Sexual behavior shapes male genitourinary microbiome composition.

The origin, composition, and significance of the distal male urethral microbiome are unclear, but vaginal microbiome dysbiosis is linked to new sex partners and several urogynecological syndromes. We characterized 110 urethral specimens from men without urethral symptoms, infections, or inflammation using shotgun metagenomics. Most urethral specimens contain characteristic lactic acid bacteria and Corynebacterium spp. In contrast, several bacteria associated with vaginal dysbiosis were present only in specimens from men who reported vaginal intercourse. Sexual behavior, but not other evaluated behavioral, demographic, or clinical variables, strongly associated with inter-specimen variance in urethral microbiome composition. Thus, the male urethra supports a simple core microbiome that is established independent of sexual exposures but can be re-shaped by vaginal sex. Overall, the results suggest that urogenital microbiology and sexual behavior are inexorably intertwined, and show that the male urethra harbors female urogenital pathobionts.

No Pathogen-Specific Sign or Symptom Predicts the Etiology of Monomicrobial Nongonococcal Urethritis in Men.

Identifying pathogen-specific signs or symptoms of nongonococcal urethritis could improve syndromic management accuracy. We evaluated nongonococcal urethritis signs and symptoms in 220 men with single-pathogen infections (Chlamydia trachomatis, Mycoplasma genitalium, Trichomonas vaginalis, or Ureaplasma urealyticum) or idiopathic urethritis. No individual sign or symptom accurately predicted the infectious etiology.

Aetiology and prevalence of mixed-infections and mono-infections in non-gonococcal urethritis in men: a case-control study.

OBJECTIVES: Chlamydia trachomatis (CT) and Mycoplasma genitalium (MG) cause the majority of non-gonococcal urethritis (NGU). The role of Ureaplasma urealyticum (UU) in NGU is unclear. Prior case-control studies that examined the association of UU and NGU may have been confounded by mixed infections and less stringent criteria for controls. The objective of this case-control study was to determine the prevalence and aetiology of mixed infections in men and assess if UU monoinfection is associated with NGU. METHODS: We identified 155 men with NGU and 103 controls. Behavioural and clinical information was obtained and men were tested for Neisseria gonorrhoeae and CT, MG, UU and Trichomonas vaginalis (TV). Men who were five-pathogen negative were classified as idiopathic urethritis (IU). RESULTS: Twelve per cent of NGU cases in which a pathogen was identified had mixed infections, mostly UU coinfections with MG or CT; 27% had IU. In monoinfected NGU cases, 34% had CT, 17% had MG, 11% had UU and 2% had TV. In controls, pathogens were rarely identified, except for UU, which was present in 20%. Comparing cases and controls, NGU was associated with CT and MG monoinfections and mixed infections. UU monoinfection was not associated with NGU and was almost twice as prevalent in controls. Men in both the case and control groups who were younger and who reported no prior NGU diagnosis were more likely to have UU (OR 0.97 per year of age, 95% CI 0.94 to 0.998 and OR 6.3, 95% CI 1.4 to 28.5, respectively). CONCLUSIONS: Mixed infections are common in men with NGU and most of these are UU coinfections with other pathogens that are well-established causes of NGU. UU monoinfections are not associated with NGU and are common in younger men and men who have never previously had NGU. Almost half of NGU cases are idiopathic.

Detection of Rectal Chlamydia trachomatis in Heterosexual Men Who Report Cunnilingus.

BACKGROUND: Rectal infection with Chlamydia trachomatis (CT) is frequent in women who deny receptive anal sex and is thought to arise from autoinoculation of the rectum from vaginal secretions. An alternate hypothesis is that oral sex inoculates and establishes gastrointestinal tract infection. Distinguishing these hypotheses is difficult in women. In men, autoinoculation is unlikely and heterosexual men frequently perform oral sex, but rarely participate in receptive anal exposure behaviors. METHODS: We enrolled high-risk men with and without nongonococcal urethritis who presented to a sexually transmitted infection clinic in Indianapolis, Indiana. Urine and rectal swabs were collected and tested for urogenital and rectal CT, Neisseria gonorrhoeae (NG), and Mycoplasma genitalium (MG). Men completed surveys concerning symptoms, sexual orientation, and detailed recent and lifetime oral and anal sexual behaviors. RESULTS: Rectal CT was detected in 2/84 (2.4%) heterosexual men who reported cunnilingus, but no lifetime receptive anal behaviors. All of the men who denied receptive anal behaviors were negative for rectal NG and MG. In homosexual and bisexual men, rectal CT prevalence was high (9.7%), and rectal NG (4.8%) and MG (4.8%) were also detected. CONCLUSIONS: We detected rectal CT infections in heterosexual men who reported cunnilingus but denied receptive anal behaviors. Oral sex may be a risk factor for rectal CT infection via oral inoculation of the gastrointestinal tract.