Disrupting the biofilm matrix improves wound healing outcomes

Local Treatment of Wound Infections: A Review of Clinical Trials from 2013 to 2024

Significance: Management of infection is a critical aspect of wound care. It involves the application of various interventions to treat the wound and prevent the infection from spreading to other parts of the body, which may lead to serious complications, including sepsis. Local treatment of skin wound infections is the favored route of administration, reducing the risk of adverse systemic effects while providing very high therapeutic concentrations at the target site. The purpose of this article was to review clinical trials from 2013 and onward, focusing on local treatment of acute wounds and burns as well as chronic wounds as their primary outcome measurement. Recent Advances: Based on our literature search, 49 clinical trials were focusing on treating infected chronic wounds, and 6 trials studied infection as their primary outcome in acute wounds during the last 10 years. Critical Issues: Currently commercially available local treatments do not prevent the onset of invasive infection. Therefore, there is a need for more effective local therapies. Future Directions: Despite multiple preclinical studies introducing novel and promising strategies in terms of novel antimicrobial agents and delivery methods to prevent and treat skin wound infections locally, many have yet to be tested in a clinical setting. These preclinically tested approaches could still be valuable additions to today's care of infected skin wounds.

A comprehensive review of the application of 3D-bioprinting in chronic wound management

INTRODUCTION

Chronic wounds require more sophisticated care than standard wound care because they are becoming more severe as a result of diseases like diabetes. By resolving shortcomings in existing methods, 3D-bioprinting offers a viable path toward personalized, mechanically strong, and cell-stimulating wound dressings.

AREAS COVERED

This review highlights the drawbacks of traditional approaches while navigating the difficulties of managing chronic wounds. The conversation revolves around employing natural biomaterials for customized dressings, with a particular emphasis on 3D-bioprinting. A thorough understanding of the uses of 3D-printed dressings in a range of chronic wound scenarios is provided by insights into recent research and patents.

EXPERT OPINION

The expert view recognizes wounds as a historical human ailment and emphasizes the growing difficulties and expenses related to wound treatment. The expert acknowledges that 3D printing is revolutionary, but also points out that it is still in its infancy and has the potential to enhance mass production rather than replace it. The review highlights the benefits of 3D printing for wound dressings by providing instances of smart materials that improve treatment results by stimulating angiogenesis, reducing pain, and targeting particular enzymes. The expert advises taking action to convert the technology's prospective advantages into real benefits for patients, even in the face of resistance to change in the healthcare industry. It is believed that the increasing evidence from in-vivo studies is promising and represents a positive change in the treatment of chronic wounds toward sophisticated 3D-printed dressings.

Interactions between Helcococcus kunzii and Staphylococcus aureus: How a commensal bacterium modulates the virulence and metabolism of a pathogen in a chronic wound in vitro model

BACKGROUND

Staphylococcus aureus is the predominant pathogen isolated in diabetic foot infections. Recently, the skin commensal bacterium, Helcococcus kunzii, was found to modulate the virulence of this pathogen in an in vivo model. This study aims to elucidate the molecular mechanisms underlying the interaction between these two bacterial species, using a proteomic approach.

RESULTS

Our results reveal that H. kunzii can coexist and proliferate alongside S. aureus in a Chronic Wound Media (CWM), thereby mimicking an in vitro chronic wound environment. We noted that the secreted proteome of H. kunzii induced a transcriptional effect on S. aureus virulence, resulting in a decrease in the expression level of agrA, a gene involved in quorum sensing. The observed effect could be ascribed to specific proteins secreted by H. kunzii including polysaccharide deacetylase, peptidoglycan DD-metalloendopeptidase, glyceraldehyde-3-phosphate dehydrogenase, trypsin-like peptidase, and an extracellular solute-binding protein. These proteins potentially interact with the agr system, influencing S. aureus virulence. Additionally, the virulence of S. aureus was notably affected by modifications in iron-related pathways and components of cell wall architecture in the presence of H. kunzii. Furthermore, the overall metabolism of S. aureus was reduced when cocultured with H. kunzii.

CONCLUSION

Future research will focus on elucidating the role of these excreted factors in modulating virulence.

The influence of maggot debridement therapy on the bacterial flora of hard-to-heal wounds

OBJECTIVE

Maggot debridement therapy (MDT) is increasingly being used in clinical practice as an alternative treatment for hard-to-heal (chronic) wounds. Among the many benefits of using MDT is its antimicrobial effect. Maggots secrete substances that are known to have antibacterial properties against both Gram-negative and Gram-positive bacteria. Clinically, this results in the effective eradication of pathogenic species and consequently, a faster healing process. The aim of this study was to evaluate the effect MDT has on the bacterial flora of hard-to-heal ulcers.

METHOD

Patients with venous, mixed arteriovenous, decubitus, diabetic and neuropathic wounds were treated with larvae of Lucilia sericata enclosed in bags. Dressings were applied to the wounds for 72 hours. Before and after the therapy, a swab was taken from the wound, and bacterial diversity and bacterial growth scores were assessed. While 16 patients were treated only once, the treatment had to be repeated in four cases until the wounds were fully debrided.

RESULTS

Bacteria of the species Pseudomonas aeruginosa, Proteus mirabilis, Staphylococcus aureus and Enterococcus faecalis were the most common strains observed. Of the 20 patients treated, the total number of bacterial strains decreased in eight wounds, but increased in five wounds, while no difference was observed in nine wounds. The average number of bacterial strains in wounds decreased after MDT. A lower incidence of alarm pathogens was also reported. In cases where multiple applications of larvae were administered, greater decreases in bacterial growth scores were observed than in cases with a single application of dressing (37.5% vs 18.1%, respectively). In 18 cases, after disinfection of the wound by larvae, it was reinfected by strains not detected before. Wounds healed completely after MDT in two patients.

CONCLUSION

In this study, MDT changed the bacterial diversity of hard-to-heal wounds. The larvae reduced overall bacterial growth scores and acted on both Gram-positive and Gram-negative bacteria as well as on alarm pathogens. Cleaned wounds appeared to become vulnerable to infection by opportunistic bacteria. The bacterial burden decreased as the number of applications of biological dressings increased.

Acquisition of Resistance to PEGylated Branched Polyethylenimine Increases Pseudomonas Aeruginosa Susceptibility to Aminoglycosides

PEGylated branched polyethylenimine (PEG-BPEI) has antibacterial and antibiofilm properties. Exposure to PEG-BPEI through serial passage leads to resistant P. aeruginosa strains. The minimum inhibitory concentration (MIC) of 600 Da BPEI and PEGylated 600 Da BPEI (PEG-BPEI) in the wild-type PAO1 strain is 16 μg/ml while, after 15 serial passages, the MIC increased to 1024 μg/mL. An additional 15 rounds of serial passage in the absence of BPEI or PEG-BPEI did not change the 1024 μg/mL MIC. Gentamicin, Neomycin, and Tobramycin, cationic antibiotics that inhibit protein synthesis, have a 16-32 fold reduction of MIC values in PEG350-BPEI resistant strains, suggesting increased permeation. The influx of these antibiotics occurs using a self-mediated uptake mechanism, suggesting changes to the outer membrane Data show that resistance causes changes in genes related to outer membrane lipopolysaccharide (LPS) assembly. Mutations were noted in the gene coding for the polymerase Wzy that participates in the assembly of the O-antigen region. Other mutations were noted with wbpE and wbpI of the Wbp pathway responsible for the enzymatic synthesis of ManNAc(3NAc)A in the LPS of P. aeruginosa. These changes suggest that an altered gene product could lead to PEG-BPEI resistance. Nevertheless, the increased susceptibility to aminoglycosides could prevent the emergence of PEG-BPEI resistant bacterial populations.

Exploring Thermal Dynamics in Wound Healing: The Impact of Temperature and Microenvironment

Exploring the critical role of thermal dynamics in wound healing, this manuscript navigates through the complex biological responses initiated upon wound infliction and how temperature variations influence the healing trajectory. Integrating biothermal physics, clinical medicine, and biomedical engineering, it highlights the significance of thermal management in wound care, emphasizing the wound microenvironment's division into internal and external domains and their collaborative impact on tissue repair. Innovations in real-time wound temperature monitoring, especially through intelligent wireless sensor dressings, are spotlighted as transformative, enabling precise wound condition management. The text underscores the necessity for further research to elucidate thermal regulation's molecular and cellular mechanisms on healing processes. It advocates for standardized protocols for localized heating treatments, integrating them into personalized wound care strategies to enhance therapeutic outcomes, improve patient well-being, and achieve cost-effective healthcare practices. This work presents a forward-looking perspective on refining wound management through sophisticated, evidence-based interventions, emphasizing the interplay between thermal dynamics and wound healing.

