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.