Objective To assess the role of Ureaplasma urealyticum and Ureaplasma parvum in patients with non-gonococcal urethritis (NGU) using specimens from a previously reported study of NGU.
Methods Species-specific PCR assays for U urealyticum and U parvum were used to detect these organisms in specimens from men enrolled in a case–control study based in a Seattle STD clinic in order to evaluate their association with NGU. Urethritis was defined by clinical examination and the presence of inflammation on Gram stained smear. Controls had normal examination findings and no evidence of inflammation on Gram stain smear or by the leucocyte esterase test.
Results U urealyticum was detected in 26% (31/119) of cases and 16% (19/117) of controls, resulting in an association with NGU (adjusted odds ratio (aOR)=2.3, 95% CI 1.04 to 4.9) after adjusting for age, race, history of prior urethritis and other NGU pathogens (Chlamydia trachomatis, Mycoplasma genitalium). The association of U urealyticum and NGU was strongest in white men <28 years of age (OR=5.4, 95% CI 1.3 to 22.2). U parvum was detected in 14% (17/119) cases and 31% (36/117 controls) and thus was negatively associated with NGU (aOR=0.4, 95% CI 0.2 to 0.8). The prevalence of U urealyticum (16%) in controls was higher than that of C trachomatis (3.4%) or M genitalium (4.3%, p<0.05, each comparison).
Conclusions Unlike U parvum, U urealyticum was associated with urethritis. The strong effect in younger white men and high rates in controls may suggest variability in virulence among U urealyticum strains or in host innate or acquired immunity.
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Our findings were presented in part at the 16th International Congress of the International Organisation for Mycoplasma, Cambridge, UK, July 2006 and at the 17th International Meeting of the International Society for STD Research, 29 July–1 Aug 2007, Seattle, Washington. The content of this publication does not necessarily reflect the views or policies of the Department of Health and Human Services, nor does the mention of trade names, commercial products, or organisations imply endorsement by the UW Government.
Funding This study was funded by a Fellowship (to ROO) from the International AIDS Research and Training Program; and AI31448 and AI48634 from the National Institute of Allergy and Infectious Diseases.
Competing interests None.
Ethics approval This study was conducted with the approval of the University of Washington.
Provenance and peer review Not commissioned; not externally peer reviewed.