A Diagnostic-Driven Prospective Clinical Study Evaluating the Combination of an Antibiofilm Agent and Negative Pressure Wound Therapy

BACKGROUND

Each year, millions of Americans develop truncal pressure ulcers (PUs) which can persist for months, years, or until the end of life. Despite the negative impact on quality of life and escalating costs associated with PUs, there is sparse evidence supporting validated and efficacious treatment options. As a result, treatment is based on opinion and extrapolation from other wound etiologies. The ideal reconstructive plan maximizes the patient's nutritional status, incorporates the basic tenets of wound bed preparation (debridement, offloading, proper moisture balance, reduction of bacterial burden), and employs diagnostics to guide therapeutic intervention. The use of combination therapies can potentially overcome several of the barriers to wound healing. Negative pressure wound therapy (NPWT), a commonly used modality in the management of PUs, facilitates healing by stimulating the formation of granulation tissue and promoting wound contraction; however, NPWT alone is not always effective. Clinical studies examining microbial bioburden in PUs determined that most ulcers contain bacteria at levels that impede wound healing (>104 CFU/g).

OBJECTIVE

Thus, we hypothesized that adding an anti-microbial agent to decrease both planktonic and biofilm bacteria in the wound would increase the efficacy of NPWT.

METHOD

In this prospective study, twenty patients with recalcitrant PUs that previously failed NPWT were treated with a biofilm-disrupting agent (Blast-X, Next Science, Jacksonville, FL, USA) in combination with NPWT. Fluorescence imaging was used to follow bacterial burden and guide therapy.

RESULTS

In total, 45% of the PUs reduced in size over the course of the four-week study, with a resolution of bacterial fluorescence in the NPWT dressing and wound bed seen in an average of three weeks.

CONCLUSION

The combination of an antibiofilm agent and NPWT reduced bacterial levels and improved wound healing in recalcitrant PUs.

A double-blind trial comparing an antimicrobial combination to standard care in hard-to-heal wounds

OBJECTIVE

Excessive numbers of bacteria in hard-to-heal wounds impede wound healing. Numerous topical antiseptics have demonstrated effectiveness in benchtop studies; however, few clinical studies have demonstrated efficacy in the target population: patients with hard-to-heal wounds. This study addressed the clinical efficacy of a novel antibiofilm cleanser and gel in reducing bacterial load and improving wound outcomes.

METHOD

Hard-to-heal wounds were photographed, measured and evaluated for bacterial load using fluorescence imaging weekly for four weeks. The target ulcers were randomised to be cleaned and treated with either a synergistic antibiofilm cleanser and antibiofilm gel with standard of care (AMC-AMG + SoC) or normal saline wash and an amorphous gel with standard of care (NSS-HG + SoC).

RESULTS

A Chi-squared test of independence determined that the relationship between the treatment and the patient reaching 40% percentage area reduction (PAR) in four weeks was not significant (χ2(1, n=54)=0.73; p=0.39 at a significance level of 0.05); however, there was a strong trend favouring the antibiofilm cleanser and gel. A significant reduction (p<0.05) in bacterial load was observed in the antibiofilm group.

CONCLUSION

This randomised controlled double-blind proof-of-concept study suggests that the performance of antibiofilm agents in vivo is comparable to that in vitro studies.

Advancements in Managing Wound Biofilm: A Systematic Review and Meta-analysis of Randomized Controlled Trials on Topical Modalities

Despite numerous available agents claiming anti-biofilm properties on wounds, the substantiating evidence remains inconclusive. This study aimed to assess the immediate impact of topical wound treatments on wound biofilm and healing outcomes in acute and chronic ulcers. We comprehensively searched PubMed, ClinicalTrials.gov, and Google Scholar. In addition, eligible gray literature was incorporated. English-language randomized controlled trials (RCTs), observational, cohort, and case-control studies targeting biofilm prevention, inhibition, or elimination across diverse wound types were included. Primary outcomes included biofilm presence and elimination, supplemented by secondary outcomes encompassing reduced wound size, complete closure, and diminished infection indicators. Bacterial load reduction and biofilm presence were also assessed. Twenty-eight articles met the inclusion criteria. Various modalities were identified, including biofilm-visualization techniques, such as wound blotting and handheld autofluorescence imaging. Pooled analysis for the primary outcomes was infeasible due to limited eligible studies and data-reporting challenges. As for the secondary outcomes, the pooled analysis for complete surgical wound closure (2 RCTs, yielding n=284) and presence of surgical site infections/inflammation (2 RCTs, yielding n=284) showed no significant difference, with a log odds ratio (LOD) of 0.58 (95% confidence interval [CI]: -.33, 1.50) and LOD -0.95 (95% CI: -3.54, 1.64; τ2 = 2.32, Q = 2.71, P = .10), respectively. Our findings suggest insufficient evidence to support anti-biofilm claims of topical modalities. Clinicians' skill appears to play a pivotal role in biofilm elimination and wound healing enhancement, with potential optimization through visual-guided techniques, such as wound blotting and autofluorescence imaging. More rigorous clinical trials are warranted to ascertain the efficacy of these techniques.Level of Evidence: Therapeutic, 1A.

Efficacy of biofilm disrupters against Candida auris and other Candida species in monomicrobial and polymicrobial biofilms

Candida species are now considered global threats by the CDC and WHO. Candida auris specifically is on the critical pathogen threat list along with Candida albicans. In addition, it is not uncommon to find Candida spp. in a mixed culture with bacterial organisms, especially Staphylococcus aureus producing polymicrobial infections. To eradicate these organisms from the environment and from patient surfaces, surface agents such as chlorhexidine (CHD) and Puracyn are used. Biofilm disrupters (BDs) are novel agents with a broad spectrum of antimicrobial activity and have been used in the management of chronic wounds and to sterilise environmental surfaces for the past several years. The goal of this study was to evaluate BDs (BlastX, Torrent, NSSD) and CHD against Candida spp. and S. aureus using zone of inhibition assays, biofilm and time-kill assays. All BDs and CHD inhibited C. auris growth effectively in a concentration-dependent manner. Additionally, CHD and the BDs showed excellent antimicrobial activity within polymicrobial biofilms. A comparative analysis of the BDs and CHD against C. auris and C. albicans using biofilm kill-curves showed at least 99.999% killing. All three BDs and CHD have excellent activity against different Candida species, including C. auris. However, one isolate of C. auris in a polymicrobial biofilm assay showed resistance/tolerance to CHD, but not to the BDs. The fungicidal activity of these novel agents will be valuable in eradicating surface colonisation of Candida spp, especially C. auris from colonised environmental surfaces and from wounds in colonised patients.

The effect of Staphylococcus aureus on innate and adaptive immunity and potential immunotherapy for S. aureus-induced osteomyelitis

Osteomyelitis is a chronic inflammatory bone disease caused by infection of open fractures or post-operative implants. Particularly in patients with open fractures, the risk of osteomyelitis is greatly increased as the soft tissue damage and bacterial infection are often more severe. Staphylococcus aureus, one of the most common pathogens of osteomyelitis, disrupts the immune response through multiple mechanisms, such as biofilm formation, virulence factor secretion, and metabolic pattern alteration, which attenuates the effectiveness of antibiotics and surgical debridement toward osteomyelitis. In osteomyelitis, immune cells such as neutrophils, macrophages and T cells are activated in response to pathogenic bacteria invasion with excessive inflammatory factor secretion, immune checkpoint overexpression, and downregulation of immune pathway transcription factors, which enhances osteoclastogenesis and results in bone destruction. Therefore, the study of the mechanisms of abnormal immunity will be a new breakthrough in the treatment of osteomyelitis.

