Role of anaerobes in polymicrobial communities and biofilms complicating diabetic foot ulcers

Infected tissues in the feet of people with diabetes in the form of a diabetic foot ulcer (DFU) present a complex pathology for clinicians to manage. This is partly attributed to the multi‐factorial nature of the disease, which may include; altered foot architecture leading to excessive plantar pressures and frictional forces peripheral arterial disease and loss of protective sensation. In addition, to the above co‐morbid variables, it is understood that a delayed wound healing state may be perpetuated by the presence of microorganisms residing in the wound tissue. The microbiology of chronic DFUs has often been reported as being polymicrobial. Of growing interest is the presence and potential role of anaerobic microorganisms in the pathology of DFUs and how they may contribute to the infective process or delayed healing. The presence of anaerobes in DFUs has been greatly underestimated, largely due to the limitations of conventional culture methods in identifying them from samples. Advancements in molecular and microscopy techniques have extended our view of the wound microbiome in addition to observing the growth and behaviour (planktonic or biofilm) of microorganisms in situ. This review paper will reflect on the evidence for the role and significance of anaerobes in DFUs and infection. A focus of this review will be to explore recent advancements in molecular genomics and microscopy techniques in order to better assess the roles of anaerobic bacteria in chronic DFUs and in biofilm‐based wound care.     

High‐dose folic acid and its effect on early stage diabetic foot ulcer wound healing

High‐dose folic acid (HDFA; vitamin B9)—5 mg, given daily, has not been evaluated as a treatment to improve early stage‐diabetic foot ulcer (ES‐DFU) wound healing. However, HDFA has been demonstrated to correct: (a) endothelial dysfunction and decreased nitric oxide (NO) bioavailability, associated with type‐2 diabetes mellitus (T2DM); and (b) hyperhomocysteinemia (HHcy) that may promote impaired DFU‐wound healing. Measures of wound area (cm²) reduction (wound closure; WC), over a 4‐week period (4 W‐WC), greater than 50% of the wound area, have been reported as a robust indicator of the potential for DFU‐wound healing. By using this model, we examined the effectiveness of a wound treatment in promoting progressive healing and complete wound closure for the chronic, nonhealing DFU‐wound. To investigate this possible relationship between HDFA and ES‐DFU wound healing, a retrospective cohort study of medical records, between November 2018 and April 2019, was performed for Veterans with T2DM and ES‐DFUs following treatment with HDFA. During the study period 29 (n = 29) Veterans with ES‐DFU wounds who received HDFA treatment were identified. Medical record reviews of this retrospective cohort of ES‐DFU Veterans receiving HDFA report 90% (26/29) experiencing complete DFU‐wound closure during the study period. Of the 29 Veterans with ES‐DFUs receiving HDFA, the medical records of nine (30%), with healed wounds, provided documentation suitable for 4 W‐WC, pre‐ and post‐HDFA treatment study comparisons. This study documents significant (P < .05) improvements comparing 4 W‐WC values for standard treatment for Veterans with poorly progressing, worsening or stagnating ES‐DFU‐wounds to those for the same subjects following HDFA treatment. These observations suggest that chronic ES‐DFUs treated with HDFA may experience significantly improved wound closure and complete healing (re‐epithelialization) when compared with standard treatments without HDFA. With validation from RCTs, HDFA may be established as an effective treatment to promote wound healing and closure for nonhealing ES‐DFUs.     

