From the Guidelines
Bactrim (trimethoprim-sulfamethoxazole) does not effectively cover enterococci and should not be relied upon for enterococcal infections. Enterococci, particularly Enterococcus faecalis and Enterococcus faecium, have intrinsic resistance to trimethoprim-sulfamethoxazole due to their ability to utilize exogenous folates, bypassing the metabolic pathway that Bactrim targets 1. For enterococcal infections, more appropriate antibiotic choices include ampicillin (for susceptible strains), vancomycin (for ampicillin-resistant strains), or combination therapy with an aminoglycoside for synergistic effects in serious infections like endocarditis. Linezolid and daptomycin may be options for vancomycin-resistant enterococci (VRE) 1. When treating suspected or confirmed enterococcal infections, it's essential to obtain cultures and susceptibility testing to guide appropriate antibiotic selection, as resistance patterns can vary significantly among enterococcal species and strains.
Some key points to consider:
- Enterococci are not typically covered by Bactrim, and alternative antibiotics should be used for suspected or confirmed enterococcal infections.
- The choice of antibiotic should be guided by susceptibility testing and local resistance patterns.
- Combination therapy with an aminoglycoside may be necessary for serious infections like endocarditis.
- Linezolid and daptomycin may be options for vancomycin-resistant enterococci (VRE), but their use should be guided by susceptibility testing and clinical experience.
It's worth noting that the guidelines for the treatment of enterococcal infections are based on the most recent and highest-quality evidence available, and empiric coverage of Enterococcus is not necessary in patients with community-acquired intra-abdominal infection 1. However, in cases where enterococcal infection is suspected or confirmed, prompt and effective antibiotic treatment is essential to prevent morbidity and mortality.
From the Research
Bactrim Coverage of Enterococci
- Bactrim, also known as trimethoprim-sulfamethoxazole, has been studied for its effectiveness against enterococci in various settings 2, 3, 4, 5.
- The combination of trimethoprim and sulfamethoxazole has been shown to have potentiated inhibitory and bactericidal activities against strains of Streptococcus faecalis 4.
- However, the effectiveness of Bactrim against enterococci can be influenced by various factors, including the presence of high-level resistance to aminoglycosides and the use of standard antimicrobial susceptibility testing, which may not accurately predict clinical outcomes 3, 4.
- Some studies suggest that Bactrim may be useful in the treatment of serious enterococcal infections, including those caused by strains with high-level resistance to aminoglycosides 4.
- The European Committee on Antimicrobial Susceptibility Testing has categorized wild-type enterococci as intermediate to trimethoprim and trimethoprim-sulfamethoxazole, allowing for the distinction between enterococci with and without acquired resistance mechanisms to trimethoprim 3.
Limitations and Considerations
- The clinical efficacy of Bactrim in enterococcal infections is debated, and treatment decisions may need to be based on individual patient factors and susceptibility testing 2, 3.
- The use of Bactrim in patients with recurrent urinary tract infections, genitourinary abnormalities, or previous use of trimethoprim-sulfamethoxazole within 90 days may be associated with increased resistance rates 6.
- The effectiveness of Bactrim against enterococci may vary depending on the specific strain and clinical setting, highlighting the need for careful consideration and individualized treatment approaches 2, 3, 4, 5.