Non-antibiotic antimicrobial interventions and antimicrobial stewardship in wound care

Refining antimicrobial photodynamic therapy: effect of charge distribution and central metal ion in fluorinated porphyrins on effective control of planktonic and biofilm bacterial forms

Antibiotic resistance represents a pressing global health challenge, now acknowledged as a critical concern within the framework of One Health. Photodynamic inactivation of microorganisms (PDI) offers an attractive, non-invasive approach known for its flexibility, independence from microbial resistance patterns, broad-spectrum efficacy, and minimal risk of inducing resistance. Various photosensitizers, including porphyrin derivatives have been explored for pathogen eradication. In this context, we present the synthesis, spectroscopic and photophysical characteristics as well as antimicrobial properties of a palladium(II)-porphyrin derivative (PdF2POH), along with its zinc(II)- and free-base counterparts (ZnF2POH and F2POH, respectively). Our findings reveal that the palladium(II)-porphyrin complex can be classified as an excellent generator of reactive oxygen species (ROS), encompassing both singlet oxygen (Φ△ = 0.93) and oxygen-centered radicals. The ability of photosensitizers to generate ROS was assessed using a variety of direct (luminescence measurements) and indirect techniques, including specific fluorescent probes both in solution and in microorganisms during the PDI procedure. We investigated the PDI efficacy of F2POH, ZnF2POH, and PdF2POH against both Gram-negative and Gram-positive bacteria. All tested compounds proved high activity against Gram-positive species, with PdF2POH exhibiting superior efficacy, leading to up to a 6-log reduction in S. aureus viability. Notably, PdF2POH-mediated PDI displayed remarkable effectiveness against S. aureus biofilm, a challenging target due to its complex structure and increased resistance to conventional treatments. Furthermore, our results show that PDI with PdF2POH is more selective for bacterial than for mammalian cells, particularly at lower light doses (up to 5 J/cm2 of blue light illumination). This enhanced efficacy of PdF2POH-mediated PDI as compared to ZnF2POH and F2POH can be attributed to more pronounced ROS generation by palladium derivative via both types of photochemical mechanisms (high yields of singlet oxygen generation as well as oxygen-centered radicals). Additionally, PDI proved effective in eliminating bacteria within S. aureus-infected human keratinocytes, inhibiting infection progression while preserving the viability and integrity of infected HaCaT cells. These findings underscore the potential of metalloporphyrins, particularly the Pd(II)-porphyrin complex, as promising photosensitizers for PDI in various bacterial infections, warranting further investigation in advanced infection models.

Considerations for an ideal post-surgical wound dressing aligned with antimicrobial stewardship objectives: a scoping review

OBJECTIVE

Most surgical wounds heal by primary or secondary intention. Surgical wounds can present specific and unique challenges including wound dehiscence and surgical site infection (SSI), either of which can increase risk of morbidity and mortality. The use of antimicrobials to treat infection in these wounds is prevalent, but there is now an imperative to align treatment with reducing antimicrobial resistance and antimicrobial stewardship (AMS). The aim of this review was to explore the published evidence identifying general considerations/criteria for an ideal post-surgical wound dressing in terms of overcoming potential wound healing challenges (including infection) while supporting AMS objectives.

METHOD

A scoping review examining evidence published from 1954-2021, conducted by two authors acting independently. Results were synthesised narratively and have been reported in line with PRISMA Extension for Scoping Reviews.

RESULTS

A total of 819 articles were initially identified and subsequently filtered to 178 for inclusion in the assessment. The search highlighted six key outcomes of interest associated with post-surgical wound dressings: wound infection; wound healing; physical attributes related to comfort, conformability and flexibility; fluid handling (e.g., blood and exudate); pain; and skin damage.

CONCLUSION

There are several challenges that can be overcome when treating a post-surgical wound with a dressing, not least the prevention and treatment of SSIs. However, it is imperative that the use of antimicrobial wound dressings is aligned with AMS programmes and alternatives to active antimicrobials investigated.

