Vulvovaginitis and the microbiome: a review of the diagnosis and treatment of acute and recurrent infection

In a recent study published in the Obstetrics and Gynecology Clinics of North America Journal, researchers explored the relationship between microbiome and vulvovaginitis.

Study: Microbiome and Vulvovaginitis. Image Credit: TolikoffPhotography/Shutterstock.com

Background

Vulvovaginitis is a common reason for patients with vaginas to visit a gynecologist. Vaginitis, which is primarily caused by yeast, trichomoniasis, or bacterial vaginosis, is a significant worldwide health issue that results in an estimated annual cost of $4.8 billion for patients as well as the healthcare system.

Despite patient anecdotes suggesting otherwise, Vaginitis symptoms are difficult to self-diagnose, as they are often nonspecific and contain 'look-alike' symptoms.

Bacterial vaginosis (BV)

BV is a prevalent form of vaginitis globally. The presence of Gardnerella vaginalis, Atopobium vaginae, Sneathia spp, Prevotella spp, and BV-associated bacteria in the vaginal microbiome is linked to BV.

This infection occurs when these bacteria displace the lactic acid-producing Lactobacillus spp. New studies on the vaginal microbiome aim to discover the factors contributing to dysbiosis, although the exact reason for BV is still unknown.

P. bivia and G. vaginalis are found in high numbers in women with BV, but they do not cause a strong inflammatory reaction from vaginal epithelial cells compared to other bacteria that stimulate the immune system more effectively.

The microbiome and BV

Lactobacillus is a significant component of the microbial colonization found in the vagina of healthy individuals. Lactobacillus can be categorized into five community state types (CSTs) based on its various species.

Among these, CST I is dominated by Lactobacillus crispatus, CST II by Lactobacillus gasseri, CST III by Lactobacillus iners, and CST V by Lactobacillus jensenii.

CST IV is mainly composed of anaerobic bacteria. Hydrogen peroxide and lactic acid are produced by L crispatus, L jensenii, and L gasseri, which reduce the pH of the vaginal environment to less than 4.5 and prevent the proliferation of important healthy bacteria and viruses. The recurrence rate of BV following oral metronidazole therapy is high, while systemic antibiotics can result in significant side effects.

Management of BV

Centers for Disease Control and Prevention (CDC)'s sexually transmitted infections (STI) Treatment Guidelines recommend treating patients with symptomatic BV with metronidazole, either orally twice a day for seven days or intravaginally daily for five days or clindamycin gel intravaginal for seven days.

The study found that oral metronidazole had a temporary beneficial influence on the vaginal microbiome of recurrent BV patients, with recurrence occurring by day 30 after therapy.

Another study found that after the primary visit, the cure rate following IBA and nitroimidazole therapy ranged between 88% and 92% at seven and 12 weeks.

Vulvovaginal candidiasis (VVC)

Vulvovaginal candidiasis (VVC) is a prevalent cause of vulvovaginitis, diagnosed by symptoms such as vaginal discharge, vulvar pruritus, external dysuria, swelling, redness, or pain.

The signs of this condition are vulvar edema, excoriations, fissures, and occasionally thick curdy vaginal discharge.

The microbiome and VVC

Further studies are needed to clarify the function of the vaginal microbiome (VMB) composition in VVC. Few vaginal bacteria showed a robust and significant correlation with the absence or presence of yeast.

The literature states that a normal vaginal pH is present during VVC, which suggests that there is a sufficient proportion of Lactobacilli to maintain vaginal acidity.

This indicated that Lactobacilli might not have a significant role in protecting against VVC in women.

Management of VVC

Vaginal or oral azoles are among the most commonly prescribed medications for VVC that effectively relieve most patients. Recurrent VVC (RVVC) can have negative social and psychological effects on patients who experience it.

RVVC is characterized by experiencing three or more symptomatic VVC episodes within a year. Notably, azole resistance is reported in C. albicans isolates, while RVVC pathogenesis is poorly understood.

Topical azoles used for seven to 14 days or oral fluconazole administered every three days for three doses have effectively treated RVVC.

Trichomoniasis (TV)

Trichomonas vaginalis (TV) is a common parasitic protozoan that causes vaginitis and is a leading cause of reproductive health issues. It is also the most widespread non-viral STI globally.

The microbiome and TV

The vaginal microbiome of patients with trichomoniasis increased the presence of anaerobic bacteria such as Megasphera 2, Prevotella, Parvimonas, and Sneathia compared to those without the infection.

TV samples were analyzed using cluster analysis, which revealed two distinct groups based on the abundance of Mycoplasma hominis. The group with higher M. hominis abundance showed clinical features of vaginal inflammation.

TV and BV are often found together in women, and research has shown a significant link between these infections.

Management of TV

Only nitroimidazoles have been clinically proven to be effective against T. vaginalis infection. The recommended treatment for women is taking metronidazole orally twice daily for seven days. Oral administration of a single dose of Tinidazole can be used as an alternative.

Also, patients are advised to refrain from sexual activity until both they and their partner have received treatment. Additionally, they should be provided with STI screening, which may include an HIV test.

Conclusion

The study findings provided an overview of recent literature on diagnosing and treating acute and recurrent vaginitis, along with related conditions such as desquamative inflammatory vaginitis.

The present article explored the role of the vaginal microbiome in these conditions and offered valuable insight to help simplify infection management.

Written by

Bhavana Kunkalikar

Bhavana Kunkalikar is a medical writer based in Goa, India. Her academic background is in Pharmaceutical sciences and she holds a Bachelor's degree in Pharmacy. Her educational background allowed her to foster an interest in anatomical and physiological sciences. Her college project work based on ‘The manifestations and causes of sickle cell anemia’ formed the stepping stone to a life-long fascination with human pathophysiology.