Can enterobacterales bacteremia with pyelonephritis be treated with ceftriaxone?

Ceftriaxone (CTRX) is the antibiotic of choice for treating urinary tract infections (UTIs). However, CTRX has a lower urinary excretion rate than other β-lactam antibiotics. In 2023, Japan had a shortage of cefotiam (CTM), increasing the demand for CTRX for patients with UTIs. This study compared the efficacy of CTRX and other β-lactam antibiotics for Enterobacterales bacteremia and pyelonephritis.

Patients with Escherichia coli, Klebsiella spp, or Proteus spp in blood and urine cultures treated with β-lactam antibiotics at Aichi Medical University Hospital between July 2014 and February 2024 were retrospectively recruited. Overall, 123 patients were included in the study and divided into two groups based on the type of antibiotic treatment: CTRX main group (CTRX for ≥5 days) and other β-lactam main group (ampicillin, cefazoline, CTM, or cefotaxime for ≥5 days). Patients were propensity score-matched by age, Charlson comorbidity index, duration of intravenous antibiotic treatment, number of patients who switched to oral antibiotics, albumin levels, white blood cell count, C-reactive protein, body temperature, and need for intensive care unit admission. The primary outcomes were treatment side effects, outcomes, and mortality at 30 and 90 days.

After propensity score matching, 26 patients were selected from each group. The all-cause 30-day mortality rate was 3.8 % in both groups. None of our patients experienced reinfections or rehospitalization for pyelonephritis.

CTRX treatment did not affect the prognosis of patients with Enterobacterales bacteremia and pyelonephritis. Therefore, avoiding using CTRX for UTIs because of lower urinary excretion rates may be unnecessary.