Polyhexamethylene biguanide and its antimicrobial role in wound healing: a narrative review

A wound offers an ideal environment for the growth and proliferation of a variety of microorganisms which, in some cases, may lead to localised or even systemic infections that can be catastrophic for the patient; the development of biofilms exacerbates these infections. Over the past few decades, there has been a progressive development of antimicrobial resistance (AMR) in microorganisms across the board in healthcare sectors. Such resistant microorganisms have arisen primarily due to the misuse and overuse of antimicrobial treatments, and the subsequent ability of microorganisms to rapidly change and mutate as a defence mechanism against treatment (e.g., antibiotics). These resistant microorganisms are now at such a level that they are of grave concern to the World Health Organization (WHO), and are one of the leading causes of illness and mortality in the 21st century. Treatment of such infections becomes imperative but presents a significant challenge for the clinician in that treatment must be effective but not add to the development of new microbes with AMR. The strategy of antimicrobial stewardship (AMS) has stemmed from the need to counteract these resistant microorganisms and requires that current antimicrobial treatments be used wisely to prevent amplification of AMR. It also requires new, improved or alternative methods of treatment that will not worsen the situation. Thus, any antimicrobial treatment should be effective while not causing further development of resistance. Some antiseptics fall into this category and, in particular, polyhexamethylene hydrochloride biguanide (PHMB) has certain characteristics that make it an ideal solution to this problem of AMR, specifically within wound care applications. PHMB is a broad-spectrum antimicrobial that kills bacteria, fungi, parasites and certain viruses with a high therapeutic index, and is widely used in clinics, homes and industry. It has been used for many years and has not been shown to cause development of resistance; it is safe (non-cytotoxic), not causing damage to newly growing wound tissue. Importantly there is substantial evidence for its effective use in wound care applications, providing a sound basis for evidence-based practice. This review presents the evidence for the use of PHMB treatments in wound care and its alignment with AMS for the prevention and treatment of wound infection.

Diagnosis and treatment of infected wounds: A multi-centre audit of current clinical practice across the UK, Ireland and Scandinavia

AIMS AND OBJECTIVES

Surveillance of wound infection including signs of infection alongside antimicrobial usage (types, duration, frequency) can highlight knowledge gaps and inconsistencies. This manuscript aims to highlight these, identify and inform opportunities for practice improvement and to show impact of infection management practice may be having on the issue of antimicrobial resistance.

BACKGROUND

Infected wounds pose challenges to healthcare professionals. Balancing risk of wound deterioration and progression to systemic infection with appropriate use of antimicrobials is necessary to minimise development of resistance.

METHODS

Analysis consisted of a practice survey of 9661 wounds across 70 community sites over a period of one week. Data were collected from projects between 2017 and 2020. The form was available to providers within the UK, Ireland, Norway, Denmark, Sweden and Finland. EQUATOR research guidelines were followed; STROBE checklist for observational research reporting was completed.

RESULTS

Infection rates of 8.9% were reported from wounds assessed. These data indicate inconsistencies with diagnosis across practice with non-specialists more likely to be unsure of wound infection. Greater confidence in infection identification was observed as number of signs increased. Inconsistencies were also observed in appropriate treatment; antimicrobials were used in 35% of wounds considered not infected and not used in 41% of wounds that were identified as infected.

CONCLUSIONS

This investigation of infection management practice of over 9000 wounds provides an insight into diagnosis and treatment of infection. Inconsistencies in diagnosis and treatment of wound infections reported highlight the need for increased education, awareness of diagnosis and treatment of infection.

RELEVANCE TO CLINICAL PRACTICE

Variability in management of infected wounds highlights opportunities to aid more effective diagnosis and treatment of infected wounds. Incorporation of support tools or evidence-based pathways into practice may enhance confidence in management of local infection, balanced with appropriate use, potentially minimising resistance and improving outcomes.

Design and development of essential oil based nanoemulsion for topical application of triclosan for effective skin antisepsis

The skin acts as physical barrier to protect the body from external physical and chemical environment. When skin is infected, the outer epidermal barrier is compromised and colonized with microbial growth. Wound infection presents an immense burden in healthcare costs and decreased quality of life for patients. Topical application of nanoemulsions (NE) at pathological sites offers the potential advantage of direct drug delivery to the skin including potential for follicular targeting. This may have application in the improvement of skin antisepsis. In this study, NEs of triclosan (TSN) were prepared using hot high shear homogenization followed by ultrasonication. The oil phases comprised eucalyptus oil (EO) and olive oil (OO) and pseudo-ternary phase diagrams used to select optimum concentrations of surfactant. EO-based NEs had smaller droplet size and higher entrapment efficiency compared to OO-based NEs. Skin permeation was higher for EO-containing formulations, likely due to higher solubility of TSN in EO, smaller droplet size, low viscosity, and permeation enhancement effects of EO. Significantly, TSN was retained within the skin, demonstrating the potential of NEs for targeting hair follicular delivery within the skin, which may help improve the success of topical antisepsis.

