The Management of Critically Colonized and Locally Infected Leg Ulcers with an Acid-Oxidizing Solution: A Pilot Study

The impact of wound pH on the antibacterial properties of Medical Grade Honey when applied to bacterial isolates present in common foot and ankle wounds. An in vitro study

BACKGROUND

Diabetic foot ulcers (DFUs) and post-surgical wound infections are amongst the most troublesome complications of diabetes and following foot and ankle surgery (FAS) respectively. Both have significant psychosocial and financial burden for both patients and the healthcare system. FAS has been reported to have higher than average post-surgical infections when compared to other orthopaedic subspecialties. Evidence also indicates that patients with diabetes and other co morbidities undergoing FAS are at a much greater risk of developing surgical site infections (SSIs). With the growing challenges of antibiotic resistance and the increasingly high numbers of resilient bacteria to said antibiotics, the need for alternative antimicrobial therapies has become critical.

AIM

The aim of this study was to investigate the use of medical grade honey (MGH) when altered to environments typically present in foot and ankle wounds including DFUs and post-surgical wounds (pH6-8).

METHODS

MGH (Activon) was altered to pH 6, 7 and 8 and experimental inoculums of Pseudomonas aeruginosa (NCTC10782), Escherichia coli, (NCTC10418), Staphylococcus aureus (NCTC10655) and Staphylococcus epidermidis (NCTC 5955) were transferred into each pH adjusted MGH and TSB solution and the positive and negative controls.

RESULTS

MGH adjusted to various pH values had the ability to reduce bacteria cell survival in all pH variations for all bacteria tested, with the most bacterial reduction/elimination noted for Staphylococcus epidermidis. No correlations were noted among the pH environments investigated and the colony counts, for which there were small amounts of bacteria survived.

CONCLUSION

This research would indicate that the antibacterial properties of honey remains the same regardless of the pH environment. MGH could therefore potentially be considered for use on non-infected foot and ankle wounds to reduce the bacterial bioburden, the risk of infections and ultimately to improve healing outcomes.

Positive effects of cold atmospheric plasma on pH in wounds: a pilot study

OBJECTIVE

Cold atmospheric plasma (CAP) is a promising new option for the treatment of hard-to-heal (chronic) wounds. The aim of this study was to observe the effect of CAP on wound pH, as a correlation between the pH of a wound and its healing tendency has been established in the literature.

METHOD

Patients with hard-to-heal wounds were treated with CAP in addition to standard treatment. Treatment was performed with the aid of a small, mobile plasma device, which was used for one minute at a time during dressing changes. The pH value, wound size, and other parameters, such as exudate and signs of infection, were recorded for each treatment.

RESULTS

A total of 10 patients took part in the study. During the observation period, there was a significant reduction in pH from a markedly alkaline pH of 9.6 to a neutral pH of 7. This was accompanied by a marked reduction in wound size by an average of 76% with seven applications of CAP within 28 days. The evaluation of tissue granulation, exudate and signs of infection showed a positive trend.

CONCLUSION

The number of patients in the present study is not sufficient to prove the relationship between the pH value of the wound and the treatment with CAP. However, there are clear indications that the positive effects of CAP on wound healing, which are recognised in several publications, are also due to its influence on wound pH value.

Evolution of the Chronic Venous Leg Ulcer Microenvironment and Its Impact on Medical Devices and Wound Care Therapies

Studies have reported that the constituents of the wound microenvironment are likely to have critical roles in the degradation and fate of the polymeric matrix and the compounds dissolved in the wound dressing matrix. Thus, chronic wound assessment and the design of effective medical devices and drug products for wound care partly rely on an in-depth understanding of the wound microenvironment. The main aim of this review is to identify and discuss the different stages of chronic wound progression, focusing on the changes in the biochemical composition of the wound microenvironment, with particular attention given to venous leg ulcers (VLUs), as they are one of the most prevalent chronic wound aetiologies. The pathophysiology of venous ulcers is detailed, followed by a thorough review of what is known about the VLU microenvironment and its changes as a function of the evolution of the VLU. Simulating conditions for VLU are then discussed with the view of highlighting potentially relevant simulating media as a function of VLU evolution for a better assessment of biological safety, in particular medical devices intended to be in contact with these wounds.

Wound pH and temperature as predictors of healing: an observational study

OBJECTIVE

The aim of this study was to measure wound pH, wound temperature and wound size together to gain further understanding of their impact as predictors of wound healing outcomes.

