New research suggests that antibiotics may increase recurrent urinary tract infections by disrupting the gut microbiome.
Urinary tract infections are caused by bacteria in the urinary tract and are characterised by frequent and painful urination. Antibiotics are typically prescribed to clear the symptoms, however, some women experience recurrent infections and require antibiotics every few months.
Most urinary tract infections are caused by E.coli bacteria from the intestines that get into the urinary tract. It can be caused by pregnancy, weakened immune system and not drinking enough fluids.
The new study, carried out by researchers at Washington University School of Medicine in St. Louis and the Broad Institute of MIT and Harvard, explores whether women with recurrent urinary tract infections are caught in a vicious cycle where antibiotics could eradicate one infection but predisposes them to develop another.
The research was published in Nature Microbiology.
The research method
The researchers studied 15 women with recurrent urinary tract infections and 16 women without. Participants provided urine, blood samples and monthly stool samples. The team analysed the bacterial composition in the stool samples, tested the urine for the presence of bacteria and measured gene expression in blood samples.
Minimising urinary tract infections
The participants reported 24 infections in one year, all found in women with recurrent urinary tract infections.
The difference between the women with recurrent urinary tract infections and those who did not was the gut microbiome.
Patients with recurrent urinary tract infections showed decreased diversity of healthy gut microbial species, providing more opportunities for disease-causing species to multiple. Additionally, the microbiomes of women with the reoccurring infection were particularly scarce in bacteria that produce butyrate, a short-chain fatty acid with anti-inflammatory effects.
“We think that women in the control group were able to clear the bacteria from their bladders before they caused disease, and women with recurrent UTIs were not because of a distinct immune response to bacterial invasion of the bladder potentially mediated by the gut microbiome,” Colin Worby, PhD, a computational biologist and the paper’s lead author said.
“Our study demonstrates that antibiotics do not prevent future infections or clear UTI-causing strains from the gut, and they may even make recurrence more likely by keeping the microbiome in a disrupted state.”
The findings highlight the importance of finding alternatives to antibiotics for treating these infections.