Emergence and Spread of<i>Chlamydia trachomatis</i>Variant, Sweden

Herrmann, Björn; Törner, Anna; Low, Nicola; Klint, Markus; Nilsson, Anders; Veličko, Inga; Söderblom, Thomas; Blaxhult, Anders

doi:10.3201/eid1409.080153

Cited by 77 publications

(108 citation statements)

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“…The collection period for Swedish heterosexual populations included the year 2006, when the incidence of the new variant of C. trachomatis peaked (13,16). The inclusion of this new variant would result in a proportion of 60% genovar E samples, but here, we found a proportion of 40% among Swedish heterosexual populations, which is a representative figure for Sweden in other years and also similar to data from reports from other countries (17,24,25,31,33).…”

Section: Discussionsupporting

confidence: 87%

“…To minimize sampling bias, we excluded samples that were known to have LGV genovars or the new variant genovar E. These two types of samples were also typed previously with the presently used MLST method and found to be completely identical in all 6 regions per genovar and were thus designated clonal isolates (6,13,16,19). Another limitation is that the categorization of sexual orientation for the included persons may have been erroneous.…”

Section: Discussionmentioning

confidence: 99%

“…Another clonal outbreak occurred mainly in Sweden and was due to a new variant of C. trachomatis, leading to the generation of false-negative results by some molecular detection systems. This variant is a genovar E strain and has not been reported to occur in MSM (13,16,19).…”

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confidence: 85%

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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

et al. 2012

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f 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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Section: Discussionsupporting

confidence: 87%

Section: Discussionmentioning

confidence: 99%

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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

et al. 2012

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“…49 However, given the nature of the intervention this was an appropriate method that allowed us to interview geographically dispersed individuals. We were reliant on young people's self-reports, which may differ from actual behaviour, and we were unable to explore the extent to which any behaviour change might be sustained.…”

Section: Strengths and Weaknesses Of The Qualitative Interviewsmentioning

confidence: 99%

Can text messages increase safer sex behaviours in young people? Intervention development and pilot randomised controlled trial

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McCarthy

French

et al. 2016

Health Technol Assess

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BackgroundYounger people bear the heaviest burden of sexually transmitted infections (STIs). Partner notification, condom use and STI testing can reduce infection but many young people lack the knowledge, skills and confidence needed to carry out these behaviours. Text messages can provide effective behavioural support. The acceptability and feasibility of a randomised controlled trial of safer sex support delivered by text message are not known.ObjectivesTo assess the acceptability and feasibility of a randomised controlled trial of a safer sex intervention delivered by text message for young people aged 16–24 years.Design(1) Intervention development; (2) follow-up procedure development; (3) a pilot, parallel-arm randomised controlled trial with allocation via remote automated randomisation (ratio of 1 : 1) (participants were unmasked, whereas researchers analysing samples and data were masked); and (4) qualitative interviews.SettingParticipants were recruited from sexual health services in the UK.ParticipantsYoung people aged 16–24 years diagnosed with chlamydia or reporting unprotected sex with more than one partner in the last year.InterventionsA theory- and evidence-based safer sex intervention designed, with young people’s input, to reduce the incidence of STIs by increasing the correct treatment of STIs, partner notification, condom use and STI testing before unprotected sex with a new partner. The intervention was delivered via automated mobile phone messaging over 12 months. The comparator was a monthly text message checking contact details.Main outcome measures(1) Development of the intervention based on theory, evidence and expert and user views; (2) follow-up procedures; (3) pilot trial primary outcomes: full recruitment within 3 months and follow-up rate for the proposed primary outcomes for the main trial; and (4) participants’ views and experiences regarding the acceptability of the intervention.ResultsIn total, 200 participants were randomised in the pilot trial, of whom 99 were allocated to the intervention and 101 were allocated to the control. We fully recruited early and achieved an 81% follow-up rate for our proposed primary outcome of the cumulative incidence of chlamydia at 12 months. There was no differential follow-up between groups. In total, 97% of messages sent were successfully delivered to participants’ mobile phones. Recipients reported that the tone, language, content and frequency of messages were appropriate. Messages reportedly increased knowledge of and confidence in how to use condoms and negotiate condom use and reduced stigma about STIs, enabling participants to tell a partner about a STI.ConclusionsOur research shows that the intervention is acceptable and feasible to deliver. Our pilot trial demonstrated that a main trial is feasible. It remains unclear which behaviour change techniques and elements of the intervention or follow-up procedures are associated with effectiveness. A further limitation is that in the trial one person entering data and the participants were unmasked. A randomised controlled trial to establish the effects of the intervention on STIs at 12 months is needed.Trial registrationCurrent Controlled Trials ISRCTN02304709.FundingThis project was funded by the National Institute for Health Research (NIHR) Health Technology Assessment programme and will be published in full inHealth Technology Assessment; Vol. 20, No. 57. See the NIHR Journals Library website for further project information.

