Probiotics to Prevent Yeast Infections After Antibiotics?

Ask Dr. Jen

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I’m genuinely curious if it’s true that I should take a probiotic alongside an antibiotic to reduce the risk of developing a yeast infection.

-Via Instagram

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Short Take

I don’t recommend it.

Tell me More…

Let’s tackle this in three parts.

How Common are Vaginal Yeast Infections After Antibiotics

Post-antibiotic vaginal yeast infections are commonly reported, and some experts estimate the risk may be as high as 10-30%, although we actually have very little quality data about this phenomenon as it is so understudied. Many symptoms and conditions that are very bothersome are considered insignificant because they are not life-threatening and they only affect women. One of the better studies that evaluated women before and after they took antibiotics found that 20% developed a yeast infection. In this study, the two major risk factors for a yeast infection after antibiotics were being colonized with yeast before starting the antibiotics and reporting being prone to yeast infections after antibiotics.

Studies like this one are important because observational studies can be problematic as many women self-diagnose and self-treat treat or are treated by their providers without receiving a correct diagnosis via testing. This means when someone reports having had a yeast infection, we don’t know if that report is accurate as self-diagnosis of a yeast infection can be incorrect up to 50% of the time. Unfortunately, many medical providers don’t perform much better when they don’t do the appropriate testing. Even in many prospective studies, women have often simply been asked about their symptoms, and so instead of receiving the appropriate test to get an accurate diagnosis, all vaginal and vulvar mayhem is assumed to be yeast. Fortunately, this is changing.

There are some studies that look at vaginal colonization after antibiotics, meaning the presence of yeast but no symptoms. Most people believe colonization is necessary before infection, so this finding supports an antibiotic-yeast connection. Some studies show an increase in yeast after antibiotics, but others do not. It’s rare to find several studies evaluating the same antibiotic, so it’s not possible to know if some antibiotics are more likely to lead to an increase vaginal colonization with yeast, hence the discrepancies between studies, or if there are other reasons for the difference.

Bottom Line: Based on limited data, about 20% of women get a yeast infection after a course of antibiotics (not an insignificant number!), and some women may be more prone than others.

What Causes Post-Antibiotic Yeast Infections?

The dogma has long been that antibiotics kill the “good bacteria” (primarily lactobacilli) that control the vaginal ecosystem, including keeping the normally present yeast in check. When the good bacteria are killed by the antibiotics, the yeast is now free to overgrow. However, there are some issues with this theory. Here are the main two, which basically drive truck-like holes in the hypothesis:

• We don’t have studies that tell us antibiotics kill off vaginal lactobacilli.

• We don’t think the lactobacilli in the vaginal microbiome play a big role in preventing yeast infections, as women with recurrent vaginal yeast infections aren’t lacking lactobacilli.

If antibiotics lead to yeast infections, it is almost certainly unrelated to lactobacilli. However, antibiotics can damage or affect the microbiome in other ways, and these changes could allow the “Hey, I’m along for the ride” vaginal yeast to become more aggressive (meaning invasive), hence causing an infection.

The fact that many women do not develop a yeast infection after antibiotics and that some women seem to be more vulnerable to this phenomenon suggests that there are likely individual risk factors at play, for example, genetics or other factors that increase the risk of colonization with yeast (for example, estrogen therapy, either in contraception or vaginal estrogen), or skin conditions, like lichen sclerosus.

What About Probiotics?

Since lactobacilli don’t appear to be involved with yeast infections, that pours cold water on the idea that probiotics could help. In 2019, Dr. Jack Sobel, a doctor and infectious diseases expert who probably knows more about vaginal yeast than any other human alive, wrote that using oral or vaginal probiotics to prevent antibiotic-related yeast infections represents “a leap of faith of extrapolation based on zero data and proof of efficacy.”

Studies tell us that oral probiotics don’t do a good job of colonizing the vagina, so even if probiotics were the thing, that method of delivery would be pointless.

The lactobacilli species that dominate the vaginal microbiome are crispatus, iners, gasseri, jensenii, and vaginalis, although reuteri, rhamnosus, and gallinarum can be found. Most commercial products don’t have crispatus and iners, which are the most commonly isolated species from healthy vaginal microbiomes. So, there’s that. There is a product called Lactin-V, which is vaginal lactobacillus crispatus. Lactin-V is still under investigation and has shown early promise for preventing bacterial vaginosis, but it is not yet commercially available. I believe the company is ultimately aiming for FDA approval, but I am not “in the know.” There is a new OTC vaginal probiotic called Seed, which also contains lactobacillus crispatus, but currently, there are no clinical trials with this product for the treatment or prevention of infections, so it can’t be recommended. Regardless, as we don't believe the loss of lactobacilli is a cause of post-antibiotic yeast infection/symptoms, this would also not be a time to consider this product.

