A case-control study of men with non-gonococcal urethritis at Auckland Sexual Health Service: rates of detection of Mycoplasma genitalium.

BACKGROUND: Previous studies have identified Mycoplasma genitalium as a cause of urethritis in men. As there is no New Zealand data, a case-control study was conducted to determine whether this organism is a significant cause of urethritis in men presenting to Auckland Sexual Health Service.
METHODS: Enrollment for the study commenced in March 2006 and finished in February 2008. Inclusion criteria for cases of non-gonococcal urethritis were onset of urethritis symptoms within one month confirmed by urethral Gram staining showing >or=10 polymorphonuclear leucocytes per high-powered field. Controls were men presenting during the same time period for asymptomatic sexual health screening. All participants were tested for Neisseria gonorrhoeae, M. genitalium, and Chlamydia trachomatis. Information regarding symptoms, sexual behaviour and treatment was collected using a standard questionnaire.
RESULTS: We recruited 209 cases and 199 controls with a participation rate of 96%. The prevalence of C. trachomatis and M. genitalium in non-gonococcal urethritis cases was 33.5% and 10% respectively. Co-infection with these organisms was uncommon (1.9%). C. trachomatis and M. genitalium were diagnosed in 4% and 2% of controls, respectively, and both infections were detected significantly less often than in the cases (P < 0.0001, P < 0.005). Cases were more likely to report inconsistent condom use, multiple sexual contacts and not having sexual intercourse in the last week (P = 0.03, P = 0.02, P = 0.03). A past history of non-gonococcal urethritis was a significant predictor of current symptoms (P < 0.0001).
CONCLUSIONS: This is the first study to investigate M. genitalium infection in New Zealand men. Our results confirm that M. genitalium is a cause of non-gonococcal urethritis in men presenting to our service.