“…By definition, the MDR strains display acquired resistance to at least one agent in three antimicrobial categories, whereas the XDR strains show susceptibility to antibiotics in 2 or fewer categories and display resistance to at least one agent in the rest of available antibiotic categories [236,237]. Ceftazidime, (a third-generation broad-spectrum cephalosporin antibiotic [238]) is also used in combination with avibactam (a synthetic non-β-lactam, β-lactamase inhibitor which inactivates β-lactamase targets via covalent acylation [239]), and has shown to be highly effective against MDR and XDR P. aeruginosa strains (>90% effectiveness) [240,241]. However, P. aeruginosa strains resistant to ceftazidime/avibactam have been reported and are on the rise, adding to the challenges associated with P. aeruginosa therapeutics [242,243].…”