Berberine coated biocomposite hemostatic film based alginate as absorbable biomaterial for wound healing

In wound treatment, severe bleeding and infection are always primary challenges. Therefore, it is highly desired to develop novel dressing with both hemostatic and antibacterial capability. Herein, a series of biocomposite hemostatic films (BHFs) based alginate/chitosan/collagen-berberine have been prepared and well characterized for further biofunctional study. We have demonstrated that the hemostatic and antibacterial activities were significantly enhanced by calcium/berberine dual-crosslinking system in the film. Through the synergistic effects, BHF-6B exhibited a shorter in vivo clotting and wound healing time than that of commercial dressing in rat tail amputation and full-thickness skin defect models. Additionally, BHF-6B showed excellent bacteriostatic activity with long-term effects. Moreover, hemolysis and cytotoxicity tests in vitro illustrated the prominent biocompatibility of the composite films. Notably, BHF-6B could be degraded quickly and completely in vivo. Overall, the present work indicated that the functionalized BHF-6B has great potential as an absorbable biomaterial for wound treatment.

Antibiotics-Free Compounds for Chronic Wound Healing

The rapid rise in the health burden associated with chronic wounds is of great concern to policymakers, academia, and industry. This could be attributed to the devastating implications of this condition, and specifically, chronic wounds which have been linked to invasive microbial infections affecting patients' quality of life. Unfortunately, antibiotics are not always helpful due to their poor penetration of bacterial biofilms and the emergence of antimicrobial resistance. Hence, there is an urgent need to explore antibiotics-free compounds/formulations with proven or potential antimicrobial, anti-inflammatory, antioxidant, and wound healing efficacy. The mechanism of antibiotics-free compounds is thought to include the disruption of the bacteria cell structure, preventing cell division, membrane porins, motility, and the formation of a biofilm. Furthermore, some of these compounds foster tissue regeneration by modulating growth factor expression. In this review article, the focus is placed on a number of non-antibiotic compounds possessing some of the aforementioned pharmacological and physiological activities. Specific interest is given to Aloevera, curcumin, cinnamaldehyde, polyhexanide, retinoids, ascorbate, tocochromanols, and chitosan. These compounds (when alone or in formulation with other biologically active molecules) could be a dependable alternative in the management or prevention of chronic wounds.

Estrategias de protección antimicrobiana en el cuidado de heridas: evidencia para el uso de apósitos recubiertos con DACC

BACKGROUND

Antimicrobial resistance (AMR) is one of the most serious health threats globally. The development of new antimicrobials is not keeping pace with the evolution of resistant microorganisms, and novel ways of tackling this problem are required. One of such initiatives has been the development of antimicrobial stewardship programmes (AMS). The use of wound dressings that employ a physical sequestration and retention approach to reduce bacterial burden offers a novel approach to support AMS. Bacterial-binding by dressings and their physical removal can minimise their damage and prevent the release of harmful endotoxins.

OBJECTIVE

To highlight AMS to promote the correct use of antimicrobials and to investigate how dialkylcarbamyl chloride (DACC)-coated dressings can support AMS.

METHOD

MEDLINE, Cochrane Database of Systematic Reviews, and Google Scholar were searched to identify articles relating to AMS, and the use of wound dressings in the prevention and treatment of wound infections. The evidence supporting alternative wound dressings that can reduce bioburden and prevent wound infection in a way that does not kill or damage the microorganisms were reviewed.

RESULTS

The evidence demonstrated that using bacterial-binding wound dressings that act in a physical manner (eg, DACC-coated dressings) to preventing infection in both acute and hard-to-heal wounds does not exacerbate AMR and supports AMS.

