Biofilms and Wounds: An Identification Algorithm and Potential Treatment Options

Recent advances in mesoporous silica nanoparticles formulations and drug delivery for wound healing

Wound healing is a natural process that can be disrupted by disease. Nanotechnology is a promising platform for the development of new therapeutic agents to accelerate acute and chronic wound healing. Drug delivery by means of nanoparticles as well as wound dressings have emerged as suitable options to improving the healing process. The characteristics of mesoporous silica nanoparticles (MSNs) make them efficient carriers of pharmaceutical agents alone or in combination with dressings. In order to maximize the effect of a drug and minimize its adverse consequences, it may be possible to include targeted and intelligent release of the drug into the design of MSNs. Its use to facilitate closure of adjacent sides of a cut as a tissue adhesive, local wound healing, controlled drug release and induction of blood coagulation are possible applications of MSNs. This review summarizes research on MSN applications for wound healing. It includes a general overview, wound healing phases, MSN formulation, therapeutic possibilities of MSNs and MSN-based drug delivery systems for wound healing.

Cuminaldehyde in combination with tetracycline shows promising antibiofilm activity against drug-resistant Pseudomonas aeruginosa

Pseudomonas aeruginosa, an opportunistic pathogen often causes biofilm-linked infections. A combinatorial approach involving tetracycline (antibiotic) and cuminaldehyde (phytochemical) was explored to combat this infectious pathogen. The results showed that both tetracycline and cuminaldehyde individually demonstrated antibacterial effects. However, when the compounds were applied together, there was a significant increase in their antimicrobial potential. The determined fractional inhibitory concentration index of 0.43 indicated a synergistic interaction between the two compounds. Furthermore, a series of experiments demonstrated that the combined application of cuminaldehyde and tetracycline could lead to a significant enhancement of their antibiofilm potential. This enhanced antibiofilm potential was attributed to the accumulation of reactive oxygen species and increased cell membrane permeability. Besides, this combinatorial application reduced the secretion of various virulence factors from P. aeruginosa. Therefore, this combined approach holds promise for effectively treating P. aeruginosa biofilms.

Biofilm formation and antibiogram profile of bacteria from infected wounds in a general hospital in southern Ethiopia

Biofilm-producing bacteria associated with wound infections exhibit exceptional drug resistance, leading to an escalation in morbidity, worse clinical outcomes (including delay in the healing process), and an increase in health care cost, burdening the whole system. This study is an attempt to estimate the prevalence and the relationship between the biofilm-forming capacity and multi-drug resistance of wound bacterial isolates. The findings intended to help clinicians, healthcare providers and program planners and to formulate an evidence-based decision-making process, especially in resource-limited healthcare settings. This study was done to assess the prevalence of bacterial infections in wounds and the antibiogram and biofilm-forming capacity of those bacteria in patients with clinical signs and symptoms, attending a General Hospital in southern Ethiopia. A cross-sectional study was performed in Arba Minch General Hospital from June to November 2021. The study participants comprised 201 patients with clinically infected wounds. Demographic and clinical data were gathered via a structured questionnaire. Specimens from wounds were taken from each participant and inoculated onto a series of culture media, namely MacConkey agar, mannitol salt agar, and blood agar, and different species were identified using a number of biochemical tests. Antimicrobial susceptibility tests were performed by means of the Kirby-Bauer disc diffusion technique following the guidelines of the Clinical and Laboratory Standards Institute. A micro-titer plate method was employed to detect the extent of biofilm formation. Bivariable and multivariable logistic regression models were applied to analyse the association between dependent and independent variables, and P values ≤ 0.05 were considered as statistically significant. Data analyses were done with Statistical Package for the Social Sciences version 25. Out of the 201 clinically infected wounds, 165 were found culture-positive with an overall prevalence of 82% (95% CI: 75.9-86.9). In total, 188 bacteria were recovered; 53.1% of them were Gram-positive cocci. The often-isolated bacterial species were Staphylococcus aureus, 38.3% (n = 72), and Pseudomonas aeruginosa, 16.4% (n = 31). The Gram-positive isolates showed considerable resistance against penicillin, 70%, and somewhat strong resistance against tetracycline, 57.7%. Gram-negative isolates showed severe resistance to ampicillin, 80.68%. The overall multi-drug resistance (MDR) among isolates was 48.4%. Extended beta-lactamase (ESBL)-producing Gram-negatives and methicillin-resistant Staphylococcus aureus (MRSA) accounted for 49 and 41.67%, respectively; 62.2% of the isolates were biofilm formers and were correlated statistically with MDR, ESBL producers, and MRSA (P < 0.005). The extent of biofilm formation and the prevalence of MDR bacteria associated with infected wounds hint at a public health threat that needs immediate attention. Thus, a more balanced and comprehensive wound management approach and antimicrobial stewardship program are essential in the study setting.

Advances in ionic liquid-based antimicrobial wound healing platforms

Wound infections, marked by the proliferation of microorganisms at surgical sites, necessitate the development of innovative wound dressings with potent bactericidal properties to curb microbial growth and prevent bacterial infiltration. This study explores the recent strides in utilizing ionic liquid-based polymers as highly promising antimicrobial agents for advanced wound healing applications. Specifically, cationic polymers containing quaternary ammonium, imidazolium, guanidinium, pyridinium, triazolium, or phosphonium groups have emerged as exceptionally effective antimicrobial compounds. Their mechanism of action involves disrupting bacterial membranes, thereby preventing the development of resistance and minimizing toxicity to mammalian cells. This comprehensive review not only elucidates the intricate dynamics of the skin's immune response and the various stages of wound healing but also delves into the synthesis methodologies of ionic liquid-based polymers. By spotlighting the practical applications of antimicrobial wound dressings, particularly those incorporating ionic liquid-based materials, this review aims to lay the groundwork for future research endeavors in this burgeoning field. Through a nuanced examination of these advancements, this article seeks to contribute to the ongoing progress in developing cutting-edge wound healing platforms that can effectively address the challenges posed by microbial infections in surgical wounds.

