Exploring the Safety and Efficacy of PHMB as an Antimicrobial Irrigation Option in Surgery

What is the role of antimicrobial irrigation in surgery?

Antimicrobial irrigation is a method commonly used during surgery with a goal of removing foreign particles, tissue debris, and microorganisms from the surgical field, thus reducing the risk of infections and supporting postoperative healing. Besides saline, antiseptics such as chlorhexidine gluconate, povidone iodine, hydrogen peroxide, and ethanol are most frequently used as part of the irrigation regimen. Given the wide array of both safety and antimicrobial efficacy profiles of antiseptics, it is crucial to evaluate alternative options with comparable or improved properties. 

This article aims to provide a scientific perspective on the use of polyhexamethylene biguanide (PHMB) as a promising antimicrobial irrigation agent in surgical settings.

What is PHMB?

Polyhexamethylene biguanide (PHMB) is a cationic polymeric biguanide, a well-established antiseptic known for its rapid and broad-spectrum antimicrobial properties against bacteria, fungi, and viruses. In recent years, PHMB has garnered attention as potential antiseptic of choice in surgical procedures. 

Here’s how PHMB compares to other common antiseptics: 

1. Safety Profile: PHMB exhibits a favorable safety profile, in particular when when compared to other commonly used antimicrobial and antiseptic agents.^1,2 This is a direct consequence of the favorable mechanism of action preferably targeting microbial cells versus mammalian cells. Studies have reported low systemic toxicity, limited local irritation, and minimal adverse effects on human tissue with PHMB usage. In contrast, irrigation solutions containing chlorhexidine gluconate or povidone iodine have been associated with a higher incidence of adverse effects, including allergic reactions, tissue damage, and impaired healing. ^3-8 
2. Antiseptic Efficacy: PHMB has demonstrated excellent efficacy as an antimicrobial agent in various studies. Its broad-spectrum activity encompasses both gram-positive and gram-negative bacteria, as well as yeasts and viruses. This includes vegetative pathogens and those with antibiotic resistance, like methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant enterococci (VRE). Unlike most of the other antiseptics and antimicrobials, antimicrobial efficacy of PHMB is not affected by the presence of organic bioburden and its efficacy increases with a rise in pH, which can be advantageous for management of infections.^9-16
3. Rapid and Prolonged Antimicrobial Activity: PHMB has a unique combination of both rapid and prolonged efficacy, related to its mechanism of action. On one hand, PHMB rapidly kills pathogenic microorganisms, on the other hand, effectiveness of PHMB a variety of environments (high organic load, high pH), allows it to exert its efficacy over extended periods of time. This characteristic has the potential to reduce the risk of microbial colonization and subsequent infections, especially in surgical procedures where prolonged exposure to the environment increases potential for microbial contamination. Other antiseptics do not share these properties.^17,18
4. Reduced Resistance Development: Although PHMB has been in use for more than 60 years, thus far there have been no reports of acquired resistance development. This can be attributed to its complex mechanism of action which makes development of resistance almost unimaginable. This is especially important given the rapid rise of antimicrobial resistance world-wide and generation of multi-drug resistant pathogens, superbugs. This phenomenon is not true for all antiseptics, for example, resistance to chlorhexidine gluconate has been reported.^19,20 

PHMB and Intraoperative Antimicrobial Irrigation

Polyhexamethylene biguanide (PHMB) presents itself as a compelling alternative for antimicrobial irrigation in surgical procedures. Its favorable safety profile, broad-spectrum efficacy against various pathogens, prolonged antimicrobial activity, and reduced resistance development make it a promising option. However, it is important to consider individual patient and procedural factors when selecting an antimicrobial agent. Further research and clinical trials will contribute to a more comprehensive understanding of PHMB’s role in surgical antimicrobial irrigation and its potential benefits for patient outcomes.

References:

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