Rapid detection of biofilm by wound blotting following sharp debridement of chronic pressure ulcers predicts wound healing: A preliminary study

For optimal wound bed preparation, wound debridement is essential to eliminate bacterial biofilms. However, it is challenging for clinicians to determine whether the biofilm is completely removed. A newly developed biofilm detection method based on wound blotting technology may be useful. Thus, we aimed to investigate the effect of biofilm elimination on wound area decrease in pressure ulcers, as confirmed using the wound blotting method. In this retrospective observational study, we enrolled patients with pressure ulcers who underwent sharp debridement with pre‐ and post‐debridement wound blotting. Biofilm was detected on the nitrocellulose membrane using ruthenium red or alcian blue staining. Patients were included if the test was positive for biofilm before wound debridement. Percent decrease in wound area after 1 week was calculated as an outcome measure. We classified the wounds into a biofilm‐eliminated group and a biofilm‐remaining group based on the post‐debridement wound blotting result. Sixteen wound blotting samples from nine pressure ulcers were collected. The percent decrease in wound area was significantly higher in the biofilm‐eliminated group (median: 14.4%, interquartile range: 4.6%‐20.1%) than in the biofilm‐remaining group (median: ?14.5%, interquartile range: ?25.3%‐9.6%; P = .040). The presence of remaining biofilms was an independent predictor for reduced percent decrease in wound area (coefficient = ?22.84, P = .040). Biofilm‐based wound care guided by wound blotting is a promising measure to help clinicians eliminate bacterial bioburden more effectively for wound area reduction.     

Effect on total microbial load and community composition with two vs six‐week topical Cadexomer Iodine for treating chronic biofilm infections in diabetic foot ulcers

This study compares two vs six weeks of topical antimicrobial therapy with Cadexomer Iodine in patients with diabetic foot ulcers (DFUs) complicated by chronic biofilm infections. Patients with non‐healing DFUs with suspected chronic biofilm infections were eligible for enrolment. Patients were randomised to receive either two or six weeks of treatment with topical Cadexomer Iodine. Tissue biopsies from the ulcers were obtained pre‐and‐post treatment and underwent DNA sequencing and real‐time quantitative polymerase chain reaction (PCR) to determine the total microbial load, community composition, and diversity of bacteria. Scanning electron microscopy confirmed biofilm in all 18 ulcers with suspected chronic biofilm infections. Cadexomer Iodine resulted in 14 of 18 (78%) samples achieving a mean 0.5 log10 reduction in microbial load. Regardless of treatment duration, there was no statistical difference in the reduction of total microbial loads. No difference in the rate of wound healing in the two groups was seen at 6 weeks. Cadexomer Iodine reduces the total microbial load in DFUs with chronic biofilm infections and affects microbial community composition and diversity. All ulcers in both groups showed an initial reduction in wound size with application of Cadexomer Iodine, which might reflect its effect on biofilms.     

Biofilms in chronic wounds

Chronic wounds including diabetic foot ulcers, pressure ulcers, and venous leg ulcers are a worldwide health problem. It has been speculated that bacteria colonizing chronic wounds exist as highly persistent biofilm communities. This research examined chronic and acute wounds for biofilms and characterized microorganisms inhabiting these wounds. Chronic wound specimens were obtained from 77 subjects and acute wound specimens were obtained from 16 subjects. Culture data were collected using standard clinical techniques. Light and scanning electron microscopy techniques were used to analyze 50 of the chronic wound specimens and the 16 acute wound specimens. Molecular analyses were performed on the remaining 27 chronic wound specimens using denaturing gradient gel electrophoresis and sequence analysis. Of the 50 chronic wound specimens evaluated by microscopy, 30 were characterized as containing biofilm (60%), whereas only one of the 16 acute wound specimens was characterized as containing biofilm (6%). This was a statistically significant difference ( p <0.001). Molecular analyses of chronic wound specimens revealed diverse polymicrobial communities and the presence of bacteria, including strictly anaerobic bacteria, not revealed by culture. Bacterial biofilm prevalence in specimens from chronic wounds relative to acute wounds observed in this study provides evidence that biofilms may be abundant in chronic wounds.     