Challenges in Biofilm Identification in Diabetic Foot Infections: Review of Literature

Foot ulcerations are one of the most common complications of diabetes and one of the major initial causes of amputations. The formation of biofilms on wounds significantly contributes to infections and delayed healing. While existing methods for identifying these biofilms have limitations, there is a need for a convenient tool for its clinical application. This literature review aimed to address the problem with current clinical biofilm identification in wound care and a proposal for biofilm-detection-based wound care in diabetic foot ulcer patients. Identifying biofilms is particularly vital due to the absence of typical signs of infection in DFUs. However, current approaches, although effective, often prove invasive and technically intricate. The wound blotting technique, involving attaching a nitrocellulose membrane and subsequent staining, presents an alternative that is swift and non-invasive. Research highlights the applicability of wound blotting with alcian blue staining in clinical scenarios, consistently producing sensitive outcomes. By addressing the critical need for early biofilm detection, wound blotting holds promise for enhancing DFU management and contributing to strategies aimed at preventing amputations.

Bacterial Biofilm in Chronic Wounds and Possible Therapeutic Approaches

Wound repair and skin regeneration is a very complex orchestrated process that is generally composed of four phases: hemostasis, inflammation, proliferation, and remodeling. Each phase involves the activation of different cells and the production of various cytokines, chemokines, and other inflammatory mediators affecting the immune response. The microbial skin composition plays an important role in wound healing. Indeed, skin commensals are essential in the maintenance of the epidermal barrier function, regulation of the host immune response, and protection from invading pathogenic microorganisms. Chronic wounds are common and are considered a major public health problem due to their difficult-to-treat features and their frequent association with challenging chronic infections. These infections can be very tough to manage due to the ability of some bacteria to produce multicellular structures encapsulated into a matrix called biofilms. The bacterial species contained in the biofilm are often different, as is their capability to influence the healing of chronic wounds. Biofilms are, in fact, often tolerant and resistant to antibiotics and antiseptics, leading to the failure of treatment. For these reasons, biofilms impede appropriate treatment and, consequently, prolong the wound healing period. Hence, there is an urgent necessity to deepen the knowledge of the pathophysiology of delayed wound healing and to develop more effective therapeutic approaches able to restore tissue damage. This work covers the wound-healing process and the pathogenesis of chronic wounds infected by biofilm-forming pathogens. An overview of the strategies to counteract biofilm formation or to destroy existing biofilms is also provided.

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.

Anti-biofilm Activity of Povidone-Iodine and Polyhexamethylene Biguanide: Evidence from In Vitro Tests

Biofilm in chronic wounds is associated with delayed healing and ineffective local treatment. The purpose of this study was to investigate the in vitro anti-biofilm activity of two commonly used antimicrobials, povidone-iodine (PVP-I) and polyhexamethylene biguanide (PHMB). The rate of anti-biofilm activity of PVP-I, PHMB, and phosphate-buffered saline (negative control) was assessed on monomicrobial biofilms of varying maturity and composition. Antimicrobial efficacy was determined by counting colony-forming units (CFU). Live/dead cell staining and time-lapse confocal microscopy were also performed. Both PVP-I and PHMB demonstrated robust in vitro anti-biofilm activity against all tested biofilms; however, PVP-I had a more rapid action versus PHMB against methicillin-resistant Staphylococcus aureus (MRSA) biofilms, as determined by both CFU counts and microscopy. PVP-I completely eradicated Pseudomonas aeruginosa biofilms of 3- and 5-day maturity (in ≤0.5 h) and 7-day maturity (in ≤3 h), while PHMB only partially depleted cell density, with no complete biofilm eradication even after 24 h. In conclusion, PVP-I had a similar in vitro anti-biofilm activity to PHMB against biofilms of varying microbial compositions and maturity, and in some cases demonstrated more potent and rapid activity versus PHMB. PVP-I may be particularly effective in treating MRSA biofilms. However, further high-quality clinical research on the efficacy of antimicrobials is required.

Biofilms in wound healing: A bibliometric and visualised study

Bibliometric analyses are often used as a means of visualising the knowledge base and associated trends and patterns in a target scientific field based on a quantitative review of the corresponding literature. In this study, we explore the current status of research pertaining to biofilms in wound healing and elucidate trends in this research space. Through this process, we gain insight into findings from papers indexed in the Web of Science Core Collection. These references were then analysed and plotted using Microsoft Excel 2019, VOSviewer, and CiteSpace V. The results provide a fresh perspective regarding global trends and hotspots in biofilm-related wound healing research. These findings also offer a foundation that researchers can use to identify active hotspots of scientific interest to guide further research endeavours.

The Impact of Antiseptic-Loaded Bacterial Nanocellulose on Different Biofilms-An Effective Treatment for Chronic Wounds?

Introduction: Pathogenic biofilms are an important factor for impaired wound healing, subsequently leading to chronic wounds. Nonsurgical treatment of chronic wound infections is limited to the use of conventional systemic antibiotics and antiseptics. Wound dressings based on bacterial nanocellulose (BNC) are considered a promising approach as an effective carrier for antiseptics. The aim of the present study was to investigate the antimicrobial activity of antiseptic-loaded BNC against in vitro biofilms. Materials and Methods: BNC was loaded with the commercially available antiseptics Prontosan^® and Octenisept^®. The silver-based dressing Aquacel^®Ag Extra was used as a positive control. The biofilm efficacy of the loaded BNC sheets was tested against an in vitro 24-hour biofilm of Staphylococcus aureus and Candida albicans and a 48-hour biofilm of Pseudomonas aeruginosa. In vivo tests using a porcine excisional wound model was used to analyze the effect of a prolonged treatment with the antiseptics on the healing process. Results: We observed complete eradication of S. aureus biofilm in BNC loaded with Octenisept^® and C. albicans biofilm for BNC loaded with Octenisept^® or Prontosan^®. Treatment with unloaded BNC also resulted in a statistically significant reduction in bacterial cell density of S. aureus compared to untreated biofilm. No difference on the wound healing outcome was observed for the wounds treated for seven days using BNC alone in comparison to BNC combined with Prontosan^® or with Octenisept^®. Conclusions: Based on these results, antiseptic-loaded BNC represents a promising and effective approach for the treatment of biofilms. Additionally, the prolonged exposure to the antiseptics does not affect the healing outcome. Prevention and treatment of chronic wound infections may be feasible with this novel approach and may even be superior to existing modalities.

A desiccation compound as a biofilm- and necrosis-removing agent: a case series

Objective:

A new compound, Debrichem (DEBx Medical BV, the Netherlands), a topical desiccation agent (TDA), is an active gel that contains an acidic species with a potent hygroscopic action. When in contact with microorganisms and necrosis, rapid desiccation and carbonisation of the proteins in these microorganisms, as well as of the extracellular matrix of biofilms and necrosis, occurs. The resulting ‘precipitate’ rapidly dislodges from the wound bed, resulting in a clean wound which granulates, which is a prerequisite for healing by secondary intention.

