Comparison of three genotyping methods to identify Chlamydia trachomatis genotypes in positive men and women

Distribution of Chlamydia trachomatis ompA genotypes and its association with abnormal cervical cytology among women of reproductive age in Shenzhen, China

Background

Many studies have focused on the distribution and specific clinical symptoms caused by Chlamydia trachomatis. Still, relatively few studies have focused on the associations between Chlamydia trachomatis genotypes and cervical intraepithelial lesions.

Objectives

This study was conducted to determine the distribution of Chlamydia trachomatis genotypes and its associations with cervical intraepithelial lesions among women of reproductive age. The presence of other STIs coinfection was also evaluated.

Method

375 Chlamydia trachomatis positive cervical swabs collected from women of reproductive age were analyzed though molecular assay. Multivariate logistic regression analyses (covariates include contraception, gravidity (≥1), abnormal vaginal discharge, adverse pregnancy outcomes, reproductive tract symptoms and abnormal cervical cytology) were performed to evaluate the associations between Chlamydia trachomatis genotypes and cervical intraepithelial lesions and genital clinical symptoms.

Results

Among 375 Chlamydia trachomatis positive cervical swabs, the prevalence of coinfection with Neisseria gonorrhoeae, Candida albicans, Trichomonas vaginitis, Vulvovaginal candidiasis, and HPV were 0.8%, 2.7%, 2.4%, 10.1% and 15.5%, respectively. 306 were genotyped successfully, and nine genotypes were identified. The most common genovar was E (25.16%, 77/306), followed by J (22.55%, 69/306), F (17%, 52/306), D (14.4%, 44/306), K (7.2%, 22/306), G (6.9%, 21/306), H (5.2%, 16/306), B (1.0%, 3/306), Ia (0.7%, 2/306). Genotype H was associated with abnormal cervical cytology [p = 0.006, aOR = 8.16 (1.86-36.6)]. However, this study observed no association between Chlamydia trachomatis genotypes and any genital clinical symptoms.

Conclusions

Chlamydia trachomatis genotype H may be a high risk factor for cervical intraepithelial lesions, which is useful for treatment and management measures for patients with cervical intraepithelial lesions.

Delayed diagnosis of lymphogranuloma venereum in a hospital setting - a retrospective observational study

OBJECTIVE

The incidence of lymphogranuloma venereum (LGV) in Europe is increasing. However, diagnosing LGV in a hospital setting is rare. We analysed the diagnostic process and clinical characteristics of patients with LGV in a hospital setting.

DESIGN AND SETTING

A retrospective observational study conducted in a teaching hospital in Amsterdam, The Netherlands. All adult patients with LGV between November 2010 and February 2019 were included. Clinical data were retrieved from electronic patient records.

RESULTS

40 patients were included. 90% of patients were men who have sex with men (MSM) and 62,5% were HIV positive. The most common presenting symptoms were rectal bleeding (47,5%), anal symptoms (30%) and change in bowel habits (25%). The mean time from first consultation to diagnosis was 28 days (range: 0 to 332, median 16,5 days). Diagnostic delay was increased by clinical presentation (ie anogenital syndrome) and the number of specialists involved. Diagnostic procedures not leading to the diagnosis were performed in 98% of cases.

CONCLUSION

To prevent late complications, unnecessary diagnostic procedures and further transmission, early testing for LGV should be incorporated in the work-up of every patient reporting MSM-activity presenting with anorectal symptoms or inguinal lymphadenopathy.

Evaluation of four commercial real-time PCR assays for the detection of lymphogranuloma venereum in Chlamydia trachomatis-positive anorectal samples

OBJECTIVES

Lymphogranuloma venereum (LGV) is a sexually transmitted infection (STI) caused by Chlamydia trachomatis (CT) genovars L. The identification of LGV is of therapeutic interest because treatment requires 3 weeks of doxycycline compared with 1 week for infection with a non-L strain. The aim of this study was to evaluate the performance of four commercial real-time PCR kits in comparison with the reference methods used for LGV diagnosis by the French National Reference Centre (NRC) for bacterial STIs.

