Lymphogranuloma venereum (LGV) ompA-subvariants of the Portuguese collection of Chlamydia trachomatis, 2007-2023.

BACKGROUND

Lymphogranuloma venereum (LGV) is a sexually transmitted infection caused by Chlamydia trachomatis ompA-genotypes L1-L3, with increasing numbers of detected cases across Europe. Here, we analysed diversity and temporal distribution of the LGV ompA-subvariants detected in Portugal between 2007 and 2023, in order to better understand the dissemination and diversification landscape of LGV strains.

METHODS

The collection of the Portuguese National Reference Laboratory includes 1188 LGV ompA-genotyped samples between 2007 and 2023. In-depth analysis of the diversity of LGV ompA-subvariants circulating in Portugal across the years was performed, identifying newly described subvariants and integrating this data in a comprehensive compilation with all representative LGV ompA-subvariants described globally.

RESULTS

L2 ompA-variant (L2/434/Bu) was consistently the most frequently detected in our collection, with annual proportions ranging from 34.0% to 82.9%, between 2016 and 2023. L2bV5 was the second most frequent followed by L2b, ranging from 5.0% to 27.9% and 2.6% to 23.7% across the years, respectively, from 2017 to 2023. We highlighted the emergence and considerable increase in circulation of L1-like ompA-subvariants in recent years, representing 13.7% of LGV sequences in 2023. We also identified 13 novel LGV ompA-subvariants that had not been described before, differing by up to three mutations from the respective genotype reference sequences.

CONCLUSIONS

This study contributes to the worldwide picture of the LGV molecular epidemiology, highlighting the importance of long-term molecular surveillance to monitor the circulation and geographical spread of LGV and to timely identify and track new strains, such as the recently emerging L1-like ompA-subvariants.