From the Guidelines
Bactrim (trimethoprim/sulfamethoxazole) is not effective against Pseudomonas aeruginosa.
Key Points
- Pseudomonas aeruginosa is often resistant to Bactrim, and its use may lead to treatment failure 1.
- For (potential) Pseudomonas aeruginosa infection, antibiotics such as piperacillin/tazobactam, ceftazidime, cefepime, aztreonam, and carbapenems are recommended 1.
- The Infectious Diseases Society of America guidelines suggest using antipseudomonal penicillins, carbapenems, or aminoglycosides for Pseudomonas aeruginosa infections 1.
Treatment Alternatives
- Alternative antibiotics such as ciprofloxacin or levofloxacin may be considered for mild to moderate skin and soft tissue infections, but not for Pseudomonas aeruginosa specifically 1.
- For more severe infections, antipseudomonal penicillins (e.g., piperacillin/tazobactam), carbapenems (e.g., meropenem), or aminoglycosides (e.g., tobramycin) are typically preferred 1.
Clinical Judgment
- The choice of antibiotic should be guided by susceptibility testing and clinical judgment 1.
From the Research
Effectiveness of Bactrim against Pseudomonas aeruginosa
- The effectiveness of Bactrim (Trimethoprim/Sulfamethoxazole) against Pseudomonas aeruginosa is limited, as evidenced by studies showing that P. aeruginosa is often resistant to this antibiotic combination 2, 3.
- A study from 1977 found that sulphamethoxazole, a component of Bactrim, had intermediate activity against P. aeruginosa, but the combination of trimethoprim and sulphamethoxazole did not act in synergy against highly resistant strains 3.
- More recent studies have focused on the treatment of P. aeruginosa infections with other antibiotics, such as novel fluoroquinolones, β-lactams/β-lactamase inhibitors, and cefiderocol, which have shown promising results 2, 4.
- There is no recent evidence to suggest that Bactrim is a effective treatment option for P. aeruginosa infections, and its use may be limited by the emergence of resistant strains 5.
Resistance to Trimethoprim-Sulfamethoxazole
- Resistance to trimethoprim-sulfamethoxazole is a significant concern, and has been linked to treatment failure in various infections, including urinary tract infections and respiratory tract infections 5.
- The use of trimethoprim-sulfamethoxazole as prophylaxis for Pneumocystis carinii infection has also been associated with the development of multidrug resistance in bacterial pathogens 5.
- The emergence of resistance to trimethoprim-sulfamethoxazole has limited its use to only a few indications, and alternative treatment options are being explored 4.