METHODS

A total of 215 French CT-positive anorectal specimens collected consecutively in 2017 were used (66 LGV and 149 non-LGV). Among these, 92 were collected from symptomatic men who have sex with men (MSM) and 123 from asymptomatic MSM using pre-exposure prophylaxis. Four commercial assays were evaluated; a single-plex assay RealCycler CHSL kit (Progenie Molecular), tested on all the specimens, and three multiplex kits, the RealCycler Universal ULCGEN (Progenie Molecular), the Allplex Genital Ulcer Assay (Seegene) and the VIASURE Haemophilus ducreyi + CT LGV Real Time PCR Detection kit (CerTest Biotec), tested on the 92 samples from symptomatic MSM. Clinical performance was determined in comparison to the in-house real time PCR targeting the pmpH and the ompA gene sequencing.

RESULTS

Overall agreement ranged between 91.3% and 100% (95% CI 83.7-100%) with very good Kappa index values (>0.8). The clinical sensitivities and specificities varied between 91% and 100% (95% CI 80.8-100%), and 97% and 100% (95% CI 87.1-100%), respectively, with some kits performing better than others.

DISCUSSION

The four assays showed very good performance for the detection of LGV on anorectal specimens.

Reduction of non-typeable results using a plasmid oriented Lymfogranuloma venereum PCR for typing of Chlamydia trachomatis positive samples

Objectives

Typing of Chlamydia trachomatis (CT) is traditionally performed by characterising the ompA gene, resulting in more than a dozen different genovars, A to L. Type L is associated with Lymphogranuloma venereum (LGV) and commonly screened for using PCR, targeting the chromosomal pmpH gene. We aimed to develop and validate a new CT/LGV plasmid-based typing assay targeting the pgp3 gene, to increase sensitivity and thus reduce the number of non-typeable results.

Methods

The new pgp3 PCR assay using LNA probes to detect point mutations was analytically and prospectively validated in a routine diagnostic laboratory setting. For the analytical tests, quantified nucleotide constructs (gBlocks) were used to perform limit of detection analyses. Quality control panel samples from 2018 and 2019 for CT were also tested. For the clinical study patient samples which were collected in two months in 2018 were tested simultaneously using the pmpH PCR and the pgp3 PCR.

Results

Analytically, the assay proved to be 100% specific relative to the previously used LGV typing assay targeting the single copy pmpH gene but it was much more sensitive to detect non-LGV CT. In the quality control panel 2 nonLGV samples and 7 LGV samples were solely positive with the pgp3 PCR and not with the pmpH PCR. None of the samples from analytical specificity panels were positive, indicating 100% specificity. In a prospective panel of 152 clinical samples, 142 (93%) were successfully typed with the pgp3 PCR compared to 78% with the pmpH PCR. The pgp3 PCR was fully concordant with the pmpH PCR to identify all LGV subtypes and detected an increased number of clinical samples of non-LGV subtype.

Conclusion

We developed and validated a sensitive and specific plasmid-based typing assay to discriminate LGV from non-LGV CT subtypes. This is useful in a clinical setting to quickly determine the optimal treatment for Chlamydia trachomatis infections.

The Nature and Extent of Plasmid Variation in Chlamydia trachomatis

Chlamydia trachomatis is an obligate intracellular pathogen of humans, causing both the sexually transmitted infection, chlamydia, and the most common cause of infectious blindness, trachoma. The majority of sequenced C. trachomatis clinical isolates carry a 7.5-Kb plasmid, and it is becoming increasingly evident that this is a key determinant of pathogenicity. The discovery of the Swedish New Variant and the more recent Finnish variant highlight the importance of understanding the natural extent of variation in the plasmid. In this study we analysed 524 plasmid sequences from publicly available whole-genome sequence data. Single nucleotide polymorphisms (SNP) in each of the eight coding sequences (CDS) were identified and analysed. There were 224 base positions out of a total 7550 bp that carried a SNP, which equates to a SNP rate of 2.97%, nearly three times what was previously calculated. After normalising for CDS size, CDS8 had the highest SNP rate at 3.97% (i.e., number of SNPs per total number of nucleotides), whilst CDS6 had the lowest at 1.94%. CDS5 had the highest total number of SNPs across the 524 sequences analysed (2267 SNPs), whereas CDS6 had the least SNPs with only 85 SNPs. Calculation of the genetic distances identified CDS6 as the least variable gene at the nucleotide level (d = 0.001), and CDS5 as the most variable (d = 0.007); however, at the amino acid level CDS2 was the least variable (d = 0.001), whilst CDS5 remained the most variable (d = 0.013). This study describes the largest in-depth analysis of the C. trachomatis plasmid to date, through the analysis of plasmid sequence data mined from whole genome sequences spanning 50 years and from a worldwide distribution, providing insights into the nature and extent of existing variation within the plasmid as well as guidance for the design of future diagnostic assays. This is crucial at a time when single-target diagnostic assays are failing to detect natural mutants, putting those infected at risk of a serious long-term and life-changing illness.

