A systematic comparison of antimicrobial wound dressings using a planktonic cell and an immobilized cell model

Shoukat, Kamran; Pilling, Sally; Rout, Simon P.; Bradbury, Jane; Humphreys, Paul

doi:10.1111/jam.12967

Cited by 5 publications

(5 citation statements)

References 36 publications

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“…Our data indicate that PHMB did not significantly reduce bacterial counts, in contrast to previous studies using planktonic culture, single and mixed biofilms treated statically, which showed significant reduction in bioburden (Lipp et al, 2010; Rembe et al, 2016). Models in which bacteria are immobilized in a collagen matrix that better represents the biofilm environment suggest that the efficacy of PHMB has been overestimated with smaller reductions in bacterial bioburden in agreement with our results (Shoukat et al, 2015). Crystal or gentian violet (CV/GV) was re‐evaluated in 1992 as a dermatological antiseptic and approved by FDA in 2013 for the treatment of diabetic foot ulcers and pressure ulcers, both of which are classed as chronic wounds (Edwards, 2016; Maley & Arbiser, 2013).…”

Section: Discussionsupporting

confidence: 92%

Testing the efficacy of topical antimicrobial treatments using a two‐ and five‐species chronic wound biofilm model

Nedelea

Plant

Robins

et al. 2021

J of Applied Microbiology

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Aims The effectiveness of commercially available wound dressings and a HOCl gel formulation was tested against two‐ and five‐species biofilms in a dynamic in vitro chronic wound infection model. Method Two‐species biofilms (Pseudomonas aeruginosa and Staphylococcus aureus) were cultured using a biofilm flow device and treated with wound dressings containing silver, iodine, polyhexamethylene biguanide, crystal violet or HOCl gel at 5 h. Five‐species biofilms (P. aeruginosa, S. aureus, Enterococcus faecalis, Streptococcus pyogenes and Escherichia coli) were similarly cultured and treated with HOCl gel at 5 and 24 h. Multidose experiments used two‐ and five‐species biofilms with HOCl applied at 24, 48 and 72 h. Results None of the treatments completely disrupted the biofilms and, with the exception of silver, bacteria recovered in number post‐treatment. HOCl was most effective when applied to 24 h established biofilms with most activity against P. aeruginosa. Recovery post‐treatment was negligible with HOCl applied at 24 h and multiple doses indicated that bacteria were not becoming tolerant to treatment. Conclusions Realistic models are necessary to test the effectiveness of antimicrobial wound treatments to ensure findings are clinically translatable. HOCl gel shows promise as a new topical antimicrobial for wounds, especially due to its ability to inhibit P. aeruginosa. Significance and Impact of the Study This study highlights a need for robust in vitro data to support development and use of wound treatments that can only be obtained from the refinement of realistic infection models. Furthermore, it indicates the potential use of HOCl gel for chronic wound management.

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Section: Discussionsupporting

confidence: 92%

Testing the efficacy of topical antimicrobial treatments using a two‐ and five‐species chronic wound biofilm model

Nedelea

Plant

Robins

et al. 2021

J of Applied Microbiology

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“…Within the same study, the lowest values consistently corresponded to the Gram-negative bacteria Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli), and the highest to the Gram-positive bacteria Pseudomonas aeruginosa (P. aeruginosa). MIC and MBC values may be higher when bacteria form biofilms, as suggested by the results of a study that show that the antimicrobial activity of a commercial PRWD was higher in a planktonic cell model than in an immobilized cell model used to mimic biofilms [49]. PHMB is well tolerated when administered topically to wounds, showing low cytotoxicity and poor skin penetration [28,44,50], and also promotes wound healing, by favoring tissue granulation on the wound surface [5].…”

Section: The Antiseptic Polyhexanide (Phmb)mentioning

confidence: 99%

“…Almost all of the reported in vitro antibacterial activity assays with PRMs employed single bacterial cultures in planktonic form or as colonies on agar (Table 8). As in chronic wounds, bacteria are present as mixed-species biofilms [189] and as PHMB is less effective when bacteria are present in biofilm form [49], these are not the most relevant types of bacterial cultures to model bacteria in chronic wounds. Additionally, the effect of exudate has to be considered, since commercial AMDs, including PRWDs, have shown reduced antimicrobial activity when evaluated in vitro in the presence of human wound exudate [87].…”

Section: Prm23amentioning

confidence: 99%

Polyhexanide-Releasing Membranes for Antimicrobial Wound Dressings: A Critical Review

