Cranberry juice has long been regarded as a “home remedy” for preventing and treating urinary tract infections. Scientists and doctors originally attributed positive benefits to the high acidity of the juice. More recent studies, however, have linked the juice’s effect to compounds that can block bacteria from attaching to cells lining the urethra.
Now, a new study shows the positive effects of cranberry juice are due to its interaction with and enhancement of antibiotics.
In the paper published in Applied and Environmental Microbiology, researchers report 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.
Fosfomycin enters bacterial cells through the same entry channels used by the microbes to acquire some sugars. Something in the cranberry juice—scientists aren’t yet sure what, exactly—induces the bacteria to increase its uptake of sugars within one of those channels, which means it also absorbs more fosfomycin. Resistance to antibiotics often results from mutations in genes associated with other nutrient channels.
While the new study doesn’t establish a connection between drinking juice and antibiotic potency, it is promising enough to warrant more research. More importantly, it supports the idea that natural compounds may be a useful frontier in fighting antibiotic resistance. Adjuvants that can bolster the efficacy of existing antibiotics are very promising because they don’t require the development of new drugs.
Data from American Society for Microbiology