Distribution of Chlamydia Trachomatis Genotypes in Infective Diseases of the Female Lower Genital Tract

The purpose of this study was to investigate the distribution of Chlamydia trachomatis (CT) genotypes in infective diseases of the female lower genital tract, especially in cervical diseases.

This study included 128 CT-positive women. DNA was extracted from cervical swabs. Omp1 gene PCR-RFLP and sequencing were used to confirm the subtypes of CT. The association of subtypes with age, clinical symptoms, cervical cytology, and biopsy results was further analyzed.

Omp1 gene PCR-RFLP and sequencing showed that the order of prevalent CT genotypes in the female lower genital tract was D (n=38, 29.69%), followed by E (n=28, 21.88%), G (n=21, 16.41%), and F (n=16,12.50%). Genotypes J, H, and K were comparatively rare. Genotype I was not identified in our samples. Further analysis showed that patients with genotype G were more frequently co-infected with other bacteria. Genotype G was also associated with mucopurulent cervicitis (MPC) and cervical intraepithelial neoplasia (CIN). Patients with genotype E were commonly co-infected with HR-HPV. Although genotype D was the most prevalent, it was a relatively low-risk type.

These results provide information on distribution of CT genotypes in infective diseases of the female lower genital tract, which is instrumental to developing a vaccine for CT.

Lymphogranuloma Venereum 2015: Clinical Presentation, Diagnosis, and Treatment

Lymphogranuloma venereum (LGV) has emerged as an important cause of proctitis and proctocolitis in men who have sex with men; classical inguinal presentation is now increasingly uncommon. We report summary findings of an extensive literature review on LGV clinical presentation, diagnosis, and treatment that form the evidence base for the 2015 Centers for Disease Control and Prevention treatment guidelines for sexually transmitted diseases. Proctitis and proctocolitis are now the most commonly reported clinical manifestations of LGV, with symptoms resembling those of inflammatory bowel disease. Newer molecular tests to confirm LGV infection are sensitive and specific, but are generally restricted to research laboratory or public health settings. Doxycycline (100 mg twice daily for 21 days) remains the treatment of choice for LGV. Patients with rectal chlamydial infection and signs or symptoms of proctitis should be tested for LGV, or if confirmatory testing is not available, should be treated empirically with a recommended regimen to cover LGV infection.

Diagnostic Procedures to Detect Chlamydia trachomatis Infections

The intracellular life style of chlamydia and the ability to cause persistent infections with low-grade replication requires tests with high analytical sensitivity to directly detect C. trachomatis (CT) in medical samples. Nucleic acid amplification tests (NAATs) are the most sensitive assays with a specificity similar to cell culture and are considered the method of choice for CT detection. In addition, NAATs can be performed on various clinical specimens that do not depend on specific transport and storage conditions, since NAATs do not require infectious bacteria. In the case of lower genital tract infections, first void urine and vaginal swabs are the recommended specimens for testing males and females, respectively. Infections of anorectal, oropharyngeal and ocular epithelia should also be tested by NAAT analysis of corresponding mucosal swabs. In particular, anorectal infections of men who have sex with men (MSM) should include evaluation of lymphogranuloma venereum (LGV) by identification of genotypes L1, L2 or L3. Detection of CT antigens by enzyme immunoassay (EIAs) or rapid diagnostic tests (RDTs) are unsuitable due to insufficient sensitivity and specificity. Recent PCR-based RDTs, however, are non-inferior to standard NAATs, and might be used at the point-of-care. Serology finds application in the diagnostic work-up of suspected chronic CT infection but is inappropriate to diagnose acute infections.

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.

