Defeating Multi Drug Resistant ESKAPEE Pathogens with Polymer Nanomaterials

The clinical efficacy of antibiotics has progressively declined over the past decades as a consequence of the global spread of antimicrobial resistance, a phenomenon that is particularly pronounced among the so-called ESKAPEE pathogens: Enterococcus species, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, Enterobacter species and Escherichia coli. Collectively, these bacteria are responsible for more than 50% of infection-related deaths worldwide, and multidrug resistance is highly prevalent among them. This alarming trend poses a critical threat to global public health and underscores the urgent need for innovative therapeutic strategies. One such approach involves the use of polymers as drug delivery systems for both conventional antibiotics and novel antimicrobial compounds, in the form of nanoparticles or polymer prodrugs, to circumvent resistance mechanisms. Other promising strategies are polycations with intrinsic antibacterial activity that act through mechanisms not widely exploited yet and polymers exerting photodynamic and photothermal effects. In this review, we summarize and discuss the current evidence for the efficacy of polymer-based strategies against drug-resistant ESKAPEE infections.