Genital Microbiome and Risk against STDs

Over the years, there has been evidence of the development of antibiotic-resistant STDs. This is rather alarming, as the cases of STDs are not reducing at any rate. In fact, it is continuously on the rise. A healthy genital microbiome is our first line defense against external pathogens, including STDs. 

There are clinical studies showing the good bacteria that constitutes the healthy genital microenvironment have an immune mechanism, and may provide protection against STDs. Treatment targeting the genital microbiome may potentially reduce the risk of acquiring STDs.

In this article, we would wish to enlighten the readers on the female and male microenvironment, the importance of maintaining a good baseline genital health and reducing one’s risk against STDs. 

Female Genital Microenvironment

The vaginal environment is mainly covered with healthy anaerobic bacteria — lactobacillus spp. In an equilibrium, the lactobacillus spp keeps the vagina sterile, lubricated, and able to clear off common pathogens. 

Unfortunately, this healthy state is easily tempered with the depletion of healthy lactobacillus spp and overgrowth of bad anaerobic bacteria. One of the commonly heard pathogenic vaginal bacteria is gardnerella vaginalis which plays a vital role in a recurring female vaginal infection known as bacterial vaginosis (BV). 

BV is known to be associated with poor quality of life due to the uncomfortable symptoms of BV, and association with poor reproductive outcome such as preterm labour and low birth weight of infants. Furthermore, the persistence presence of bad anaerobic bacteria predisposes one towards contracting STDs and spreading STDs to others.

Changes in Vaginal Microflora

The actual mechanism of the destabilisation of the vagina flora remains unknown.

Factors that can shift the microflora to bad anaerobic bacteria rather than lactobacillus spp include:

• Frequent sexual intercourse
• Increased number of sexual partners
• Existing untreated vaginal infections (including STDs)
• Changes in one’s one immunity
• Changes in one’s hormonal levels
• Douching
• Cigarette smoking

Male Genital Microenvironment

Intriguingly, the male genital region is less discussed. In comparison to the female genital anatomy, the male genitalia are ‘externally’ seen. Yet, the male genital also has its own healthy microflora.

The penis is mainly covered with similar bacteria seen on our normal skin such as Corynebacterium spp and staphylococcus spp. Occasionally, bad anaerobic bacteria (that can be associated in BV in females) can be found in the male genital region as well.

As predicted and logically, men with female partners with BV infection tend to have genital microenvironments that have more bad anaerobic bacteria, such as gardnerella vaginalis, while men with female partners without BV are likely to carry normal skin bacterias such as, Lactobacillus spp, Corynebacterium spp and staphylococcus spp on the penis.

Uncircumcised vs Circumcised

The male foreskin can also affect the microbiome in the penis. As the foreskin provides a physical layer, it can also house many bad anaerobic bacteria. In a circumcised man, as the penis is exposed, the quantity of bad anaerobic bacteria is lesser, with predominantly skin bacteria found on the penis surface. It is known that circumcised men have lower risk of acquiring HIV, herpes infection, HPV infection and lower risk to trigger BV in their female partners.

How can the normal men and women microflora protect against STDs?

The actual mechanism of how the  female genital microbiome can protect one against STDs has been a common clinical research topic though there remain gaps in the knowledge.

The healthy vaginal lactobacillus spp provides a more acidic sterile environment that prevents pathogens from replicating as they thrive better in alkaline environments. Additionally, the lactobacillus spp can protect women from STDs by: 

• Providing anti-bacterial properties, preventing pathogens from producing byproducts. 
• Halting the interaction of pathogens and vaginal cells, protecting the vagina from infection.
• Forming tight bindings among the vaginal cells, providing a physical barrier against STDs. 
• Competing against pathogens/STDs to bind themselves onto vaginal cells. This prevents the STDs pathogens from latching onto the vaginal cells and infecting a person.

In males, the role of genital microbiome against STDs are not as straightforward. Nonetheless, there are medical studies that show susceptibility of contracting HIV with higher numbers of bad anaerobic bacteria in the male genital region. 

Bad anaerobic bacteria can be pro-inflammatory and they can create an environment that is easily succumbed to external pathogens. Men with skin flora bacteria predominant over the genitalia and less anaerobic bacteria may have lower risk of contracting STDs and triggering BV in their female partners.

What increases my risk of getting STDs?

For females 

You may have higher risk of STDs if

• You have multiple sexual partner(s), or your partner(s) has/have multiple other sexual partner(s).
• If you are predisposed towards female related vaginal infections such as bacterial vaginosis
• If you have existing STDs infections that have yet to be treated.
• Your sexual partner(s) has existing STDs infections that have yet to be treated.

As a female, the general risk of contracting STDs is higher than males due to:

• The female anatomy with greater genital surface area of exposure when comparison to male genital surface area
• The ability of semen to survive in the female genitalia up to 3-5 days, allowing STDs infections to survive longer in the female organ.
• The hormone changes with more watery mucus during the ovulatory phase of the menstrual cycle. This can facilitate STDs infections to invade the female pelvic structures,

For males

You may have higher risk of STDs if

• You have multiple sexual partner(s), or your partner(s) has/have multiple other sexual partner(s).
• If you have existing STDs infections that have yet to be treated.
• Your sexual partner(s) has existing STDs infections that have yet to be treated.
• If your female sexual partner is predisposed to female related vaginal infections such as bacterial vaginosis.
• If you are uncircumcised.

What should I do if I may be at risk of STDs?

Although STDs can be associated with abnormal genital symptoms, very often, STDs can be insidious without any tell-tale signs. You are advised to seek medical advice with your doctor if you are concerned of possible exposure to STDs and contracting the infections from your partner(s). STDs do not resolve on their own and will require the right medication and right dose to clear off the infection(s).

What have I learnt?

• The maintenance of a healthy microbiome in both female and male genital regions may be able to reduce risk of acquiring STD.
• Disequilibrium of the genital microbiome with predisposition towards bad anaerobic bacteria promotes an environment that is susceptible to pathogens and infections.
• Treating any ongoing female and male genital bacterial infection is imperative in restoring a healthy microbiome in the genitals, thereafter reducing the risk of acquiring STD.
• If there is concern of concurrent exposure and acquisition of STDs, one should consider screening and early treatment.

References:

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