Method:

In a retrospective study, a series of mostly large and hard-to-heal lesions of different aetiologies were treated with a one-time application of the TDA, followed by weekly dressing changes.

Results:

Of the total of 54 lesions included in this case series, 22 were diagnosed as venous leg ulcers (VLUs), 20 as diabetic foot ulcers (DFUs), nine as post-traumatic, hard-to-heal lesions, two as vascular ulcers and one as an ischaemic ulcer. All of the VLUs, 75% of the DFUs and all of the other lesions reached complete granulation.

Conclusion:

The use of a TDA may contribute to the consistent, fast and easy removal of both biofilms and necrosis, and hence to wound healing.

Chitosan-based microneedle arrays for dermal delivery of Centella Asiatica

Centella asiatica, a medicinal herb used for wound healing, has a limited effect when delivered as an ointment. Centella asiatica's active component asiatic acid (AA) increases extracellular matrix development and reduces inflammation but cannot penetrate the stratum corneum to access deeper skin layers. To bypass the stratum corneum, we formulated two types of AA-loaded microneedle arrays. We fabricated, characterised and optimised a dissolving array made from chitosan and PVA and a hydrogel array made from chitosan and PVP. Both needles were strong and long enough to pierce the epidermis without breaking. Both were biocompatible with keratinocytes and fibroblasts (>75% viability at 100% concentration) and showed a sustained drug release over 48 hours. The hydrogel microneedle released more AA (52.2%) than the dissolving formulation (26.4%); thus, we evaluated them in an excisional rat model. The hydrogel microneedle arrays significantly increased the rate of wound closure compared to the control. This research has shown that the chitosan-PVA hydrogel microneedles could penetrate the epidermis, effectively release AA, and increase the wound closure rate. This AA-loaded delivery system shows promise as a natural treatment for wound healing and may be applied to other bioactive compounds with similar physiochemical properties in the future.

[Not Available]

Hard-to-heal wounds are a problem for both patients and caregivers. The biofi lm is one of the local factors of delayed healing. Wound hygiene carried out in 4 steps (cleansing, debridement, refashion - care of the edges, and dressing) constitutes the basis of proactive and curative anti-biofi lm strategies.

Advances in the Sensing and Treatment of Wound Biofilms

Wound biofilms represent a particularly challenging problem in modern medicine. They are increasingly antibiotic resistant and can prevent the healing of chronic wounds. However, current treatment and diagnostic options are hampered by the complexity of the biofilm environment. In this review, we present new chemical avenues in biofilm sensors and new materials to treat wound biofilms, offering promise for better detection, chemical specificity, and biocompatibility. We briefly discuss existing methods for biofilm detection and focus on novel, sensor-based approaches that show promise for early, accurate detection of biofilm formation on wound sites and that can be translated to point-of-care settings. We then discuss technologies inspired by new materials for efficient biofilm eradication. We focus on ultrasound-induced microbubbles and nanomaterials that can both penetrate the biofilm and simultaneously carry active antimicrobials and discuss the benefits of those approaches in comparison to conventional methods.

Advances in the Sensing and Treatment of Wound Biofilms

Wound biofilms represent a particularly challenging problem in modern medicine. They are increasingly antibiotic resistant and can prevent the healing of chronic wounds. However, current treatment and diagnostic options are hampered by the complexity of the biofilm environment. In this review, we present new chemical avenues in biofilm sensors and new materials to treat wound biofilms, offering promise for better detection, chemical specificity, and biocompatibility. We briefly discuss existing methods for biofilm detection and focus on novel, sensor-based approaches that show promise for early, accurate detection of biofilm formation on wound sites and that can be translated to point-of-care settings. We then discuss technologies inspired by new materials for efficient biofilm eradication. We focus on ultrasound-induced microbubbles and nanomaterials that can both penetrate the biofilm and simultaneously carry active antimicrobials and discuss the benefits of those approaches in comparison to conventional methods.

Preparation and characterization of succinyl chitosan and succinyl chitosan nanoparticle film: In vitro and in vivo evaluation of wound healing activity

Development of novel wound dressing materials having the ability to prevent bacterial infections and capable of accelerating the tissue regeneration process is utmost important, since the wounds in patients can cause severe health issues. In the present work, we synthesized novel N-succinyl chitosan nanoparticles (N-SuC NPs) films and tested their antimicrobial, cytotoxicity, and in vitro and in vivo wound healing activity. N-SuC NPs were synthesized by ionic gelation method, and subsequently N-SuC NPs films were prepared by solution casting method using synthesized N-SuC NPs. The prepared N-SuC NPs films showed significant antimicrobial activity against Escherichia coli and Staphylococcus aureus with a minimum inhibitory concentration of 6 mg/mL and <8 mg/mL, respectively. The biocompatibility and the in vitro wound healing activity of N-SuC NPs films were analyzed using human dermal fibroblast (HDF) cells. In vivo cutaneous wound healing of the N-SuC NPs film was investigated using the Wister rat model, and the studies showed that the N-SuC NPs film significantly accelerated the wound healing process by inducing more blood vessels formation and tissue granulation. The experimental results showed that synthesized N-SuC NPs film had excellent antimicrobial, cytotoxicity and wound healing activity, indicating that it could be used in biomedical applications.

Biofilm and Equine Limb Wounds

In chronic wounds in humans, biofilm formation and wound chronicity are linked, as biofilms contribute to chronic inflammation and delayed healing. Biofilms are aggregates of bacteria, and living as biofilms is the default mode of bacterial life; within these aggregates, the bacteria are protected from both antimicrobial substances and the immune response of the host. In horses, delayed healing is more commonly seen in limb wounds than body wounds. Chronic inflammation and hypoxia are the main characteristics of delayed wound healing in equine limbs, and biofilms might also contribute to this healing pattern in horses. However, biofilm formation in equine wounds has been studied to a very limited degree. Biofilms have been detected in equine traumatic wounds, and recent experimental models have shown that biofilms protract the healing of equine limb wounds. Detection of biofilms within wounds necessitates advanced techniques that are not available in routine diagnostic yet. However, infections with biofilm should be suspected in equine limb wounds not healing as expected, as they are in human wounds. Treatment should be based on repeated debridement and application of topical antimicrobial therapy.