Most of the existing studies looking at probiotics to treat/prevent vaginal yeast infections are generally of lower quality, but based on the evidence (such as it is), a recent meta-analysis concluded that probiotics didn’t appear to hold much promise for vaginal yeast infections in general. This fits with what we know. One prospective placebo-controlled clinical trial evaluated two different probiotics for preventing yeast infections after treatment for urinary tract infections. The study used an oral probiotic containing Lactobacillus rhamnosus and Bifidobacterium longum and a vaginal probiotic containing L. rhamnosus, L. delbrueckii, L. acidophilus, and Streptococcus thermophilus, and neither were effective. There is some preliminary evidence that supports vaginal lactobacillus crispatus for the prevention of urinary tract infections, but more work is needed.

Ultimately, developing a prescription product for any probiotic that appears to be effective would be ideal. Research to get FDA approval would be required, so we’d really know if it works. In addition, these products are not cheap, and you deserve more than any company’s claims about effectiveness. And with a prescription product, there would be regulatory requirements, so we would really know that it contains what it claims.

The best course of action for someone with a history of yeast infections after antibiotics is to be evaluated the next time symptoms occur after antibiotics so they can be formally tested for yeast to ensure the diagnosis is correct. Once the diagnosis has been confirmed, oral fluconazole or over-the-counter anti-fungal medications can be used to prevent an infection. I recommend oral fluconazole (150 mg) once a week while taking an antibiotic, but a vaginal over-the-counter weekly therapy could also be used.

Bottom Line: Based on the data, probiotics, either oral or vaginal, will not prevent a yeast infection after antibiotics.

As always, the information here is not direct medical advice. If you have questions, leave them below. I try to reply to the easier ones directly in the comments (obviously, again, not individual medical advice). For those questions that are more complex, I tuck them away to try to incorporate them in future posts, as I am always looking for “Ask Dr. Jen” questions.

References

Shukla, A., Sobel, J.D. Vulvovaginitis Caused by Candida Species Following Antibiotic Exposure. Curr Infect Dis Rep 21, 44 (2019). https://doi.org/10.1007/s11908-019-0700-y

Tabrizi SN, Pirotta MV, Rudland E, Garland SM. Detection of Candida species by PCR in self-collected vaginal swabs of women after taking antibiotics. Mycoses. 2006 Nov;49(6):523-4. doi: 10.1111/j.1439-0507.2006.01312.x. PMID: 17022774.

Rocha RM, Zanni PC, de Souza Bonfim-Mendonça P, Gimenes F, Alczuk SS, Svidzinski TI, Consolaro ME. Effect of norfloxacin therapy for acute, uncomplicated lower urinary tract infection on vaginal Candida prevalence. Int Urogynecol J. 2016 May;27(5):773-80. doi: 10.1007/s00192-015-2884-5. Epub 2015 Nov 13. PMID: 26564224.

Pirotta M, Gunn J, Chondros P, Grover S, O'Malley P, Hurley S, Garland S. Effect of lactobacillus in preventing post-antibiotic vulvovaginal candidiasis: a randomised controlled trial. BMJ. 2004 Sep 4;329(7465):548. doi: 10.1136/bmj.38210.494977.DE. Epub 2004 Aug 27. PMID: 15333452; PMCID: PMC516107.

van de Wijgert J, Verwijs MC. Lactobacilli-containing vaginal probiotics to cure or prevent bacterial or fungal vaginal dysbiosis: a systematic review and recommendations for future trial designs. BJOG. 2020 Jan;127(2):287-299. doi: 10.1111/1471-0528.15870. Epub 2019 Aug 8. PMID: 31299136.

Pirotta MV, Garland SM 2006. Genital Candida Species Detected in Samples from Women in Melbourne, Australia, before and after Treatment with Antibiotics. J Clin Microbiol 44:https://doi.org/10.1128/jcm.00218-06

Varsha Gupta, Paola Mastromarino, Ritu Garg, Effectiveness of Prophylactic Oral and/or Vaginal Probiotic Supplementation in the Prevention of Recurrent Urinary Tract Infections: A Randomized, Double-Blind, Placebo-Controlled Trial, Clinical Infectious Diseases, Volume 78, Issue 5, 15 May 2024, Pages 1154–1161, https://doi.org/10.1093/cid/ciad766