A comparison of the antimicrobial efficacy of two silver-containing wound dressings on burn wound isolates

Measuring the microbiome of chronic wounds with use of a topical antimicrobial dressing - A feasibility study

BACKGROUND

Polymicrobial communities colonize all wounds, and biofilms are hypothesized to be a key link to the chronic state and stalled healing. Molecular methods offer greater insight when studying microbial ecology in chronic wounds, as only a small fraction of wound bacteria are cultured by currently available methods and studies have shown little agreement between culture and molecular based approaches. Some interventions, like dressings with oxidized silver, are reported to help the stalled wounds move to a normal healing trajectory but the underlying mechanisms are difficult to measure. One hypothesis is that the use of topical antimicrobial dressings targets the wound microbiome and reduces bioburden.

OBJECTIVES

Our objective was to determine if culture-independent molecular methods could be used to identify the microbial composition in chronic wounds, and measure the microbiome over time when a topical antimicrobial dressing is used to reduce bioburden.

METHODS

Patients with chronic wounds defined as >6 weeks in duration and not taking systemic antibiotics were recruited to participate. A wound contact layer containing silver oxynitrate was applied immediately after routine sharp debridement material was collected and swabs of the wound bed taken. Next-generation sequencing of the bacterial 16S rRNA gene in each specimen was used to measure the microbiome.

RESULTS

Distinct bacterial communities were observed between swab and debridement samples, highlighting spatial differences and the importance of sampling consistency. The microbial communities appeared to be similar between different diabetes statuses, but different among the three wound categories included.

CONCLUSIONS

Culture-independent methods can be applied to measure the microbiome of chronic wounds even when a topical antimicrobial dressing is applied to the wound.

Silver and Alginates: Role in Wound Healing and Biofilm Control

Significance: Chronic wounds are known to be a significant issue globally. Of concern in wounds are the numbers and types of residing microorganisms and the ability of the host's immune system to control their proliferation. Wound healing is impeded by colonizing microorganisms growing within the biofilm phenotypic state. In this state microorganisms are recalcitrant to routinely impeded by used antimicrobial interventions. Recent advances: Silver has been reported to demonstrate efficacy on planktonic microorganisms both within the in vitro and in vivo environments. However, when silver is incorporated into a wound dressing, its antimicrobial efficacy on biofilms within the in vivo environment remains contentious. Critical Issues: Unequivocal evidence of the efficacy of silver, and wound dressings containing silver, on biofilms in clinical situations is lacking. This is principally due to the deficiency of definite biofilm definitions, markers, and evidence in the chronic wound environment. Future Direction: Research studies demonstrating antimicrobial efficacy on in vitro biofilms can be used to generate data and information appropriate for extrapolation and applicability to the in vivo environment. It is very important that inventors of antimicrobial wound dressings ensure efficacy against both planktonic and sessile microorganisms, within the in vitro and in vivo environments.

Low-level laser therapy as an antimicrobial and antibiofilm technology and its relevance to wound healing

ABSTRACT 

The biostimulative effect of low-level laser therapy (LLLT) in tissues has been noted in reference to the treatment of various diseases but little information exists on its effectiveness on chronic wounds and biofilm. The scope of this review was to identify literature reporting on LLLT alone, without photodynamic agents, as an antimicrobial/antibiofilm technology and determine its effects on wound healing. Overall the beneficial effects of LLLT in promoting wound healing in animal and human studies has been demonstrated. However, the lack of credible studies using reproducible models and light dosimetry restricts the analysis of current data. Efforts must be addressed to standardize phototherapy procedures as well as to develop suitable in vitro and in vivo biofilm models to test LLLT efficacy in promoting biofilm eradication and wound healing.

Wound care: biofilm and its impact on the latest treatment modalities for ulcerations of the diabetic foot

Biofilm is an increasingly important topic of discussion in the care of the chronic diabetic foot wound. Treatment modalities have focused on biofilm reduction or eradication through debridement techniques, topical therapies, negative pressure therapy, and ultrasound. In addition, advanced wound healing modalities, such as bioengineered alternative tissues, require optimal wound bed preparation with specific consideration of biofilm reduction before their application. Although fundamental principles of diabetic wound care still apply, critical thought must be given to biofilm before implementing a treatment plan for the closure of these complex wounds.