Efficacy of Noncarbapenem β-Lactams Compared to Carbapenems for Extended-Spectrum β-Lactamase-Producing Enterobacterales Urinary Tract Infections.

Background: Extended-spectrum β-lactamase (ESBL)-producing Enterobacterales are frequent causes of urinary tract infections (UTIs). Severe infections caused by ESBL Enterobacterales are often treated with carbapenems, but optimal treatment for less severe infections such as UTIs is unclear.

Methods: This retrospective cohort study included patients admitted to 4 hospitals in an academic healthcare system with an ESBL UTI treated with either a noncarbapenem β-lactam (NCBL) or a carbapenem for at least 48 hours from 1 April 2014 to 30 April 2018. Those who received an NCBL were compared to those receiving a carbapenem, with a primary outcome of hospital length of stay (LOS) and secondary outcomes of clinical and microbiological response, days until transition to oral therapy, rate of relapsed infection, and rate of secondary infections with a multidrug-resistant organism.

Results: Characteristics were similar among patients who received carbapenems (n = 321) and NCBLs (n = 171). There was no difference in LOS for the NCBL group compared to the carbapenem group (13 days vs 15 days,  = .66). The NCBL group had higher rates of microbiologic eradication (98% vs 92%,  = .002), shorter time to transition to oral therapy (5 days vs 9 days,  < .001), shorter overall durations of therapy (7 days vs 10 days,  < .001), and lower rates of relapsed infections (5% vs 42%,  = .0003).

Conclusions: Patients treated with NCBLs had similar LOS, higher rates of culture clearance, and shorter durations of antibiotic therapy compared to patients treated with carbapenems, suggesting that treatment for ESBL UTIs should not be selected solely based on phenotypic resistance.