Jama Logo Urinary tract infections (UTIs) are a common occurrence in women, and around 30 percent of them suffer from recurrent problems. As per a study conducted by scientists at Academic Medical Centre in Amsterdam, antibiotic trimethoprim-sulfamethoxazole (TMP-SMX) treats persistent urinary tract infections in women with greater efficiency than cranberry capsules. The former seems to prohibit repeated infections though they come with the risk of building on antibiotic resistance.

The team of scientists undertook a double-blind noninferiority experiment of cranberry capsules and TMP-SMX. It constituted 221 participants who were premenopausal adult women reportedly with at least three symptoms of UTI last fall. They were administered 480mg of TMP-SMX at night with a placebo pill twice a day or 500mg of cranberry capsules twice a day in addition to a placebo tablet at night for a period of 12 months.

“However, this may lead to drug resistance not only of the causative microorganisms but also of the indigenous flora. Studies of cranberries and cranberry products have shown some effectiveness in preventing rUTIs, but these trials have not compared those interventions directly with TMP-SMX, the standard antibiotic used in these cases,” expressed the ariëlle A.J. Beerepoot, M.D., from the Academic Medical Center, Amsterdam, and colleagues.

The analysts evaluated participants’ clinical conditions once a month and for three months after the study therapies were ceased. They examined their urine and feces samples along with a survey. The enrolled women were told to submit their urine dipslides too, if they appeared to encounter UTI-like symptoms.

At the end of 12 months, the median number of clinical recurrences was 1.8 in the TMP-SMX set and 4.0 in the cranberry capsules clan. Recurrent conditions took place after eight months on an average in the drug group and after four months among those who consumed cranberry capsules. Antibiotic resistance levels increased by three folds in the pathogens present in patients who received TMP-SMX. However, after 3 months, when the medication was stopped, the rates reverted to the amounts when the study had just begun.

The investigators found that many women were reluctant to use antibiotic prophylaxis and preferred nonantibiotic prophylaxis instead or none at all. For such users, cranberry phophylaxis may be a better option though it is not overly effective.

Another follow-up of this study by Bill J. Gurley, Ph.D., from the University of Arkansas for Medical Sciences, Little Rock, evaluated the findings of Beerepoot and his team in the nonpharmacologic remedies context. According to him, most of the U.S. consumers expect health advantages from dietary supplements they consume. Moreover, cranberry capsules apparently do not produce optimal efficiency owing to its poor water solubility and the accompanying metabolism.

According to Dr. Gurley, the above study revealed that the antibiotic resistance Escherichia coli was above 85 percent in the TMP-SMX group but less than 30 percent in the cranberry capsule group. This significant difference offers cranberry as a natural UTI controller. He also believes that though TMP-SMX showed more efficacy than cranberry capsules, this result seemed to have taken place due to the low rate of bioavailbality of bacteria fighting chemicals in the dosage used for cranberry.

The study is published in the July 25 issue of Archives of Internal Medicine, one of the JAMA/Archives journals.