METHOD

This study employed a quantitative non-comparative, prospective, descriptive observational design. Participants with both acute and hard-to-heal (chronic) wounds were observed weekly for four weeks. Wound pH was measured using pH indicator strips, wound temperature was measured using an infrared camera and wound size was measured using the ruler method.

RESULTS

Most of the 97 participants (65%, n=63) were male; participant's ages ranged between 18 and 77 years (mean: 42±17.10. Most of the wounds observed were surgical 60%, (n=58) and 72% (n=70) of the wounds were classified as acute, with 28% (n=27) classified as hard-to-heal wounds. At baseline, there was no significant difference in pH between acute and hard-to-heal wounds; overall the mean pH was 8.34±0.32, mean temperature was 32.86±1.78°C) and mean wound area was 910.50±1132.30mm2. In week 4, mean pH was 7.71±1.11, mean temperature was 31.90±1.76°C and mean wound area was 339.90±511.70mm2. Over the study follow-up period, wound pH ranged from 5-9, from week 1 to week 4, mean pH reduced by 0.63 units from 8.34 to 7.71. Furthermore, there was a mean 3% reduction in wound temperature and a mean 62% reduction in wound size.

CONCLUSION

The study demonstrated that a reduction in pH and temperature was associated with increased wound healing as evidenced by a corresponding reduction in wound size. Thus, measuring pH and temperature in clinical practice may provide clinically meaningful data pertaining to wound status.

Chronic wounds treated with cold atmospheric plasmajet versus best practice wound dressings: a multicenter, randomized, non-inferiority trial

The use of phase-adapted wound dressings represents best practice (BP) in chronic wound treatment. However, efficacy is often limited and associated care requirements are high. Cold atmospheric plasmajet (CAP-jet) is a promising new therapeutic tool for these wounds. In the present multicenter, randomized, open-label, prospective, clinical trial, non-inferiority of the CAP-jet versus BP was assessed in 78 patients with infected or non-infected chronic wounds of different etiology. Primary outcome measure was the sum of granulation tissue, furthermore wound area reduction, healing rate, time to complete healing, changes in wound pH value, infection score, exudate level and local tolerability were assessed. In CAP-jet treated wounds compared to control, the sum of granulation tissue was significantly higher (p < 0.0001) and wound area reduced significantly faster (p < 0.001). Furthermore, wound pH value decreased significantly faster (p = 0.0123) and local infection was overcome more rapidly by CAP-jet therapy. In 58.97% CAP-jet- vs. 5.13% BP-treated patients, complete healing of chronic ulcers was documented after 6 weeks. Treatment with CAP-jet appeared not only non-inferior, but even superior to BP in all wound entities analyzed with a favorable tolerability profile. Thus, treatment with the CAP-jet provides beneficial effects in chronic wound treatment regarding promotion of the wound healing process.

The skin microbiome of infected pressure ulcers: A review and implications for health professionals

BACKGROUND

Pressure ulcers (PUs) are injuries resulting from ischaemia caused by prolonged compression or shear forces on the skin, adjacent tissues and bones. Advanced stages of PUs are associated with infectious complications and constitute a major clinical challenge, with high social and economic impacts in health care.

GOALS

This study aims to identify and describe the relationship between PU risk factors, stages and anatomical locations, and the relevance of microbial cohabitation and biofilm growth.

METHODS

The narrative review method to advocating a critical and objective analysis of the current knowledge on the topic was performed. Indexed databases and direct consultation to specialized and high-impact journals on the subject were used to extract relevant information, guided by co-authors. The Medical Subject Headings of pressure ulcer (or injury), biofilms, infection and other analogues terms were used.

RESULTS

Development of PUs and consequent infection depends on several direct and indirect risk factors, including cutaneous/PU microbiome, microclimate and behavioural factors. Infected PUs are polymicrobial and characterized by biofilm-associated infection, phenotypic hypervariability of species and inherent resistance to antimicrobials. The different stages and anatomical locations also play an important role in their colonization. The prevention and monitoring of PUs remain crucial for avoiding the emergence of systemic infections and reducing health care-associated costs, improve the quality of life of patients and reduce the mortality-associated infected PUs.

