The penile urethra can become infected by viruses, bacteria, and other pathogens that are transferred sexually, despite the epithelia of the penile urethra having immune cells that can detect and mount immune responses against germs.
While commensal microbial communities are known to protect the female reproductive system and gastrointestinal tract from infections, it is unknown whether the penile urethra is home to a microbiome that has a similar protective function.
Due to the uncomfortable nature of sampling, the penile urethral microbiome is hardly examined in healthy humans. Furthermore, non-invasive techniques, such collecting urine samples, may not accurately depict the variety of microbial communities that might present in the penile urethra.
Therefore, the available information on the penile urethral microbiome comes from studies involving
It is challenging to determine the function of a healthy penile urethral microbiome in males who have STDs.
Concerning the study
Using strict inclusion/exclusion criteria that included clinical examinations, urethral inflammations, tests for sexually transmitted diseases, and behavioral surveys, the researchers in the current study collected penile urethral samples from healthy men who met the inclusion/exclusion criteria. The study also included a validation cohort that comprised vaginal samples.
Shotgun metagenomic sequencing identified the penile urethral and vaginal microbiome. In addition, the researchers assessed the effects of sexual practices and risk factors for STDs on the makeup of the penile urethral microbiome.
The specimens were grouped into urethrotypes using the sequence data clustering. Examining if a person belongs to one of the two urethrotypes.
The results reported that Corynebacterium species and some lactic acid bacteria were found in most penile urethral specimens. When the urethrotypes were examined in association with sexual behaviors, specific sexually transmitted infection risk factors, and demographic characteristics, the findings indicated that while infection risk factors and demographics showed no significant associations, vaginal sex in the previous two months to one year was associated with urethrotype two.
In contrast, penetrative penile oral or anal sex was not associated with any of the urethrotypes, and bacteria associated with dysbiosis in the vagina were present in the penile urethral specimens of only those men who reported having vaginal sex. This suggested that sexual behavior was linked to the variation in species composition of the urethral microbiome.