Emerging Treatments and the Clinical Trial Landscape for Hidradenitis Suppurativa-Part II: Procedural and Wound Care Therapies

Procedural treatments are a cornerstone of hidradenitis suppurativa (HS) management. New interventional therapies are being studied as part of the upsurge in HS research and clinical trials. Additionally, draining wounds can impart a significant negative impact on patients' quality of life, requiring daily dressing changes. However, standardized guidelines on how to best manage HS wounds both day-to-day and post-procedure are lacking. In part II of this emerging therapies review, procedural treatments and wound care dressings and devices that are being investigated for HS management are discussed.

Diabetic foot ulcers: weekly versus second-weekly conservative sharp wound debridement

Diabetic foot ulcers (DFU) are a serious and costly long-term complication of diabetes, and are one of the most prevalent hard-to-heal (chronic) wound types. Conservative sharp wound debridement (CSWD) is a mainstay of care. It is performed regularly until healing is achieved (when there is adequate blood flow for healing) to support endogenous healing and improve the efficacy of advanced healing therapies. CSWD is supported by evidence-based treatment guidelines, despite a lack of prospective studies. The first prospective randomised study to compare different frequencies of CSWD-the Diabetes Debridement Study (DDS)-showed no difference in healing outcomes at 12 weeks between those ulcers debrided weekly and those debrided every second week. A DFU may require more or less frequent debridement according to individual wound characteristics; however, the new data from DDS can inform clinical decisions and service provision. The implications of weekly versus second-weekly debridement are discussed.

Superficial Surgical Site Infections in Primary Total Joint Arthroplasty: A Retrospective Analysis of Topical Anti-Biofilm Therapy

Introduction Surgical site infections (SSI) following orthopedic procedures can cause significant morbidity and mortality, particularly in total joint arthroplasty. Biofilm formation in surgical wounds has made it difficult to prevent and treat these infections. SURGX® Antimicrobial Wound Gel (Next Science, Jacksonville, Florida, USA) was developed to disrupt biofilm formation but has not been evaluated in prophylactic use in total joint arthroplasty to prevent superficial SSI. Methods A retrospective chart review was performed at a single institution comparing the rate of SSI in patients undergoing primary total hip arthroplasty (THA) and total knee arthroplasty (TKA). SSI data were collected from patients with standard postoperative dressings (Group A: Control) and patients with SURGX® applied as part of a standardized dressing following THA/TKA (Group B: Study). Rates of SSI were compared.  Results SURGX® was administered to 120 patients, including 91 TKAs and 29 THAs. The overall infection rate in this cohort was 2.5%. No superficial site infections developed. The control group constituted 566 patients, with 386 TKAs and 180 THAs. The infection rate was 1.24%, which included one superficial infection. Binary logistic regression did not show different odds of developing infections with the use of SURGX® (OR = 2.23, 95% CI: 0.54-9.13, p = 0.27). Conclusion In our small retrospective study, Next Science SURGX® Antimicrobial Wound Gel did not demonstrate a statistically significant difference in the rate of superficial SSI in total joint arthroplasty; however, Group B did not have any superficial SSI.

Biofilm and wound healing: from bench to bedside

The bubbling community of microorganisms, consisting of diverse colonies encased in a self-produced protective matrix and playing an essential role in the persistence of infection and antimicrobial resistance, is often referred to as a biofilm. Although apparently indolent, the biofilm involves not only inanimate surfaces but also living tissue, making it truly ubiquitous. The mechanism of biofilm formation, its growth, and the development of resistance are ever-intriguing subjects and are yet to be completely deciphered. Although an abundance of studies in recent years has focused on the various ways to create potential anti-biofilm and antimicrobial therapeutics, a dearth of a clear standard of clinical practice remains, and therefore, there is essentially a need for translating laboratory research to novel bedside anti-biofilm strategies that can provide a better clinical outcome. Of significance, biofilm is responsible for faulty wound healing and wound chronicity. The experimental studies report the prevalence of biofilm in chronic wounds anywhere between 20 and 100%, which makes it a topic of significant concern in wound healing. The ongoing scientific endeavor to comprehensively understand the mechanism of biofilm interaction with wounds and generate standardized anti-biofilm measures which are reproducible in the clinical setting is the challenge of the hour. In this context of "more needs to be done", we aim to explore various effective and clinically meaningful methods currently available for biofilm management and how these tools can be translated into safe clinical practice.

Defensins of Lucilia sericata Larvae and Their Influence on Wound Repair Processes in Practical Assessment-A Study of Three Cases

Bacteria inhabiting chronic wounds form a biofilm that prolongs and slows down the healing process. Increasingly common antibiotic resistance requires clinicians to search for effective and alternative treatment methods. Defensins are the most common antimicrobial peptides capable of eradicating pathogens. Their discovery in maggot secretions allowed for a broader understanding of the healing mechanisms, and approving the use of Lucilia sericata fly larvae in the treatment of infected wounds resulted in an effective and safe procedure. The aim of the study was to present the possibility of biofilm elimination in a chronic wound by means of medical maggots (Lucilia sericata) with the example of three selected clinical cases. The observation included three women who met the inclusion criterion of having venous insufficiency ulcers with inhibited regeneration processes. Medical maggots were applied in a biobag for three days, and observation was conducted for 21 consecutive days. In 2 cases, a significant elimination of necrotic tissue from the wound bed with local granulation tissue was observed 72 h after application of a larvae colony on the wounds. In 1 case, the application of the larvae accelerated the repair process by reducing the wound area by approximately 40% at the time of observation. The formation of biofilm in a chronic wound is one of the main causes of disturbances in its effective healing. Combining procedures (scraping, antiseptic compresses, MDT, NPWT) related to wound debridement increases the effectiveness of biofilm elimination. The use of medical maggots is a safe and effective method of choice, and it enhances the processes of debridement. However, confirmed indisputable data on their effectiveness and frequency of use in the process of stimulating healing processes are still not available in the literature.

Colonizing microbiota is associated with clinical outcomes in diabetic wound healing

With the development of society and the improvement of life quality, more than 500 million people are affected by diabetes. More than 10 % of people with diabetes will suffer from diabetic wounds, and 80 % of diabetic wounds will reoccur, so the development of new diabetic wound treatments is of great importance. The development of skin microbe research technology has gradually drawn people's attention to the complex relationship between microbes and diabetic wounds. Many studies have shown that skin microbes are associated with the outcome of diabetic wounds and can even be used as one of the indicators of wound prognosis. Skin microbes have also been found to have the potential to treat diabetic wounds. The wound colonization of different bacteria can exert opposing therapeutic effects. It is necessary to fully understand the skin microbes in diabetic wounds, which can provide valuable guidance for clinical diabetic wound treatment.

Larval Therapy and Larval Excretions/Secretions: A Potential Treatment for Biofilm in Chronic Wounds? A Systematic Review

Chronic wounds present a global healthcare challenge and are increasing in prevalence, with bacterial biofilms being the primary roadblock to healing in most cases. A systematic review of the to-date knowledge on larval therapy's interaction with chronic-wound biofilm is presented here. The findings detail how larval therapy-the controlled application of necrophagous blowfly larvae-acts on biofilms produced by chronic-wound-relevant bacteria through their principle pharmacological mode of action: the secretion and excretion of biologically active substances into the wound bed. A total of 12 inclusion-criteria-meeting publications were identified following the application of a PRISMA-guided methodology for a systematic review. The findings of these publications were qualitatively analyzed to provide a summary of the prevailing understanding of larval therapy's effects on bacterial biofilm. A further review assessed the quality of the existing evidence to identify knowledge gaps and suggest ways these may be bridged. In summary, larval therapy has a seemingly unarguable ability to inhibit and degrade bacterial biofilms associated with impaired wound healing. However, further research is needed to clarify and standardize the methodological approach in this area of investigation. Such research may lead to the clinical application of larval therapy or derivative treatments for the management of chronic-wound biofilms and improve patient healing outcomes at a time when alternative therapies are desperately needed.

Bacterial Interactions in the Context of Chronic Wound Biofilm: A Review

Chronic wounds, defined by their resistance to care after four weeks, are a major concern, affecting millions of patients every year. They can be divided into three types of lesions: diabetic foot ulcers (DFU), pressure ulcers (PU), and venous/arterial ulcers. Once established, the classical treatment for chronic wounds includes tissue debridement at regular intervals to decrease biofilm mass constituted by microorganisms physiologically colonizing the wound. This particular niche hosts a dynamic bacterial population constituting the bed of interaction between the various microorganisms. The temporal reshuffle of biofilm relies on an organized architecture. Microbial community turnover is mainly associated with debridement (allowing transitioning from one major representant to another), but also with microbial competition and/or collaboration within wounds. This complex network of species and interactions has the potential, through diversity in antagonist and/or synergistic crosstalk, to accelerate, delay, or worsen wound healing. Understanding these interactions between microorganisms encountered in this clinical situation is essential to improve the management of chronic wounds.

