Pooling of urine samples for molecular detection of Chlamydia trachomatis, Neisseria gonorrhoeae and Mycoplasma genitalium as a screening strategy among young adults in Catalonia

Introduction Bacterial sexually transmitted infections (STIs) have an important impact on reproductive health, highlighting the increase in Chlamydia trachomatis infection rates among young people. To reduce the costs of STI detection, the pooling strategy is beneficial for high-throughput tests in low-prevalence populations using non-invasive samples. Objectives (1) To describe the performance of a 7-STI PCR assay using the pooling of three urine samples to detect C. trachomatis, Neisseria gonorrhoeae and Mycoplasma genitalium; (2) to estimate the cost saving of the pooling strategy; (3) to describe the prevalence, risk factors and coinfections of C. trachomatis, N. gonorrhoeae and M. genitalium in young people ≤25 years in Catalonia. Methods cross-sectional prevalence study conducted in 2016 among young people ≤25 years of age seen in sexual and reproductive health centres throughout Catalonia from pools of three urine samples. A standardized questionnaire was used to collect clinical-epidemiological and behavioural variables. Results 1032 young people were tested. The prevalence of C. trachomatis, N. gonorrhoeae and M. genitalium was 8.5%, 0.6% and 3.5%, respectively. The pooling strategy provided a 33% savings in reagent costs. Conclusions The pooling strategy implemented for epidemiological studies in our context provides a savings that has an impact on the viability of STI detection programmes. In the same way, this study shows that C. trachomatis prevalence continues to increase in this population and, for the first time in Catalonia, the prevalence of M. genitalium in young people is shown.