Intravenous to oral antibiotics versus intravenous antibiotics: a step-up or a step-down for extended spectrum β-lactamase (ESBL)-producing urinary tract infections without concomitant bacteraemia?

The Infectious Diseases Society of America (IDSA) recommends numerous antibiotics for the treatment of urinary tract infections (UTIs) caused by extended-spectrum β-lactamase (ESBL)-producing bacteria. The purpose of this study was to evaluate clinical outcomes of oral step-down antibiotics compared with continued intravenous therapy in UTIs without bacteraemia. This multicentre, retrospective, cohort study was conducted in hospitalised patients with ESBL-producing UTIs between July 2016 and March 2020. The primary outcome was a composite all-cause clinical failure, defined as 30-day re-admission, 30-day hospital mortality or a change in oral antibiotics during hospitalisation. Secondary outcomes included individual primary outcome components, re-admission due to a recurrent UTI, change in antibiotic during hospitalisation, hospital length of stay (LOS), antibiotic costs and adverse events. The study included 153 patients. The primary outcome occurred in 28% of both groups (27/95 vs. 16/58; P = 0.91). The primary outcome components were similar: re-admission (26% vs. 26%; P = 0.95); hospital mortality (2% vs. 2%; P = 1.0); and change in antibiotics (0% vs. 2%; P = 0.38). Mean hospital LOS and direct antibiotic costs were 8 ± 6 days vs. 5 ± 2 days (P < 0.01) and US$278 ± 244 vs. US$180 ± 104 (P < 0.01), respectively. Adverse events were similar, except diarrhoea (15% vs. 2%; P = 0.01). There was no difference in clinical failure, re-admission rate, re-admission due to a recurrent UTI, mortality rate or antibiotic change between groups. The switch group was associated with reduced hospital LOS and inpatient antibiotic costs.