Chapter 5. Synthetic Cationic Water-soluble Antimicrobial Polymers: An Alternative to Conventional Small-molecule Antibiotics

The emergence of microbial resistance to several antimicrobials of last resort is causing a global crisis and presents a scenario where hospitals will be unable to address healthcare issues that become complicated due to drug-resistant bacteria. Natural or synthetic antimicrobials are the standard of care for addressing bacterial infections. However, due to the rapid emergence of resistance to these classes of antimicrobials, alternative platforms such as antimicrobial polymers are being evaluated as viable options. In this regard, synthetic cationic water-soluble polymers are an emerging class of antimicrobials that deserve a closer look. Over the decades, several classes of antimicrobial polymers have been explored and have been demonstrated to have good antimicrobial activity, which is normally due to the cationic nature of the polymers. The challenge in such cationic polymers is to maximize their bacterial activity while minimizing the collateral damage to mammalian cells. In this chapter, various classes of synthetic cationic water-soluble antimicrobial polymers are described, spanning both older versions such as polyhexanide and newer cationic polyurethanes.