The effects of free condom distribution on HIV and other sexually transmitted infections in men who have sex with men.

BACKGROUND: HIV and other sexually transmitted infections remain a burden on men who have sex with men in the era of effective combination antiretroviral therapy. New prevention efforts are therefore needed. One of these approaches is the current country-wide free condom distribution at gay bars with darkrooms and gay saunas in the Netherlands. This study assessed the effects of free condom distribution on incidence and burden of disease of HIV and other sexually transmitted infections. METHODS: A static model was constructed to calculate the impact of free condom distribution on HIV, hepatitis C, chlamydia, gonorrhoea, and syphilis among men who have sex with men visiting these venues. Outcomes included new infections averted and disability-adjusted life years averted. Scenario studies were performed to predict the effects of a further increase of condom use, condom effectiveness and coverage. Lastly, cost-effectiveness and sensitivity analyses were performed. RESULTS: Our model showed that condom use at public sex venues increased after the intervention. Annual incidence risk decreased, ranging from 5.73% for gonorrhoea to 7.62% for HIV. The annual number of new infections averted was largest for chlamydia and gonorrhoea (261 and 394 infections, respectively), but 42 new HIV infections were averted as well. In scenarios where condom use and condom effectiveness were further increased, the number of infections reduced more extensively. Over 99% of the decrease in burden of disease was due to HIV. The intervention was cost-effective and cost-saving (for every €1 spent on condom distribution, €5.51 was saved) and remained this in all sensitivity analyses. CONCLUSIONS: Free condoms at public sex venues could reduce the transmission of HIV and other sexually transmitted infections. Condom distribution is an affordable and easily implemented intervention that could reduce the burden of disease in men who have sex with men substantially.

Urogenital Chlamydia trachomatis strain types, defined by high-resolution multilocus sequence typing, in relation to ethnicity and urogenital symptoms among a young screening population in Amsterdam, The Netherlands.

INTRODUCTION: Previous studies found conflicting results regarding associations between urogenital Chlamydia trachomatis infections and ethnicity or urogenital symptoms among at-risk populations using either ompA-based genotyping or high-resolution multilocus sequence typing (MLST). This study applied high-resolution MLST on samples of individuals from a selected young urban screening population to assess the relationship of C. trachomatis strain types with ethnicity and self-reported urogenital symptoms. Demographic and sexual risk behaviour characteristics of the identified clusters were also analysed. METHODS: We selected C. trachomatis-positive samples from the Dutch Chlamydia Screening Implementation study among young individuals in Amsterdam, the Netherlands. All samples were typed using high-resolution MLST. Clusters were assigned using minimum spanning tree analysis and were combined with epidemiological data of the participants. RESULTS: We obtained full MLST data for C. trachomatis-positive samples from 439 participants and detected nine ompA genovars. MLST analysis identified 175 sequence types and six large clusters; in one cluster, participants with Surinamese/Antillean ethnicity were over-represented (58.8%) and this cluster predominantly consisted of genovar I. In addition, we found one cluster with an over-representation of participants with Dutch ethnicity (90.0%) and which solely consisted of genovar G. No association was observed between C. trachomatis clusters and urogenital symptoms. CONCLUSIONS: We found an association between urogenital C. trachomatis clusters and ethnicity among young screening participants in Amsterdam, the Netherlands. However, no association was found between C. trachomatis clusters and self-reported urogenital symptoms.

Use of Chlamydia trachomatis high-resolution typing: an extended case study to distinguish recurrent or persistent infection from new infection.

OBJECTIVES: Repeated infections of Chlamydia trachomatis may be new infections or persistent infections due to treatment failure or due to unresolved infections in sexual partners. We aimed to establish the value of using high-resolution multilocus sequence typing (CT-MLST) to discriminate repeated C trachomatis infections. METHODS: Paired C trachomatis positive samples (baseline (T0) and after 6 months (T1)) were selected from two Dutch screening implementation studies among young heterosexual people. Typing with six CT-MLST loci included the ompA gene. The uniqueness of strains was assessed using 256 reference CT-MLST profiles. RESULTS: In 27 out of 34 paired cases, full sequence types were obtained. A multilocus (13 cases) or single locus variant (4 cases) was seen, indicating 17 new C trachomatis infections at T1. The ompA genovar was identical for 5 of 17 discordant cases. The 10 cases with concordant typing results were categorised as treatment failure (5 cases) versus persistent or recurrent infections (5 cases). Surprisingly, these concordant cases had C trachomatis strains that were either unique or found in small clusters. The median time between T0 and T1 did not differ between the concordant and discordant cases. CONCLUSIONS: High-resolution typing was superior in discriminating new infections compared with only using ompA genovar typing. Many cases (37%) showed exactly the same C trachomatis strain after 6 months. CT-MLST is not conclusive in distinguishing recurrent infections from treatment failure.

Multilocus sequence typing of Chlamydia trachomatis among men who have sex with men reveals cocirculating strains not associated with specific subpopulations.

