Background The aetiology of non-gonococcal urethritis (NGU) in men is unknown in 30%–50% of cases. Little is known about the relation of bacterial vaginosis (BV) associated bacteria in men with urethritis of unknown aetiology (UUE). Urethral swabs from men with and without NGU were analysed with PCR for BV associated bacteria to show a possible association with UUE.
Methods Urethral swabs from 9 and 19 men with symptomatic and asymptomatic NGU (>5 PMNL/hpf), respectively, and 30 asymptomatic men without NGU were collected. All samples were negative for Neisseria gonorrhoeae, Chlamydia trachomatis, Mycoplasma genitalium, Ureaplasma urealyticum and U parvum with specific PCR assays. Quantitative real-time PCR with TaqMan based assays were performed to detect Atopobium vaginae (Av), Sneathia sanguinegens (Ss), Leptotrichia amnionii (La) and Gardnerella vaginalis (Gv), and with SYBR green assays for BVAB 1, 2 and 3, and Megasphaera phylotype 1 (M1).
Results Gv was detected in 93% of cases with UUE and in 37% of controls (p<0.0001). There was no difference in organism load. In the 28 NGU cases Av, Ss and La were found in 3, 2 and 1 samples, respectively, and in 6, 2 and 1 of the control samples, respectively. The median corresponding organism loads were 14, 95 and 51 for the NGU cases and 16, 10 566 and 353 for the controls. All samples were negative for BVAB 1, 2 and 3 and M1, except one control with 10 genome copies of BVAB 1.
Conclusions Gardnerella vaginalis was associated with male urethritis in this study, especially in men with asymptomatic urethritis, while BVAB 1, 2 and 3, Megasphaera phylotype 1, Atopobium vaginae, Sneathia sanguinegens, and Leptotrichia amnionii were not.