# Effect of oral beta-lactam dosing on outcomes of bacteremic Gram-negative urinary tract infections: a real-world analysis

## TL;DR

This study found no significant difference in recurrence rates of Gram-negative bacteremia when using higher versus lower doses of oral beta-lactam antibiotics.

## Contribution

The study provides real-world evidence on the effectiveness of higher versus standard dosing of oral beta-lactams for Gram-negative bacteremia.

## Key findings

- Higher dosing of oral beta-lactams did not significantly reduce 60-day recurrence rates compared to standard dosing.
- The study was limited by small sample size and confounding factors like complicated urinary tract infections.

## Abstract

Among 452 adult patients with Gram-negative bacteremia from a urinary tract infection source who received oral step-down therapy with highly bioavailable oral beta-lactam, we observed no difference in 60-day recurrence in patients treated with higher consensus-recommended dosing compared to lower, standard dosing (odds ratio = 0.76 [95% confidence interval = 0.43–1.32]), although the directionality of the effect was favorable. The study was limited by inadequate sample size and confounding. Randomized or large observational comparative effectiveness studies are needed.

Definitive treatment of Gram-negative bacteremia with oral antibiotic agents is not one size fits all. Use of oral fluoroquinolones and sulfamethoxazole/trimethoprim is evidence-based but carries risk for adverse events. Data supporting the use of oral beta-lactams are mixed, likely in part due to variable agent selection and dosing. This analysis shows that higher, consensus-recommended dosing of highly bioavailable beta-lactam antibiotics was not significantly different from patients treated with lower dosing on 60-day recurrence. Our study was limited by the number of patients with discrete MICs and overinfluence of complicated urinary tract infection on outcomes.