The microbiome and urology consist of:
- Direct contact (urinary microbiotas): including the urethra, bladder, kidney (and stones), semen, and more. It is a relatively new concept that this system is not sterile
- Indirect role (gut): includes metabolism, immune regulation and acts as a “UTI reservoir”
The Food and Agriculture Organization of the United Nations and the World Health Organization definition of a probiotic is “live microorganisms which when administered in adequate amounts confer a health benefit on the host”. Dating back to 1973, vaginal lactobacilli were deemed the ‘gatekeepers’ for the urinary tract. Extracellular ATP is produced by urinary bacteria such as Gardnerella vaginalis and Escherichia coli, whereas the protective effect of Lactobacillus has been shown to sequester and stop ATP induced calcium influx via secreted molecules. Despite this protective mechanism, the 2019 AUA/CUA/SUFU guideline on recurrent uncomplicated urinary tract infections in women notes that “[we are] unable to recommend the use of lactobacillus as a prophylactic agent for recurrent UTI given the current lack of data indicating benefit in comparison to other available agents.” As such, perhaps probiotic delivery is the problem. Dr. Burton notes that oral probiotics can indeed reach the female urogenital tract through the GI tract, as this is the route that pathogens take to cause infection. Direct microbe delivery has previously been shown to work for decades utilizing Mycobacterium bovis (BCG) vaccine directly into the bladder for bladder cancer patients. However, only limited studies have described other direct microbe delivery methods, as there are still safety concerns (despite the success of BCG) for more invasive delivery modalities.
The intestinal microbiota is also important for urology, acting as a UTI reservoir for drug resistant and other disease-causing bacteria. So, the question remains whether microbiota transplantation therapy will impact Urology? Fecal Microbiota Transplant entails the transfer of bacteria, viruses, and metabolites, which is currently one of the most potent microbiota changing therapies available. Experimentally, it has been used to treat recurrent Clostridium difficile infections, but whether it has this potential to improve gut-linked urologic conditions remains to be seen. Furthermore, early data suggests that there may be a role in combining probiotics with traditional oncologic therapies, although this data is still developing.
Dr. Burton concluded with the following summary statements from his talk on the microbiota and probiotics in Urology:
- Traditional delivery of probiotics has had limited efficacious success for Urology
- Despite limited success today, the microbiome plays a huge role in urological health and has many potential applications
- We need to start to be more innovative in what probiotic strains we use and how we deliver them, and if so we may see other experimental therapies emerge
Presented by: Jeremy Burton, BSc, MSc, PhD, dBA, Lawson Health Research Institute, London, ON, Canada
Written by: Zachary Klaassen, MD, MSc – Assistant Professor of Urology, Georgia Cancer Center, Augusta University/Medical College of Georgia Twitter: @zklaassen_md at the 2020 American Urological Association (AUA) Annual Meeting, Virtual Experience #AUA20, June 27- 28, 2020
References:
- Spor A, Koren O, Ley R. Unravelling the Effects of the Environment and Host Genotype on the Gut Microbiome. Nat Rev Microbiol 2011 Apr;9(4):279-290.