An Overview of Diabetic Foot Ulcers and Associated Problems with Special Emphasis on Treatments with Antimicrobials

One of the most significant challenges of diabetes health care is diabetic foot ulcers (DFU). DFUs are more challenging to cure, and this is particularly true for people who already have a compromised immune system. Pathogenic bacteria and fungi are becoming more resistant to antibiotics, so they may be unable to fight microbial infections at the wound site with the antibiotics we have now. This article discusses the dressings, topical antibacterial treatment, medications and debridement techniques used for DFU and provides a deep discussion of DFU and its associated problems. English-language publications on DFU were gathered from many different databases, such as Scopus, Web of Science, Science Direct, Springer Nature, and Google Scholar. For the treatment of DFU, a multidisciplinary approach involving the use of diagnostic equipment, skills, and experience is required. Preventing amputations starts with patient education and the implementation of new categorization systems. The microbiota involved in DFU can be better understood using novel diagnostic techniques, such as the 16S-ribosomal DNA sequence in bacteria. This could be achieved by using new biological and molecular treatments that have been shown to help prevent infections, to control local inflammation, and to improve the healing process.

Advanced Wound Diagnostics: Toward Transforming Wound Care into Precision Medicine

Significance: Nonhealing wounds are an ever-growing global pandemic, with mortality rates and management costs exceeding many common cancers. Although our understanding of the molecular and cellular factors driving wound healing continues to grow, standards for diagnosing and evaluating wounds remain largely subjective and experiential, whereas therapeutic strategies fail to consistently achieve closure and clinicians are challenged to deliver individualized care protocols. There is a need to apply precision medicine practices to wound care by developing evidence-based approaches, which are predictive, prescriptive, and personalized. Recent Advances: Recent developments in "advanced" wound diagnostics, namely biomarkers (proteases, acute phase reactants, volatile emissions, and more) and imaging systems (ultrasound, autofluorescence, spectral imaging, and optical coherence tomography), have begun to revolutionize our understanding of the molecular wound landscape and usher in a modern age of therapeutic strategies. Herein, biomarkers and imaging systems with the greatest evidence to support their potential clinical utility are reviewed. Critical Issues: Although many potential biomarkers have been identified and several imaging systems have been or are being developed, more high-quality randomized controlled trials are necessary to elucidate the currently questionable role that these tools are playing in altering healing dynamics or predicting wound closure within the clinical setting. Future Directions: The literature supports the need for the development of effective point-of-care wound assessment tools, such as a platform diagnostic array that is capable of measuring multiple biomarkers at once. These, along with advances in telemedicine, synthetic biology, and "smart" wearables, will pave the way for the transformation of wound care into a precision medicine. Clinical Trial Registration number: NCT03148977.

Diabetic foot ulcer, antimicrobial remedies and emerging strategies for the treatment

According to the International Diabetes Federation's 2015 study, diabetes affects over 415 million people globally (5 million of whom die each year), and the incidence of diabetes is expected to climb to over 640 million (1 in 10) by 2040. (IDF 2015). Diabetes foot ulcers (DFU) are one of the most significant diabetic health consequences. Antimicrobial treatments, such as dressings, topical therapies, medicines, drugs, debridement procedures, molecular, cellular, and gene therapies, plant extracts, antimicrobial peptides, growth factors, devices, ozone, and energy-based therapies, would be the focus of this study. Scopus, Web of Science, Bentham Science, Science Direct, and Google Scholar were among the sources used to compile the English-language publications on DFU. DFU treatment requires a multidisciplinary approach that includes the use of proper diagnostic tools, competence, and experience. To prevent amputations, this starts with patient education and the use of new categories to steer treatment. New diagnostic methods, such as the 16S ribosomal DNA sequence in bacteria, should become available to acquire a better knowledge of the microbiota in DFUs. 

Novel Diagnostic Technologies and Therapeutic Approaches Targeting Chronic Wound Biofilms and Microbiota

Purpose of Review

To provide an up-to-date overview of recent developments in diagnostic methods and therapeutic approaches for chronic wound biofilms and pathogenic microbiota.

Recent Findings

Biofilm infections are one of the major contributors to impaired wound healing in chronic wounds, including diabetic foot ulcers, venous leg ulcers, pressure ulcers, and nonhealing surgical wounds. As an organized microenvironment commonly including multiple microbial species, biofilms develop and persist through methods that allow evasion from host immune response and antimicrobial treatments. Suppression and reduction of biofilm infection have been demonstrated to improve wound healing outcomes. However, chronic wound biofilms are a challenge to treat due to limited methods for accurate, accessible clinical identification and the biofilm's protective properties against therapeutic agents. Here we review recent approaches towards visual markers for less invasive, enhanced biofilm detection in the clinical setting. We outline progress in wound care treatments including investigation of their antibiofilm effects, such as with hydrosurgical and ultrasound debridement, negative pressure wound therapy with instillation, antimicrobial peptides, nanoparticles and nanocarriers, electroceutical dressings, and phage therapy.

Summary

Current evidence for biofilm-targeted treatments has been primarily conducted in preclinical studies, with limited clinical investigation for many therapies. Improved identification, monitoring, and treatment of biofilms require expansion of point-of-care visualization methods and increased evaluation of antibiofilm therapies in robust clinical trials.

Hydrogen-peroxide generating electrochemical bandage is active in vitro against mono- and dual-species biofilms

Biofilms formed by antibiotic-resistant bacteria in wound beds present unique challenges in terms of treating chronic wound infections; biofilms formed by one or more than one bacterial species are often involved. In this work, the in vitro anti-biofilm activity of a novel electrochemical bandage (e-bandage) composed of carbon fabric and controlled by a wearable potentiostat, designed to continuously deliver low amounts of hydrogen peroxide (H2O2) was evaluated against 34 mono-species and 12 dual-species membrane bacterial biofilms formed by Staphylococcus aureus, S. epidermidis, Enterococcus faecium, E. faecalis, Streptococcus mutans, Escherichia coli, Pseudomonas aeruginosa, Acinetobacter baumannii, Klebsiella pneumoniae, Cutibacterium acnes, and Bacteroides fragilis. Biofilms were grown on polycarbonate membranes placed atop agar plates. An e-bandage, which electrochemically reduces dissolved oxygen to H2O2 when polarized at -0.6 VAg/AgCl, was then placed atop each membrane biofilm and polarized continuously for 12, 24, and 48 h using a wearable potentiostat. Time-dependent decreases in viable CFU counts of all mono- and dual-species biofilms were observed after e-bandage treatment. 48 h of e-bandage treatment resulted in an average reduction of 8.17 ± 0.40 and 7.99 ± 0.32 log10 CFU/cm2 for mono- and dual-species biofilms, respectively. Results suggest that the described H2O2 producing e-bandage can reduce in vitro viable cell counts of biofilms grown either in mono- or dual-species forms, and should be further developed as a potential antibiotic-free treatment strategy for treating chronic wound infections.

New Perspectives on Old and New Therapies of Staphylococcal Skin Infections: The Role of Biofilm Targeting in Wound Healing

Among the most common complications of both chronic wound and surgical sites are staphylococcal skin infections, which slow down the wound healing process due to various virulence factors, including the ability to produce biofilms. Furthermore, staphylococcal skin infections are often caused by methicillin-resistant Staphylococcus aureus (MRSA) and become a therapeutic challenge. The aim of this narrative review is to collect the latest evidence on old and new anti-staphylococcal therapies, assessing their anti-biofilm properties and their effect on skin wound healing. We considered antibiotics, quorum sensing inhibitors, antimicrobial peptides, topical dressings, and antimicrobial photo-dynamic therapy. According to our review of the literature, targeting of biofilm is an important therapeutic choice in acute and chronic infected skin wounds both to overcome antibiotic resistance and to achieve better wound healing.