Biofilm Management in Wound Care

LEARNING OBJECTIVES

After studying this article, the participant should be able to: 1. Understand the basics of biofilm infection and be able to distinguish between planktonic and biofilm modes of growth. 2. Have a working knowledge of conventional and emerging antibiofilm therapies and their modes of action as they pertain to wound care. 3. Understand the challenges associated with testing and marketing antibiofilm strategies and the context within which these strategies may have effective value.

SUMMARY

The Centers for Disease Control and Prevention estimate for human infectious diseases caused by bacteria with a biofilm phenotype is 65 percent and the National Institutes of Health estimate is closer to 80 percent. Biofilms are hostile microbial aggregates because, within their polymeric matrix cocoons, they are protected from antimicrobial therapy and attack from host defenses. Biofilm-infected wounds, even when closed, show functional deficits such as deficient extracellular matrix and impaired barrier function, which are likely to cause wound recidivism. The management of invasive wound infection often includes systemic antimicrobial therapy in combination with débridement of wounds to a healthy tissue bed as determined by the surgeon who has no way of visualizing the biofilm. The exceedingly high incidence of false-negative cultures for bacteria in a biofilm state leads to missed diagnoses of wound infection. The use of topical and parenteral antimicrobial therapy without wound débridement have had limited impact on decreasing biofilm infection, which remains a major problem in wound care. Current claims to manage wound biofilm infection rest on limited early-stage data. In most cases, such data originate from limited experimental systems that lack host immune defense. In making decisions on the choice of commercial products to manage wound biofilm infection, it is important to critically appreciate the mechanism of action and significance of the relevant experimental system. In this work, the authors critically review different categories of antibiofilm products, with emphasis on their strengths and limitations as evident from the published literature.

Biofilms in Diabetic Foot Ulcers: Impact, Risk Factors and Control Strategies

Diabetic foot ulcers (DFUs) are a serious complication from diabetes mellitus, with a huge economic, social and psychological impact on the patients' life. One of the main reasons why DFUs are so difficult to heal is related to the presence of biofilms. Biofilms promote wound inflammation and a remarkable lack of response to host defences/treatment options, which can lead to disease progression and chronicity. In fact, appropriate treatment for the elimination of these microbial communities can prevent the disease evolution and, in some cases, even avoid more serious outcomes, such as amputation or death. However, the detection of biofilm-associated DFUs is difficult due to the lack of methods for diagnostics in clinical settings. In this review, the current knowledge on the involvement of biofilms in DFUs is discussed, as well as how the surrounding environment influences biofilm formation and regulation, along with its clinical implications. A special focus is also given to biofilm-associated DFU diagnosis and therapeutic strategies. An overview on promising alternative therapeutics is provided and an algorithm considering biofilm detection and treatment is proposed.

The sensitivity of planktonic cultures and biofilms of gram-negative bacteria to commercial disinfectant and antiseptic preparations

The in vitro antibacterial activity of 11 commercial disinfectant preparations and 8 antiseptics against 10 strains of the bacteria Klebsiella pneumoniae, Pseudomonas aeruginosa, Acinetobacter baumannii, Enterobacter cloaceae and Providencia stuartii obtained from international collections and isolated from neuroresuscitation patients in Moscow in 2018 was studied. The sensitivity of planktonic cultures to the preparations was determined by the method of serial dilutions in broth and the spot method on solid nutrient media, the sensitivity of biofilms by the applicator method. A general pattern was revealed: the level of sensitivity to tested disinfectants in clinical strains was lower than in reference strains. It was found that the disinfectants «Mikrobak-Forte», «SAT-22», «Neobak-Oksi» at the concentrations recommended by the manufacturers were effective against bacteria of all test strains, both in the plankton state and in the form of biofilms. On the contrary, the disinfectant preparations «Biodez-Optima», «Biodez-Extra DVU», «Novodez-Aktiv», «Triosept-Oksi», «Tristel Fusion for Surfaces», «Effect-Forte Plus», «Lactic-Oxy» did not have sufficient effectiveness in the concentrations recommended by the manufacturers, therefore it is proposed to use these drugs in higher concentrations. It was found that the disinfectant «Biodez-Extra DVU» is able to inhibit the growth of biofilms of bacteria of the species K. pneumoniae. The ability to suppress the growth of bacterial biofilms of K. pneumoniae, A. baumannii, P. aeruginosa was revealed for the «Triestel Fusion for surfaces disinfectant». The bacteria of all used test strains in the planktonic state were sensitive to all tested antiseptic preparations. However, the biofilms of the clinical strains of P. aeruginosa and P. stuartii. possessed resistance to the antiseptics «Octenidol», «Octenisept», «Miramistin», «Hexoral». Our studies indicate the need for sensitivity analysis of antibacterial drugs in representatives of hospital pathogens, including the modeling of bacterial biofilms, which is a very relevant and important scientific direction, necessary to improve the control of nosocomial infections in the Russian Federation.

Concurrent validity of biofilm detection by wound blotting on hard-to-heal wounds

OBJECTIVE

Wound biofilms delay healing of hard-to-heal wounds. Convenient biofilm identification tools for clinical settings are currently not available, hindering biofilm-based wound management. Wound blotting with biofilm staining is a potential tool for biofilm detection, owing to its convenience. Although predictive validity of wound blotting has been established, it is necessary to confirm its concurrent validity. Furthermore, current staining systems employing ruthenium red have some disadvantages for clinical use. This study aimed to evaluate the usability of alcian blue as a substitute for ruthenium red.

METHOD

Both in vitro and in vivo clinical samples were used to investigate validity and usability.

RESULTS

The in vitro study showed that proteins and extracellular DNA in biofilms did not affect staining ability of ruthenium red and alcian blue in the detection of biofilms. In the in vivo study, using a wound biofilm model with Pseudomonas aeruginosa, the staining sensitivity of ruthenium red was 88.9% and 100% for alcian blue, with correlation coefficients of signal intensities with native polyacrylamide gel electrophoresis (PAGE) of r=0.67 (p=0.035) and r=0.67 (p=0.036) for ruthenium red and alcian blue, respectively. Results from clinical samples were r=0.75 (p=0.001) for ruthenium red and r=0.77 (p<0.001) for alcian blue. The sensitivities of wound blotting staining by ruthenium red and alcian blue were very high and had a good correlation with native PAGE analysis.

