Impact of Allergy and Resistance on Antibiotic Selection for Recurrent Urinary Tract Infections in Older Women

Objectives: To review the impact of antibiotic allergy and resistance in older women with recurrent urinary tract infections (RUTIs) as determinants for a suitable oral antibiotic treatment choice. Methods: A prospectively maintained database of women 65 years old and older with documented RUTIs (≥3 UTI/y) and trigonitis on cystoscopy was reviewed. Demographic data, known drug allergies, renal function, antibiotic susceptibility of most recent urine culture, allergy, or resistance to trimethoprim-sulfamethoxazole (TMP-SMX), fluoroquinolones, and nitrofurantoin were obtained. Results: From 2006 to 2014, 86 women with RUTIs met study criteria. Mean age was 77.9 ± 7.8, with 94% being Caucasian. An estimated glomerular filtration rate >30 mL/min was noted in 94%. The percentage of women allergic, resistant, or both allergic and resistant to TMP-SMX was 33%, 29%, and 15%, to fluoroquinolones was 14%, 34%, and 8.1%, or nitrofurantoin was 16%, 14%, and 5%, respectively. Twenty-eight percent (24 of 86) of women who were allergic and/or resistant to TMP-SMX and fluoroquinolones were sensitive to nitrofurantoin. Twenty percent (17 of 86) were allergic and/or resistant to all 3 antibiotics. Women who were allergic or resistant to TMP-SMX had a significantly higher number of other antibiotic resistances compared with women sensitive to TMP-SMX (4.9 ± 3.6 vs 2.1 ± 2.3; P <.0001). Similarly, women with fluoroquinolone allergy or resistance had significantly more antibiotic resistances than those who were fluoroquinolone sensitive (5.8 ± 3.5 vs 2.3 ± 2.5; P <.0001). Conclusion: Because of allergy and/or antibiotic resistance, several first-line antibiotics are not available for many older women with RUTIs. In nearly a third of women, nitrofurantoin was the only viable alternative.