Abstract
All chronic wounds are colonised by bacteria; for some, colonisation progresses to become infection. Alginate wound dressings are used for highly exuding chronic wounds as they are very absorbent, taking up large quantities of exudate while maintaining a moist wound bed to support healing. Some alginate dressings are doped with antimicrobials, most commonly silver, but evidence regarding the efficacy of these is largely inconclusive. This manuscript describes the development and in vitro assessment of alginate materials doped with chlorhexidine hexametaphosphate (CHX-HMP), a sparingly soluble salt which when exposed to aqueous environments provides sustained release of the common antiseptic chlorhexidine. Comparator materials were a commercial silver alginate dressing material and an alginate doped with chlorhexidine digluconate (CHXdg). CHX-HMP alginates provided a dose-dependent CHX release which was sustained for over 14 days, whereas CHXdg alginates released limited CHX and this ceased within 24 h. CHX-HMP and silver alginates were efficacious against 5 major wound pathogens (MRSA, E. coli, P. aeruginosa, K. pneumoniae, A. baumannii) in a total viable count (TVC) and an agar diffusion zone of inhibition (ZOI) model. At baseline the silver alginate was more effective than the CHX-HMP alginate in the TVC assay but the CHX-HMP alginate was the more effective in the ZOI assay. After 7 days’ artificial aging the CHX-HMP alginate was more effective than the silver alginate for four of the five bacteria tested in both assays. These materials may ultimately find application in the development of wound dressings for chronic wounds that provide sustained antimicrobial protection.
Highlights
Chronic wounds present substantial challenges to healthcare practitioners and are a source of discomfort and debility to millions of people worldwide
There is in vitro evidence to indicate that the antimicrobial efficacy of silver alginate dressings diminishes over time, with an agar diffusion assay revealing a reduction in zone of inhibition of 60% after 1 day and no zone at all at 7 days [9]
Alginate discs with 3and 6-chlorhexidine hexametaphosphate (CHX-HMP) and 6-chlorhexidine digluconate (CHXdg) were placed in individual semi-micro cuvettes (BRAND® semi-micro cuvettes, BRAND GMBH + CO KG, Wertheim, Germany), covered with distilled water (2.25 mL) and the cuvette sealed with a lid and parafilm (n = 30 for each CHX doping)
Summary
Chronic wounds present substantial challenges to healthcare practitioners and are a source of discomfort and debility to millions of people worldwide. Venous ulcers are the most common chronic leg wounds, and prevalence rises with age, affecting 1.7% of people over 65 [3]. All of these chronic wounds can be considered to be colonised by bacteria; only some progress to clinical infection, and the factors which determine whether and when this occurs are not well understood, resulting in uncertainty as to how to best prevent and treat them [4]. There is insufficient evidence to conclude whether they aid healing of diabetic foot ulcers [7], and a Cochrane review of the efficacy of silver to prevent wound infection found low quality evidence to suggest that silver products can detrimentally affect wound healing [8]. There is in vitro evidence to indicate that the antimicrobial efficacy of silver alginate dressings diminishes over time, with an agar diffusion assay revealing a reduction in zone of inhibition of 60% after 1 day and no zone at all at 7 days [9]
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callMore From: Journal of Materials Science: Materials in Medicine
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
