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Antibiotic susceptibility of urinary isolates in nursing home residents consuming cranberry capsules versus placebo

Madden GR, Argraves SM, Van Ness PH, Juthani-Mehta M
Infect Control Hosp Epidemiol 36(3):356-7

Urinary tract infection (UTI) is the most common infection
among nursing home residents, and the microorganisms pre-valent in this setting pose significant challenges for treatment. Cranberries (Vaccinium macrocarpon Aiton
) are thought to reduce UTIs; this view is supported by a placebo-controlled trial showing lower rates of bacteriuria plus pyuria with daily ingestion of 300 mL of cranberry juice cocktail (15.0% versus 28.1% in controls). However, subsequent studies of cranberries for prevention of UTI, including a large Cochrane meta-analysis, have shown mixed results. Various mechanisms of the bacteriologic effect of cranberries are postulated; however, inhibition of P fimbriae–mediated adhesion of E. coli by proanthocyanidin (PAC) remains the leading theory.
We sought to compare antibiotic susceptibility and proportions of non–E. coli Enterobacteriaceae among Gram-negative urinary isolates from participants randomized to cranberry capsules compared to placebo.