The L2b real-time PCR targeting the pmpH gene of Chlamydia trachomatis used for the diagnosis of lymphogranuloma venereum is not specific to L2b strains

The French Reference Centre for chlamydiae uses two real-time PCRs targeting the pmpH gene of Chlamydia trachomatis to differentiate between L strains and variant L2b, responsible for a lymphogranuloma venereum outbreak in Europe. We compared the results obtained for 122 L2b C. trachomatis-positive specimens, using the two real-time PCRs, with the sequencing of the ompA gene. Only 91 specimens were confirmed as L2b. Our results demonstrate that the lymphogranuloma venereum outbreak is no longer dominated by the variant L2b, and that many L-positive specimens were misidentified as L2b with the method used, which raises the question of its specificity.

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.

No indication for tissue tropism in urogenital and anorectal Chlamydia trachomatis infections using high-resolution multilocus sequence typing

Background

Previous studies showed that C. trachomatis strains found in MSM are different from those in heterosexuals. This study investigates whether the differences in strain distribution between MSM and heterosexuals are due to tissue tropism.

Methods

C. trachomatis positive samples were collected from MSM (anorectal) and women (anorectal, cervical, vaginal, pharyngeal) visiting the STI outpatient clinic of Amsterdam between 2008 and 2013. All samples were typed using multilocus sequence typing (MLST). Epidemiological data were derived from electronic patient records.

Results

We obtained full MLST data for C. trachomatis from 207 MSM and 185 women, all with anorectal infections. Six large clusters were identified of which 3 consisted predominantly of samples from women (89%-100%), whereas the other 3 consisted predominantly of samples from MSM (97%-100%). Furthermore, we obtained full MLST data from 434 samples of 206 women with concurrent infections at multiple anatomical locations. No association was observed between C. trachomatis cluster and the anatomical location of infection.

Conclusion

We found no indication for tissue tropism in urogenital, pharyngeal and anorectal C. trachomatis infections. Combined with results from previously conducted studies, we hypothesize that MSM and heterosexuals have different distributions of C. trachomatis strains due to their separate sexual networks.

Electronic supplementary material

The online version of this article (doi:10.1186/1471-2334-14-464) contains supplementary material, which is available to authorized users.

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.

Serovar D and E of serogroup B induce highest serological responses in urogenital Chlamydia trachomatis infections

Background

Chlamydia trachomatis is the most prevalent bacterial sexually transmitted infection (STI) worldwide. A strong link between C. trachomatis serogroup/serovar and serological response has been suggested in a previous preliminary study. The aim of the current study was to confirm and strengthen those findings about serological IgG responses in relation to C. trachomatis serogroups and serovars.

Methods

The study population (n = 718) consisted of two patient groups with similar characteristics of Dutch STI clinic visitors. We performed genotyping of serovars and used titre based and quantitative commercially available ELISA kits (medac Diagnostika) to determine specific serum IgG levels. Optical density (OD) values generated by both tests were used to calculate the IgG titres (cut-off 1:50). Analyses were conducted stratified by gender.

Results

We observed very significant differences when comparing the median IgG titres of three serogroups, B, C and I: in women for B vs. C: p < 0.0001 (median titres B 200 vs. C <50); B vs. I: p < 0.0001 (200 vs. 50), and in men for B vs. C: p = 0.0006 (150 vs. <50); B vs. I: p = 0.0001 (150 vs. <50); C vs. I was not significant for both sexes. Serovars D and E of serogroup B had the highest median IgG titres compared to the other serovars in both men and women: 200 and 200 vs. ≤ 100 for women and 100 and 200 vs. ≤ 75 for men, respectively.

Conclusions

This study shows that B group serovars induce higher serological responses compared to the C and I group serovars in vivo in both men and women.

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.

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.

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.

Clinical and epidemiological characterization of a lymphogranuloma venereum outbreak in Madrid, Spain: co-circulation of two variants

The lymphogranuloma venereum (LGV) outbreak described in the Netherlands in 2003, increased the interest in the genotyping of Chlamydia trachomatis. Although international surveillance programmes were implemented, these studies slowly decreased in the following years. Now data have revealed a new accumulation of LGV cases in those European countries with extended surveillance programmes. Between March 2009 and November 2011, a study was carried out to detect LGV cases in Madrid. The study was based on screening of C. trachomatis using commercial kits, followed by real-time pmpH-PCR discriminating LGV strains, and finally ompA gene was sequenced for phylogenetic reconstruction. Ninety-four LGV infections were identified. The number of cases increased from 10 to 30 and then to 54 during 2009-2011. Incidence of LGV was strongly associated with men who have sex with men; but in 2011, LGV cases were described in women and heterosexual men. Sixty-nine patients were also human immunodeficiency virus (HIV) positive, with detectable viral loads at the moment of LGV diagnosis, suggesting a high-risk of co-transmission. In fact, in four patients the diagnosis of HIV was simultaneous with LGV infection. The conventional treatment with doxycycline was prescribed in 75 patients, although in three patients the treatment failed. The sequencing of the ompA gene permitted identification of two independent transmission nodes. One constituted by 25 sequences identical to the L2b variant, and a second node including 37 sequences identical to L2. This epidemiological situation characterized by the co-circulation of two LGV variants has not been previously described, reinforcing the need for screening and genotyping of LGV strains.

