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A recent study showed that prior UTI history and race were top predictors of antibiotic nonsusceptibility in uncomplicated UTIs caused by E coli bacteria.

The top predictors for nonsusceptibility to four commonly prescribed antibiotic classes in patients with uncomplicated urinary tract infection (UTI) caused by Escherichia coli are number of previous UTI episodes and race, according to study findings published in Clinical Infectious Diseases.

“Our identification of race as a predictor of antibiotic nonsusceptibility may be due in part to its strong correlation with factors (eg, socioeconomic indicators) that were not available in the data and are associated with antibiotic nonsusceptibility,” wrote corresponding author Ryan K. Shields, PharmD, and colleagues. “Considering this limitation, the association between race and antibiotic nonsusceptibility … should not be endowed with a causal interpretation or used alone to inform treatment decisions.”

Researchers developed predictive models for nonsusceptibility to nitrofurantoin, trimethoprim-sulfamethoxazole, β-lactams, and fluoroquinolones using deidentified electronic health record data for 87,487 patients with E coli–caused uncomplicated UTI.

In addition to previous UTIs and race, common predictive features for nonsusceptibility across at least three of the four classes were US Census Bureau region (particularly the South), prior nonsusceptibility to β-lactams, and prior treatment with fluoroquinolones, researchers reported.

According to the study’s risk categorization framework, 8.1% of patients had isolates at high risk for nonsusceptibility to nitrofurantoin, 14.4% had isolates at high risk for nonsusceptibility to trimethoprim-sulfamethoxazole, 17.4% had isolates at high risk for nonsusceptibility to β-lactams, and 6.3% had isolates at high risk for nonsusceptibility to fluoroquinolones.

“Across all antibiotic classes, the proportion of patients categorized as having an isolate at high risk of nonsusceptibility was 3- to 12-fold higher among patients with truly nonsusceptible isolates than in patients with truly susceptible isolates,” researchers wrote. “Moreover, the proportion of patients with truly nonsusceptible isolates was 3- to 10-fold higher among patients with isolates categorized as high risk of nonsusceptibility versus those with isolates categorized as low risk of nonsusceptibility.”

The study demonstrates how data-driven strategies can ease challenges in identifying patients at high risk for nonsusceptibility to common antibiotic treatments, the authors noted.

“Findings from our study provide valuable insight on key patient characteristics to consider when assessing risk of antibiotic nonsusceptibility,” they wrote, “thereby advancing the understanding of antibiotic nonsusceptibility in uUTI [uncomplicated UTI], and potentially informing optimal treatment strategies in this population.”