Male non-gonococcal urethritis: From microbiological etiologies to demographic and clinical features.

OBJECTIVES: To detect microorganisms responsible for male acute urethritis and to define the microbiology of non-gonococcal urethritis.

METHODS: The present study comprised 424 men with symptoms and signs compatible with acute urethritis. Their urethral swabs and first-voided urine underwent detection of the microorganisms. Demographic characteristics and clinical features of Mycoplasma genitalium-, Ureaplasma urealyticum-, Haemophilus influenza-, adenovirus- or Herpes simplex virus-positive monomicrobial non-gonococcal urethritis, or all-examined microorganism-negative urethritis in heterosexual men were compared with urethritis positive only for Chlamydia trachomatis.

RESULTS: Neisseria gonorrhoeae was detected in 127 men (30.0%). In 297 men with non-gonococcal urethritis, C. trachomatis was detected in 143 (48.1%). In 154 men with non-chlamydial non-gonococcal urethritis, M. genitalium (22.7%), M. hominis (5.8%), Ureaplasma parvum (9.1%), U. urealyticum (19.5%), H. influenzae (14.3%), Neisseria meningitidis (3.9%), Trichomonas vaginalis (1.3%), human adenovirus (16.2%), and Herpes simplex virus types 1 (7.1%) and 2 (2.6%) were detected. Although some features of monomicrobial non-chlamydial non-gonococcal urethritis or all-examined microorganism-negative urethritis were significantly different from those of monomicrobial chlamydial non-gonococcal urethritis, most features were superimposed.

CONCLUSIONS: Predicting causative microorganisms in men with non-gonococcal urethritis based on demographic and clinical features is difficult. However, the present study provides useful information to better understand the microbiological diversity in non-gonococcal urethritis, and to manage patients with non-gonococcal urethritis appropriately.