The impact of topical agents and dressing on pH and temperature on wound healing: A systematic, narrative review

To assess the impact of topical agents and dressings on surface wound pH, temperature, and subsequent wound healing. This was a systematic, narrative review of the literature, following the PRISMA (2020) guidelines. The databases searched were Medline PubMed, Cumulative Index to Nursing and Allied Health Literature (CINAHL), Cochrane Library, Embase, Web of Science, and Scopus. Data synthesis and analysis were conducted using a structured narrative synthesis. The quality of the included clinical studies was appraised using the Evidence-Based Literature (EBL) Critical Appraisal Tool. A total of six clinical studies were assessed as eligible for inclusion, A total of six dressings/topical agents were assessed and the types of wounds included non-healing chronic wounds. Of the studies, five explored pH and one explored temperature. The EBL validity of the clinical studies was low (mean quality score was 51.3%). The five clinical studies that explored pH investigated different dressings and topical agents reporting an associated reduction in pH and improved wound outcomes. One clinical study investigated the impact of topical sodium nitrite on temperature and found that sodium nitrite increased peri-wound skin temperature and improved wound outcomes with a reduction in leg ulcer size. Given the low certainty of the evidence, we cannot confidently recommend the use of any particular topical agent or dressing to manipulate pH, or temperature to improve wound outcomes. Thus, there is a need for further research to develop a greater understanding of this topic. Irish Research Council, Enterprise Partnership Scheme.

Microbiological Status of Venous Leg Ulcers and Its Predictors: A Single-Center Cross-Sectional Study

Venous leg ulcers are frequently colonized by microbes. This can be particularly devastating if the ulcer is infected with alert pathogens, i.e., highly virulent microorganisms with well-developed mechanisms of antibiotic resistance. We analyzed the microbiological status of venous leg ulcers and identified the clinicodemographic predictors of culture-positive ulcers, especially in ulcers with colonization by alert pathogens.

METHODS

This study included 754 patients with chronic venous leg ulcers. Material for microbiological analysis was collected by swabbing only from patients who did not receive any antibiotic treatment.

RESULTS

A total of 636 (84.3%) patients presented with culture-positive ulcers. Alert pathogens, primarily Pseudomonas aeruginosa, were detected in 28.6% of the positive cultures. In a logistic regression model, culture-positive ulcers were predicted independently by age > 65 years, current ulcer duration > 12 months, and ulceration area greater than 8.25 cm². Two of these factors, duration of current ulcer > 12 months and ulceration area > 8.25 cm², were also identified as the independent predictors of colonization by alert pathogens.

CONCLUSIONS

Colonization/infection is particularly likely in older persons with chronic and/or large ulcers. Concomitant atherosclerosis was an independent predictor of culture-negative ulcers.

Oxygen, pH, Lactate, and Metabolism-How Old Knowledge and New Insights Might Be Combined for New Wound Treatment

Over time, we have come to recognize a very complex network of physiological changes enabling wound healing. An immunological process enables the body to distinguish damaged cells and begin a cleaning mechanism by separating damaged proteins and cells with matrix metalloproteinases, a complement reaction, and free radicals. A wide variety of cell functions help to rebuild new tissue, dependent on energy provision and oxygen supply. Like in an optimized “bio-reactor,” disturbance can lead to prolonged healing. One of the earliest investigated local factors is the pH of wounds, studied in close relation to the local perfusion, oxygen tension, and lactate concentration. Granulation tissue with the wrong pH can hinder fibroblast and keratinocyte division and proliferation, as well as skin graft takes. Methods for influencing the pH have been tested, such as occlusion and acidification by the topical application of acidic media. In most trials, this has not changed the wound’s pH to an acidic one, but it has reduced the strong alkalinity of deeper or chronic wounds. Energy provision is essential for all repair processes. New insights into the metabolism of cells have changed the definition of lactate from a waste product to an indispensable energy provider in normoxic and hypoxic conditions. Neovascularization depends on oxygen provision and lactate, signaling hypoxic conditions even under normoxic conditions. An appropriate pH is necessary for successful skin grafting; hypoxia can change the pH of wounds. This review describes the close interconnections between the local lactate levels, metabolism, healing mechanisms, and pH. Furthermore, it analyzes and evaluates the different possible ways to support metabolism, such as lactate enhancement and pH adjustment. The aim of wound treatment must be the optimization of all these components. Therefore, the role of lactate and its influence on wound healing in acute and chronic wounds will be assessed.

