Multilocus sequence typing of Treponema pallidum subsp. pallidum in Barcelona

Aim: To implement the multilocus sequence typing (MLST) methodology in syphilis samples previously characterized by enhanced CDC typing (ECDCT) and macrolide resistance. Materials & methods: MLST was performed on genital ulcer and blood samples by analyzing a region of the tp0136, tp0548 and tp0705 loci using Sanger sequencing. Results: Up to 59/85 (69.4%) of genital ulcer and 4/39 (10.3%) of whole blood samples were fully typed. The most frequent profiles were 1.3.1 (56%) and 1.1.1 (11%). All the 1.3.1 samples typed carried the A2058G mutation, responsible for macrolide resistance. MLST and ECDCT showed similar overall typing yields. Conclusion: Several allelic profiles of T. pallidum subsp. pallidum were identified and classified into two major genetic clades in Barcelona. Our results were similar to that described in Europe. Tweetable abstract We successfully identified 11 allelic profiles of T. pallidum from 63 fully typed syphilis samples using the MLST methodology. Profile 1.3.1 was found in 56% of samples, all of them being macrolide resistant.