Lymphogranuloma venereum genovariants in men having sex with men in Italy

Genetic characterisation of lymphogranuloma venereum in Spain: a multicentre study

INTRODUCTION

Lymphogranuloma venereum (LGV) is a sexually transmitted infection caused by Chlamydia trachomatis genotypes L1-L3. A combination of techniques with high discriminatory capacity such as multilocus sequence typing (MLST) and the analysis of the ompA gene may be useful to determine the greater penetration of certain strains in transmission networks and their relationship with certain tropisms.

AIM

The aim of this study was to investigate the molecular epidemiology of LGV isolates from different regions of Spain.

METHODS

Genetic characterisation of LGV isolates detected in six hospitals from Spain between 2018 and 2019 was performed. MLST (five variable regions: hctB, CT058, CT144, CT172 and pbpB) and ompA sequence determination were used to study the LGV strains.

RESULTS

Most of the 161 LGV isolates (93.8%) were detected in men who have sex with men (MSM). At least 43.5% of the patients presented with HIV coinfection and 53.4% were symptomatic, with proctitis being the most prevalent symptom (73.3%). Most isolates were detected in Barcelona (n=129).The distribution of ompA genovariants was as follows: 56.1% belonged to L2, 24.3% to L2b, 5.4% to L2bV1, 4.7% to L2bV4, 4.1% to L1, 2.7% to L2b/D-Da, 2.0% to L2bV2 and 0.7% to L2bV7. MLST was successfully performed in 81 samples and 9 different sequence types (STs) were detected. The ompA and MLST combination obtained 17 different genetic profiles, with L2-ST53 and L2-ST58 being the most prevalent (29.5% and 14.1%, respectively). L1 genotype strains belonged to ST23 (n=3) and ST2 (n=3).

CONCLUSION

LGV infections were mainly found in MSM living with HIV and with proctitis. The joint analysis of ompA and MLST genetic characterisation techniques showed a high discriminatory capacity. Our findings suggest a cocirculation of L2 and L2b ompA genotypes, and with the inclusion of MLST characterisation, the most prevalent profiles were ompA genotype L2-MLST ST53 and L2-MLST ST58.

Anorectal lymphogranuloma venereum among men who have sex with men: a 3-year nationwide survey, France, 2020 to 2022

BackgroundIn France, lymphogranuloma venereum (LGV) testing switched from universal to selective testing in 2016.AimTo investigate changes in LGV-affected populations, we performed a nationwide survey based on temporarily reinstated universal LGV testing from 2020 to 2022.MethodsEach year, during three consecutive months, laboratories voluntarily sent anorectal Chlamydia trachomatis-positive samples from men and women to the National Reference Centre for bacterial sexually transmitted infections. We collected patients' demographic, clinical and biological data. Genovars L of C. trachomatis were detected using real-time PCR. In LGV-positive samples, the ompA gene was sequenced.ResultsIn 2020, LGV positivity was 12.7% (146/1,147), 15.2% (138/907) in 2021 and 13.3% (151/1,137) in 2022 (p > 0.05). It occurred predominantly in men who have sex with men (MSM), with rare cases among transgender women. The proportion of HIV-negative individuals was higher than that of those living with HIV. Asymptomatic rectal LGV increased from 36.1% (44/122) in 2020 to 52.4% (66/126) in 2022 (p = 0.03). Among users of pre-exposure prophylaxis (PrEP), LGV positivity was 13.8% (49/354) in 2020, 15.6% (38/244) in 2021 and 10.9% (36/331) in 2022, and up to 50% reported no anorectal symptoms. Diversity of the LGV ompA genotypes in the Paris region increased during the survey period. An unexpectedly high number of ompA genotype L1 variant was reported in 2022.ConclusionIn rectal samples from MSM in France, LGV positivity was stable, but the proportion of asymptomatic cases increased in 2022. This underscores the need of universal LGV testing and the importance of continuous surveillance.

Whole Genome Sequencing of a Chlamydia trachomatis Strain Responsible for a Case of Rectal Lymphogranuloma Venereum in Italy

Lymphogranuloma venereum (LGV) is a systemic sexually transmitted infection caused by Chlamydia trachomatis serovars L1 to L3. The current LGV cases in Europe are mainly characterized by an anorectal syndrome, spreading within men who have sex with men (MSM). Whole-genome sequencing of LGV strains is crucial to the study of bacterial genomic variants and to improve strategies for contact tracing and prevention. In this study, we described the whole genome of a C. trachomatis strain (LGV/17) responsible for a case of rectal LGV. LGV/17 strain was isolated in 2017 in Bologna (North of Italy) from a HIV-positive MSM, presenting a symptomatic proctitis. After the propagation in LLC-MK2 cells, the strain underwent whole-genome sequencing by means of two platforms. Sequence type was determined using the tool MLST 2.0, whereas the genovariant was characterized by an ompA sequence evaluation. A phylogenetic tree was generated by comparing the LGV/17 sequence with a series of L2 genomes, downloaded from the NCBI website. LGV/17 belonged to sequence type ST44 and to the genovariant L2f. Nine ORFs encoding for polymorphic membrane proteins A-I and eight encoding for glycoproteins Pgp1-8 were detected in the chromosome and in the plasmid, respectively. LGV/17 was closely related to other L2f strains, even in the light of a not-negligible variability. The LGV/17 strain showed a genomic structure similar to reference sequences and was phylogenetically related to isolates from disparate parts of the world, indicative of the long-distance dynamics of transmission.

