From the Guidelines
Gram-negative rod urinary tract infections (UTIs) should be treated with antibiotics targeting these specific bacteria, with a recommended treatment duration of 7 days for complicated infections, as suggested by the most recent guidelines 1.
Treatment Options
- For uncomplicated UTIs, first-line treatment includes trimethoprim-sulfamethoxazole (Bactrim) 160/800mg twice daily for 3 days, or nitrofurantoin (Macrobid) 100mg twice daily for 5 days.
- For more complicated infections, fluoroquinolones like ciprofloxacin 500mg twice daily for 7 days may be used, though resistance is increasing, and should only be used if the local resistance rate is <10% 1.
- In hospitalized patients or those with severe infections, intravenous options include ceftriaxone 1-2g daily, gentamicin 5mg/kg daily, or piperacillin-tazobactam 3.375g every 6 hours.
Patient Factors
- Treatment should be guided by local resistance patterns and patient factors including pregnancy status, renal function, and allergy history.
- Gram-negative rods in UTIs typically include Escherichia coli (most common), Klebsiella, Proteus, and Pseudomonas species.
- Patients should complete the full antibiotic course, increase fluid intake, and seek follow-up if symptoms persist.
Duration of Treatment
- The optimal duration of treatment for gram-negative bacteremia from a urinary source is 7 days, as demonstrated by multiple RCTs 1.
- For adult pyelonephritis, a 7-day course of treatment may be adequate, but further prospective investigation is needed 1.
Management
- Manage any urological abnormality and/or underlying complicating factors, as recommended by the European Association of Urology guidelines 1.
From the FDA Drug Label
Cefixime for oral suspension and cefixime capsule is indicated in the treatment of adults and pediatric patients six months of age or older with uncomplicated urinary tract infections caused by susceptible isolates of Escherichia coli and Proteus mirabilis.
Treatment of Gram-Negative Rod UTI: Cefixime is indicated for the treatment of uncomplicated urinary tract infections (UTIs) caused by susceptible isolates of Escherichia coli and Proteus mirabilis, which are both Gram-negative rods.
- The recommended dose of cefixime for adults is 400 mg daily. 2
From the Research
Treatment Options for Gram-Negative Rod UTIs
- First-line empiric antibiotic therapy for acute uncomplicated bacterial cystitis in otherwise healthy adult nonpregnant females includes a 5-day course of nitrofurantoin, a 3-g single dose of fosfomycin tromethamine, or a 5-day course of pivmecillinam 3, 4
- Second-line options include oral cephalosporins such as cephalexin or cefixime, fluoroquinolones, and β-lactams, such as amoxicillin-clavulanate 3, 4
- Treatment options for UTIs due to AmpC-β-lactamase-producing Enterobacteriales include nitrofurantoin, fosfomycin, pivmecillinam, fluoroquinolones, cefepime, piperacillin-tazobactam, and carbapenems 3, 4
- Treatment options for UTIs due to ESBLs-producing Enterobacteriales include nitrofurantoin, fosfomycin, pivmecillinam, amoxicillin-clavulanate, finafloxacin, and sitafloxacin 3
Resistance and Antimicrobial Stewardship
- High rates of resistance to trimethoprim-sulfamethoxazole and ciprofloxacin preclude their use as empiric treatment of UTIs in several communities, particularly if patients were recently exposed to them or are at risk of infections with ESBLs-producing Enterobacteriales 3
- The use of fluoroquinolones for empiric treatment of UTIs should be restricted due to increased rates of resistance 4
- Antimicrobial stewardship remains important in preserving the utility of the antibiotic agents currently available 5
Novel Antibiotics and Treatment Outcomes
- Several new antibiotic agents for urinary tract infections are in development, including β-lactam/β-lactamase inhibitor combinations, siderophore cephalosporins, novel aminoglycosides, fluoroquinolones, and tetracyclines 5
- Short courses of twice-daily cephalexin appear to be a safe and effective option for the empiric treatment of uncomplicated UTIs, with a clinical success rate of 81.1% 6