From the Guidelines
Keflex (cephalexin) is not effective for treating pseudomonas urinary tract infections (UTIs). Pseudomonas aeruginosa is naturally resistant to Keflex and other first-generation cephalosporins because these antibiotics cannot penetrate the bacterium's outer membrane effectively 1. For pseudomonas UTIs, more appropriate antibiotic choices include:
- Fluoroquinolones (such as ciprofloxacin)
- Certain antipseudomonal beta-lactams (like piperacillin-tazobactam)
- Carbapenems (such as meropenem)
- Aminoglycosides (like gentamicin) Treatment typically requires 7-14 days of an appropriate antibiotic, with the exact choice depending on susceptibility testing results. Pseudomonas infections often require culture and sensitivity testing to determine which antibiotics will be most effective, as this organism frequently develops resistance 1. If you suspect a pseudomonas UTI, it's essential to consult with a healthcare provider for proper diagnosis and treatment, as these infections can be more difficult to eradicate than typical UTIs caused by other bacteria. The most recent guidelines recommend using an antipneumococcal, antipseudomonal β-lactam plus either ciprofloxacin or levofloxacin for Pseudomonas infection 1.
From the Research
Treatment of Pseudomonas Urinary Tract Infections (UTIs)
- Cephalexin is not typically recommended as a first-line treatment for Pseudomonas UTIs, as it may not be effective against this type of bacteria 2.
- The recommended treatment options for UTIs caused by multidrug-resistant (MDR) Pseudomonas spp. include fluoroquinolones, ceftazidime, cefepime, piperacillin-tazobactam, carbapenems, and fosfomycin 2.
- Combination therapy with levofloxacin or ciprofloxacin and ceftazidime, cefepime, imipenem, piperacillin-tazobactam, or amikacin has been shown to be effective against Pseudomonas aeruginosa 3, 4.
- Novel antibiotics such as cefiderocol, a new cephalosporin, have shown promising results against Pseudomonas aeruginosa 5.
- Ceftazidime, carbapenems, or piperacillin-tazobactam can be used as single definitive therapy for Pseudomonas aeruginosa bloodstream infection, but the choice of antibiotic should be guided by the patient's risk factors, the site of infection, and the available treatment options 6.
Cephalexin and Pseudomonas UTIs
- There is no evidence to suggest that cephalexin is effective against Pseudomonas UTIs, and it is not recommended as a treatment option for this type of infection 2.
- Cephalexin may be used as a second-line option for UTIs caused by other types of bacteria, but it is not a suitable choice for Pseudomonas UTIs 2.