CONCLUSION

Because the alcian blue procedure is more convenient than the ruthenium red procedure, wound blotting with alcian blue staining would be a promising tool to guide clinicians in delivering biofilm-based wound management.

Diagnostics for Wound Infections

Significance: Infections can significantly delay the healing process in chronic wounds, placing an enormous economic burden on health care resources. Identification of infection biomarkers and imaging modalities to observe and quantify them has seen progress over the years. Recent Advances: Traditionally, clinicians determine the presence of infection through visual observation of wounds and confirm their diagnosis through wound culture. Many laboratory markers, including C-reactive protein, procalcitonin, presepsin, and bacterial protease activity, have been quantified to assist diagnosis of infection. Moreover, imaging modalities like plain radiography, computed tomography, magnetic resonance imaging, ultrasound imaging, spatial frequency domain imaging, thermography, autofluorescence imaging, and biosensors have emerged for real-time wound infection diagnosis and showed their unique advantages in deeper wound infection diagnosis. Critical Issues: While traditional diagnostic approaches provide valuable information, they are time-consuming and depend on clinicians' experiences. There is a need for noninvasive wound infection diagnostics that are highly specific, rapid, and accurate, and do not require extensive training. Future Directions: While innovative diagnostics utilizing various imaging instrumentation are being developed, new biomarkers have been investigated as potential indicators for wound infection. Products may be developed to either qualitatively or quantitatively measure these biomarkers. This review summarizes and compares all available diagnostics for wound infection, including those currently used in clinics and still under development. This review could serve as a valuable resource for clinicians treating wound infections as well as patients and wound care providers who would like to be informed of the recent developments.

Update on the role of antiseptics in the management of chronic wounds with critical colonisation and/or biofilm

Biofilms play a major role in delaying chronic wounds from healing. A wound infiltrated with biofilm, or "critically colonised" wound, may become clinically infected if the number of microbes exceeds a critical level. Chronic wound biofilms represent a significant treatment challenge by demonstrating recalcitrance towards antimicrobial agents. However, a "window of opportunity" may exist after wound debridement when biofilms are more susceptible to topical antiseptics. Here, we discuss the role of antiseptics in the management of chronic wounds and biofilm, focusing on povidone-iodine (PVP-I) in comparison with two commonly used antiseptics: polyhexanide (PHMB) and silver. This article is based on the literature reviewed during a focus group meeting on antiseptics in wound care and biofilm management, and on a PubMed search conducted in March 2020. Compared with PHMB and silver, PVP-I has a broader spectrum of antimicrobial activity, potent antibiofilm efficacy, no acquired bacterial resistance or cross-resistance, low cytotoxicity, good tolerability, and an ability to promote wound healing. PVP-I represents a viable therapeutic option in wound care and biofilm management, with the potential to treat biofilm-infiltrated, critically colonised wounds. We propose a practical algorithm to guide the management of chronic, non-healing wounds due to critical colonisation or biofilm, using PVP-I.

Wound Repair and Extremely Low Frequency-Electromagnetic Field: Insight from In Vitro Study and Potential Clinical Application

Wound healing is a complex, staged process. It involves extensive communication between the different cellular constituents of various compartments of the skin and its extracellular matrix (ECM). Different signaling pathways are determined by a mutual influence on each other, resulting in a dynamic and complex crosstalk. It consists of various dynamic processes including a series of overlapping phases: hemostasis, inflammation response, new tissue formation, and tissue remodeling. Interruption or deregulation of one or more of these phases may lead to non-healing (chronic) wounds. The most important factor among local and systemic exogenous factors leading to a chronic wound is infection with a biofilm presence. In the last few years, an increasing number of reports have evaluated the effects of extremely low frequency (ELF) electromagnetic fields (EMFs) on tissue repair. Each experimental result comes from a single element of this complex process. An interaction between ELF-EMFs and healing has shown to effectively modulate inflammation, protease matrix rearrangement, neo-angiogenesis, senescence, stem-cell proliferation, and epithelialization. These effects are strictly related to the time of exposure, waveform, frequency, and amplitude. In this review, we focus on the effect of ELF-EMFs on different wound healing phases.

Antibiofilm and Antivirulence Properties of Indoles Against Serratia marcescens

Indole and its derivatives have been shown to interfere with the quorum sensing (QS) systems of a wide range of bacterial pathogens. While indole has been previously shown to inhibit QS in Serratia marcescens, the effects of various indole derivatives on QS, biofilm formation, and virulence of S. marcescens remain unexplored. Hence, in the present study, we investigated the effects of 51 indole derivatives on S. marcescens biofilm formation, QS, and virulence factor production. The results obtained revealed that several indole derivatives (3-indoleacetonitrile, 5-fluoroindole, 6-fluoroindole, 7-fluoroindole, 7-methylindole, 7-nitroindole, 5-iodoindole, 5-fluoro-2-methylindole, 2-methylindole-3-carboxaldehyde, and 5-methylindole) dose-dependently interfered with quorum sensing (QS) and suppressed prodigiosin production, biofilm formation, swimming motility, and swarming motility. Further assays showed 6-fluoroindole and 7-methylindole suppressed fimbria-mediated yeast agglutination, extracellular polymeric substance production, and secretions of virulence factors (e.g., proteases and lipases). QS assays on Chromobacterium violaceum CV026 confirmed that indole derivatives interfered with QS. The current results demonstrate the antibiofilm and antivirulence properties of indole derivatives and their potentials in applications targeting S. marcescens virulence.

Superabsorbent crosslinked bacterial cellulose biomaterials for chronic wound dressings

In this work, we present a novel ex situ modification of bacterial cellulose (BC) polymer, that significantly improves its ability to absorb water after drying. The method involves a single inexpensive and easy-to-perform process of BC crosslinking, using citric acid along with catalysts, such as disodium phosphate, sodium bicarbonate, ammonium bicarbonate or their mixtures. In particular, the mixture of disodium phosphate and sodium bicarbonate was the most promising, yielding significantly greater water capacity (over 5 times higher as compared to the unmodified BC) and slower water release (over 6 times as compared to the unmodified BC). Further, our optimized crosslinked BC had over 1.5x higher water capacity than modern commercial dressings dedicated to highly exuding wounds, while exhibiting no cytotoxic effects against fibroblast cell line L929 in vitro. Therefore, our novel BC biomaterial may find application in super-absorbent dressings, designed for chronic wounds with imbalanced moisture level.