BACKGROUND: Previous studies identified specific Chlamydia trachomatis strains circulating among men who have sex with men (MSM). This study investigates whether distinct C. trachomatis strains circulate among subpopulations within the MSM community. METHODS: Participants were recruited at the sexually transmitted infection clinic of the Public Health Service of Amsterdam from 2008 to 2009. C. trachomatis samples were typed using multilocus sequence typing. Epidemiological and clinical data were derived from questionnaires and patient records. RESULTS: Typing of 277 samples from 260 MSM identified distinct C. trachomatis strains circulating concurrently over time. Men with lymphogranuloma venereum (LGV)-inducing strains were more likely to be infected with human immunodeficiency virus, more often had a history of STI, and had a higher frequency of risky sexual behavior. No such associations were found for non-LGV-inducing strains. MSM infected with heterosexual-associated strains were often younger (P = .04) and more often reported sex with women (P = .03), compared with men infected with MSM-associated strains. CONCLUSIONS: With the exception of LGV-inducing strains, no evidence was found that different C. trachomatis strains circulated in distinct subpopulations of MSM. This indicates that no separate transmission networks for C. trachomatis among MSM existed. However, younger MSM and bisexuals were more often infected with heterosexual-associated C. trachomatis strains.

High-resolution typing reveals distinct Chlamydia trachomatis strains in an at-risk population in Nanjing, China.

We investigated Chlamydia trachomatis strains from Nanjing, China, and whether these strains differed from Amsterdam, the Netherlands. C. trachomatis type was determined with multilocus sequence typing. Most strains were specific to Nanjing, but some clustered with strains from Amsterdam. This demonstrates a geographical variation in C. trachomatis previously left undetected.

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.

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.

Evaluation of high-resolution typing methods for Chlamydia trachomatis in samples from heterosexual couples.

We aimed to compare conventional ompA typing of Chlamydia trachomatis with multilocus sequence typing (MLST) and multilocus variable-number tandem-repeat (VNTR) analysis (MLVA). Previously used MLST and MLVA systems were compared to modified versions that used shorter target regions and nested PCR. Heterosexual couples were selected from among persons with urogenital C. trachomatis infections visiting the sexually transmitted infection outpatient clinic in Amsterdam, The Netherlands. We identified 30 couples with a total of 65 C. trachomatis-positive samples on which MLST and MLVA for eight target regions were performed. All regions were successfully sequenced in 52 samples, resulting in a complete profile for 18 couples and 12 individuals. Nine ompA genovars from D to K, with two variants of genovar G, were found. The numbers of sequence type and MLVA type profiles were 20 for MLST and 21 for MLVA, and a combination of MLST and MLVA yielded 28 profiles, with discriminatory indexes (D) ranging from 0.95 to 0.99. Partners in 17 couples shared identical profiles, while partners in 1 couple had completely different profiles. Three persons had infections at multiple anatomical locations, and within each of these three individuals, all profiles were identical. The discriminatory capacity of all MLST and MLVA methods is much higher than that of ompA genotyping (D = 0.78). No genotype variation was found within the samples of the same person or from heterosexual couples with a putative single transmission. This shows that the chlamydial genome in clinical specimens has an appropriate polymorphism to enable epidemiological cluster analysis using MLST and MLVA.

Identification of a dominant Chlamydia trachomatis strain in patients attending sexual transmitted infection clinic and female sex workers in Tunisia using a high resolution typing method.

BACKGROUND: The distribution of Chlamydia trachomatis genotypes in Tunisia was previously studied using the reverse hybridization method. In this study, we used multilocus sequence typing (MLST) to describe Chlamydia trachomatis genetic diversity among heterosexual populations in Tunisia. The obtained sequence types (STs) were compared with those from a heterosexual population from Amsterdam, the Netherlands. METHODS: Clinical Tunisian patients and female sex workers provided 107 Chlamydia trachomatis positive samples that were used for MLST. Samples from 256 heterosexuals visiting the Amsterdam STI clinic were included as a reference group. Six highly variable genetic regions including the ompA gene were amplified and sequenced. The ST numbers were derived from a Chlamydia typing database (http://mlstdb.uu.se) and used to draw minimum spanning trees. RESULTS: ompA sequencing detected 7 genotypes among the Tunisian populations of which genotype E was the most prevalent (66.3%). This genotype E resolved into 23 different STs and among these the ST3 was predominant (53.5%). MLST displayed 43 STs, of which 28 (65%) were new in the database. Minimum spanning tree analysis of all Tunisian samples identified 4 clusters of which one formed a clonal cluster with samples presenting the most prevalent ST3. When comparing samples from the Tunisian and Dutch populations in one minimum spanning tree, there was little overlap between the Chlamydia trachomatis samples. CONCLUSION: The CT-hrMLST scheme allowed us to identify that the Tunisian distribution was dominated by one genotype E (ST3) strain which is also highly prevalent in many other countries worldwide.

Urogenital Chlamydia trachomatis infections among ethnic groups in Paramaribo, Suriname; determinants and ethnic sexual mixing patterns.

