ceftazidime-avibactam + colistin + polymyxin B

This is a **combination therapy** consisting of three antibiotics: **ceftazidime-avibactam**, **colistin**, and **polymyxin B**. Ceftazidime-avibactam is a combination of a third-generation cephalosporin (ceftazidime) and a non-β-lactam β-lactamase inhibitor (avibactam), designed to inhibit β-lactamase enzymes and restore antibiotic efficacy against resistant Gram-negative bacteria. Colistin (polymyxin E) and polymyxin B are both polymyxin-class antibiotics with similar mechanisms of action; they disrupt the bacterial cell membrane of Gram-negative organisms. This triple-combination is not a single marketed product but may be used in refractory or salvage therapy for severe multidrug-resistant infections, particularly those caused by carbapenem-resistant Enterobacteriaceae (CRE) or Pseudomonas aeruginosa. Studies indicate the combination aims to maximize bacterial killing and suppress resistance emergence, although nephrotoxicity risks (especially with polymyxins) are notable[1][2][5].