From the Guidelines
Enterococcus faecium and Citrobacter freundii complex generally do not respond well to azithromycin, making it an ineffective treatment choice for infections caused by these bacteria. Azithromycin, a macrolide antibiotic, has poor activity against these organisms due to their intrinsic resistance mechanisms. E. faecium typically demonstrates resistance to macrolides through target site modifications and efflux pumps, while C. freundii complex, as gram-negative bacteria, possess an outer membrane that limits azithromycin penetration and often carry resistance genes. For E. faecium infections, more appropriate treatment options include ampicillin (if susceptible), vancomycin, daptomycin, or linezolid depending on susceptibility testing 1. For C. freundii complex, third or fourth-generation cephalosporins, carbapenems, fluoroquinolones, or aminoglycosides are typically more effective, again guided by susceptibility results 1. When treating infections caused by these organisms, it's essential to obtain antimicrobial susceptibility testing to guide therapy, as resistance patterns can vary significantly between isolates and geographic regions. Some key points to consider when treating these infections include:
- The importance of susceptibility testing to guide therapy
- The potential for resistance to multiple antibiotics, including azithromycin
- The need for alternative treatment options, such as ampicillin, vancomycin, daptomycin, or linezolid for E. faecium, and third or fourth-generation cephalosporins, carbapenems, fluoroquinolones, or aminoglycosides for C. freundii complex
- The potential for severe consequences if left untreated or inadequately treated, including increased morbidity and mortality. It is crucial to prioritize the most recent and highest quality studies when making treatment decisions, and to consider the specific circumstances of each patient, including their medical history, current health status, and potential allergies or interactions with other medications. In the case of E. faecium and C. freundii complex, the most recent and highest quality studies suggest that azithromycin is not an effective treatment option, and that alternative antibiotics should be used instead 1.
From the Research
Response to Azithromycin
- There is no direct evidence in the provided studies that specifically addresses the response of Enterococcus faecium and Citrobacter freundii complex to azithromycin 2, 3, 4, 5, 6.
- Azithromycin is a macrolide antibiotic that prevents bacteria from growing by interfering with their protein synthesis, and it is used to treat or prevent certain bacterial infections 5.
- The provided studies focus on the treatment of vancomycin-resistant Enterococcus faecium infections and the in vitro activity of various antimicrobial agents against Enterococcus species 2, 3, 4, 6.
- However, none of the studies mention the effectiveness of azithromycin against Enterococcus faecium or Citrobacter freundii complex, making it unclear how these bacteria respond to azithromycin 2, 3, 4, 5, 6.
Limitations of Current Evidence
- The current evidence does not provide sufficient information to determine the response of Enterococcus faecium and Citrobacter freundii complex to azithromycin 2, 3, 4, 5, 6.
- Further research is needed to investigate the effectiveness of azithromycin against these bacteria and to provide guidance for treatment options 2, 3, 4, 5, 6.