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“…The third scheme was developed by Klint et al (10); it is intended for short-term clinical epidemiology and outbreak investigations and is based on five highly variable genomic loci (hctB [CT046], CT058, CT144, CT172, and pbpB [CT682]). The MLST scheme has been slightly modified to facilitate rational processing with only 1% loss of discriminatory capacity (13), and the current setup can be found at the Uppsala University C. trachomatis MLST database (http: //mlstdb.bmc.uu.se).Since its development in 2007, the scheme has been applied to a variety of clinical specimens, including samples from cases of urogenital chlamydia (7,(13)(14)(15)(16)(17)(18)(19)(20)(21), LGV (22,23), and trachoma (24). It has been useful for different purposes: (i) identification of clonal spread of LGV (22) …”

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Global Multilocus Sequence Type Analysis of Chlamydia trachomatis Strains from 16 Countries

et al. 2015

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eThe Uppsala University Chlamydia trachomatis multilocus sequence type (MLST) database (http://mlstdb.bmc.uu.se) is based on five target regions (non-housekeeping genes) and the ompA gene. Each target has various numbers of alleles-hctB, 89; CT058, 51; CT144, 30; CT172, 38; and pbpB, 35-derived from 13 studies. Our aims were to perform an overall analysis of all C. trachomatis MLST sequence types (STs) in the database, examine STs with global spread, and evaluate the phylogenetic capability by using the five targets. A total of 415 STs were recognized from 2,089 specimens. The addition of 49 ompA gene variants created 459 profiles. ST variation and their geographical distribution were characterized using eBURST and minimum spanning tree analyses. There were 609 samples from men having sex with men (MSM), with 4 predominating STs detected in this group, comprising 63% of MSM cases. Four other STs predominated among 1,383 heterosexual cases comprising, 31% of this group. The diversity index in ocular trachoma cases was significantly lower than in sexually transmitted chlamydia infections. Predominating STs were identified in 12 available C. trachomatis whole genomes which were compared to 22 C. trachomatis full genomes without predominating STs. No specific gene in the 12 genomes with predominating STs could be linked to successful spread of certain STs. Phylogenetic analysis showed that MLST targets provide a tree similar to trees based on whole-genome analysis. The presented MLST scheme identified C. trachomatis strains with global spread. It provides a tool for epidemiological investigations and is useful for phylogenetic analyses. Chlamydia trachomatis is one of the most common sexually transmitted infections (STIs) worldwide (1), and besides urogenital infections, it also causes lymphogranuloma venereum (LGV), which is a rare but more invasive sexually transmitted disease. In addition, C. trachomatis causes the eye infection trachoma, which is the major infectious cause of preventable blindness worldwide. Severe sequelae from urogenital chlamydia infections include ectopic pregnancy and infertility (2). In spite of testing, treatment, partner notification, and counseling, huge public health efforts have not been able to control urogenital chlamydia infections. Current knowledge about the role of repeated infections and transmission in sexual networks is still limited and needs to be extended to achieve a reduction in the rate of infections.In this context, it is important to have adequate tools for genotyping to understand the epidemiology of chlamydia infections. Traditional typing of C. trachomatis was based on serotyping of the major outer membrane protein (MOMP) and, later on, genotyping of the ompA gene, which encodes MOMP. However, neither MOMP nor ompA provides sufficient discriminatory power for epidemiological purposes (3). In most countries, almost half of all urogenital chlamydia infections are of serotype E, and within this serotype the ompA E/Bour genotype predominates (4-8). Therefore, other typ...

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Emergence and Spread ofChlamydia trachomatisVariant, Sweden

Cited by 77 publications

References 10 publications

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

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

Can text messages increase safer sex behaviours in young people? Intervention development and pilot randomised controlled trial

Global Multilocus Sequence Type Analysis of Chlamydia trachomatis Strains from 16 Countries

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