CONCLUSION

Some wound dressings work via a mechanism that promotes the binding and physical sequestration and removal of intact microorganisms from the wound bed (eg, a wound dressing that uses DACC technology to prevent/reduce infection). They provide a valuable tool that aligns with the requirements of AMS by effectively reducing wound bioburden without inducing/selecting for resistant bacteria.

Therapeutic index for local infections score (TILI): a new diagnostic tool

OBJECTIVE

Local wound infections are a major challenge for patients and health professionals. Various diagnostic and therapeutic options are available. However, a generally accepted standard is still lacking in Europe. The aim was to develop an easy-to-use clinical score for the early detection of local wound infections, as a basis for decision-making on antiseptic therapy or decolonisation.

METHOD

An interdisciplinary and interprofessional panel of experts from seven European countries was brought together to discuss the various aspects of diagnosing local wound infections.

RESULTS

The result was the adoption of the Therapeutic Index for Local Infections (TILI) score, developed in Germany by Initiative Chronische Wunden e.V., specifically for health professionals not specialised in wound care. Available in six European languages, the TILI score could also be adapted for different European countries, depending on their specific national healthcare requirements. The six clinical criteria for local wound infection are erythema to surrounding skin; heat; oedema, induration or swelling; spontaneous pain or pressure pain; stalled wound healing; and increase and/or change in colour or smell of exudate. Meeting all criteria indicates that antiseptic wound therapy could be started. Regardless of these unspecific clinical signs, there are also health conditions for the clinical situation which are a direct indication for antimicrobial wound therapy. These include the presence of wound pathogens, such as meticillin-resistant Staphylococcus aureus, septic surgical wound or the presence of free pus.

CONCLUSION

The development of the new internationally adapted TILI score, which could also be used by any caregiver in daily practice to diagnose local infections in acute and hard-to-heal wounds, is the result of expert consensus. However, the score system has to be validated through a clinical evaluation. This is to be performed in expert centres throughout Europe.

Antimicrobial Peptide Dendrimers and Quorum-Sensing Inhibitors in Formulating Next-Generation Anti-Infection Cell Therapy Dressings for Burns

Multidrug resistance infections are the main cause of failure in the pro-regenerative cell-mediated therapy of burn wounds. The collagen-based matrices for delivery of cells could be potential substrates to support bacterial growth and subsequent lysis of the collagen leading to a cell therapy loss. In this article, we report the development of a new generation of cell therapy formulations with the capacity to resist infections through the bactericidal effect of antimicrobial peptide dendrimers and the anti-virulence effect of anti-quorum sensing MvfR (PqsR) system compounds, which are incorporated into their formulation. Anti-quorum sensing compounds limit the pathogenicity and antibiotic tolerance of pathogenic bacteria involved in the burn wound infections, by inhibiting their virulence pathways. For the first time, we report a biological cell therapy dressing incorporating live progenitor cells, antimicrobial peptide dendrimers, and anti-MvfR compounds, which exhibit bactericidal and anti-virulence properties without compromising the viability of the progenitor cells.

Antimicrobial stewardship strategies in wound care: evidence to support the use of dialkylcarbamoyl chloride (DACC)- coated wound dressings

BACKGROUND

Traditionally, infections are treated with antimicrobials (for example, antibiotics, antiseptics, etc), but antimicrobial resistance (AMR) has become one of the most serious health threats of the 21st century (before the emergence of COVID-19). Wounds can be a source of infection by allowing unconstrained entry of microorganisms into the body, including antimicrobial-resistant bacteria. The development of new antimicrobials (particularly antibiotics) is not keeping pace with the evolution of resistant microorganisms and novel ways of addressing this problem are urgently required. One such initiative has been the development of antimicrobial stewardship (AMS) programmes, which educate healthcare workers, and control the prescribing and targeting of antimicrobials to reduce the likelihood of AMR. Of great importance has been the European Wound Management Association (EWMA) in supporting AMS by providing practical recommendations for optimising antimicrobial therapy for the treatment of wound infection. The use of wound dressings that use a physical sequestration and retention approach rather than antimicrobial agents to reduce bacterial burden offers a novel approach that supports AMS. Bacterial-binding by dressings and their physical removal, rather than active killing, minimises their damage and hence prevents the release of damaging endotoxins.