Guiomar

Urbano

2022

Membranes

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The prevalence of chronic, non-healing skin wounds in the general population, most notably diabetic foot ulcers, venous leg ulcers and pressure ulcers, is approximately 2% and is expected to increase, driven mostly by the aging population and the steady rise in obesity and diabetes. Non-healing wounds often become infected, increasing the risk of life-threatening complications, which poses a significant socioeconomic burden. Aiming at the improved management of infected wounds, a variety of wound dressings that incorporate antimicrobials (AMDs), namely polyhexanide (poly(hexamethylene biguanide); PHMB), have been introduced in the wound-care market. However, many wound-care professionals agree that none of these wound dressings show comprehensive or optimal antimicrobial activity. This manuscript summarizes and discusses studies on PHMB-releasing membranes (PRMs) for wound dressings, detailing their preparation, physical properties that are relevant to the context of AMDs, drug loading and release, antibacterial activity, biocompatibility, wound-healing capacity, and clinical trials conducted. Some of these PRMs were able to improve wound healing in in vivo models, with no associated cytotoxicity, but significant differences in study design make it difficult to compare overall efficacies. It is hoped that this review, which includes, whenever available, international standards for testing AMDs, will provide a framework for future studies.

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“…Within a same study, the lowest values consistently corresponded to the Gram-negative bacteria Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli), and the highest to the Gram-positive bacteria Pseudomonas aeruginosa (P. aeruginosa). MIC and MBC values may be higher when bacteria form biofilms, as suggested by the results of a study showing that the antimicrobial activity of a commercial PRWD was higher in a planktonic cell model than in an immobilized cell model used to mimic biofilms [52]. PHMB is well tolerated when administered topically to wounds, showing low cytotoxicity and poor skin penetration [28,44,53], and also promotes wound healing, by favoring tissue granulation on the wound surface [5].…”

Section: The Antiseptic Polyhexanide (Phmb)mentioning

confidence: 99%

“…Almost all reported in vitro antibacterial activity assays with the novel PRMs employed single bacterial cultures in planktonic form or as colonies on agar (Table 8). As, in chronic wounds, bacteria are present as mixed-species biofilms [190] and as PHMB is less effective when bacteria are present in biofilm form [52], these are not the most relevant type of bacterial cultures to model bacteria in chronic wounds. Additionally, the effect of exudate has to be considered, since commercial AMDs, including PRWDs, have shown reduced antimicrobial activity when evaluated in vitro in the presence of human wound exudate [71].…”

Section: Prm23amentioning

confidence: 99%

Novel Polyhexanide-Releasing Membranes for Antimicrobial Wound Dressings: A Critical Review

Guiomar¹,

Urbano²

2022

Preprint

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The prevalence for chronic, non-healing skin wounds in the general population, most notably diabetic foot ulcers, venous leg ulcers and pressure ulcers, is approximately 2% and is expected to increase, driven mostly by an aging population and the steady rise in obesity and diabetes. Non-healing wounds often become infected, increasing the risk of life-threatening complications, which poses a significant socioeconomic burden. Aiming at an improved management of infected wounds, a variety of wound dressings incorporating antimicrobials (AMDs), namely polyhexanide (poly(hexamethylene biguanide); PHMB), have been introduced in the wound care market. However, many wound care professionals agree that none shows comprehensive and optimal antimicrobial activity. This manuscript summarizes and discusses studies on novel PHMB-releasing membranes (PRMs) for wound dressings, detailing their preparation, physical properties relevant in the context of AMDs, drug loading and release, antibacterial activity, biocompatibility, wound healing capacity, and clinical trials conducted. Some of these PRMs were able to improve wound healing in in vivo models, with no associated cytotoxicity, but significant differences in study design make it difficult to compare overall effi-cacies. It is hoped that this review, which includes, whenever available, international standards for testing AMDs, will provide a framework for future studies.their preparation, physical properties relevant in the context of AMDs, drug loading and release, antibacterial activity, biocompatibility, wound healing capacity, and clinical trials conducted. Some of these PRMs were able to improve wound healing in in vivo models, with no associated cytotoxicity, but significant differences in study design make it difficult to compare overall efficacies. It is hoped that this review, which includes, whenever available, international standards for testing AMDs, will provide a framework for future studies.

show abstract

A systematic comparison of antimicrobial wound dressings using a planktonic cell and an immobilized cell model

Cited by 5 publications

References 36 publications

Testing the efficacy of topical antimicrobial treatments using a two‐ and five‐species chronic wound biofilm model

Testing the efficacy of topical antimicrobial treatments using a two‐ and five‐species chronic wound biofilm model

Polyhexanide-Releasing Membranes for Antimicrobial Wound Dressings: A Critical Review

Novel Polyhexanide-Releasing Membranes for Antimicrobial Wound Dressings: A Critical Review

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