BACKGROUND: Little is known about the epidemiology of urogenital Chlamydia trachomatis infection (chlamydia) in Suriname. Suriname is a society composed of many ethnic groups, such as Creoles, Maroons, Hindustani, Javanese, Chinese, Caucasians, and indigenous Amerindians. We estimated determinants for chlamydia, including the role of ethnicity, and identified transmission patterns and ethnic sexual networks among clients of two clinics in Paramaribo, Suriname. METHODS: Participants were recruited at two sites a sexually transmitted infections (STI) clinic and a family planning (FP) clinic in Paramaribo. Urine samples from men and nurse-collected vaginal swabs were obtained for nucleic acid amplification testing. Logistic regression analysis was used to identify determinants of chlamydia. Multilocus sequence typing (MLST) was performed to genotype C. trachomatis. To identify transmission patterns and sexual networks, a minimum spanning tree was created, using full MLST profiles. Clusters in the minimum spanning tree were compared for ethnic composition. RESULTS: Between March 2008 and July 2010, 415 men and 274 women were included at the STI clinic and 819 women at the FP clinic. Overall chlamydia prevalence was 15% (224/1508). Age, ethnicity, and recruitment site were significantly associated with chlamydia in multivariable analysis. Participants of Creole and Javanese ethnicity were more frequently infected with urogenital chlamydia. Although sexual mixing with other ethnic groups did differ significantly per ethnicity, this mixing was not independently significantly associated with chlamydia. We typed 170 C. trachomatis-positive samples (76%) and identified three large C. trachomatis clusters. Although the proportion from various ethnic groups differed significantly between the clusters (P = 0.003), all five major ethnic groups were represented in all three clusters. CONCLUSION: Chlamydia prevalence in Suriname is high and targeted prevention measures are required. Although ethnic sexual mixing differed between ethnic groups, differences in prevalence between ethnic groups could not be explained by sexual mixing.

Distinct transmission networks of Chlamydia trachomatis in men who have sex with men and heterosexual adults in Amsterdam, The Netherlands.

BACKGROUND: Genovar distributions of Chlamydia trachomatis based on ompA typing differ between men who have sex with men (MSM) and heterosexuals. We investigated clonal relationships using a high resolution typing method to characterize C. trachomatis types in these two risk groups. METHODS: C. trachomatis positive samples were collected at the STI outpatient clinic in Amsterdam between 2008 and 2010 and genotyped by multilocus sequence typing. Clusters were assigned using minimum spanning trees and these were combined with epidemiological data of the hosts. RESULTS: We typed 526 C. trachomatis positive samples: 270 from MSM and 256 from heterosexuals. Eight clusters, containing 10-128 samples were identified of which 4 consisted of samples from MSM (90%-100%), with genovars D, G, J, and L2b. The other 4 clusters consisted mainly of samples from heterosexuals (87%-100%) with genovars D, E, F, I, and J. Genetic diversity was much lower in the MSM clusters than in heterosexual clusters. Significant differences in number of sexual partners and HIV-serostatus were observed for MSM-associated clusters. CONCLUSIONS: C. trachomatis transmission patterns among MSM and heterosexuals were largely distinct. We hypothesize that these differences are due to sexual host behavior, but bacterial factors may play a role as well.

The role of Surinamese migrants in the transmission of Chlamydia trachomatis between Paramaribo, Suriname and Amsterdam, The Netherlands.

The large Surinamese migrant population in the Netherlands is a major risk group for urogenital Chlamydia trachomatis infection. Suriname, a former Dutch colony, also has a high prevalence of C. trachomatis. Surinamese migrants travel extensively between the Netherlands and Suriname. Our objective was to assess whether the Surinamese migrants in the Netherlands form a bridge population facilitating transmission of C. trachomatis between Suriname and the Netherlands. If so, joint prevention campaigns involving both countries might be required. Between March 2008 and July 2010, participants were recruited at clinics in Paramaribo, Suriname and in Amsterdam, the Netherlands. Participants were grouped as native Surinamese, native Dutch, Surinamese migrant, Dutch migrant, or Other, based on country of residence and country of birth of the participant and of their parents. Risk behavior, such as sexual mixing between ethnic groups, was recorded and C. trachomatis positive samples were typed through multilocus sequence typing (MLST). A minimum spanning tree of samples from 426 participants showed four MLST clusters. The MLST strain distribution of Surinamese migrants differed significantly from both the native Surinamese and Dutch populations, but was not an intermediate state between these two populations. Sexual mixing between the Surinamese migrants and the Dutch and Surinamese natives occurred frequently. Yet, the MLST cluster distribution did not differ significantly between participants who mixed and those who did not. Sexual mixing occurred between Surinamese migrants in Amsterdam and the native populations of Suriname and the Netherlands. These migrants, however, did not seem to form an effective bridge population for C. trachomatis transmission between the native populations. Although our data do not seem to justify the need for joint campaigns to reduce the transmission of C. trachomatis strains between both countries, intensified preventive campaigns to decrease the C. trachomatis burden are required, both in Suriname and in the Netherlands.