AIM

Our objective is to highlight AMS for the promotion of the judicious use of antimicrobials and to investigate how dialkylcarbamoyl chloride (DACC)-coated dressings can support AMS goals.

METHOD

MEDLINE, Cochrane Database of Systematic Reviews, and Google Scholar were searched to identify published articles describing data relating to AMS, and the use of a variety of wound dressings in the prevention and/or treatment of wound infections. The evidence supporting alternative wound dressings that can reduce bioburden and prevent and/or treat wound infection in a manner that does not kill or damage the microorganisms (for example, by actively binding and removing intact microorganisms from wounds) were then narratively reviewed.

RESULTS

The evidence reviewed here demonstrates that using bacterial-binding wound dressings that act in a physical manner (for example, DACC-coated dressings) as an alternative approach to preventing and/or treating infection in both acute and hard-to-heal wounds does not exacerbate AMR and supports AMS.

CONCLUSION

Some wound dressings work via a mechanism that promotes the binding and physical uptake, sequestration and removal of intact microorganisms from the wound bed (for example, a wound dressing that uses DACC technology to successfully prevent/reduce infection). They provide a valuable tool that aligns with the requirements of AMS (for example, reducing the use of antimicrobials in wound treatment regimens) by effectively reducing wound bioburden without inducing/selecting for resistant bacteria.

A new silver dressing, StopBac, used in the prevention of surgical site infections

Ideal dressings of surgical wounds should provide moist, semi-permeable, and antiseptic environments for optimal wound healing. To maximise patient comfort, surgical dressings must be hypoallergenic, not restrict movement, and allow patients to manage their personal hygiene. From the aspect of health care personnel, dressings should enable visual monitoring of the wound without the need for removing them, thus reducing the number of dressing changes. The active antimicrobial effect of silver cations has been demonstrated by many studies. StopBac is a unique surgical dressing based on the sol-gel process. Silver cations are bound in a colloidal solution in an organic-inorganic hybrid organosilicate oligomer. This gel is deposited on a pad using spray atomisation. The result is a polymer nanolayer matrix with prolonged and controlled release of silver ions. This pad forms part of a waterproof hypoallergenic transparent adhesive bandage. The goal of this study was to prospectively evaluate the ability of StopBac to prevent surgical site infections (SSIs) in patients after abdominal surgery. The secondary goal was to compare costs and determine the properties of this new material. A total of 32 patients were included in the study. The patients were followed up until their surgical wounds healed completely. An SSI occurred only in one patient.

A porcine model of subcutaneous Staphylococcus aureus infection: a pilot study

In this descriptive pilot study, we aim to establish a porcine Staphylococcus aureus skin infection model by subcutaneous injection (s.c.) of the porcine S54F9 S. aureus strain in the groin area. Six pigs were used in the study: Five pigs were injected with S. aureus, inocula ranging from 7 × 10³ to 5 × 10⁷ colony-forming units per kg bodyweight; one pig was injected with saline exclusively. Lesions were recorded up to 6 days postinoculation using clinical evaluation, ultrasound evaluation, microbiology, flow cytometry, and pathology. Inoculation gave rise to lesions ranging from localized skin infection, that is, minute histological changes, intracellular infection, and macroscopic abscess formation with sequestration of soft tissue, to generalized infection and development of disseminated intravascular coagulation necessitating euthanasia only 10 h after inoculation. Ultrasound assessment of maximum width and characteristics was not able to disclose the progress of the local infection. Flow cytometry and immunohistochemistry revealed the participation of γδT cells in the immune response. In conclusion, we did see a graded inflammatory response associated with the dose of s.c. inoculated bacteria, which may be useful for studying, in particular, the interaction of bacteria and inflammatory mononuclear cell populations. It needs to be investigated if the model is discriminatory and robust.