Antibacterial-Integrated Collagen Wound Dressing for Diabetes-Related Foot Ulcers: An Evidence-Based Review of Clinical Studies

Diabetic foot ulcer (DFU) is a chronic wound frequently delayed from severe infection. Wound dressing provides an essential barrier between the ulcer and the external environment. This review aimed to analyse the effectiveness of antibacterial collagen-based dressing for DFU treatment in a clinical setting. An electronic search in four databases, namely, Scopus, PubMed, Ovid MEDLINE(R), and ISI Web of Science, was performed to obtain relevant articles published within the last ten years. The published studies were included if they reported evidence of (1) collagen-based antibacterial dressing or (2) wound healing for diabetic ulcers, and (3) were written in English. Both randomised and non-randomised clinical trials were included. The search for relevant clinical studies (n) identified eight related references discussing the effectiveness of collagen-based antibacterial wound dressings for DFU comprising collagen impregnated with polyhexamethylene biguanide (n = 2), gentamicin (n = 3), combined-cellulose and silver (n = 1), gentian violet/methylene blue mixed (n = 1), and silver (n = 1). The clinical data were limited by small sample sizes and multiple aetiologies of chronic wounds. The evidence was not robust enough for a conclusive statement, although most of the studies reported positive outcomes for the use of collagen dressings loaded with antibacterial properties for DFU wound healing. This study emphasises the importance of having standardised clinical trials, larger sample sizes, and accurate reporting for reliable statistical evidence confirming DFU treatment efficiency.

A review of iodine-based compounds, with a focus on biofilms: results of an expert panel

Biofilms play a central role in the chronicity of non-healing lesions such as venous leg ulcers and diabetic foot ulcers. Therefore, biofilm management and treatment is now considered an essential part of wound care. Many antimicrobial treatments, whether topical or systemic, have been shown to have limited efficacy in the treatment of biofilm phenotypes. The antimicrobial properties of iodine compounds rely on multiple and diverse interactions to exert their effects on microorganisms. An expert panel, held in Las Vegas during the autumn Symposium on Advanced Wound Care meeting in 2018, discussed these properties, with the focus on iodine and iodophors and their effects on biofilm prevention and treatment.

Hyaluronic Acid Reduces Bacterial Fouling and Promotes Fibroblasts' Adhesion onto Chitosan 2D-Wound Dressings

Wound healing is a dynamic process that can be seriously delayed by many factors including infectious complications. The development of dressings with intrinsic wound healing activity and/or releasing bioactive compounds may help with addressing such an issue. In this study, hyaluronic acid (HA) at different percentages (1–35%) was used to modify chitosan (CS) biological and physico-chemical properties in order to obtain 2D-matrices able to promote healing and protect from infection. HA incorporation in the CS matrix decreased film transparency and homogeneity, but improved film water uptake and surface wettability. The water vapor transmission rate (WVTR) increased up to a 5% HA content, where it reached the highest value (672 g/m² day), and decreased for higher HA contents. At all of the tested HA concentrations, HA affected mechanical properties providing matrices more flexible than pure CS with benefit for wound care. Pure CS films permitted S. epidermidis adhesion and biofilm formation. That was not true for CS/HA matrices, where HA at concentrations equal to or greater than 5% was able to avoid S. epidermidis adhesion. Fibroblasts adhesion also took benefit from the HA presence in the film, especially at 5% content, where the best adhesion and proliferation was found.

Original hardware-software method for treatment of infected superficial wounds in a liquid environment

Aim ― development of a hardware-software system allowing to treat infected superficial wounds in a liquid environment, designed to provide continuous flow of various irrigation solutions (depending on the wound healing stage) under airtight and water-resistant film tightly fixed over the wound. Methods ― in this experiment wound irrigation with antiseptic, oxidizing antiseptic and osmotically active agents with subsequent exposure and drainage was performed using the novel device. Efficacy of the proposed hardware-software system was evaluated by comparing it with standard wound dressings by planimetry and wound biopsy results. Results ― according to study results the novel device reduces the time of wound healing by 26.1%, while the time to wound proliferation is 1.7 times shorter when compared with standard wound dressings. Conclusion ― the proposed method stimulates wound repair and limits purulent inflammation in infected wounds. Using the novel method of superficial wound management helps to prevent the development of re-infection and suppuration.

Chronic Wounds: Innovations in Diagnostics and Therapeutics

BACKGROUND

A major global health issue is the existence of chronic wounds. Appropriate diagnosis and treatment is essential to promote wound healing and prevent further complications. Traditional methods for treatment and diagnosis of chronic wounds have shown to be of limited effectiveness. Therefore, there is a need for the development of diagnostic and therapeutic innovations in chronic wound care.

OBJECTIVE

This mini-review aims to provide insight in the current knowledge of the wound healing process and the deficiencies encountered in chronic wounds, which provides a basis for the development of innovations in chronic wound care. Furthermore, promising diagnostic and therapeutic innovations will be highlighted.

METHODS

Literature was searched for recent articles (=<10 years) describing the current knowledge about the wound healing process and chronic wounds. The most promising diagnostic and therapeutic innovations were gathered from articles published in the past 5 years.

RESULTS/CONCLUSION

Wound healing is a well-organized process consisting of four phases: coagulation, inflammation, proliferation and wound remodelling. Chronic wounds often stagnate in the inflammatory phase and/or experience an impaired proliferative phase. This mini-review has demonstrated that increased knowledge about the processes involved in wound healing has paved the way for the development of new diagnostic tools and treatments for chronic wounds. Increased knowledge about bacterial invasion and infection in has encouraged researchers to develop diagnostic tools to help clinicians detect these phenomena appropriately and in time. Other researchers have shown that they are able to design/extract biochemical compounds that intervene in the disrupted healing processes in chronic wounds.

