Do all men attending departments of genitourinary medicine need to be screened for non-gonococcal urethritis?

We investigated the influence of symptoms and signs on the detection of Chlamydia trachomatis, Mycoplasma genitalium and Ureaplasma urealyticum organisms (ureaplasmas) in men with non-gonococcal urethritis (NGU). Two hundred and forty-two men attending the Jefferiss Wing at St Mary's Hospital for a sexual health assessment were evaluated, of whom 169 had NGU. Urethral inflammation was diagnosed if there were either ≥5 polymorphonuclear leucocytes (PMNLs) per high-power field (HPF) in five or more microscope fields of a Gram-stained urethral smear, or ≥10 PMNLs per HPF in five or more fields of a Gram-stained thread from 15-20 mL of a first-passed urine (FPU) specimen. C. trachomatis was diagnosed by direct immunofluoresence, M. genitalium by a polymerase chain reaction assay and ureaplasmas by culture. On multivariate analysis, to control for potential confounding by age, ethnicity, sexual lifestyle and co-infection, an urethral discharge remained significantly associated with the detection of C. trachomatis and M. genitalium in men with acute urethritis [OR 12.3, 95% CI (2.39-63.5) and OR 35.2, 95% CI (3.9-319.6), respectively], but dysuria or penile irritation did not. The detection of ureaplasmas was not associated with any clinical feature. In addition, on multivariate analysis men with NGU who were either symptomatic or had an observable discharge were more likely to have C. trachomatis or M. genitalium detected [(OR 6.92, 95% CI 1.41-33.9) and (OR 5.18, 95% CI 0.99-27.1), respectively], but not ureaplasmas (OR 1.19, 95% CI 0.33-4.35). The findings suggest that in men with acute NGU, symptoms or signs, and in particular a urethral discharge, are associated with the detection of C. trachomatis and M. genitalium, but not ureaplasmas. Currently, there is no precise answer to the question of whether all men attending a GUM clinic need to be screened for NGU, but if clinically asymptomatic NGU is found not to be associated with a sexually transmitted pathogen, the UK clinical guidelines requiring the preparation of a urethral smear from such men would need to be revised.