Prevalence of and Risk Factors Associated with Mono-Infections and Coinfections in Nongonococcal Urethritis.

Background: Chlamydia trachomatis (CT), Ureaplasma urealyticum (UU), and Mycoplasma genitalium (MG) cause most cases of nongonococcal urethritis (NGU). The treatment options for different pathogens vary, and an accurate diagnosis of the pathogen species allows targeted treatment. This study explored the prevalence and etiology of coinfections and monoinfections with NGU.

Methods: Neisseria gonorrhoeae (NG), CT, UU, and MG RNA were detected in urine and secretion samples of 1,430 patients with urethritis and 527 patients without urethritis (control group) using simultaneous amplification and testing. The corresponding clinical information was obtained. When these four pathogens were not detected, idiopathic urethritis (IU) was diagnosed.

Results: Among the enrolled patients, 1,249 had NGU, 181 had gonococcal urethritis, and 28.26% (353/1,249) had IU. The average age of patients with NGU was 31 years. Additionally, 81.67% (1,020/1,249) of patients with NGU were men. Coinfections with NGU were observed in 13.05% (163/1,249) of patients, and they mainly comprised UU and CT. Among the patients with NGU, UU was the most common cause (40.59%; 507/1,249). Seventy-six patients with urethral symptoms were excluded from the control group. A comparison of the NGU and control groups revealed that NGU was caused by single UU, CT, and MG infections as well as coinfections. Single UU infections were the most common cause of NGU. The prevalence of single UU infections significantly exceeded that of single CT and MG infections. A follow-up analysis of 310 patients showed that the CT and UU infection rates significantly decreased after 1 to 2 weeks of treatment; however, the MG infection rate was not significantly reduced after at least 4 weeks of treatment.

Conclusions: The incidence of NGU is significantly higher than that of gonorrhea, and coinfections are common in men with NGU. Furthermore, most men with NGU had UU coinfections. UU is the most common cause of NGU. Additionally, UU infections were commonly observed in young men without a history of NGU. Our results provide guidance for relevant clinical therapies.