Detection of bacterial fluorescence from in vivo wound biofilms using a point-of-care fluorescence imaging device

Wound biofilms must be identified to target disruption and bacterial eradication but are challenging to detect with standard clinical assessment. This study tested whether bacterial fluorescence imaging could detect porphyrin-producing bacteria within a biofilm using well-established in vivo models. Mouse wounds were inoculated on Day 0 with planktonic bacteria (n = 39, porphyrin-producing and non-porphyrin-producing species, 107  colony forming units (CFU)/wound) or with polymicrobial biofilms (n = 16, 3 biofilms per mouse, each with 1:1:1 parts Staphylococcus aureus/Escherichia coli/Enterobacter cloacae, 107  CFU/biofilm) that were grown in vitro. Mouse wounds inoculated with biofilm underwent fluorescence imaging up to Day 4 or 5. Wounds were then excised and sent for microbiological analysis. Bacteria-matrix interaction was assessed with scanning electron microscopy (SEM) and histopathology. A total of 48 hours after inoculation with planktonic bacteria or biofilm, red fluorescence was readily detected in wounds; red fluorescence intensified up to Day 4. Red fluorescence from biofilms persisted in excised wound tissue post-wash. SEM and histopathology confirmed bacteria-matrix interaction. This pre-clinical study is the first to demonstrate the fluorescence detection of bacterial biofilm in vivo using a point-of-care wound imaging device. These findings have implications for clinicians targeting biofilm and may facilitate improved visualisation and removal of biofilms.

Evaluation of the combination of a biofilm-disrupting agent and negative pressure wound therapy: a case series

OBJECTIVE

Approximately three million people in the US have hard-to-heal pressure ulcers (PUs), including 10% of hospitalised patients. Healing depends on ulcer stage and patient comorbidities. Despite advances in nutrition and wound care, PUs can take months or years to reach complete closure. To date, clinical studies have focused on single modality therapy. However, there is no one therapy that can address all of the deficits in these complex, hard-to-heal wounds. A commonly used treatment for PUs, negative pressure wound therapy (NPWT), has demonstrated improved healing in Stage 3 and 4 PUs. NPWT entails applying suction to a porous sponge fitted into the wound cavity and sealed with an occlusive dressing. Negative pressure facilitates wound healing by removing wound fluid containing harmful proteases, stimulating the formation of granulation tissue and promoting wound contracture. However, it does not affect biofilm formation. We hypothesised that adding an antibiofilm agent might increase the effectiveness of NPWT in recalcitrant PUs.

METHOD

A prospective case series was conducted in outpatient wound care centres and a skilled nursing facility to examine the combination of a biofilm-disrupting antimicrobial agent (Blast-X, Next Science, US) in combination with NPWT (VAC, 3M, US) in healing and reducing bacterial burden in treatment-resistant pressure ulcers. Patients consented to application of the antibiofilm agent and NPWT three times per week for four weeks. The wounds were measured, imaged for bacteria and tested for host and bacterial protease activity weekly.

RESULTS

Of the 10 patients, four dropped out of the study before the end of the four weeks. Of the remaining six, four patients experienced a reduction in wound surface area and volume, reduced protease activity and lower bacterial levels.

CONCLUSION

The results of this study showed that multimodal therapy, including NPWT and biofilm disruption, may restart the healing of stagnant treatment-resistant PUs.

Dual-Function Potentiation by PEG-BPEI Restores Activity of Carbapenems and Penicillins against Carbapenem-Resistant Enterobacteriaceae

The rise of life-threatening carbapenem-resistant Enterobacteriaceae (CRE) infections has become a critical medical threat. Some of the most dangerous CRE bacteria can produce enzymes that degrade a wide range of antibiotics, including carbapenems and β-lactams. Infections by CRE have a high mortality rate, and survivors can have severe morbidity from treatment with toxic last-resort antibiotics. CRE have mobile genetic elements that transfer resistance genes to other species. These bacteria also circulate throughout the healthcare system. The mobility and spread of CRE need to be curtailed, but these goals are impeded by having few agents that target a limited range of pathogenic CRE species. Against CRE possessing the metallo-β-lactamase NDM-1, Klebsiella pneumoniae ATCC BAA-2146 and Escherichia coli ATCC BAA-2452, the potentiation of meropenem and imipenem is possible with low-molecular weight branched polyethylenimine (600 Da BPEI) and its poly(ethylene glycol) (PEG)ylated derivative (PEG-BPEI) that has a low in vivo toxicity. The mechanism of action is elucidated with fluorescence assays of drug influx and isothermal calorimetry data showing the chelation of essential Zn2+ ions. These results suggested that 600 Da BPEI and PEG-BPEI may also improve the uptake of antibiotics and β-lactamase inhibitors. Indeed, the CRE E. coli strain is rendered susceptible to the combination of piperacillin and tazobactam. These results expand the possible utility of 600 Da BPEI potentiators, where previously we have demonstrated the ability to improve antibiotic efficacy against antibiotic resistant clinical isolates of Pseudomonas aeruginosa, Staphylococcus aureus, and Staphylococcus epidermidis.

A Novel Biofilm-Disrupting Wound Care Technology for the Prevention of Surgical Site Infections Following Total Joint Arthroplasty: A Conceptual Review

Surgical site infections (SSIs) are a major driver for increased costs following lower extremity joint arthroplasty procedures. It has been estimated that these account for over $2 billion in annual costs in the United States. While many of the current strategies for the prevention and treatment of SSIs target planktonic bacteria, 80 to 90% of bacterial pathogens exist in a sessile state. These sessile bacteria can produce extracellular polymeric substance (EPS) as protective barriers from host immune defenses and antimicrobial agents and thus, can be exceedingly difficult to eradicate. A novel wound care gel that disrupts the EPS and destroys the inciting pathogens has been developed for the treatment and prevention of biofilm-related infections. This is achieved by the simultaneous action of four key ingredients: (1) citric acid; (2) sodium citrate; (3) benzalkonium chloride; and (4) polyethylene glycol. Together, these constituents create a high osmolarity, pH-controlled environment that deconstructs and prevents biofilm formation, while destroying pathogens and promoting a moist environment for optimal wound healing. The available clinical evidence demonstrating the efficacy of this technology has been summarized, as well as the economic implications of its implementation and the authors' preferred method of its use. Due to the multifaceted burden associated with biofilm-producing bacteria in arthroplasty patients, this technology may prove to be beneficial for patients who have higher risks for infection, or perhaps, as a prophylactic measure to prevent infections for all patients.

Evidence-Based Review of Antibiofilm Agents for Wound Care

Significance: Biofilms in vivo are small densely packed aggregations of microbes that are highly resistant to host immune responses and treatment. They attach to each other and to nearby surfaces. Biofilms are difficult to study and identify in a clinical setting as their quantification necessitates the use of advanced microscopy techniques such as confocal laser scanning microscopy. Nonetheless, it is likely that biofilms contribute to the pathophysiology of chronic skin wounds. Reducing, removing, or preventing biofilms is thus a logical approach to help clinicians heal chronic wounds. Recent Advances: Wound care products have demonstrated varying degrees of efficacy in destroying biofilms in in vitro and preclinical models, as well as in some clinical studies. Critical Issues: Controlled studies exploring the beneficial role of biofilm eradication and its relationship to healing in patients with chronic wounds are limited. This review aims to discuss the mode of action and clinical significance of currently available antibiofilm products, including surfactants, dressings, and others, with a focus on levels of evidence for efficacy in disrupting biofilms and ability to improve wound healing outcomes. Future Directions: Few available products have good evidence to support antibiofilm activity and wound healing benefits. Novel therapeutic strategies are on the horizon. More high-quality clinical studies are needed. The development of noninvasive techniques to quantify biofilms will facilitate increased ease of research about biofilms in wounds and how to combat them.

