingly resistant to antimicrobials, we show that there is no evidence of circulating genomic resistance in C. trachomatis.
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| 9. |
- Ruettger, Anke, et al.
(författare)
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Genotyping of Chlamydia trachomatis strains from culture and clinical samples using an ompA-based DNA microarray assay
- 2011
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Ingår i: Molecular and Cellular Probes. - : Elsevier BV. - 0890-8508 .- 1096-1194. ; 25:1, s. 19-27
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Tidskriftsartikel (refereegranskat)abstract
- Current typing methods of Chlamydia (C) trachomatis are mainly based on the diversity of the ompA gene, which is coding for the major outer membrane protein A. The present study aimed at facilitating genotyping of strains of this obligate intracellular human pathogen by developing a DNA microarray assay using the ArrayTube (TM) format for individual samples and the ArrayStrip (TM) format for higher throughput. The new test is exploiting multiple discriminatory sites by involving a total of 61 oligonucleotide probes representing genotype-specific polymorphisms in variable domains 1, 2 and 4 of the ompA gene. After multiplex amplification of these domains using biotinylated primers, the sample is hybridized in the microarray vessel under highly stringent conditions. The resulting binding pattern is genotype specific, thus allowing direct identification. We were able to show that DNA from each of the currently accepted genotypes (serovars) yielded a unique, theoretically expected and distinct hybridization pattern. The assay was also shown to be highly sensitive as a dilution containing the equivalent of 1 inclusion-forming unit was still correctly genotyped. In addition, when 62 clinical samples were examined and compared to PCR-RFLP typing results, the genotype was correctly identified by the DNA microarray in all cases. The present test is easy to handle and economically affordable, and it allows genotyping of C. trachomatis to be accomplished within a working day, thus lending itself for epidemiological studies and routine diagnosis.
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