ABSTRACT
IMPORTANCE: Numerous international organizations, including the World Health Organization, have been drawing attention to the global increase in sexually transmitted infections. Twenty years ago, lymphogranuloma venereum (LGV) was mainly considered a tropical disease; in recent decades, however, LGV has been increasingly present in high-income countries. This increase has been linked to men who have sex with men who participate in highly interconnected sexual networks, leading to a rapid spread of LGV. This study focuses on the spread of LGV, presenting the largest time series of LGV prevalence in Spain, which includes more than a thousand diagnosed cases in one large city. The number of LGV cases diagnosed was analyzed over time, and a selection of strains was subjected to molecular genotyping. The results indicate that the LGV epidemic is gradually evolving toward an increasingly complex diversification due to the selection of successful genovariants that have emerged by mutation and recombination events, suggesting that we are moving toward an unpredictable scenario.
Subject(s)
Epidemics , Lymphogranuloma Venereum , Sexual and Gender Minorities , Male , Humans , Lymphogranuloma Venereum/epidemiology , Lymphogranuloma Venereum/diagnosis , Chlamydia trachomatis/genetics , Homosexuality, MaleABSTRACT
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.
ABSTRACT
Despite social distancing measures implemented in Madrid to prevent the propagation of SARS-CoV-2, a significant increase (57.1%; 28.5 to 38.5 cases/month) in cases of lymphogranuloma venereum was detected during the COVID-19 pandemic. This unusual scenario might have accelerated a shift in Chlamydia trachomatis (CT) epidemiology towards a higher proportion of L genotypes compared with non-L genotypes in CT-positive samples. Our data underscore the importance of surveillance of sexually transmitted infections during the pandemic, in particular among vulnerable populations.