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.

Evaluation of a novel Chlamydia trachomatis microsphere suspension assay for detection and genotyping of the different serovars in clinical samples

A novel Chlamydia trachomatis (Ct) microsphere suspension (MS) assay was evaluated for identification of the different serovars, using the same PCR primer set established for the Ct Detection and genoTyping assay. Both assays can detect and identify all 14 major serovars (A, B/Ba, C, D/Da, E, F, G/Ga, H, I/Ia, J, K, L1, L2/L2a, and L3) and one genovariant of serovar J. The probe specificity for the Ct-MS assay was determined using 14 Ct reference strains and 1 clinical isolate from a genovariant of serovar J. Also, the Ct-MS assay and the Ct detection and genoTyping assay were compared in 712 Ct-positive clinical samples. The Ct-MS assay showed a highly specific reaction for all probes with the amplicons of the reference strains, giving a very low background median fluorescence intensity signal (median fluorescence intensity ≤ 10). An excellent overall agreement in the Ct detection (kappa = 0.947, 95% confidence interval, 0.89 to 0.999; McNemar's test, P = 1.000) and the Ct genotyping (kappa = 0.993, 95% confidence interval, 0.977 to 1.000; McNemar's test, P = 0.053) was observed between the Ct detection and genoTyping (DT) assay and the Ct-MS assay. In conclusion, the novel Ct-MS assay permits simultaneous detection and genotyping of Ct serovars, making the Ct-MS assay an excellent high throughput method.

Anal infections with concomitant Chlamydia trachomatis genotypes among men who have sex with men in Amsterdam, the Netherlands

Background

Lymphogranuloma venereum (LGV) proctitis is caused by Chlamydia trachomatis (Ct) genotype L and is endemic among men who have sex with men (MSM) in western society. Genotype L infections need to be distinguished from non-LGV (genotypes A-K) Ct infections since they require prolonged antibiotic treatment. For this purpose, an in-house developed pmpH based LGV polymerase chain reaction (PCR) test is used at the Amsterdam STI outpatient clinic. We investigated retrospectively the anal Ct genotype distribution, and the frequency of concomitant genotype infections in MSM infected with LGV and non-LGV Ct infections. To detect concomitant Ct genotype infections, the pmpH LGV PCR and genoTyping Reverse Hybridization Assay (Ct-DT RHA) were used.

Methods

A total of 201 Ct positive rectal swabs from MSM were selected, which were previously diagnosed as either LGV (n = 99) or non-LGV Ct infection (n = 102) according to the algorithm of Ct detection by the commercially available Aptima Combo 2 assay followed by an in-house pmpH LGV PCR. The samples were retested with the commercially available Ct-DT RHA, which differentiates between 14 major genotypes and is able to detect concomitant Ct genotypes.

Results

Excellent genotyping agreement was observed between the Ct-DT RHA and the pmpH LGV PCR (Kappa = 0.900, 95%CI = 0.845-0.955, McNemar's p = 1.000). A concomitant non-LGV genotype was detected in 6/99 (6.1%) LGV samples. No additional LGV infections were observed with the Ct-DT RHA among the non-LGV Ct group. In the non-LGV group genotype G/Ga (34.3%) was seen most frequent, followed by genotype D/Da (22.5%) and genotype J (13.7%). All LGV infections were caused by genotype L2.

Conclusions

Concomitant non-LGV genotypes do not lead to missed LGV proctitis diagnosis. The pmpH LGV PCR displayed excellent agreement with the commercially available Ct-DT genotyping RHA test. The genotypes G/Ga, D/Da and J were the most frequent non-LGV Ct strains in MSM.