Antibiotics & Vaginal Microbiome

If you have, or recently have had, bacterial vaginosis (BV) or a yeast infection (thrush) you likely will have taken an antibiotic or antifungal medication which attacks the pathogen directly. However, this may not entirely rid the system of the pathogen as it can lie dormant and resurface causing reinfection. Within a year, more than 50% of women will contract BV again after an antibiotic treatment (1). This causes major shifts in the nature and components of vaginal microbiome communities.

Why antimicrobials may fail to work?

There are a few major reasons why antimicrobials won’t kill the pathogens:

  • Resistance of bacterial or fungal organisms to therapy

Unfortunately, bad bugs get smarter to survive. Repeated use of antibiotic or antifungal therapy may no longer kill the pathogens. Some types of pathogen can also be less susceptible to the certain prescription treatment. For example, certain Atopobium vaginae bacterial strains have shown a high-level of resistance to metronidazole treatment (2).

  • Creation of a biofilm on the vaginal wall

Bad bacteria have the ability to create a biofilm layer which adheres to the cells of the vaginal wall, preventing the treatment from reaching the pathogens. So, the biofilm acts as a reservoir of bacteria and protects them from the effect of an antibiotic. One study took 18 BV patients treated with oral metronidazole for 1 week, and followed them up to 5 weeks after treatment. Even though all patients initially recovered after the treatment, dense and active bacterial biofilms were invariably re-emerging. These biofilms consisted predominantly of the main bacteria responsible for BV: Gardnerella vaginalis and Atopobium vaginae (3).

Interaction between antibiotics and vaginal microbiome

If you’re taking an antibiotic for a vaginal infection, it can disrupt vaginal natural flora. This disruption may cause a reduction in good bugs in the vagina which are important for maintenance of a healthy vagina. 

 

How does a healthy vaginal microbiome work?

A healthy vaginal microbiome can support vaginal health through different mechanisms.

  • Anti-biofilm properties

Bad bugs can create a biofilm. Well, good bugs can do it too. Not only that. Certain Lactobacillus species have the ability to disrupt bad bugs’ biofilm formations and expose bacteria to the influence of antimicrobial agents. It was found, in a laboratory experiment, that healthy bacteria have the ability to penetrate into the biofilms created by Gardnerella vaginalis and Atopobium vaginae and cause disruptions of the biofilm (4).

  • Lactic acid and other antimicrobial agent secretion

Lactic acid is a naturally occurring acid that helps keep the vaginal microbiome healthy. Healthy Lactobacillus species secrete lactic acid. Furthermore, it was shown that certain lactobacilli have also the remarkable ability to produce and release antibiotic-like compounds (5). 

 

How to keep vaginal infections from coming back?

If you experience recurrent vaginal infections, consult your health practitioner to discuss the most effective treatment options and preventive strategies. You may want to explore lifestyle changes to reduce exposure to harmful bacteria, such as using condoms and avoiding douching. Additionally, if you have a regular partner and are prone to reinfection, they may need to be treated simultaneously. Lastly, always complete the full course of antibiotics prescribed by your doctor, even if symptoms subside before finishing the treatment.

 

 

References:

  1. Bradshaw CS, Tabrizi SN, Fairley CK, Morton AN, Rudland E, Garland SM. The association of Atopobium vaginae and Gardnerella vaginalis with bacterial vaginosis and recurrence after oral metronidazole therapy. J Infect Dis. 2006 Sep 15;194(6):828-36.

  2. De Backer E, Verhelst R, Verstraelen H, Claeys G, Verschraegen G, Temmerman M, Vaneechoutte M. Antibiotic susceptibility of Atopobium vaginae. BMC Infect Dis. 2006 Mar 16;6:51.

  3. Swidsinski A, Mendling W, Loening-Baucke V, Swidsinski S, Dörffel Y, Scholze J, Lochs H, Verstraelen H. An adherent Gardnerella vaginalis biofilm persists on the vaginal epithelium after standard therapy with oral metronidazole. Am J Obstet Gynecol. 2008 Jan;198(1):97.e1-6.

  4. McMillan A, Dell M, Zellar MP, Cribby S, Martz S, Hong E, Fu J, Abbas A, Dang T, Miller W, Reid G. Disruption of urogenital biofilms by lactobacilli. Colloids Surf B Biointerfaces. 2011 Aug 1;86(1):58-64.

  5. Atassi F, Pho Viet Ahn DL, Lievin-Le Moal V. Diverse Expression of Antimicrobial Activities Against Bacterial Vaginosis and Urinary Tract Infection Pathogens by Cervicovaginal Microbiota Strains of Lactobacillus gasseri and Lactobacillus crispatus. Front Microbiol. 2019 Dec 20;10:2900.

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