Research published in the Archives of Internal Medicine concluded that an antibiotic was more effective than cranberry capsules in preventing recurrent urinary tract infections (UTIs), however, at the expense of emerging antibiotic resistance.

The randomized, double-blind study compared 12-month prophylaxis use of the antibiotic, trimethoprim-sulfamethoxazole (TMP-SMX), and 500 mg twice daily of cranberry capsules in 221 premenopausal women suffering from recurrent UTI.

Although it is well-known within the medical and research community that low-dose antibiotic use can lead to massive antibiotic resistance, it is prescribed for preventing infection in some situations. This study attempted to address this issue by comparing the use of low-dose antibiotics to a safe, natural and clinically effective alternative—the cranberry.

Results indicated both the low-dose antibiotic and the cranberry capsule (at a low dose) helped to prevent recurrent UTIs—with the antibiotic being slightly more effective. However, those taking the low-dose antibiotic developed significant resistance to several major antibiotics used to prevent and treat UTIs. Of concern was the increase in resistance to Cipro from 8% to 23% after 12 months of low-dose antibiotic use.

The Cranberry Institute, Carver, MA, responded to the study results by noting that cranberry use did not cause any antibiotic resistance.

Amy Howell, PhD, from the Marucci Center for Blueberry Cranberry Research at Rutgers University said, “Unlike antibiotics, cranberry does not kill bacteria. The fruit contains compounds that prevent the pathogenic bacteria from sticking to the bladder wall, which is the initial step in the infection process. Interrupting the adhesion prevents the bacteria from growing and causing a UTI.”

The results of this latest study confirm that low-dose antibiotics should not be the first choice in UTI prevention given the substantial increase in multiple antibiotic resistance development, the Cranberry Institute said. The study also showed that cranberry should still be considered as an alternative for prevention of recurrent UTI, even though its efficacy was slightly lower than that of the drug. Dr. Howell concurred, adding, “Cranberry has not only been shown clinically to prevent UTI, but it also has a wide range of other health benefits, including reducing certain risk factors for heart disease.”

Dean Mosca, president of Proprietary Nutritionals, Inc., said, “The study confirmed the concern that many women have about contracting drug-resistant bacteria using a long-term antibiotic therapy. The authors also rightfully pointed out that any advantages of the drug should be weighed against the greater development of antibiotic resistance. Although the study didn’t confirm that all women took the cranberry capsules, the findings were similar to an independent study, published in the Journal of Antimicrobial Chemotherapy in November 2008, showing that the administration of Cran-Max was comparable to trimethoprim, for the prevention of recurrent UTIs in older women.”