Oral Beta-Lactams Effective Step-Down Therapy for Bacteremic UTI

urinary tract infection, UTI
Study authors compared clinical cure in patients with E coli bacteremic UTI who were stepped down to oral beta-lactams compared to oral fluoroquinolones.

Beta lactams may be a safe and effective alternative step-down option compared to oral fluoroquinolones in the treatment of bacteremic Escherichia coli (E coli) urinary tract infections (UTIs), according to a study published in BMC Infectious Diseases.

Although oral fluoroquinolones are an accepted and common step-down option for bacteremic UTIs, the mounting safety concerns highlight the need to identify effective alternatives. This multicenter, retrospective cohort study compared clinical cure rates in patients with E coli bacteremic UTIs who were stepped down to oral beta-lactams compared to oral fluoroquinolones.

In total, 207 patients with E coli-positive blood and urine cultures and received empiric intravenous beta-lactam therapy followed by step down oral beta-lactam or oral fluoroquinolone for treatment completion were included. All patients who stepped down to an oral fluoroquinolone (n=77) were prescribed ciprofloxacin; patients who stepped down to an oral beta-lactam (n=103) were prescribed either amoxicillin (n=7), amoxicillin-clavulanate (n=17), cephalexin (n=19), cefuroxime (n=7), or cefixime (n=43). The primary outcome of this study was clinical cure. Secondary outcomes of this study included length of hospitalization, all-cause mortality, and Clostridioides (Clostridium) difficile infection.

Patients who stepped down to an oral beta-lactam were more likely to have acquired UTI in a community acquired healthcare-associated setting, such as a long-term care facility or nursing home, and less likely to have acquired the infection in a community acquired setting compared to patients who stepped down to an oral fluoroquinolone. There were no other notable baseline differences in severity of infection, ICU admission, Pitt bacteremia score, median number of days of intravenous treatment, oral treatment duration, or total treatment duration.

Results suggest that beta-lactams are a safe and effective step-down option for the treatment of bacteremic E coli UTIs. Clinical cure was achieved in 94% (n=72) of patients in the oral beta-lactam group and 98% of patients (n=127) in the oral fluoroquinolone group (95% CI, -10.3-1.9%; P =.13). The unadjusted analysis demonstrated no significant difference between the oral beta-lactams and oral fluoroquinolones for clinical cure (odds ratio [OR], 0.34; 95% CI, 0.08-1.47; P =.15). Similar results were observed using multivariate adjustment (adjusted OR, 0.31; 95% CI, 0.05-1.90; P =.2) and propensity scoring adjustment (OR, 3.1; 95% CI, 0.07-1.38; P =.12).

There were no statically significant differences between the oral beta-lactam group and the oral fluoroquinolone group in secondary outcomes. The median length of hospitalization was 6 days in both groups (P =.43). In total, 1 mortality occurred in the oral fluoroquinolone group and each group had 1 patient develop a C difficile infection.

The study is limited due to its retrospective design, may be underpowered to identify a difference in treatment arms, and cannot be extrapolated to the whole population due to exclusion of complicated cases in its inclusion criteria. Future research is needed to establish the optimal duration of step-down therapy.

“Given the potential adverse effects associated with fluoroquinolones, beta-lactams present a safe and efficacious alternative oral step-down agent,” the study authors concluded.


Saad S, Mina N, Lee C, Afra K. Oral beta-lactam step down in bacteremic E. coli urinary tract infections. BMC Infect Dis. Published online October 21, 2020. doi: 10.1186/s12879-020-05498-2.