From the Guidelines
Amoxicillin-clavulanate should not be used as the first-line treatment for UTIs with E. coli due to increasing resistance rates, and instead, other options such as nitrofurantoin, fosfomycin, or mecillinam should be considered. According to the 2010 update by the Infectious Diseases Society of America and the European Society for Microology and Infectious Diseases 1, the resistance rates for amoxicillin-clavulanic acid show regional variability, but are generally <10%. However, this does not guarantee its effectiveness against all E. coli strains, and local antimicrobial susceptibility patterns should be considered in empirical antimicrobial selection for uncomplicated UTIs. Some key points to consider when treating UTIs with E. coli include:
- Resistance patterns vary geographically, and some E. coli strains have developed resistance to amoxicillin-clavulanate 1
- Urine culture and sensitivity testing is recommended when possible to confirm susceptibility 1
- Patients should complete the full course of antibiotics even if symptoms improve, drink plenty of fluids, and contact their healthcare provider if symptoms worsen or don't improve within 48-72 hours of starting treatment
- Other options such as nitrofurantoin, fosfomycin, or mecillinam had good in vitro activity in all the countries investigated and could be considered appropriate antimicrobials for empirical therapy in most regions 1
From the FDA Drug Label
1.5 Urinary Tract Infections – caused by beta-lactamase–producing isolates of E. coli, Klebsiella species, and Enterobacter species. Amoxicillin-clavulanate may be used to treat UTIs with E. coli, but only if the E. coli isolate is beta-lactamase-producing.
- Key points:
- The drug label does not provide information on the effectiveness of amoxicillin-clavulanate against non-beta-lactamase-producing E. coli.
- Susceptibility testing is recommended to guide therapy. 2
From the Research
Amoxicillin-Clavulanate Coverage for UTI with E. coli
- Amoxicillin-clavulanate may be effective against urinary tract infections (UTIs) caused by E. coli, including those producing extended-spectrum beta-lactamases (ESBLs) 3, 4.
- A study found that amoxicillin-clavulanate recipients did not have higher failure rates compared to standard of care recipients for UTIs caused by ceftriaxone non-susceptible Enterobacterales, including E. coli 3.
- Another study reported that amoxicillin-clavulanic acid treatment was successful in 84.7% of patients with ESBL-positive UTIs, including those caused by E. coli 4.
- However, treatment failure was more frequent in Klebsiella spp. than in E. coli, and high minimum inhibitory concentrations (MICs) of amoxicillin-clavulanate were associated with resistance development and therapeutic failure 4.
Recommended Treatment Options for UTI with E. coli
- The recommended first-line empiric antibiotic therapy for acute uncomplicated bacterial cystitis in otherwise healthy adult nonpregnant females includes nitrofurantoin, fosfomycin tromethamine, or pivmecillinam 5.
- Amoxicillin-clavulanate is considered a second-line option for UTIs, including those caused by ESBL-producing E. coli 5, 4.
- Other treatment options for UTIs caused by ESBL-producing E. coli include fluoroquinolones, cefepime, piperacillin-tazobactam, and carbapenems 5.