PEGylation of Polyethylenimine Lowers Acute Toxicity while Retaining Anti-Biofilm and β-Lactam Potentiation Properties against Antibiotic-Resistant Pathogens

Bacterial biofilms, often impenetrable to antibiotic medications, are a leading cause of poor wound healing. The prognosis is worse for wounds with biofilms of antimicrobial-resistant (AMR) bacteria, such as methicillin-resistant Staphylococcus aureus (MRSA), methicillin-resistant S. epidermidis (MRSE), and multi-drug resistant Pseudomonas aeruginosa (MDR-PA). Resistance hinders initial treatment of standard-of-care antibiotics. The persistence of MRSA, MRSE, and/or MDR-PA often allows acute infections to become chronic wound infections. The water-soluble hydrophilic properties of low-molecular-weight (600 Da) branched polyethylenimine (600 Da BPEI) enable easy drug delivery to directly attack AMR and biofilms in the wound environment as a topical agent for wound treatment. To mitigate toxicity issues, we have modified 600 Da BPEI with polyethylene glycol (PEG) in a straightforward one-step reaction. The PEG-BPEI molecules disable β-lactam resistance in MRSA, MRSE, and MDR-PA while also having the ability to dissolve established biofilms. PEG-BPEI accomplishes these tasks independently, resulting in a multifunction potentiation agent. We envision wound treatment with antibiotics given topically, orally, or intravenously in which external application of PEG-BPEIs disables biofilms and resistance mechanisms. In the absence of a robust pipeline of new drugs, existing drugs and regimens must be re-evaluated as combination(s) with potentiators. The PEGylation of 600 Da BPEI provides new opportunities to meet this goal with a single compound whose multifunction properties are retained while lowering acute toxicity.

Expanding the Spectrum of Antibiotics Capable of Killing Multidrug-Resistant Staphylococcus aureus and Pseudomonas aeruginosa

Infections from antibiotic-resistant Staphylococcus aureus and Pseudomonas aeruginosa are a serious threat because reduced antibiotic efficacy complicates treatment decisions and prolongs the disease state in many patients. To expand the arsenal of treatments against antimicrobial-resistant (AMR) pathogens, 600-Da branched polyethylenimine (BPEI) can overcome antibiotic resistance mechanisms and potentiate β-lactam antibiotics against Gram-positive bacteria. BPEI binds cell-wall teichoic acids and disables resistance factors from penicillin binding proteins PBP2a and PBP4. This study describes a new mechanism of action for BPEI potentiation of antibiotics generally regarded as agents effective against Gram-positive pathogens but not Gram-negative bacteria. 600-Da BPEI is able to reduce the barriers to drug influx and facilitate the uptake of a non-β-lactam co-drug, erythromycin, which targets the intracellular machinery. Also, BPEI can suppress production of the cytokine interleukin IL-8 by human epithelial keratinocytes. This enables BPEI to function as a broad-spectrum antibiotic potentiator, and expands the opportunities to improve drug design, antibiotic development, and therapeutic approaches against pathogenic bacteria, especially for wound care.

Potential for repurposing the personal care product preservatives bronopol and bronidox as broad-spectrum antibiofilm agents for topical application

OBJECTIVES

Bacterial biofilms represent a major impediment to healing in chronic wounds and are largely refractory to the antibacterial agents currently used in wound management. From a repurposing screen of compounds considered safe for topical application in humans, we report the identification of the personal care product preservatives bronopol and bronidox as broad-spectrum antibiofilm agents and potential candidates for reducing biofilm burden in chronic wounds.

METHODS

Antibiofilm activity was assessed by viable counting against single-species biofilms of Staphylococcus aureus and Pseudomonas aeruginosa in the Calgary Biofilm Device, and against mixed-species biofilms of the two organisms growing on nitrocellulose discs.

RESULTS

Bronopol and bronidox exhibited broad-spectrum antibiofilm activity that encompassed the two major wound pathogens, S. aureus and P. aeruginosa. When impregnated into gauze dressings at their existing maximum authorized concentrations for safe use and placed onto an established mixed-species biofilm, bronopol and bronidox completely eradicated P. aeruginosa and achieved an ∼5 log10 reduction in the S. aureus population. The antibiofilm action of bronopol and bronidox was attributed to their ability to kill slow- or non-growing bacteria found in biofilms, and both compounds exhibited synergistic antibiofilm effects in combination with established wound-treatment agents.

CONCLUSIONS

Bronopol and bronidox kill bacteria regardless of growth state, a property that endows them with broad-spectrum antibiofilm activity. As this effect is observed at concentrations authorized for use on human skin, these compounds represent promising candidates for the treatment of chronic wounds.

Staphylococcus aureus Biofilm Infection Compromises Wound Healing by Causing Deficiencies in Granulation Tissue Collagen

OBJECTIVE

The objective of this work was to causatively link biofilm properties of bacterial infection to specific pathogenic mechanisms in wound healing.

BACKGROUND

Staphylococcus aureus is one of the four most prevalent bacterial species identified in chronic wounds. Causatively linking wound pathology to biofilm properties of bacterial infection is challenging. Thus, isogenic mutant stains of S. aureus with varying degree of biofilm formation ability was studied in an established preclinical porcine model of wound biofilm infection.

METHODS

Isogenic mutant strains of S. aureus with varying degree (ΔrexB > USA300 > ΔsarA) of biofilm-forming ability were used to infect full-thickness porcine cutaneous wounds.

RESULTS

Compared with that of ΔsarA infection, wound biofilm burden was significantly higher in response to ΔrexB or USA300 infection. Biofilm infection caused degradation of cutaneous collagen, specifically collagen 1 (Col1), with ΔrexB being most pathogenic in that regard. Biofilm infection of the wound repressed wound-edge miR-143 causing upregulation of its downstream target gene matrix metalloproteinase-2. Pathogenic rise of collagenolytic matrix metalloproteinase-2 in biofilm-infected wound-edge tissue sharply decreased collagen 1/collagen 3 ratio compromising the biomechanical properties of the repaired skin. Tensile strength of the biofilm infected skin was compromised supporting the notion that healed wounds with a history of biofilm infection are likely to recur.

CONCLUSION

This study provides maiden evidence that chronic S. aureus biofilm infection in wounds results in impaired granulation tissue collagen leading to compromised wound tissue biomechanics. Clinically, such compromise in tissue repair is likely to increase wound recidivism.

Traditional and advanced therapeutic modalities for wounds in the paediatric population: an evidence-based review

OBJECTIVE

Children can have non-healing wounds due to a wide range of pathologies, including epidermolysis bullosa (EB), pilonidal disease and Stevens-Johnson syndrome, with some causes being iatrogenic, including extravasation injuries and medical device-related hospital-acquired pressure ulcers. Furthermore, paediatric wounds are vastly different from adult wounds and therefore require a different treatment approach. While there are numerous types of dressings, topical remedies, and matrices with high-tier evidence to support their use in adults, evidence is scarce in the neonatal and paediatric age groups. The purpose of this review is to discuss the basic principles in paediatric wound management, as well as to present new treatment findings published in the literature to date. The benefits and risks of using different types of debridement are discussed in this review. Various topical formulations are also described, including the need to use antibiotics judiciously.

METHOD

Databases were searched for relevant sources including Pubmed, Embase, Web of Science and DynaMed. Search terms used included 'wound care', 'wound management', 'paediatrics', 'children', 'skin substitutes', and 'grafts'. Additionally, each treatment and disease entity was searched for relevant sources, including, for example: 'Apligraf', 'dermagraft', 'Manuka honey', 'antibiotic', 'timolol', and 'negative pressure wound therapy' (NPWT).

RESULTS

Amniotic membrane living skin equivalent is a cellular matrix that has been reportedly successful in treating paediatrics wounds and is currently under investigation in randomised clinical trials. Helicoll is an acellular matrix, which shows promise in children with recessive dystrophic EB. NPWT may be used as a tool to accelerate wound closure in children; however, caution must be taken due to limited evidence to support its safety and efficacy in the paediatric patient population. Integra has been reported as a useful adjunctive treatment to NPWT as both may act synergistically. Hospitalised children and neonates frequently have pressure ulcers, which is why prevention in this type of wound is paramount.

CONCLUSION

Advancements in wound care are rapidly expanding. Various treatments for non-healing wounds in paediatric and neonatal patients have been reported, but high tier evidence in these populations is scarce. We hope to shed light on existing evidence regarding the different therapeutic modalities, from debridement techniques and dressing types to tissue substitutes and topical remedies. There have been promising results in many studies to date, but RCTs involving larger sample sizes are necessary, in order to determine the specific role these innovative agents play in paediatric wounds and to identify true safety and efficacy.