Statins may be associated with six‐week diabetic foot ulcer healing

Diabetic foot ulcers (DFUs) affect 1.5 million Americans annually, of which only a minority heal with standard care, and they commonly lead to amputation. To improve care, investigations are underway to better understand DFU pathogenesis and develop more effective therapies. Some currently used medications may improve healing. One small, randomized clinical trial found statins improve DFU healing. In this secondary analysis of a large multisite prospective observational cohort of 139 patients with DFUs receiving standard care, we investigated whether there was an association between 6‐week DFU wound size reduction and use of a variety of medications including alpha‐blockers, beta‐blockers, angiotensin converting enzyme inhibitors (ACEi) and statins. We found no significant (p < 0.05) association between six‐week wound reduction and use of any of the evaluated drugs; however, statins did trend toward an association (p = 0.057). This suggests a potential benefit of statins on DFU healing, and larger, targeted studies are warranted.     

A clinical trial of Integra Template for diabetic foot ulcer treatment

Individuals with diabetes mellitus are at an increased risk of developing a diabetic foot ulcer (DFU). This study evaluated the safety and efficacy of Integra Dermal Regeneration Template (IDRT) for the treatment of nonhealing DFUs. The Foot Ulcer New Dermal Replacement Study was a multicenter, randomized, controlled, parallel group clinical trial conducted under an Investigational Device Exemption. Thirty‐two sites enrolled and randomized 307 subjects with at least one DFU. Consented patients were entered into the 14‐day run‐in phase where they were treated with the standard of care (0.9% sodium chloride gel) plus a secondary dressing and an offloading/protective device. Patients with less than 30% reepithelialization of the study ulcer after the run‐in phase were randomized into the treatment phase. The subjects were randomized to the control treatment group (0.9% sodium chloride gel; n = 153) or the active treatment group (IDRT, n = 154). The treatment phase was 16 weeks or until confirmation of complete wound closure (100% reepithelialization of the wound surface), whichever occurred first. Following the treatment phase, all subjects were followed for 12 weeks. Complete DFU closure during the treatment phase was significantly greater with IDRT treatment (51%) than control treatment (32%; p = 0.001) at sixteen weeks. The median time to complete DFU closure was 43 days for IDRT subjects and 78 days for control subjects in wounds that healed. The rate of wound size reduction was 7.2% per week for IDRT subjects vs. 4.8% per week for control subjects (p = 0.012). For the treatment of chronic DFUs, IDRT treatment decreased the time to complete wound closure, increased the rate of wound closure, improved components of quality of life and had less adverse events compared with the standard of care treatment. IDRT could greatly enhance the treatment of nonhealing DFUs.     

Evidence of differential microbiomes in healing versus non‐healing diabetic foot ulcers prior to and following foot salvage therapy

Diabetic foot ulcers (DFU) contribute to 80% of lower extremity amputations. Although physicians currently rely on clinical signs along with non‐specific biomarkers of infection, such as erythrocyte sedimentation rate and C‐reactive protein, to diagnose and monitor DFU, there is no specific and sensitive measure available to monitor or prognosticate the success of foot salvage therapy (FST). To address this we performed a prospective, observational microbiome analysis to test the hypotheses that: (i) the initial microbiomes of healed versus non‐healed DFU are distinct; (ii) the microbial load, diversity and presence of pathogenic organism of the DFU change in response to antibiotics treatment; and (iii) the changes in the DFU microbiome during treatment are prognostic of clinical outcome. To test this, microbiome analyses were performed on 23 DFU patients undergoing FST, in which wound samples were collected at zero, four, and eight weeks following wound debridement and antibiotics treatment. Bacterial abundance was determined using quantitative polymerase chain reaction (qPCR). Eleven patients healed their DFU, while FDT failed to heal DFU in the other 12 patients. Microbiome results demonstrated that healing DFUs had a larger abundance Actinomycetales and Staphylococcaceae (p < 0.05), while DFUs that did not heal had a higher abundance of Bacteroidales and Streptococcaceae (p < 0.05). FST marked increases Actinomycetales in DFU, and this increase is significantly greater in patients that healed (p < 0.05). Future studies to confirm the differential microbiomes, and that increasing Actinomycetales is prognostic of successful FST are warranted. Statement of Clinical Significance: Tracking changes in the prevalence of pathogens in diabetic foot ulcers may be a clinical tool for monitoring treatment response to foot salvage therapy and prognosticating the need for further surgical intervention. The initial wound sample microbiome may provide important prognostic information on the eventual clinical outcome of foot salvage therapy. It may serve as an important clinical tool for patient counseling and making surgical decision of pursuing foot salvage versus amputation. © 2019 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 37:1596–1603, 2019.     

