Cefixime-clavulanic acid in ESBL-producing E. coli lower urinary tract infections: a 13-patient case series

Urinary tract infections (UTIs) represent a substantial proportion of community-acquired infections. The increasing prevalence of Escherichia coli strains that produce extended spectrum beta-lactamases (ESBL) poses a significant obstacle to effective infection treatment. Although carbapenems remain highly effective against ESBL-producing isolates, their use in lower UTIs is limited by the need for intravenous or intramuscular administration, hospitalization, high cost, and the risk of collateral damage due to their broad-spectrum activity. Therefore, there is a growing need for effective oral alternatives.

This retrospective study evaluated the clinical and microbiological outcomes of 13 patients diagnosed with lower UTIs caused by ESBL-producing E. coli (ESBL-PE), treated with oral cefixime-clavulanic acid (400/125 mg every 12 hours for 14 days). Follow-up urine cultures were obtained on days 3-5 and/or at the end of treatment (days 11-14).

On days 3-5 of treatment, microbiological and clinical success rates were 53.8% (7/13) and 61.5% (8/13) respectively. At the end of the treatment, urine culture results could be evaluated in 10 cases, microbiological success was 80% (8/10). Clinical success was 84.6% (11/13). Re-infection and relapse rates on day 30 post-treatment were 7.7% (1/13) and 30.8% (4/13), respectively.

Cefixime-clavulanic acid may be considered an alternative to older antibiotics such as fosfomycin and nitrofurantoin in the treatment of uncomplicated urinary tract infections, and may also contribute to the prevention of carbapenem resistance development. However, these findings should be interpreted with caution due to important limitations, including the small sample size, retrospective design, absence of standardized minimum inhibitor concentration (MIC) testing, and lack of a control group. Larger prospective studies are needed to confirm these results.