Specific high-resolution scheme to improve understanding of the spatio-temporal dispersion of lymphogranuloma venereum epidemic

Introduction

Lymphogranuloma venereum (LGV) is already endemic in vulnerable populations in several European countries; however, molecular epidemiology data with improved accuracy are necessary to better understand LGV epidemic in these countries. Current strategies to study the molecular epidemiology of LGV cases involve schemes based on a few genetic fragments of Chlamydia trachomatis, which have demonstrated limited discriminatory power for LGV. Therefore, this study aimed to propose a new combination of molecular markers based on the most variable genes of L-genotype genomes to improve the characterization of the current LGV epidemic in Madrid, Spain.

Methods

Four genes were selected according to their diversity index (CTLon_0054, CTLon_0087, CTLon_0243 and CTLon_0301) for use in combination with ompA. In silico and experimental studies were performed to compare the previously described multilocus sequence typing (MLST) schemes with our proposal. Moreover, the proposed scheme was applied (n = 68) to analyze the spatio-temporal spread of the LGV cases.

Results

Our proposal demonstrated higher diversity allowing the identification of three main groups compared to the previously published MLST based on hypervariable genes wherein only a single sequence type was identified. The temporal analysis showed that the major cluster was progressively diversifying, revealing a very active transmission chain. Furthermore, an L2b genome identical to that of the origin of the epidemic was detected, suggesting reintroductions or a low screening rate in vulnerable populations. The spatial distribution suggests that the selection and spread of new variants occurs from the central district to the peripheral regions.

Discussion

The scheme proposed in this study has proven to be useful for appropriate discrimination of LGV strains. This study, to our knowledge for the first time, demonstrates a spatio-temporal spread that increases our understanding and identifies areas with special susceptibility for maintenance of the endemic situation of LGV.

Prevalence of anatomically specific infections with Chlamydia trachomatis among men who have sex with men in China: protocol for a nationwide cross-sectional study as part of Disease Burden Surveillance of Infections with Chlamydia (DBSIC)

INTRODUCTION

Chlamydia trachomatis (CT) causes the most prevalent bacterial sexually transmitted infection in the world, and men who have sex with men (MSM) are considered as a high-risk population for this infection. Data regarding the prevalence of CT infection in China are limited and fragmented. In this study, we aim to determine at the national level the anatomically specific CT prevalence and genotype distribution of CT strains among MSM, recruiting from the venues where MSM commonly seek sexual partners.

METHODS AND ANALYSIS

The study will be a nationwide cross-sectional survey to estimate the prevalence of chlamydial infections among MSM who meet the inclusion criteria over a period of 6 months (May-October 2022). A total of 2429 participants will be recruited from the venues where MSM most often seek sex partners in 14 cities of the 7 geographical regions in China. A mobile phone app-based anonymous self-administered questionnaire will be used to collect sociodemographic and behavioural data, and specimens of urine, anorectal and pharyngeal swabs will be collected for identifying the infections of CT and Neisseria gonorrhoeae and genotypes of CT. The data will be analysed using the IBM SPSS program V.20 ETHICS AND DISSEMINATION: The study protocol has been approved by the Medical Ethics Committee of the Chinese Academy of Medical Sciences Institute of Dermatology and the National Center for STD Control on 9 October 2021 (approval number 2021-KY-037). The study is based on voluntary participation and a written informed consent process. The study results will be submitted for publication in peer-reviewed journals and reported in conferences. The relevant data will be made available to development of control programmes and used as health education materials to disseminate to the community. The dataset will be deposited in a public repository.

TRIAL REGISTRATION NUMBER

ChiCTR2100052869.

Rapid Increase in Lymphogranuloma Venereum among HIV-Negative Men Who Have Sex with Men, England, 2019

Incidence of lymphogranuloma venereum increased in England during 2018–2019, after a period of decline. Our retrospective analysis of national surveillance data identified a rapid increase in diagnoses among HIV-negative men who have sex with men. These findings indicate a need for sustained surveillance and targeted public health action.

Ongoing evolution of Chlamydia trachomatis lymphogranuloma venereum: exploring the genomic diversity of circulating strains

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 overrepresented 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.

Transcontinental Dissemination of the L2b/D-Da Recombinant Chlamydia trachomatis Lymphogranuloma venereum (LGV) Strain: Need of Broad Multi-Country Molecular Surveillance

Previously, we identified a Chlamydia trachomatis lymphogranuloma venereum (LGV) recombinant strain possessing a non-LGV ompA genotype. Here, culture-independent genome sequencing confirms its circulation in Europe, Middle East, and North America, and unveils emergence of antibiotic resistance. Broad surveillance is needed.