Altered ECM deposition by diabetic foot ulcer‐derived fibroblasts implicates fibronectin in chronic wound repair

Current chronic wound treatments often fail to promote healing of diabetic foot ulcers (DFU), leading to amputation and increased patient morbidity. A critical mediator of proper wound healing is the production, assembly, and remodeling of the extracellular matrix (ECM) by fibroblasts. However, little is known about how these processes are altered in fibroblasts within the DFU microenvironment. Thus, we investigated the capacity of multiple, primary DFU‐derived fibroblast strains to express, produce, and assemble ECM proteins compared to diabetic patient‐derived fibroblasts and healthy donor‐derived fibroblasts. Gene expression microarray analysis showed differential expression of ECM and ECM‐regulatory genes by DFU‐derived fibroblasts which translated to functional differences in a 3D in vitro ECM tissue model. DFU‐derived fibroblasts produced thin, fibronectin‐rich matrices, and responded abnormally when challenged with transforming growth factor‐beta, a key regulator of matrix production during healing. These results provide novel evidence that DFU‐derived fibroblasts contribute to the defective matrices of DFUs and chronic wound pathogenesis.     

Outcome predictors for wound healing in patients with a diabetic foot ulcer

The aim of this study was to identify diabetic foot ulcer (DFU) patients at risk for the development of a hard‐to‐heal wound. This is a post‐hoc analysis of a prospective cohort study including a total of 208 patients with a DFU. The primary endpoints were time to healing and the development of a hard‐to‐heal‐wound. Univariable and multivariable logistic and Cox regression analysis were used to study the associations of patient characteristics with the primary endpoints. The number of previous DFUs [odds ratio (OR): 1.42, 95% confidence interval (CI): 1.01‐1.99, P = .04], University of Texas (UT) classification grade 2 (OR: 2.93, 95% CI: 1.27‐6.72, P = .01), UT classification grade 3 (OR: 2.80, 95% CI: 1.17‐6.71, P = .02), and a diagnosis of foot stand deformation (OR: 1.54, 95% CI: 0.77‐3.08, P = .05) were significantly associated with the development of a hard‐to‐heal wound. Only UT classification grade 3 (HR: 0.61, 95% CI: 0.41‐0.90, P = .01) was associated with time to healing. The number of previous DFUs, UT classification grade, and a diagnosis of foot deformation are significantly associated with development of a hard‐to‐heal wound in patients with a DFU. The only predictor significantly associated with time to healing was UT classification grade 3. These patient characteristics can be used to identify patients at risk for the development of hard‐to‐heal wounds, who might need an early intervention to prevent wound problems.     

A multicentre prospective randomised controlled comparative parallel study of dehydrated human umbilical cord (EpiCord) allograft for the treatment of diabetic foot ulcers