Antimicrobial stewardship of antiseptics that are pertinent to wounds: the need for a united approach

Long before the nature of infection was recognized, or the significance of biofilms in delayed healing was understood, antimicrobial agents were being used in wound care. In the last 70 years, antibiotics have provided an effective means to control wound infection, but the continued emergence of antibiotic-resistant strains and the documented antibiotic tolerance of biofilms has reduced their effectiveness. A range of wound dressings containing an antimicrobial (antibiotic or non-antibiotic compound) has been developed. Whereas standardized methods for determining the efficacy of non-antibiotic antimicrobials in bacterial suspension tests were developed in the early twentieth century, standardized ways of evaluating the efficacy of antimicrobial dressings against microbial suspensions and biofilms are not available. Resistance to non-antibiotic antimicrobials and cross-resistance with antibiotics has been reported, but consensus on breakpoints is absent and surveillance is impossible. Antimicrobial stewardship is therefore in jeopardy. This review highlights these difficulties and in particular the efficacy of current non-antibiotic antimicrobials used in dressings, their efficacy, and the challenges of translating in vitro efficacy data to the efficacy of dressings in patients. This review calls for a unified approach to developing standardized methods of evaluating antimicrobial dressings that will provide an improved basis for practitioners to make informed choices in wound care.

Bacteriophages, a New Therapeutic Solution for Inhibiting Multidrug-Resistant Bacteria Causing Wound Infection: Lesson from Animal Models and Clinical Trials

Wound infection kills a large number of patients worldwide each year. Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, and Pseudomonas aeruginosa are the most important colonizing pathogens of wounds that, with various virulence factors and impaired immune system, causes extensive tissue damage and nonhealing wounds. Furthermore, the septicemia caused by these pathogens increases the mortality rate due to wound infections. Because of the prevalence of antibiotic resistance in recent years, the use of antibiotics to inhibit these pathogens has been restricted, and the topical application of antibiotics in wound infections increases antibiotic resistance. Therefore, finding a new therapeutic strategy against wound infections is so essential since these infections have a destructive effect on the patient’s mental health and high medical costs. In this review, we discussed the use of phages for the prevention of multidrug-resistant (MDR) bacteria, causing wound infection and their role in wound healing in animal models and clinical trials. The results showed that phages have a high ability to inhibit different wound infections caused by MDR bacteria, heal the wound faster, have lower side effects and toxicity, destroy bacterial biofilm, and they are useful in controlling immune responses. Many studies have used animal models to evaluate the function of phages, and this study appears to have a positive impact on the use of phages in clinical practice and the development of a new therapeutic approach to control wound infections, although there are still many limitations.

Risk and clinical impact of bacterial resistance/susceptibility to silver-based wound dressings: a systematic review

Objective:

To perform a systematic review of the literature on bacterial resistance, tolerance and susceptibility of silver within the context of wound therapy using silver-based dressings.

Methods:

A literature search was carried out using PubMed, Embase and Cochrane Library databases, the focus was whether results from microbiological experimental in vitro tests with reference strains and clinical wound isolates are reflected in clinical practice with regards to their ‘resistance’ profiles, comparable with those observed for antibiotics. The search results were allocated to six categories: resistance and resistance mechanism, in vitro tests with standard strains and wound isolates, prevalence and incidence, impact on clinical practice and impact on antibiotic therapy as well as reviews, expert opinions and consensus.

Results:

Based on all findings of the literature, it cannot be confirmed that a related clinical resistance to silver-ions in silver-based dressings has clinical impact, although endogenous and exogenous genetic resistance patterns have been described and intensively investigated. A translation of these genetic resistance-expression structures to phenotypic appearances, similar to those known for antibiotics, has not been demonstrated for silver in the literature.

Conclusion:

It can be concluded that there is no definitive evidence available and further studies should be conducted.

Efficacy of Using Probiotics with Antagonistic Activity against Pathogens of Wound Infections: An Integrative Review of Literature

