Impact of Urine pH on Antibiotic Response in Women with Uropathogenic Eschericia [sic] coli Recurrent Urinary Tract Infections




Chavez, Jacqueline

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INTRODUCTION AND OBJECTIVES: As early as Brumfitt in 1948, the relationship between the effectiveness of certain uro-antibiotics and urinary pH levels has been considered.1 Some antibiotics are more effective at a urine pH range 5-6, whereas others work better at a more alkaline (urine pH 7-8) range. We compared the urine pH of women infected with E. coli to their antibiotic treatment response. METHODS: An IRB-approved, prospectively maintained database of well-characterized women with antibiotic-refractory recurrent urinary tract infections (RUTI) managed with electrofulguration (F) at a tertiary care center was reviewed. Included were women with at least 6 months follow-up post-F, an electronic medical record (EMR) documenting urine pH value at the time of each urine culture, and at least one E. coli positive urine culture. Total number of urine cultures post-F, urine pH variability, antibiotics prescribed, and the interval (months) between antibiotic administration and another UTI episode were reviewed. RESULTS: From 2006-2016 23 women met study criteria, with mean follow-up of 2 (1-9) years and mean age of 66 (28-92) years. Total number of urine cultures was 181, including 93 positive (I), 88 negative (NI), and 54 with E. coli. The average number of urine cultures per patient was 7 ± 3.8 (2-16). Median urine pH observed was 6, with no difference between I, NI, or E. coli urine cultures. There was no change in urine pH with aging. Six individuals were prescribed antibiotics for which pH has not been shown to change efficacy, 10 in whom urine pH aligned with the reported best efficacy range for their prescribed antibiotic, and 7 whom urine pH was not in the ideal antibiotic pH range. Mean interval time between first and second positive urine culture was longer for those with the appropriate urine pH for the prescribed antibiotic (26 months, 2-63) compared to those with a mismatch between urine pH and optimal pH range for their antibiotic (18 months, 1-33). CONCLUSION: This observational study explores the possible link between the urine pH of a woman with RUTIs and her response to antibiotic treatment administered without taking her urine pH into account. Future studies are needed to determine if an individual's urine pH needs to match the optimal pH range of a prescribed antibiotic to result in maximum therapeutic efficacy.

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The 57th Annual Medical Student Research Forum at UT Southwestern Medical Center (Tuesday, January 22, 2019, 3-6 p.m., D1.600)

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Chavez, J. A., Christie, A. L., & Zimmern, P. E. (2019, January 22). Impact of urine pH on antibiotic response in women with uropathogenic eschericia coli recurrent urinary tract infections. Poster session presented at the 57th Annual Medical Student Research Forum, Dallas, TX. Retrieved from

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