The aim of this study was to determine the safety and effectiveness of dehydrated human umbilical cord allograft (EpiCord) compared with alginate wound dressings for the treatment of chronic, non‐healing diabetic foot ulcers (DFU). A multicentre, randomised, controlled, clinical trial was conducted at 11 centres in the United States. Individuals with a confirmed diagnosis of Type 1 or Type 2 diabetes presenting with a 1 to 15 cm² ulcer located below the ankle that had been persisting for at least 30 days were eligible for the 14‐day study run‐in phase. After 14 days of weekly debridement, moist wound therapy, and off‐loading, those with ≤30% wound area reduction post‐debridement (n = 155) were randomised in a 2:1 ratio to receive a weekly application of EpiCord (n = 101) or standardised therapy with alginate wound dressing, non‐adherent silicone dressing, absorbent non‐adhesive hydropolymer secondary dressing, and gauze bandage roll (n = 54). All wounds continued to have appropriate off‐loading during the treatment phase of the study. Study visits were conducted for 12 weeks. At each weekly visit, the DFU was cleaned and debrided as necessary, with the wound photographed pre‐ and post‐debridement and measured before the application of treatment group‐specific dressings. A follow‐up visit was performed at week 16. The primary study end point was the percentage of complete closure of the study ulcer within 12 weeks, as assessed by Silhouette camera. Data for randomised subjects meeting study inclusion criteria were included in an intent‐to‐treat (ITT) analysis. Additional analysis was conducted on a group of subjects (n = 134) who completed the study per protocol (PP) (EpiCord, n = 86, alginate, n = 48) and for those subjects receiving adequate debridement (EpiCord, n = 67, alginate, n = 40). ITT analysis showed that DFUs treated with EpiCord were more likely to heal within 12 weeks than those receiving alginate dressings, 71 of 101 (70%) vs 26 of 54 (48%) for EpiCord and alginate dressings, respectively, P = 0.0089. Healing rates at 12 weeks for subjects treated PP were 70 of 86 (81%) for EpiCord‐treated and 26 of 48 (54%) for alginate‐treated DFUs, P = 0.0013. For those DFUs that received adequate debridement (n = 107, ITT population), 64 of 67 (96%) of the EpiCord‐treated ulcers healed completely within 12 weeks, compared with 26 of 40 (65%) of adequately debrided alginate‐treated ulcers, P < 0.0001. Seventy‐five subjects experienced at least one adverse event, with a total of 160 adverse events recorded. There were no adverse events related to either EpiCord or alginate dressings. These results demonstrate the safety and efficacy of EpiCord as a treatment for non‐healing DFUs.     

Efficacy of a surfactant‐based wound dressing on biofilm control

The aim of this study was to evaluate the efficacy of both a nonantimicrobial and antimicrobial (1% silver sulfadiazine—SSD) surfactant‐based wound dressing in the control of Pseudomonas aeruginosa, Enterococcus sp, Staphylococcus epidermidis, Staphylococcus aureus, and methicillin‐resistant S. aureus (MRSA) biofilms. Anti‐biofilm efficacy was evaluated in numerous adapted American Standards for Testing and Materials (ASTM) standard biofilm models and other bespoke biofilm models. The ASTM standard models employed included the Minimum biofilm eradication concentration (MBEC) biofilm model (ASTM E2799) and the Centers for Disease Control (CDC) biofilm reactor model (ASTM 2871). Such bespoke biofilm models included the filter biofilm model and the chamberslide biofilm model. Results showed complete kill of microorganisms within a biofilm using the antimicrobial surfactant‐based wound dressing. Interestingly, the nonantimicrobial surfactant‐based dressing could disrupt existing biofilms by causing biofilm detachment. Prior to biofilm detachment, we demonstrated, using confocal laser scanning microscopy (CLSM), the dispersive effect of the nonantimicrobial surfactant‐based wound dressing on the biofilm within 10 minutes of treatment. Furthermore, the non‐antimicrobial surfactant‐based wound dressing caused an increase in microbial flocculation/aggregation, important for microbial concentration. In conclusion, this nonantimicrobial surfactant‐based wound dressing leads to the effective detachment and dispersion of in vitro biofilms. The use of surfactant‐based wound dressings in a clinical setting may help to disrupt existing biofilm from wound tissue and may increase the action of antimicrobial treatment.     

