Polyhexamethylene biguanide and its antimicrobial role in wound healing: a narrative review

Abstract

A wound offers an ideal environment for the growth and proliferation of a variety of microorganisms which, in some cases, may lead to localised or even systemic infections that can be catastrophic for the patient; the development of biofilms exacerbates these infections. Over the past few decades, there has been a progressive development of antimicrobial resistance (AMR) in microorganisms across the board in healthcare sectors. Such resistant microorganisms have arisen primarily due to the misuse and overuse of antimicrobial treatments, and the subsequent ability of microorganisms to rapidly change and mutate as a defence mechanism against treatment (e.g., antibiotics). These resistant microorganisms are now at such a level that they are of grave concern to the World Health Organization (WHO), and are one of the leading causes of illness and mortality in the 21st century. Treatment of such infections becomes imperative but presents a significant challenge for the clinician in that treatment must be effective but not add to the development of new microbes with AMR. The strategy of antimicrobial stewardship (AMS) has stemmed from the need to counteract these resistant microorganisms and requires that current antimicrobial treatments be used wisely to prevent amplification of AMR. It also requires new, improved or alternative methods of treatment that will not worsen the situation. Thus, any antimicrobial treatment should be effective while not causing further development of resistance. Some antiseptics fall into this category and, in particular, polyhexamethylene hydrochloride biguanide (PHMB) has certain characteristics that make it an ideal solution to this problem of AMR, specifically within wound care applications. PHMB is a broad-spectrum antimicrobial that kills bacteria, fungi, parasites and certain viruses with a high therapeutic index, and is widely used in clinics, homes and industry. It has been used for many years and has not been shown to cause development of resistance; it is safe (non-cytotoxic), not causing damage to newly growing wound tissue. Importantly there is substantial evidence for its effective use in wound care applications, providing a sound basis for evidence-based practice. This review presents the evidence for the use of PHMB treatments in wound care and its alignment with AMS for the prevention and treatment of wound infection.

Review of the role of biofilms in equine wounds: Clinical indications and treatment strategies

“…Polyhexamethylene biguanide (PHMB) is a cationic polymer that can be used as an adjunctive therapy in the early post‐debridement period to reduce biofilm surface tension to increase their permeability (Hendrickson, 2019; Palumbo et al., 2016; Percival et al., 2019; Rippon et al., 2023; Weigelt et al., 2021). PHMB is a broad‐spectrum biocide that kills Gram‐positive and Gram‐negative bacteria, fungi, parasites and certain viruses with a high therapeutic index, and has further been used for years clinically and in industry without development of resistance (Rippon et al., 2023; Weigelt et al., 2021). PHMB is a strong base, which is positively charged at physiological pH (Fjeld & Lingaas, 2016).…”

“…PHMB is a strong base, which is positively charged at physiological pH (Fjeld & Lingaas, 2016). Furthermore, it has been shown to be noncytotoxic nor damaging to epithelialising tissue in healing wounds, with substantial evidence reviewed elsewhere for its application in wound management and importantly, its alignment with recently described antimicrobial stewardship policies to prevent and treat wound infection (Rippon et al., 2023). PHMB is the most used antiseptic to treat critically colonised and locally infected wounds (Alves et al., 2021; Dissemond et al., 2010) and is available in equine practice bound to roll gauze, sponges or other types of dressings (Hendrickson, 2019).…”

“…In addition, multiple studies to date have documented the evidence of biofilms in nonhealing wounds of horses specifically (Freeman et al., 2009; Westgate et al., 2011). Furthermore, there has been a progressive development of antimicrobial resistance in microorganisms across human and veterinary healthcare sectors, which has been considered by the World Health Organization to be one of the leading causes of illness and mortality in the 21st century (Rippon et al., 2023). The high prevalence of biofilms in wounds with delayed healing, the frequency with which equine practitioners treat wounds in daily practice and the increasing reported incidence of multi‐drug resistant bacterial strains in equine practice in general (Herdan et al., 2012; Loncaric et al., 2014; Theelen et al., 2014; van den Eede et al., 2012) highlight the need for implementation of more advanced training in wound care strategies to address these clinical scenarios.…”

When silver doesn't shine anymore: The threat of increasing resistance to antibiotics and silver antiseptics

“…Quaternary ammonia compounds, in wastewater, have been associated with the emergence of ammonia-resistant Gram-negative bacteria [ 5 ]. Newer antiseptics, such as polyhexamethylene biguanide, seem to have good antimicrobial coverage for use in wound care and have not been associated (yet, at least) with the emergence of resistant organisms [ 6 ].…”

Effectiveness of a polyhexamethylene biguanide-containing wound cleansing solution using experimental biofilm models

“…PHMB is a polymer used as a disinfectant and antiseptic in various industries including wound care. 39 It is a cationic polymer, meaning binds to negatively charged surfaces such as cell membranes. PHMB is effective against a broad spectrum of microorganisms including bacteria, viruses, and fungi.…”