Clinical experience with surgical debridement and simultaneous meshed skin grafts in treating biofilm-associated infection: an exploratory retrospective pilot study

Current treatment guidelines for biofilm-associated infections (BAI) recommend repeated sharp/surgical debridement followed by treatment with antimicrobial agents until the wound becomes self-sustaining in terms of a positive wound-healing trajectory. However, complete removal of a biofilm is unlikely, and biofilms reform rapidly. We have treated BAI in patients with chronic diabetic ulcers using a meshed skin graft combined with negative pressure wound therapy (NPWT) immediately after surgical debridement, rather than waiting until the development of clean and healthy granulation tissue; the purpose of this exploratory study was to report the clinical results of this treatment strategy. This retrospective study included 75 patients with chronic diabetic ulcers who were treated for BAI by using surgical debridement, simultaneous meshed skin grafts, and NPWT. Healing time along with the percentage of complete wound closure within 12 weeks were evaluated; bacteria isolated from the wounds and their relation to the wound healing rate were investigated. All 75 wounds healed successfully, and the mean time for complete wound healing was 3.5 ± 1.8 weeks. In particular, 76% of wounds healed uneventfully without graft loss. A mean of 3.3 bacterial colonies/wound were isolated; however, no significant difference in wound healing was observed between the monomicrobial and polymicrobial groups. This exploratory study suggests that surgical debridement and simultaneous meshed skin grafts combined with NPWT may be successfully used to combat BAI in patients with chronic diabetic ulcers. We look forward to larger pivotal studies to confirm or refute these initially promising findings.

Effect of Native Type I Collagen with Polyhexamethylene Biguanide Antimicrobial on Wounds: Interim Registry Results

BACKGROUND

Biofilm can impair wound healing by maintaining an elevated, but ineffective, inflammatory state. This article describes interim results from the prospective RESPOND postmarketing registry evaluating the use of a native type 1, porcine collagen matrix with the embedded antimicrobial polyhexamethylene biguanide (PCMP) in the management of chronic wounds.

METHODS

Adults ≥18 years of age with ≥1 appropriate wound were eligible for inclusion. Data that were final on January 26, 2018 were included in this analysis. At week 0, wounds were cleaned, debrided, and prepared as necessary and PCMP was applied, with a dressing to fix it in place. Patients received standard wound care plus PCMP weekly, up to 24 weeks, at the investigator's discretion. At each visit, wounds were assessed for area and quality of granulation tissue.

RESULTS

Most common wound types (N = 63) were venous ulcers (28.6%), trauma and lacerations (22.2%), postsurgical open wounds (15.9%), pressure injuries (12.7%), and diabetic ulcers (9.5%). Median baseline wound area was 6.5 cm2; mean wound duration at baseline was 4 months. Of the 63 wounds, 43 (68.3%) achieved complete wound closure, 41 of 43 (95.3%) closed after PCMP treatment, and 2 of 43 (4.7%) after bridging to other modalities and surgical closure. Twelve out of 63 wounds were bridged to other modalities after PCMP treatment. Mean time to closure for PCMP wounds was 5.0 weeks.

CONCLUSIONS

PCMP appears to be a useful adjunct for treating various wound types. PCMP use should be considered when managing chronic or acute wounds.

Biofilm systems as tools in biotechnological production

The literature provides more and more examples of research projects that develop novel production processes based on microorganisms organized in the form of biofilms. Biofilms are aggregates of microorganisms that are attached to interfaces. These viscoelastic aggregates of cells are held together and are embedded in a matrix consisting of multiple carbohydrate polymers as well as proteins. Biofilms are characterized by a very high cell density and by a natural retentostat behavior. Both factors can contribute to high productivities and a facilitated separation of the desired end-product from the catalytic biomass. Within the biofilm matrix, stable gradients of substrates and products form, which can lead to a differentiation and adaptation of the microorganisms' physiology to the specific process conditions. Moreover, growth in a biofilm state is often accompanied by a higher resistance and resilience towards toxic or growth inhibiting substances and factors. In this short review, we summarize how biofilms can be studied and what most promising niches for their application can be. Moreover, we highlight future research directions that will accelerate the advent of productive biofilms in biology-based production processes.

Rapid Identification of Biofilms Using a Robust Multichannel Polymer Sensor Array

Infections caused by bacterial biofilms are challenging to diagnose because of the complexity of both the bacteria and the heterogeneous biofilm matrix. We report here a robust polymer-based sensor array that uses selective interactions between polymer sensor elements and the biofilm matrix to identify bacteria species. In this array, an appropriate choice of fluorophore enabled excimer formation and interpolymer FRET, generating six output channels from three polymers. Selective multivalent interactions of these polymers with the biofilm matrices caused differential changes in fluorescent patterns, providing a species-based signature of the biofilm. The real-world potential of the platform was further validated through identification of mixed-species bacterial biofilms and discrimination of biofilms in a mammalian cell-biofilm co-culture wound model.

Silver, biofilms and wounds: resistance revisited

Silver is added to an array of commercially available healthcare products including wound dressings. However, overuse of silver is being raised as a potential health concern due to the possible selection of tolerant or resistant bacteria and as a factor that may induce cross resistance to antibiotics. To date, there are only a limited number of studies that have documented evidence of silver resistance in bacteria isolated from medical situations. These studies have indicated low levels of silver resistance in bacteria. However, in comparison to antibiotics, only a small number of studies have been undertaken to investigate silver resistance. It is clear that more studies are required to confirm the most effective therapeutic levels of silver that are needed to kill microbes. In addition, it is probable that sub-therapeutic levels of silver may potentially select for enhanced microbial tolerance. Nevertheless, to date, there still remains very little evidence that silver resistance is a growing health concern in wound care; more studies are clearly needed to substantiate this concern, which has not been observed clinically to any major degree. The issue of biofilm tolerance to silver is more complicated and data on the effect of silver on biofilms is sparse at present.

Use of Native Type I Collagen Matrix Plus Polyhexamethylene Biguanide for Chronic Wound Treatment

Background:

Chronic wounds represent a significant financial burden to the healthcare system and a quality-of-life burden to patients. Many chronic wounds have elevated bioburden in the form of biofilm, which has been associated with delayed wound healing. This study examined the use of a native type I collagen matrix with the antimicrobial polyhexamethylene biguanide (PCMP) in the management of bioburden and treatment of chronic, nonhealing wounds over 12 weeks.

Methods:

A prospective case series of PCMP enrolled adults ≥18 years old with a nonhealing wound. At week 0, the wound was prepared by sharp or mechanical debridement. Patients received standard wound care plus PCMP applications at week 0 and then weekly up to week 12 at the investigator’s discretion. Dressings were applied over PCMP to fix it in place. At each visit, wounds were assessed for the extent of healing and signs of wound infection.