Overcoming Multidrug Resistance and Biofilms of Pseudomonas aeruginosa with a Single Dual-Function Potentiator of β-Lactams

Clinicians prescribe hundreds of millions of β-lactam antibiotics to treat the majority of patients presenting with bacterial infections. Patient outcomes are positive unless resistant bacteria, such as Pseudomonas aeruginosa (P. aeruginosa), are present. P. aeruginosa has both intrinsic and acquired antibiotic resistance, making clinical management of infection a real challenge, particularly when these bacteria are sequestered in biofilms. These problems would be alleviated if, upon the initial presentation of bacterial infection symptoms, clinicians were able to administer an antibiotic that kills both susceptible and otherwise resistant bacteria and eradicates biofilms. As the most common class of antibiotics, β-lactams could be used in a new drug if the leading causes of β-lactam antibiotic resistance, permeation barriers from lipopolysaccharide, efflux pumps, and β-lactamase enzymes, were also defeated. Against P. aeruginosa and their biofilms, the potency of β-lactam antibiotics is restored with 600 Da branched polyethylenimine (600 Da BPEI). Checkerboard assays using microtiter plates demonstrate the potentiation of piperacillin, cefepime, Meropenem, and erythromycin antibiotics. Growth curves demonstrate that only a combination of 600 Da BPEI and piperacillin produces growth inhibition against antibiotic resistant P. aeruginosa. Scanning electron microscopy (SEM) was used to confirm that the combination treatment leads to abnormal P. aeruginosa morphology. Data collected with isothermal titration calorimetry and fluorescence spectroscopy demonstrate a mechanism of action in which potentiation at low concentrations of 600 Da BPEI reduces diffusion barriers from lipopolysaccharides without disrupting the outer membrane itself. Coupled with the ability to overcome a reduction in antibiotic activity created by biofilm exopolymers, targeting anionic sites on lipopolysaccharides and biofilm exopolysaccharides with the same compound provides new opportunities to counter the rise of multidrug-resistant infections.

Electric Field Based Dressing Disrupts Mixed-Species Bacterial Biofilm Infection and Restores Functional Wound Healing

OBJECTIVE

This study was designed to employ electroceutical principles, as an alternative to pharmacological intervention, to manage wound biofilm infection. Mechanism of action of a United States Food and Drug Administration-cleared wireless electroceutical dressing (WED) was tested in an established porcine chronic wound polymicrobial biofilm infection model involving inoculation with Pseudomonas aeruginosa PAO1 and Acinetobacter baumannii 19606.

BACKGROUND

Bacterial biofilms represent a major wound complication. Resistance of biofilm toward pharmacologic interventions calls for alternative therapeutic strategies. Weak electric field has anti-biofilm properties. We have previously reported the development of WED involving patterned deposition of Ag and Zn on fabric. When moistened, WED generates a weak electric field without any external power supply and can be used as any other disposable dressing.

METHODS

WED dressing was applied within 2 hours of wound infection to test its ability to prevent biofilm formation. Alternatively, WED was applied after 7 days of infection to study disruption of established biofilm. Wounds were treated with placebo dressing or WED twice a week for 56 days.

RESULTS

Scanning electron microscopy demonstrated that WED prevented and disrupted wound biofilm aggregates. WED accelerated functional wound closure by restoring skin barrier function. WED blunted biofilm-induced expression of (1) P. aeruginosa quorum sensing mvfR (pqsR), rhlR and lasR genes, and (2) miR-9 and silencing of E-cadherin. E-cadherin is critically required for skin barrier function. Furthermore, WED rescued against biofilm-induced persistent inflammation by circumventing nuclear factor kappa B activation and its downstream cytokine responses.

CONCLUSION

This is the first pre-clinical porcine mechanistic study to recognize the potential of electroceuticals as an effective platform technology to combat wound biofilm infection.

Improving the quality of clinical research on chronic wound infection treatment: expert-based recommendations

OBJECTIVE:

To produce recommendations for the design of reliable and informative clinical investigations in chronic wound infection.

METHOD:

A multidisciplinary panel of international experts from four countries (Italy, UK, Ireland and the US) were involved in a detailed, semi-structured discussion on how to better select and describe a target population, interventions and outcomes, and which infection-related criteria to apply in order to achieve a high-quality trial. Consent among the experts was measured using the Delphi method and GRADE Working Group suggestions. The project was fully supported by AISLeC 2016 (Italian Nursing Society for Wound Care Study).

RESULTS:

In total, 37 recommendations achieved substantial agreement among the experts; 10 concerned the most appropriate description and selection of a target population, four related to interventions and 15 to outcomes. A further eight statements about critical methodological points were approved.

CONCLUSION:

Developing recommendations in a systematic manner through a representative group of experts could generate tools for improving the design of clinical trials in this challenging area.

Effectiveness of Chronic Wound Debridement with the Use of Larvae of Lucilia Sericata

The process of successful wound healing depends on effective debridement and infection control. One method of wound debridement, known since antiquity, is based on the use of fly larvae. Solid scientific evidence proves that maggot debridement therapy (MDT), like surgical intervention, can be effectively and safely used to remove necrotic tissue. Based on a review of the related literature, this study was designed to assess the effectiveness of chronic wound cleansing with the use of larvae of Lucilia sericata (Phaenicia sericata). Maggot therapy, applied in wound debridement and treatment, is a safe and effective method. Its benefits are associated with debridement, disinfection and faster tissue growth. MDT may reduce the duration of antibiotic therapy and the need for hospitalization, or it may decrease the number of outpatient visits required. It is a relatively cost-effective method, and, in addition to financial gains, it may reduce the frequency of inpatient treatment. In the literature, an increasing amount of scientific evidence confirms that such treatment can effectively reduce the biofilm and bacterial load in a wound.

Análise da “1a Recomendação Brasileira para o Gerenciamento do Biofilme em Feridas Crônicas e Complexas”

Objetivos: Analisar criticamente a “1ª Recomendação brasileira para o gerenciamento de biofilme em feridas crônicas e complexas”. Método: Realizou-se revisão da literatura atual às informações nele contidas. Resultados: Observou-se que a publicação carece de metodologia compatível com o título, existem lacunas nas recomendações quanto à classificação das evidências e com ausência de fundamentação a partir de importantes consensos internacionais para o tratamento das feridas complexas com suspeita de biofilme, publicados nos últimos três anos. Conclusão: Conclui-se que o manuscrito não deve ser usado como guia de recomendações clínicas, mas como revisão bibliográfica sobre o tema.

Analysis of “1st Brazilian Recommendation for Biofilm Management in Chronic and Complex Wounds”

Objectives: Analyze critically the “1st Brazilian Recommendation for Biofilm Management in Chronic and Complex Wounds” (from Portuguese, “1a Recomendação Brasileira para o Gerenciamento de Biofilme em Feridas Crônicas e Complexas”). Method: Reviewing information contained in said document according to current literature. Results: The publication was showed to lack methodology compatible with its title; gaps in the recommendations were perceived regarding evidence classification, as well as an absence of grounding from important international consensus, published in the last three years, about treatment of complex wounds with suspected biofilm. Conclusion: The document was concluded to be inadequate for use as a clinical guideline, being considered only a bibliographic review about the theme.

Biofilm management using monofilament fibre debridement technology: outcomes and clinician and patient satisfaction

Objective:

Best practice in wound bed preparation and biofilm-based wound management includes debridement to create a clean wound bed and to assist in minimising the redevelopment of biofilm. Biofilm that is not removed inhibits healing and redevelops if not prevented from doing so with topical antimicrobial agents. Monofilament fibre debriding technology (MFDT) is used for effective and rapid mechanical debridement of loose material, slough and biofilm. The objective of this evaluation was to determine the clinical effect and consequential levels of health professional and patient satisfaction with the results of a biofilm pathway that included MFDT to achieve debridement.

Methods:

This non-comparative, open label evaluation was conducted in static and non-static wounds that required debridement. MFDT was used to debride in a two-week evaluation of a biofilm pathway. Wounds were debrided three times in week one and twice in week two. Each debridement was followed by treatment with an antimicrobial dressing. Other care included secondary dressings and compression delivered according to local practice, guidelines and formularies. After the clinical evaluation, health professionals were invited to complete an online survey of the clinical outcomes and their satisfaction with the biofilm pathway.