The skin and its microbiota serve as physical barriers to prevent invasion of pathogens. Skin damage can be a consequence of illness, surgery, and burns. The most effective wound management strategy is to prevent infections, promote healing, and prevent excess scarring. It is well established that probiotics can aid in skin healing by stimulating the production of immune cells, and they also exhibit antagonistic effects against pathogens via competitive exclusion of pathogens. Our aim was to conduct a review of recent literature on the efficacy of using probiotics against pathogens that cause wound infections. In this integrative review, we searched through the literature published in the international following databases: PubMed, ScienceDirect, Web of Science, and Scopus using the search terms “probiotic” AND “wound infection.” During a comprehensive review and critique of the selected research, fourteen in vitro studies, 8 animal studies, and 19 clinical studies were found. Two of these in vitro studies also included animal studies, yielding a total of 39 articles for inclusion in the review. The most commonly used probiotics for all studies were well-known strains of the species Lactobacillus plantarum, Lactobacillus casei, Lactobacillus acidophilus, and Lactobacillus rhamnosus. All in vitro studies showed successful inhibition of chosen skin or wound pathogens by the selected probiotics. Within the animal studies on mice, rats, and rabbits, probiotics showed strong opportunities for counteracting wound infections. Most clinical studies showed slight or statistically significant lower incidence of surgical site infections, foot ulcer infection, or burn infections for patients using probiotics. Several of these studies also indicated a statistically significant wound healing effect for the probiotic groups. This review indicates that exogenous and oral application of probiotics has shown reduction in wound infections, especially when used as an adjuvant to antibiotic therapy, and therefore the potential use of probiotics in this field remains worthy of further studies, perhaps focused more on typical skin inhabitants as next-generation probiotics with high potential.

Non-antibiotic antimicrobial agents to combat biofilm-forming bacteria

Biofilms can be produced by multiple species or by a single strain of bacteria. The biofilm state enhances the resistance of the resident microorganisms to antimicrobial agents by producing extracellular polymeric substances. Typically, antibiotics are used to stop the growth of bacteria, but emerging resistance has limited their effectiveness. Bacteria in biofilms are less susceptible to antibiotics compared with their free-floating state, as biofilms impair antibiotic penetration. To obviate this challenge, non-antibiotic antimicrobial agents are needed. This review describes two classes of these agents, namely antimicrobial nanoparticles and antimicrobial peptides. Applications of these antimicrobials in the food industry and medical applications are discussed, and the directions for future research are highlighted.

Treating drug-resistant wound pathogens with non-medicated dressings: an in vitro study

Objective:

To assess the in vitro antimicrobial performance of a non-medicated hydro-responsive wound dressing (HRWD) on the sequestration and killing of wound relevant microorganisms found on the World Health Organization (WHO) priority pathogens list.

Methods:

Suspensions of Pseudomonas aeruginosa, Acinetobacter baumannii and methicillin-resistant Staphylococcus aureus (MRSA) were placed on petri dishes. Dressings were each placed on top, incubated for 30 minutes and then removed from the inoculated petri dish. The surface of the dressings previously in contact with the bacterial suspensions were placed directly onto a tryptone soy agar (TSA) plate and incubated for 24 hours. Dressings were then removed from the TSA plate and the level of bacterial growth on the plates was assessed. Sequestered microorganism viability was assessed using LIVE/DEAD viability kits and visualisation by epifluorescence.

Results:

Our results indicated that HRWDs sequester and retain Pseudomonas aeruginosa, Acinetobacter baumannii and MRSA within the dressing. Non-medicated HRWDs containing bound PHMB (polyhexamethylene biguanide, HRWD+PHMB) killed the microorganisms sequestered within the dressing matrix.

Conclusion:

These data suggest that non-medicated HRWD+PHMB is an effective against WHO priority pathogens and promoting goal of antimicrobial stewardship in wound care.

Appropriate use of dressings containing nanocrystalline silver to support antimicrobial stewardship in wounds

Antimicrobial resistance is an ever-increasing global concern, with the era of untreatable infection becoming a reality. Wound care is no exception, with increasing issues of antibiotic-resistant infections across different wound types and care settings. Antibiotic resistance and stewardship have been the priority for most strategic interventions so far; however, in wound care, alternative or supplementary strategies using antiseptics should be considered. Antiseptics such as silver can provide effective cidal activity across a broad range of wound pathogens, assuming they are used at the correct level for an appropriate duration. Evidence summarised in this manuscript suggests that effective antiseptics, such as nanocrystalline silver, have an increasing body of evidence in support of their use to minimise transmission of antibiotic-resistant organisms as part of institutional infection control procedures and, in addition, through appropriate early use and stewardship on local wound infections, in conjunction with local procedures, to minimise the need for systemic antibiotic therapy. Engagement, alignment, and collaboration between wound care professionals and wider related teams and governments on antimicrobial stewardship, and the potential role of antiseptics within this, will help to generate further evidence for such interventions in the fight against antimicrobial-resistant infections in wound care.