From the Guidelines
Colistin is not recommended as a first-line treatment for New Delhi Metallo-beta-lactamase (NDM) producing Carbapenem-Resistant Enterobacteriaceae (CRE) infections due to its limited efficacy and high mortality rates compared to other antibiotics. For NDM CRE infections, consider a combination of two or more of the following antibiotics, based on susceptibility testing:
- Ceftazidime-avibactam (2.5g IV q8h)
- Aztreonam
- Cefiderocol Treatment duration is typically 7-14 days, depending on the site and severity of infection. The combination of ceftazidime/avibactam plus aztreonam is preferred due to its in vitro synergy and lower 30-day mortality rates compared to other antibiotics, including colistin, as shown in a recent observational study 1. Cefiderocol may also be considered as an alternative option, with a conditional recommendation based on results from the RCT CREDIBLE-CR, which showed higher rates of clinical cure and microbiological eradication, and lower 28-day mortality in patients who received cefiderocol 1. Colistin may be considered as part of combination therapy only if the isolate is resistant to all other options, but its use is associated with significant nephrotoxicity and neurotoxicity, and higher mortality rates compared to other antibiotics 1. Always perform susceptibility testing to guide antibiotic selection, and consult with an infectious disease specialist for complex cases.
From the Research
Effectiveness of Colistin against NDM-producing CRE
- The effectiveness of colistin against New Delhi Metallo-beta-lactamase (NDM) producing Carbapenem-Resistant Enterobacteriaceae (CRE) is a topic of ongoing research 2, 3, 4, 5, 6.
- Studies have shown that colistin can be effective against CRE infections, but its use is often limited by the emergence of colistin resistance genes, such as mcr-1 3.
- Compared to ceftazidime-avibactam, colistin has been shown to have a higher mortality rate in patients with CRE infections 4, 5.
- However, a recent study found that colistin monotherapy may be as effective as colistin-fosfomycin combination therapy for the treatment of CRE infections 6.
Comparison with Other Treatments
- Ceftazidime-avibactam has been shown to be a reasonable alternative to colistin in the treatment of K. pneumoniae carbapenemase-producing CRE infections 4.
- The effectiveness of ceftazidime-avibactam versus colistin in treating CRE bacteremia has been compared in several studies, with ceftazidime-avibactam showing a lower risk of 14-day mortality 5.
- The use of colistin-based regimens, including colistin monotherapy and colistin-fosfomycin combination therapy, has been compared in a propensity score analysis, showing comparable treatment effectiveness and mortality between the two groups 6.
Limitations and Future Directions
- The emergence of colistin resistance genes, such as mcr-1, limits the use of colistin as a treatment option for CRE infections 3.
- Further research is needed to confirm the findings of existing studies and to establish optimal treatment strategies for CRE infections 4, 5, 6.
- The development of new antimicrobial agents and the use of combination therapy may be necessary to combat the growing threat of CRE infections 2, 6.