Efficacy of an acid-oxidising solution (AOS) against Mycobacterium ulcerans

For the treatment of chronic wounds, acid-oxidizing solutions (AOSs) with broad-spectrum microbicidal activity without disturbing granulation tissue formation have been developed. We found AOSs to efficiently kill Mycobacterium ulcerans, the causative agent of Buruli ulcer, which is able to survive harsh decontamination treatments. Topical AOS treatment of Buruli ulcer lesions may support the recommended antibiotic therapy (oral rifampin and clarithromycin), prevent contamination of the environment by the mycobacteria, and control secondary infections, which are a prevalent wound management problem in resource-poor settings where Buruli ulcer is endemic.

Hard-to-heal ulcers treated with hypochlorous acid oxidising solution and standard of care: a 32-week follow-up

OBJECTIVE

Immediately following a two-year prospective case series in which the wounds of 60 patients with hard-to-heal ulcers were treated with a hypochlorous acid oxidising solution (AOS) in addition to standard of care (SoC) for 70 days (T0-T70), a subset of 31 patients (51.7%) whose wounds had not fully healed by T70 opted to continue with treatment for a further 22 weeks (days T70-T224, a total treatment time of 32 weeks (224 days). The objective was to provide long-term evidence on the clinical performance and safety of AOS when used in association with the usual SoC in patients with stalled, hard-to-heal ulcers of various aetiologies.

METHOD

As per the main study, wounds were formally assessed by the study lead at 28 days (±14 days, depending on patient attendance). Parameters assessed at fortnightly visits included area, depth and duration of ulcer; pain; wound bed preparation (WBP) score; and infection status. Wounds were managed in accordance with the SoC protocol.

RESULTS

By T224, 35.5% (n=11) of wounds healed completely and 83.9% showed some types of improvement. All wounds were free of infection and colonisation, the WBP score improved (100% A1-A2 at T196), and pain scores fell. Use of AOS in combination with several types of dressing (SoC) for such a long period confirmed a good safety profile.

CONCLUSION

This follow-up evaluation, coupled with the primary study, suggests that AOS might represent a valuable therapeutic addition for the management of hard-to-heal ulcers for long periods of treatment.

DECLARATION OF INTEREST

ER worked as a consultant for APR Applied Pharma Research S.A. The authors have no other conflicts of interest.

Wound bed preparation with hypochlorous acid oxidising solution and standard of care: a prospective case series

OBJECTIVE

This prospective case series aims to evaluate the clinical impact of a hypochlorous acid oxidising solution (AOS) in association with usual standard of care (SoC) on wound bed preparation (WBP) in patients with hard-to-heal ulcers of various aetiologies. The AOS (Nexodyn, APR Applied Pharma Research S.A., Switzerland) comprises three main features: highly pure and stabilised hypochlorous acid, acidic pH and high reduction-oxidation potential.

METHOD

Between February 2015 and February 2017, patients who met the inclusion criteria were treated with AOS and usual SoC. Data collection ran for 70 days: T0-T70. A baseline assessment was undertaken at T0; parameters assessed at fortnightly visits included: WBP score, area and depth of ulcer, duration, pain, Bates-Jensen score and infection status.

RESULTS

A total of 60 patients took part in the study. By T70, 68.3% of wounds had healed or improved and a significant wound size reduction of 21% was observed (p<0.001), despite a mean wound duration of 20.6 months. All wounds were free of local infection and cellulitis; 10% were colonised. WBP scores improved, while Bates-Jensen and pain scores fell significantly over time.

CONCLUSION

This evaluation suggests that AOS might represent a valuable therapeutic addition for an optimal WBP in the routine management of hard-to-heal ulcers of different aetiologies.

DECLARATION OF INTEREST

ER worked as a consultant for APR Applied Pharma Research S.A. The authors have no other conflicts of interest.

Management of hard-to-heal leg ulcers with an acid-oxidising solution versus standard of care: the MACAN study

OBJECTIVE

The efficacy of available wound dressings in the treatment of hard-to-heal wounds is limited. A new therapeutic approach using an acid-oxidising solution (AOS) was developed. Its effect on healing progress, tolerability and safety properties were investigated in a clinical study, and compared with standard of care (SOC) wound dressings. The study aimed to demonstrate the non-inferiority of AOS to SOC in terms of wound healing progress.