Results:

Of the 41 wounds studied, 44% were pressure ulcers, 22% were surgical wounds, 12% were venous ulcers, 10% were diabetic ulcers, and 12% were another type. The median (interquartile range) baseline wound area was 7.2 (14.9) cm², and the mean wound duration was 103 weeks. Of the 41 wounds, 73% demonstrated a reduction in wound area at 12 weeks, and 37% achieved complete wound closure, with a mean time of 6.7 weeks to complete closure.

Conclusion:

PCMP treatment appeared to positively impact the course of wound healing in a variety of complex, chronic wounds that were unresponsive to prior treatment.

Differentiating Nonpermanent Injectable Fillers: Prevention and Treatment of Filler Complications

Though the incidence of complications and adverse events with dermatological fillers is inherently low, practitioners should be well versed in both prevention of filler complications and the treatment algorithms for addressing "granulomas," nodules, infection, and vascular compromise. Appropriate preventative measures, coupled with timely and effective treatment, are critically important for patient safety and satisfaction. In addition to the preventive measures and treatment algorithms outlined here, the authors emphasize that the broad classification and treatment of nodules as "granulomas" is likely to lead to ineffective treatment, or worse, unnecessary exposure to incorrect treatment. In practice, nodules are classified and treated based on clinical manifestation (eg, late vs early or noninflammatory vs inflammatory) rather than on histology. Indeed, classification of a nodule as a granuloma requires a histological examination, rarely available (or necessary) in clinical practice to guide treatment. Thus, the apparent inflammatory nature of the nodule and the time of onset should drive treatment approach. The treatment algorithms presented here are based on these clinically meaningful parameters.

Recent perspectives on the molecular basis of biofilm formation by Pseudomonas aeruginosa and approaches for treatment and biofilm dispersal

Pseudomonas aeruginosa, a Gram-negative, rod-shaped bacterium causes widespread diseases in humans. This bacterium is frequently related to nosocomial infections such as pneumonia, urinary tract infections (UTIs) and bacteriaemia especially in immunocompromised patients. The current review focuses on the recent perspectives on biofilms formation by these bacteria. Biofilms are communities of microorganisms in which cells stick to each other and often adhere to a surface. These adherent cells are usually embedded within a self-produced matrix of extracellular polymeric substance (EPS). Pel, psl and alg operons present in P. aeruginosa are responsible for the biosynthesis of extracellular polysaccharide which plays an important role in cell surface interactions during biofilm formation. Recent studies suggested that cAMP signalling pathway, quorum-sensing pathway, Gac/Rsm pathway and c-di-GMP signalling pathway are the main mechanism that leads to the biofilm formation. Understanding the bacterial virulence depends on a number of cell-associated and extracellular factors and is very essential for the development of potential drug targets. Thus, the review focuses on the major genes involved in the biofilm formation, the state of art update on the biofilm treatment and the dispersal approaches such as targeting adhesion and maturation, targeting virulence factors and other strategies such as small molecule-based inhibitors, phytochemicals, bacteriophage therapy, photodynamic therapy, antimicrobial peptides and natural therapies and vaccines to curtail the biofilm formation by P. aeruginosa.

The Effect of Cryopreserved Human Placental Tissues on Biofilm Formation of Wound-Associated Pathogens

Biofilm, a community of bacteria, is tolerant to antimicrobial agents and ubiquitous in chronic wounds. In a chronic DFU (Diabetic Foot Ulcers) clinical trial, the use of a human cryopreserved viable amniotic membrane (CVAM) resulted in a high rate of wound closure and reduction of wound-related infections. Our previous study demonstrated that CVAM possesses intrinsic antimicrobial activity against a spectrum of wound-associated bacteria under planktonic culture conditions. In this study, we evaluated the effect of CVAM and cryopreserved viable umbilical tissue (CVUT) on biofilm formation of S. aureus and P. aeruginosa, the two most prominent pathogens associated with chronic wounds. Firstly, we showed that, like CVAM, CVUT released antibacterial activity against multiple bacterial pathogens and the devitalization of CVUT reduced its antibacterial activity. The biofilm formation was then measured using a high throughput method and an ex vivo porcine dermal tissue model. We demonstrate that the formation of biofilm was significantly reduced in the presence of CVAM- or CVUT-derived conditioned media compared to control assay medium. The formation of P. aeruginosa biofilm on CVAM-conditioned medium saturated porcine dermal tissues was reduced 97% compared with the biofilm formation on the control medium saturated dermal tissues. The formation of S. auerus biofilm on CVUT-conditioned medium saturated dermal tissues was reduced 72% compared with the biofilm formation on the control tissues. This study is the first to show that human cryopreserved viable placental tissues release factors that inhibit biofilm formation. Our results provide an explanation for the in vivo observation of their ability to support wound healing.

Topical chlorhexidine, povidone-iodine and erythromycin in the repair of traumatic ulcers on the rat tongue: Clinical, histological and microbiological evaluation

OBJECTIVE

This study investigated the effect of topical application of 0.12% chlorhexidine, 10% povidone-iodine and 50% erythromycin on the optimization of healing process of traumatic ulcers made on ventral tongue of rats.

DESIGN

Forty-Eight Wistar rats were randomly divided into four groups: control, chlorhexidine (Chx), povidone-iodine (PvI) and erythromycin (Er). An ulcer of 5 mm in diameter was made on the ventral tongue of the animals. After 24 h, a microbiological sample was taken and daily application of the substances started. Six animals each group were euthanized at 4 days and the others at 8 days postoperative, totaling three and seven days of treatment. Prior to euthanasia, a new microbiological collection was performed.

RESULTS

The experimental groups showed less area of residual ulcer. A significant difference was seen between the PvI and Chx in relation to the control after three days of treatment (p < 0.05). Although the experimental groups displayed greater newly formed epithelial area, there was no significant difference compared to the control (p > 0.05). Er exhibed the lowest inflammation scores after seven days of treatment (p < 0.05). PvI showed reduction of microorganisms at both times and under aerobic (p < 0.01 at 3 days and p < 0.001 at 7 days) and microaerophilic (p < 0.05) conditions. Er significantly reduced the count of microorganisms in aerobic condition when compared to control group (p < 0.05 at 3 days and p < 0.01 at 7 days).

CONCLUSIONS

All drugs promoted reduction of the microorganisms at the site of the injury, which may have a direct effect on the tissue repair process.