Probiotics & Antibiotics

Why antimicrobials may fail to work?

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

1. 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. The type of pathogen can also be less susceptible to prescription treatment. For example, certain Atopobium vaginae bacterial strains have shown a high-level of resistance to metronidazole treatment (2).
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 BV bacteria: Gardnerella vaginalis and Atopobium vaginae (3).
3. Antimicrobials can disrupt the vaginal microbiome. If you’re taking an antimicrobial for an infection of the vagina or another area of the body it can disrupt the natural flora in the vagina, inhibiting healthy recovery. This disruption may cause a reduction in good bugs which keep the pathogen bacterial colonies at bay.

How do post-antibiotic vaginal probiotics work?

Most clinical studies support probiotics in the maintenance of vaginal health, and no adverse effects have been reported. In a nutshell, probiotics can help repopulate the healthy bacteria in the vagina, which can support vaginal healthy by producing healthy lactic acid and creating stable colonies. 

• Colonization of healthy bugs. Sounds good in theory, however, there have been a great deal of failures in this department. Some scientists attempted to do so but good bugs failed to recolonize vagina, simply because they were using wrong Lactobacillus strains. A simple application of probiotic species orally or intravaginally is not good enough to restore a healthy flora balance because not all Lactobacillus species have the same adherence abilities. This means that there was no ability for the good bugs to grow, thrive and stick around and "hold the fort".
  It was found that Lactobacillus crispatus, which is also known as the ‘super hero of the vagina’ colonized for over 8 months in 8x more female subjects compared with other Lactobacillus species (40% vs 5%) (4). This demonstrates that L. crispatus has superior adherence abilities compared with other good bugs and can support healthy vaginal flora after antibiotics.
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• Anti-biofilm properties. Biofilm is a matrix made by bacteria themselves. Think of it like a protective layer which surrounds and encloses clusters of bacteria and attaches itself to a body surface. Bad bugs are known to form biofilms in order to protect themselves from the adverse environmental conditions. Certain probiotics 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 strains Lactobacillus rhamnosus, GR-1® and Lactobacillus reuteri, RC-14® have the ability to penetrate into the biofilms created by Gardnerella vaginalis and Atopobium vaginae and cause disruption of the biofilm (5).
  

• ‍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. Certain L. crispatus and L. gasseri strains have also the remarkable ability to produce and release antibiotic-like compounds (6). 

There are also ways to make lifestyle changes to help avoid contact with bad bacteria that you can implement, like using condoms, avoiding douching and, if prescribed them, using the full course of antibiotics your doctor has prescribed even after symptoms have diminished. Plus if you have a regular partner, and you’re prone to reinfection, they may need to be treated at the same time as you.

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. Vallor AC, Antonio MA, Hawes SE, Hillier SL. Factors associated with acquisition of, or persistent colonization by, vaginal lactobacilli: role of hydrogen peroxide production. J Infect Dis. 2001 Dec 1;184(11):1431-6.
5. 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.
6. 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.