Diagnosis of Chlamydia trachomatis, Neisseria gonorrhoeae, Trichomonas vaginalis and Mycoplasma genitalium: an observational study of testing patterns, prevalence and co-infection rates in northern New Zealand.

Abstract

A total of 2643 samples submitted for STI testing between 26 November 2015 and 7 December 2015 underwent analysis by Aptima Combo 2 (Hologic, San Diego, CA, USA), Trichomonas vaginalis (TV), and Mycoplasma genitalium (MG) assays. Results were analysed by patient demographics. Four hundred and eleven pathogens were detected from 359 patients, with Chlamydia trachomatis (CT), Neisseria gonorrhoeae (NG), TV, and MG detected in 178 (6.7%), 19 (0.7%), 80 (3%) and 134 (5.1%) samples respectively. With the exception of TV, STI prevalence was highest in people <25 years of age. Infection was more common in men for NG (odds ratio (OR) 5.05, P<0.001) and CT (OR 2.72, P<0.001). Māori and Pacific ethnicity were associated with increased risk of MG (OR 1.82, P=0.006,) TV (OR 6.1, P<0.001) and CT (OR 3.31, P<0.001) infection, and TV and NG infections were more prevalent as social deprivation increased. A mismatch between testing rates and prevalence of infection was seen, with fewer tests performed for males (OR 0.2, P<0.001) than females and no difference in testing of Māori and Pacific men (3064/100000) compared with men of European background (3181/100000, OR 0.96, P=0.76), despite an increased risk of disease. There are disparately low testing rates for STIs in certain high-risk groups in northern New Zealand.