Anti-biofilm efficacy of a lactoferrin/xylitol wound hydrogel used in combination with silver wound dressings

With an epidemic increase in obesity combined with an ageing population, chronic wounds such as diabetic foot ulcers, pressure ulcers and venous leg ulcers are an increasing clinical concern. Recent studies have shown that bacterial biofilms are a major contributor to wound bioburden and interfere with the normal wound healing process; therefore, rational design of wound therapies should include analysis of anti‐biofilm characteristics. Studies using the combined treatment of bacterial biofilms with the innate immune molecule lactoferrin and the rare sugar‐alcohol xylitol have demonstrated an antimicrobial capacity against a clinical wound isolate. Studies presented here used a colony‐drip‐flow reactor biofilm model to assess the anti‐biofilm efficacy of a lactoferrin/xylitol hydrogel used in combination with commercially available silver‐based wound dressings. Log reductions in biofilm viability are compared with a commercially available wound hydrogel used in combination with the silver‐based wound dressings. For both a single species biofilm and a dual species biofilm, the lactoferrin/xylitol hydrogel in combination with the silver wound dressing Acticoat? had a statistically significant reduction in biofilm viability relative to the commercially available wound hydrogel. This study also demonstrated a statistical interaction between the lactoferrin/xylitol hydrogel and the silver wound dressing.     

Diabetic foot infection: A critical complication

The number of people in the world with diabetes has nearly quadrupled in the past 40 years. Current data show that 25% of these diabetics will develop a foot ulcer in their lifetime and that the cost of care for a diabetic foot ulcer (DFU) is over twice that of any other chronic ulcer aetiology. Microbial biofilm has been linked to both wound chronicity and infection. Close to 1 in 2 diabetics with a DFU are predicted to go on to develop a diabetic foot infection (DFI). The majority of these DFIs have been found to evolve even before the diabetic individual has received an initial referral for expert DFU management. Of these infected DFUs, less than half have been shown to heal over the next year; many of these individuals will require costly hospitalisation, and current data show that far too many DFIs will require extremity amputation to achieve infection resolution. The development of an infection in a DFU is critical at least in part because paradigms of infection prevention and management are evolving. The effectiveness of our current practice standards is being challenged by a growing body of research related to the prevalence and recalcitrance of the microbes in biofilm to topical and systemic antimicrobials. This article will review the magnitude of current challenges related to DFI prevention and management along with what is currently considered to be standard of care. These ideas will be compared and contrasted with what is known about the biofilm phenotype; then, considerations to support progress towards the development of more cost‐effective protocols of care are highlighted.     

Integrative analysis of miRNA and mRNA paired expression profiling of primary fibroblast derived from diabetic foot ulcers reveals multiple impaired cellular functions

Diabetic foot ulcers (DFUs) are one of the major complications of diabetes. Its molecular pathology remains poorly understood, impeding the development of effective treatments. Although it has been established that multiple cell types, including fibroblasts, keratinocytes, macrophages, and endothelial cells, all contribute to inhibition of healing, less is known regarding contributions of individual cell type. Thus, we generated primary fibroblasts from nonhealing DFUs and evaluated their cellular and molecular properties in comparison to nondiabetic foot fibroblasts (NFFs). Specifically, we analyzed both micro‐RNA and mRNA expression profiles of primary DFU fibroblasts. Paired genomic analyses identified a total of 331 reciprocal miRNA–mRNA pairs including 21 miRNAs (FC > 2.0) along with 239 predicted target genes (FC > 1.5) that are significantly and differentially expressed. Of these, we focused on three miRNAs (miR‐21‐5p, miR‐34a‐5p, miR‐145‐5p) that were induced in DFU fibroblasts as most differentially regulated. The involvement of these microRNAs in wound healing was investigated by testing the expression of their downstream targets as well as by quantifying cellular behaviors in prospectively collected and generated cell lines from 15 patients (seven DFUF and eight NFF samples). We found large number of downstream targets of miR‐21‐5p, miR‐34a‐5p, miR‐145‐5p to be coordinately regulated in mRNA profiles, which was confirmed by quantitative real‐time PCR. Pathway analysis on paired miRNA–mRNA profiles predicted inhibition of cell movement and cell proliferation, as well as activation of cell differentiation and senescence in DFU fibroblasts, which was confirmed by cellular assays. We concluded that induction of miR‐21‐5p, miR‐34a‐5p, miR‐145‐5p in DFU dermal fibroblasts plays an important role in impairing multiple cellular functions, thus contributing to overall inhibition of healing in DFUs.     

