Locating the source of recurring UTIs

A research team led by The University of Queensland (UQ) has successfully located the source of recurring urinary tract infections (UTIs) in a female patient — a breakthrough that has been published in the journal Nature Communications and could lead to more effective treatments.

Study co-author Professor Mark Schembri, from UQ’s School of Chemistry and Molecular Biosciences, described UTIs as one of the most common bacterial infections and “a major burden on global health care”, with approximately 25% of women who suffer UTI experiencing a recurrence within six months of initial infection.

“It’s a problem magnified by increasing antibiotic resistance — antibiotic treatments can sometimes just stop working on these patients, with dire results,” he said.

Collaborating with The University of Utah, the UQ researchers followed a long-term recurrent UTI sufferer who has suffered from recurring UTIs for the past 45 years. The longest period she can recall being UTI-free is nine months.

“During that time she’s taken almost every type of antibiotic and the same bacteria has been able to survive and escape treatment, even when the patient used some of the strongest antibiotics available in our armoury,” Prof Schembri said.

Looking to find out whether the infection came from a single bacterial ‘reservoir’ in the body, the research team isolated E. coli from the patient’s urine during repeat infections and determined its entire DNA sequence. According to UQ Associate Professor Scott Beatson, the analysis showed the bacteria causing recurring UTIs were identical.

“This was proof — her infections did indeed originate from a common reservoir,” he said.

“To find the reservoir, we also collected and sequenced the DNA of E. coli recovered from the patient’s faecal samples.

“These E. coli were the same as those that caused the recurring UTI, proving that the woman had a persistent reservoir of E. coli residing in her intestine — the source of her infections.

“We now know that bacteria can reside in the intestine for very long periods and cause recurring UTIs, despite antibiotic treatment.

“Therefore, it’s time we consider using antibiotics that will not just treat the UTI in the bladder, but also eliminate the infection reservoir in the intestine that seeds recurrent infection of the bladder.”

The paper’s first author, UQ’s Dr Brian Forde, said when a patient suffers a UTI episode, a faecal sample could determine if the infecting strain also resided in the intestine, by combining bacterial culture with genome sequencing technology.

“If the same strain keeps being identified, we could design tailored treatment to eliminate the bacteria from not just the patient’s urine, but also the intestinal reservoir,” he said.

Prof Schembri concluded, “We predict a treatment like this would lead to reduced incidences of recurring UTI in patients suffering from this debilitating, chronic disease for which there is currently no effective cure.”

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