Multilocus sequence typing of Trichomonas vaginalis clinical samples from Amsterdam, the Netherlands

Objectives: In this cross-sectional epidemiological study we aimed to identify molecular profiles for Trichomonas vaginalis and to determine how these molecular profiles were related to patient demographic and clinical characteristics. Setting: Molecular typing methods previously identified two genetically distinct subpopulations for T. vaginalis; however, few molecular epidemiological studies have been performed. We now increased the sensitivity of a previously described multilocus sequence typing (MLST) tool for T. vaginalis by using nested PCR. This enabled the typing of direct patient samples. Participants: From January to December 2014, we collected all T. vaginalis positive samples as detected by routine laboratory testing. Samples from patients either came from general practitioners offices or from the sexually transmitted infections (STI) clinic in Amsterdam. Epidemiological data for the STI clinic patients were retrieved from electronic patient files. Primary and secondary outcome measures: The primary outcome was the success rate of genotyping direct T. vaginalis positive samples. The secondary outcome was the relation between T. vaginalis genotypes and risk factors for STI. Results: All 7 MLST loci were successfully typed for 71/87 clinical samples. The 71 typed samples came from 69 patients, the majority of whom were women (n = 62; 90%) and half (n = 34; 49%) were STI clinic patients. Samples segregated into a two population structure for T. vaginalis representing genotypes I and II. Genotype I was most common (n = 40; 59.7%). STI clinic patients infected with genotype II reported more sexual partners in the preceding 6 months than patients infected with genotype I (p = 0.028). No other associations for gender, age, ethnicity, urogenital discharge or co-occurring STIs with T. vaginalis genotype were found. Conclusions: MLST with nested PCR is a sensitive typing method that allows typing of direct (uncultured) patient material. Genotype II is possibly more prevalent in high-risk sexual networks.