Noncontact,low‐frequency ultrasound as an effective therapy against Pseudomonas aeruginosa–infected biofilm wounds

Bacterial biofilms, a critical chronic wound mediator, remain difficult to treat. Energy‐based devices may potentially improve healing, but with no evidence of efficacy against biofilms. This study evaluates noncontact, low‐frequency ultrasound (NLFU) in the treatment of biofilm‐infected wounds. Six‐millimeter dermal punch wounds in rabbit ears were inoculated with 10⁷ colony‐forming units of Pseudomonas aeruginosa or left as sterile controls. A biofilm was established in vivo using our published model. NLFU treatment was carried out every other day or every day, with contralateral ear wounds acting as internal, untreated controls. Wounds were harvested for several quantitative endpoints and scanning electron microscopy to evaluate the biofilm structure. The P. aeruginosa biofilm consistently impaired wound epithelialization and granulation. NLFU, both every other day and every day, improved healing and reduced bacterial counts relative to untreated controls (p < 0.05). Scanning electron microscopy confirmed a qualitative decrease in bacteria after both treatments. NLFU also reduced inflammatory cytokine expression (p < 0.05). Our study suggests that NLFU is an effective therapy against P. aeruginosa wound biofilm. This represents the first in vivo evidence of energy‐based modalities' impact on wound biofilm, setting the foundation for future mechanistic studies. Continued wound care technology research is essential to improving our understanding, and treatment, of biofilm‐infected chronic wounds.     

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

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

Effect of honey dressing in the management of diabetic foot ulcers: A meta-analysis

A meta-analysis study to assess the effect of honey dressing (HD) in the management of diabetic foot ulcer (DFU). A comprehensive literature examination till January 2023 was implemented and 1794 linked studies were appraised. The picked studies contained 882 subjects with DFUs were in the picked studies' baseline, 424 of them were using HD, and 458 were using a control. Odds ratio (OR) in addition to 95% confidence intervals (CIs) were used to calculate the consequence of HD in the management of DFUs after DFU by the dichotomous and continuous styles and a fixed or random model. The HD applied to DFUs caused a significantly higher wound healing rate (OR, 2.06; 95% CI, 1.45-2.93, P < .001) and lower wound healing time (MD, −10.42; 95% CI, −16.27- −4.58, P < .001) compared with the control. The HD applied to DFUs caused a significantly higher wound healing rate and lower wound healing time compared with the control. Although precautions should be taken when commerce with the consequences since most of the picked studies for this meta-analysis was with low sample sizes.     

Delayed wound healing in diabetic (db/db) mice with Pseudomonas aeruginosa biofilm challenge: a model for the study of chronic wounds

Chronic wounds are a major clinical problem that lead to considerable morbidity and mortality. We hypothesized that an important factor in the failure of chronic wounds to heal was the presence of microbial biofilm resistant to antibiotics and protected from host defenses. A major difficulty in studying chronic wounds is the absence of suitable animal models. The goal of this study was to create a reproducible chronic wound model in diabetic mice by the application of bacterial biofilm. Six‐millimeter punch biopsy wounds were created on the dorsal surface of diabetic (db/db) mice, subsequently challenged with Pseudomonas aeruginosa (PAO1) biofilms 2 days postwounding, and covered with semiocclusive dressings for 2 weeks. Most of the control wounds were epithelialized by 28 days postwounding. In contrast, none of biofilm‐challenged wounds were closed. Histological analysis showed extensive inflammatory cell infiltration, tissue necrosis, and epidermal hyperplasia adjacent to challenged wounds—all indicators of an inflammatory nonhealing wound. Quantitative cultures and transmission electron microscopy demonstrated that the majority of bacteria were in the scab above the wound bed rather than in the wound tissue. The model was reproducible, allowed localized cutaneous wound infections without high mortality, and demonstrated delayed wound healing following a biofilm challenge. This model may provide an approach to study the role of microbial biofilms in chronic wounds as well as the effect of specific biofilm therapy on wound healing.