Results:

There were 706 health professionals who provided answers to the survey questions. Wound types evaluated were leg ulcers (67.4%), pressure ulcers (10%), dehisced surgical wounds (1.7%), diabetic foot ulcers (7.4%) and other wounds (13.4%). Of the wounds, 9% were reported as non-static despite the eligibility criteria. Not all wounds followed the pathway. The most frequently-used antimicrobial was silver. Non-antimicrobial products used included all-in-one dressings, other secondary dressings and compression. There was a change in 77% of wounds overall after two weeks. Change was reported almost equally for both static and non-static wounds. Health professionals who did or did not follow the pathway were ‘completely satisfied’ or ‘satisfied’ with the overall clinical outcome 96% and 95%, respectively. Of the patients, 77% were ‘completely satisfied’ or ‘satisfied’ with healing after following the pathway, as reported by the treating health professional.

Conclusion:

The biofilm pathway that includes MFDT appears effective. Wounds managed on the pathway were debrided effectively and healing progressed to the satisfaction of both health professionals and patients.

Antibiofilm Synergy of β-Lactams and Branched Polyethylenimine against Methicillin-Resistant Staphylococcus epidermidis

Microbial biofilms are ubiquitous in nature, and they pose a serious threat to public health. Staphylococcus epidermidis is the most common clinical isolate from healthcare- and medical device-related biofilm infections. No antibiotic currently on the market can eradicate pathogenic biofilms, which contain complex defense mechanisms composed of slimelike extracellular polymeric substances. Understanding the need to develop alternative approaches, we examine 600 Da branched polyethylenimine (BPEI) against methicillin-resistant Staphylococcus epidermidis (MRSE) biofilms. Here, a microtiter biofilm model is used to test the synergistic effects between the two components of our combination treatment: BPEI and β-lactam antibiotics. Electron microscopy was used to confirm the growth of MRSE biofilms from the model. Minimum biofilm eradication concentration assays, crystal violet assays, and biofilm kill curves suggest that BPEI exhibits antibiofilm activity and can potentiate β-lactams to eradicate MRSE biofilms.

Rapid debridement with monofilament fibre debridement technology: clinical outcomes and practitioner satisfaction

Objective:

To determine the clinical effect and consequential levels of health professionals and patient satisfaction with the results of debridement episodes of wounds with visible slough and/or scaly skin using monofilament fibre debridement technology.

Methods:

This was a non-comparative, open label evaluation conducted in static/non-healing acute and chronic wounds with visible slough and/or scaly skin that required debridement. Monofilament fibre debridement technology was applied in 1–2 sequential treatment episodes during normal clinical practice which followed local practice, guidelines or formularies. Following the clinical phase of the evaluation, health professionals were invited to complete an online survey of the clinical outcomes and their satisfaction with them.

Results:

Survey questions were answered by 1129 health professionals. Wounds managed using the monofilament fibre debridement technology during this evaluation included leg ulcers (63%), pressure ulcers (10%), dehisced surgical wounds (3%), diabetic foot ulcers (8%) and other wounds (13%). ‘Other’ wound types included acute dirty wounds, burns, cellulitis, psoriasis, diabetic amputation wounds, dry flaky skin, moisture wounds, trauma, varicose eczema. Of the wounds, 12% were reported as non-static. There was visible change in the wound and/or skin after first use of the monofilament fibre debridement technology in a high proportion of all wound types, and a further increase in the proportion of wounds with visible change after the second use. The visible difference was significant for both static and non-static wounds. User and patient satisfaction with all clinical outcomes were high, whether or not the user and patient had previous experience of monofilament fibre debridement technology.

Conclusion:

Monofilament fibre debridement technology provides rapid, visible and effective debridement of slough and scaly skin after one application and further visible improvement after two applications in static and non-static wounds. Health professionals and patients report high levels of satisfaction with outcomes following application of the monofilament fibre debridement technology.

Cost-utility of a biofilm-disrupting gel versus standard of care in chronic wounds: a Markov microsimulation model based on a randomised controlled trial

OBJECTIVE

Analyse the cost-effectiveness and treatment outcomes of debridement (standard of care) plus BlastX, a biofilm-disrupting wound gel (group 1) or a triple-antibiotic, maximum-strength ointment (group 2), comparing a subset of patients who had not healed at four weeks using the ointment crossed-over to the biofilm-disrupting gel (group 3).

METHODS

A series of Markov microsimulation models were built using health states of an unhealed non-infected ulcer, healed ulcer, and infected non-healed ulcer and absorbing states of dead or amputation. All patients started with unhealed non-infected ulcers at cycle 0. Complications and healing rates were based on a randomised controlled trial (RCT). Costs were incurred by patients for procedures at outpatient wound care clinics and hospitals (if complications occurred) and were in the form of Medicare allowable charges. Quality-adjusted life years (QALYs) were computed using literature utility values. Incremental cost-effectiveness ratios (ICERs) were calculated for group 1 versus group 2, and group 3 versus group 2. One-way, multi-way and probabilistic sensitivity analysis (PSA) was conducted.

RESULTS

After one year, the base case ICER was $8794 per QALY for group 1 versus group 2, and $21,566 per QALY for group 3 versus group 2. Product cost and amputation rates had the most influence in one-way sensitivity analysis. PSA showed that the majority of costs were higher for group 1 but effectiveness values were always higher than for group 2. Average product use of 3.1ml per application represented 9.4% of the total group 1 cost (average $24.52 per application/$822.50 per group 1 patient). The biofilm-disrupting gel group performed substantially better than the current cost-effectiveness benchmarks, $8794 versus $50,000, respectively. Furthermore, when biofilm-disrupting gel treatment was delayed, as in group 3, the ICER outcomes were less substantial but it did remain cost-effective, suggesting the added benefits of immediate use of biofilm-disrupting gel. Also, when product cost assumptions used in the study were halved (Wolcott study usage), the model indicates important reductions in ICER to $966/QALY when comparing group 1 with group 2. It should be noted that product cost can hypothetically be affected not only by direct product purchase costs, but also by application intervals and technique. This suggests additional opportunities exist to optimise these parameters, maximising wound healing efficacy while providing significant cost savings to the payer.

CONCLUSION

The addition of the biofilm-disrupting gel treatment to standard of care is likely to be cost-effective in the treatment of chronic wounds but when delayed by as little as 9-12 weeks the ICER is still far less than current cost-effectiveness benchmarks. The implication for payers and decision-makers is that biofilm-disrupting gel should be used as a first-line therapy at the first clinic visit rather than waiting as it substantially decreases cost-utility.

Vibrio cholerae filamentation promotes chitin surface attachment at the expense of competition in biofilms

The human pathogen Vibrio cholerae, when not inside of a host, grows in cell clusters (biofilms) on pieces of detritus in aquatic environments. Here we discovered that some isolates of V. cholerae can change their shape from small comma-shaped cells to long filaments in seawater. This altered cell shape allows cells to make new types of biofilms, and provides an advantage in quickly colonizing particles in seawater, at the expense of longer-term competitive ability. The filamentous cell-shape strategy is particularly effective at competing in environments with quick turnover of chitin particles. This result showcases how bacterial cell shape can be coupled to environmental success during surface occupation, competition within biofilms, and dispersal to new resource patches.

Collective behavior in spatially structured groups, or biofilms, is the norm among microbes in their natural environments. Though biofilm formation has been studied for decades, tracing the mechanistic and ecological links between individual cell morphologies and the emergent features of cell groups is still in its infancy. Here we use single-cell–resolution confocal microscopy to explore biofilms of the human pathogen Vibrio cholerae in conditions mimicking its marine habitat. Prior reports have noted the occurrence of cellular filamentation in V. cholerae, with variable propensity to filament among both toxigenic and nontoxigenic strains. Using a filamenting strain of V. cholerae O139, we show that cells with this morphotype gain a profound competitive advantage in colonizing and spreading on particles of chitin, the material many marine Vibrio species depend on for growth in seawater. Furthermore, filamentous cells can produce biofilms that are independent of primary secreted components of the V. cholerae biofilm matrix; instead, filamentous biofilm architectural strength appears to derive at least in part from the entangled mesh of cells themselves. The advantage gained by filamentous cells in early chitin colonization and growth is countered in long-term competition experiments with matrix-secreting V. cholerae variants, whose densely packed biofilm structures displace competitors from surfaces. Overall, our results reveal an alternative mode of biofilm architecture that is dependent on filamentous cell morphology and advantageous in environments with rapid chitin particle turnover. This insight provides an environmentally relevant example of how cell morphology can impact bacterial fitness.