Increased diagnostic yield of routine multiplex PCR compared to clinician requested testing for detection of Trichomonas vaginalis

Trichomonas vaginalis (TV) infection is the leading cause of non-viral sexually transmitted infection (STI) globally and is endemic in rural and remote Australia. However, current accurate prevalence data for TV in urban Australia are scarce as TV is not a notifiable infection outside of the Northern Territory (NT). This study evaluated Australian guidelines for TV testing and determined TV prevalence among patients at a large urban public hospital in Melbourne, Australia. A retrospective analysis of genitourinary samples screened for STIs by multiplex polymerase chain reaction (MPCR) between May 2017 and April 2019 was performed. A total of 7155 results (5064 females) were included in the analysis. A prevalence for TV of 1.7% (n=123) was found, which was higher than Neisseria gonorrhoeae (1.4%, n=103) but less than Chlamydia trachomatis (5%, n=358). The highest rate of TV (3%) was found in females aged 30–44 years (n = 48). Routine MPCR improved TV detection almost six-fold compared with clinician request based testing. Current targeted testing guidelines for TV were inadequate for case finding in an urban setting, and clinical request among symptomatic patients was rare. MPCR testing provides a comprehensive testing strategy for curable STI, and removes the need for clinical suspicion of TV. Implementation of MPCR for STI screening can improve TV detection in populations not normally suspected to be at risk and therefore potentially reduce disease transmission or complications associated with undiagnosed infection.