Drinking cranberry juice may help boost the effectiveness of antibiotics used to treat urinary tract infections (UTIs) against drug-resistant bacteria, a new study suggests. Approximately half of all women in the UK will experience at least one UTI in their lifetime, causing symptoms such as pain or burning when urinating, a frequent need to urinate, and a high temperature.
Most UTIs are caused by pathogenic strains of Escherichia coli bacteria, and the antibiotic fosfomycin is often prescribed as a first-line treatment. However, the rise of antibiotic resistance makes these infections more difficult to treat. While there is no evidence that cranberry juice alone can treat a UTI, new research indicates it may lend a helping hand to antibiotics.
Researchers exposed lab-grown strains of UTI-causing bacteria to cranberry juice and found that compounds in the juice made resistant strains more sensitive to antibiotic treatment. The study, published in the journal Applied and Environmental Microbiology, showed that in 72% of uropathogenic E. coli strains tested, cranberry juice both boosted the antibiotic activity of fosfomycin and suppressed the emergence of mutations related to resistance.
Microbiologist Dr Eric Déziel, from the Institut National de la Recherche Scientifique in Montreal, Canada, cautioned that the results are preliminary and whether cranberry juice offers an antibiotic boost in people requires further study. He noted that the study does not show if drinking cranberry juice gives the same results, as it is unknown whether the metabolites will reach the infection site. However, if they could, the juice may increase the efficacy of antibiotic treatment.
Cranberry juice has long been regarded as a folk remedy for preventing and treating UTIs, with scientists originally attributing the benefit to its high acidity. More recently, researchers linked its effect to compounds that block bacteria from attaching to cells lining the urethra. The new study suggests that something in cranberry juice induces bacteria to increase their uptake of sugars, which also leads to increased absorption of fosfomycin. Dr Déziel emphasised that with the challenge of multi-drug resistance, new approaches are needed from many different directions.
