Recurrent urinary tract infections (rUTIs) are among the most common bacterial infections worldwide. The difficult-to-treat condition, which affects primarily women, is defined as two urinary tract infections (UTIs) within six months or three UTIs within the past year. They are a leading cause of outpatient antibiotic use, accounting for more than 15% of all prescriptions.
While antibiotics remain the standard treatment, frequent recurrences and rising antibiotic resistance highlight the need for alternative therapeutic approaches. Now, researchers have, for the first time, administered a combined phage therapy (PT) with fecal microbiota transplantation (FMT), to decolonize urinary and intestinal reservoirs of rUTI patients.
The novel treatment approach, combining PT and elective FMT, was administered to three female patients, between May and July 2023, with rUTI that did not respond to antibiotics and commonly used non-antibiotic strategies. All had microbiologically confirmed E. coli in multiple infections.
All three women received PT orally and intravesically (locally applied to the bladder via catheter) for eight days outside of acute episodes. Two of these three patients were elected to receive subsequent FMT. Since the bacteria causing the recurring infections often reside in the gut as well as the urinary tract, the FMT treatment targeted the intestinal reservoirs of E. coli that survive antibiotic treatment of acute infections and can become increasingly resistant.
“While phage therapy acts to remove the pathogen, FMT aims to restore a healthy microbiome, combining both immediate and long-term effects,” Lena Biehl, MD, PhD, group leader at Fraunhofer ITMP, deputy lead of Cologne Microbiota Bank, University Hospital Cologne.
This work is published in Nature Microbiology in the paper, “Combined Phage therapy and fecal microbiota transplantation to treat recurrent urinary tract infection: a case series.”
The treatments were well tolerated and did not result in noticeable side effects. The two patients who received the combination therapy have experienced a long-term reduction of UTIs over the course of two years, while the one patient with PT only has experienced further episodes but with reduced symptoms. For all patients, although E. coli was detected in follow-up samples, quality of life improved significantly, while the need for antibiotic treatment was substantially reduced.
“Three patients are not a sufficiently large sample to establish this new therapy, and control groups were lacking. However, this experience has helped to lay the foundation for a clinical trial in order to test the clinical utility of this treatment approach and make it more widely available and sustainable for patients,” comments Shawna McCallin, MD, at the Balgrist University Hospital in Zurich.
The clinical trial is scheduled to begin in June 2027 at the participating institutions as part of the REPhRAME project, which is funded by the European Commission through the Horizon Europe funding programme.
