Significant and rapid reduction of free endotoxin using a dialkylcarbamoyl chloride-coated wound dressing

OBJECTIVE

Endotoxin causes inflammation and can impair wound healing. Conventional methods that reduce bioburden in wounds by killing microorganisms using antibiotics, topical antimicrobials or antimicrobial dressings may induce endotoxin release from Gram-negative bacteria. Another approach is to reduce bioburden by adsorbing microorganisms, without killing them, using dialkylcarbamoyl chloride (DACC)-coated wound dressings. This study evaluated the endotoxin-binding ability of a DACC-coated wound dressing (Sorbact Compress, Abigo Medical AB, Sweden) in vitro, including its effect on the level of natural endotoxin released from Gram-negative bacteria.

METHOD

Different concentrations of purified Pseudomonas aeruginosa endotoxin and a DACC-coated dressing were incubated at 37°C for various durations. After incubation, the dressing was removed and endotoxin concentration in the solution was quantified using a Limulus amebocyte lysate (LAL) assay. The DACC-coated dressing was also incubated with Pseudomonas aeruginosa cells for one hour at 37°C. After incubation, the dressing and bacterial cells were removed and shed endotoxin remaining in the solution was quantified.

RESULTS

Overnight incubation of the DACC-coated wound dressing with various concentrations of purified Pseudomonas aeruginosa endotoxin (96-11000 EU/ml) consistently and significantly reduced levels of free endotoxin by 93-99% (p<0.0001). A significant endotoxin reduction of 39% (p<0.001) was observed after five minutes. The DACC-coated dressing incubated with clinically relevant Pseudomonas aeruginosa cells also reduced shed endotoxin by >99.95% (p<0.0001).

CONCLUSION

In this study, we showed that a DACC-coated wound dressing efficiently and rapidly binds both purified and shed endotoxin from Pseudomonas aeruginosa in vitro. This ability to remove both endotoxin and bacterial cells could promote the wound healing process.

Implications of endotoxins in wound healing: a narrative review

Bacterial toxins are thought to play a role in delayed wound healing in critically colonised and infected wounds. Endotoxins are released from Gram-negative bacteria when they are lysed by host phagocytic cells during an immune response, or by antimicrobial agents, potentially leading to a detrimental effect on the host tissues. Endotoxins can affect all aspects of the wound healing process, leading to delayed healing and contributing to wound chronicity. Release of endotoxins by bacteria can also have serious systemic effects (for example, septic shock) that can lead to high levels of patient mortality. This review summarises the role and implications on wound healing of bacterial endotoxins, describing the impact of endotoxins on the various phases of the wound healing response. There is a paucity of in vivo/clinical evidence linking endotoxins attributed to a wound (via antibiotic treatment) or their release from infecting bacteria with parameters of delayed wound healing. Future work should investigate if this link is apparent and determine the mechanism(s) by which such detrimental effects occur, offering an opportunity to identify possible treatment pathways. This paper describes the phenomenon of antimicrobial-induced endotoxin release and summarises the use of wound dressings to reduce wound bioburden without inducing microbial death and subsequent release of endotoxins, thus limiting their detrimental effects.

Treating a non-healing postoperative sternal wound in a woman with type 2 diabetes mellitus: A case report

One of the leading causes of impaired chronic wound healing is diabetes mellitus because it involves many factors that influence the physiopathology of tissue healing. Therefore, it is strategic to analyse clinical cases of this population. We presented a clinical case report of a 51-year-old female with type 2 diabetes mellitus, presenting a non-healing sternal wound after open heart surgery. Appropriate dressing and assessment contributed to the healing of the sternal wound in 5 weeks.

In vitro and clinical experience of Cutimed Sorbact: the evidence base

In the previous chapter, Keith Cutting and James McGuire explored the link between infection and wound chronicity and explained how Cutimed Sorbact can be used to promote healing in chronic wounds. The following sections summarise the existing evidence for the Cutimed Sorbact range of dressings.

Wound infection: a clinician's guide to assessment and management

Wound infection significantly increases the cost of wound care and has significant detrimental effects on patients' quality of life. It is imperative that all health-care professionals are able to promptly recognise and assess for wound infection and initiate effective management. Clinicians must be able to recognise the different levels of bacterial bioburden and to act accordingly. This article provides clear guidance for recognising an infected wound, understanding the different levels of wound bioburden and practical guidance on different forms and appropriateness of antimicrobial agents.