METHOD

This open-label, randomised controlled trial was conducted at two study centres in Austria with patients with either infected or non-infected hard-to-heal leg ulcers of different aetiology. Patients were treated for six weeks either with AOS or SOC wound dressings. Outcome assessments included the percentage of granulation and re-epithelialisation tissue, wound size reduction, changes in wound pH, infection control and wound pain, local tolerability and adverse events (AEs). Healing time and rate were also assessed.

RESULTS

A total of 50 patients took part. In the AOS group, wounds exhibited higher amounts of granulation and re-epithelialisation tissue, and a faster and more pronounced wound size reduction compared with wounds in the SOC group. In the AOS-treated versus SOC-treated patients, a greater percentage of complete healing of hard-to-heal ulcers was achieved by the end of the study period (32% versus 8%, respectively). Furthermore, the wound pH decreased significantly faster in these wounds (p<0.0001). In all patients with infected leg ulcers, local infection was overcome more rapidly under AOS treatment. In the AOS group, one AE and no serious adverse events (SAEs) were detected versus 24 AEs and two SAEs in the SOC group.

CONCLUSION

In this study, AOS proved to be a highly effective treatment to support wound healing in infected or non-infected hard-to-heal leg ulcers of different aetiology. Efficacy was found to be not only non-inferior but superior to SOC wound dressings. Furthermore, tolerability and safety profiles were favourable for AOS.

Comparison of topical nanocolloidal silver formulation use with eosin 2% solution in management of hard-to-heal ulcers in patients with pemphigus vulgaris

OBJECTIVE

To examine the effect of a nanocolloidal silver-based gel called SilvoGel (ChitoTech, Iran) versus eosin (prepared by Razi Hospital, Iran) among patients with immunobullous disease.

METHOD

This blind, randomised controlled study was carried out on patients with pemphigus vulgaris who had hard-to-heal ulcers, divided into two equal-sized groups: one treatment group receiving the nanocolloidal silver-based gel and the control group receiving the conventional eosin.

RESULTS

A total of 32 patients participated in the study. In both the treatment and control groups, ulcer area, exudate and tissue type improved significantly (p<0.001 for all measures). A significantly higher rate of improvement in ulcer area was observed in the treatment group compared with the control group (p<0.001). Both patient and physician satisfaction were significantly higher in the treatment group compared with the control group (p=0.003 and p=0.01, respectively).

CONCLUSION

The results of this study indicate that use of the nanocolloidal silver-based gel for treating patients with immunobullous disease including pemphigus could potentially increase the rate and quality of wound healing.

Are Antimicrobial Peptide Dendrimers an Escape from ESKAPE?

Significance: The crisis of antimicrobial resistance (AMR) increases dramatically despite all efforts to use available antibiotics or last resort antimicrobial agents. The spread of the AMR, declared as one of the most important health-related issues, warrants the development of new antimicrobial strategies. Recent Advances: Antimicrobial peptides (AMPs) and AMP dendrimers (AMPDs), as well as polymer dendrimers are relatively new and promising strategies with the potential to overcome drug resistance issues arising in ESKAPE pathogens (Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacter species) colonizing chronic wounds. Critical Issues: AMPs-AMPDs suffer from limited efficacy, short-lasting bioactivity, and concerns of toxicity. To circumvent these drawbacks, their covalent coupling to biopolymers and/or encapsulation into different drug carrier systems is investigated, with a special focus on topical applications. Future Directions: Scientists and the pharmaceutical industry should focus on this challenging subject to either improve the activity of existing antimicrobial agents or find new drug candidates. The focus should be put on the discovery of new drugs or the combination of existing drugs for a better synergy, taking into account all kinds of wounds and existing pathogens, and more specifically on the development of next-generation antimicrobial peptides, encompassing the delivery carrier toward improved pharmacokinetics and efficacy.

Challenges and opportunities of pH in chronic wounds

Regarded as a silent epidemic, chronic wounds are a global public health issue. Wound healing is a complex, synchronized cascade of physiological processes restoring the anatomic and functional integrity of the skin; however, chronic wounds fail to proceed through the wound healing cascade. Wound pH oscillates during wound healing, usually traversing from a neutral pH to an acidic pH, while chronic wounds perpetuate in an elevated alkaline milieu. Although a neglected clinical parameter, pH has implications for relatively all pathologies of wound healing affecting oxygen release, angiogenesis, protease activity, bacterial toxicity and antimicrobial activity. Despite the array of wound healing products currently marketed, understanding the implications of pH on arresting wound healing can stimulate innovation within this vast market.