Incidence of Nongonococcal Urethritis in Men Who Have Sex With Women and Associated Risk Factors

Bacterial vaginosis-associated bacteria in cisgender men who have sex with women: prevalence, association with non-gonococcal urethritis and natural history

OBJECTIVES

Bacterial vaginosis-associated bacterium 2 (BVAB2), Mageeibacillus indolicus and Sneathia spp are highly predictive of bacterial vaginosis (BV) in cisgender women. They have been associated with non-gonococcal urethritis (NGU) in cisgender men in some but not all populations. We evaluated this association in a cross-sectional study of cisgender men who have sex with women only (MSW).

METHODS

MSW without gonorrhoea attending a sexual health clinic (SHC) from 2014 to 2018 completed a computer-assisted self-interview, clinical interview and examination. NGU was defined as ≥5 polymorphonuclear leucocytes/high-power field in urethral exudates plus either urethral symptoms or visible discharge. Urine was tested for Chlamydia trachomatis and Mycoplasma genitalium using Aptima (Hologic) and for BVAB2, M. indolicus, Sneathia spp, Trichomonas vaginalis, Ureaplasma urealyticum, Haemophilus influenzae, herpes simplex virus and adenovirus using quantitative PCR.

RESULTS

Of 317 MSW age 17-71, 67 (21.1%) had Sneathia spp, 36 (11.4%) had BVAB2, and 17 (5.4%) had M. indolicus at enrolment. Having ≥3 partners in the past 2 months was the only characteristic that was more common among MSW with than those without these bacteria (BVAB2: 47% vs 23%, M. indolicus: 53% vs 24%, Sneathia spp: 42% vs 22%; p≤0.03 for all). One-hundred seventeen men (37%) were diagnosed with NGU at enrolment. There was no significant association of BVAB2, M. indolicus or Sneathia spp with NGU (adjusted OR=0.59, 95% CI 0.14 to 2.43; aOR=3.40, 95% CI 0.68 to 17.06; aOR=0.46, 95% CI 0.16 to 1.27). Of 109 MSW with monthly samples, 34 (31.2%) had one of the bacteria at one or more follow-up visits, 22 of which were co-colonised with >1. Median persistence over 6 months did not differ significantly (BVAB2=30.5 days, IQR=28-87; M. indolicus=87 days, IQR=60-126; Sneathia spp=70 days, IQR=30-135; p≥0.20 for each comparison).

CONCLUSIONS

Neither BVAB2, M. indolicus nor Sneathia spp were associated with increased risk of prevalent NGU in MSW attending an SHC.

Mycoplasma genitalium Protein of Adhesion Promotes the Early Proliferation of Human Urothelial Cells by Interacting with RPL35

Mycoplasma genitalium is a newly recognized pathogen associated with sexually transmitted diseases (STDs). MgPa, the adhesion protein of Mycoplasma genitalium, is the main adhesin and the key factor for M. genitalium interacting with host cells. Currently, the long-term survival mechanism of M. genitalium in the host is not clear. In this study, a T7 phage-displayed human urothelial cell (SV-HUC-1) cDNA library was constructed, and the interaction of MgPa was screened from this library using the recombinant MgPa (rMgPa) as a target molecule. We verified that 60S ribosomal protein L35 (RPL35) can interact with MgPa using far-Western blot and co-localization analysis. According to the results of tandem mass tag (TMT) labeling and proteome quantitative analysis, there were altogether 407 differentially expressed proteins between the pcDNA3.1(+)/MgPa-transfected cells and non-transfected cells, of which there were 6 downregulated proteins and 401 upregulated proteins. The results of qRT-PCR demonstrated that interaction between rMgPa and RPL35 could promote the expressions of EIF2, SRP68, SERBP1, RPL35A, EGF, and TGF-β. 3-(4,5)-Dimethylthiahiazo(-z-y1)-3,5-di-phenytetrazoliumromide bromide (MTT) assays corroborated that the interaction between rMgPa and RPL35 could promote SV-HUC-1 cell proliferation. Therefore, our findings indicated that the interaction between rMgPa and RPL35 can enhance the expressions of transcription-initiation and translation-related proteins and thus promote cell proliferation. This study elucidates a new biological function of MgPa and can explain this new mechanism of M. genitalium in the host.