Randomized clinical study to compare negative pressure wound therapy with simultaneous saline irrigation and traditional negative pressure wound therapy for complex foot infections

The aim of this study was to compare the efficacy of different negative pressure wound therapy (NPWT) devices and NPWT with and without simultaneous irrigation in patients admitted to hospital with moderate and severe foot infections. Ninety patients were randomized in a 12‐week prospective, randomized noninferiority trial to compare wound healing in patients with moderate and severe infected foot wounds treated with NPWT after surgery. Inclusion criteria included ABI > 0.5 or toe pressures >30 PVR/mmHg, >18 years of age and exclusion included active Charcot arthropathy, collagen vascular disease, HIV, and hypercoagulable state. We compared two different traditional devices, NPWT‐K (KCI, VAC Ulta) and NPWT‐C (Cardinal, PRO), and NPWT‐I with saline irrigation (Cardinal, PRO). All patients had therapy delivered at 125 mmHg continuous pressure. In patients who received simultaneous saline irrigation (NPWT‐I), the administration rate was 15 ml per hour. The primary outcome was the proportion of healed wounds in 12 weeks. Secondary outcomes included surgical wound closure, number of surgeries, length of stay, and time to wound healing. Continuous data was presented as mean ± standard deviation. Analysis of variance was used to compare continuous variables and chi‐square to compare dichotomous variables with an alpha of 0.05. There were no differences in outcomes among NPWT‐I, NPWT‐C, and NPWT‐K groups in proportion of healed wounds (63.3%, 50.0%, 46.7% p = 0.39), surgical wound closure (83.3%, 80.0%, 63.3%, p = 0.15), number of surgeries (2.0 ± 0.49, 2.4 ± 0.77, 2.4 ± 0.68, p = 0.06), length of stay (16.3 ± 15.7, 14.7 ± 7.4, 15.3 ± 10.5 days, p = 0.87), time to wound healing (46.2 ± 22.8, 40.9 ± 18.8, 45.9 ± 28.3 days, p = 0.78). We did not identify any significant differences in clinical outcomes or adverse events between patients treated with different NPWT devices or NPWT with and without irrigation.     

The impact of negative‐pressure wound therapy with instillation on wounds requiring operative debridement: Pilot randomised,controlled trial

Presence of bacteria in wounds can delay healing. Addition of a regularly instilled topical solution over the wound during negative‐pressure wound therapy (NPWT) may reduce bioburden levels compared with standard NPWT alone. We performed a prospective, randomised, multi‐centre, post‐market trial to compare effects of NPWT with instillation and dwell of polyhexamethylene biguanide solution vs NPWT without instillation therapy in wounds requiring operative debridement. Results showed a significantly greater mean decrease in total bacterial counts from time of initial surgical debridement to first dressing change in NPWT plus instillation (n = 69) subjects compared with standard NPWT (n = 63) subjects (?0.18 vs 0.6 log₁₀ CFU/g, respectively). There was no significant difference between the groups in the primary endpoint of required inpatient operating room debridements after initial debridement. Time to readiness for wound closure/coverage, proportion of wounds closed, and incidence of wound complications were similar. NPWT subjects had 3.1 times the risk of re‐hospitalisation compared with NPWT plus instillation subjects. This study provides a basis for exploring research options to understand the impact of NPWT with instillation on wound healing.     

Impact of negative‐pressure wound therapy on bacterial behaviour and bioburden in a contaminated full‐thickness wound

The use of negative‐pressure wound therapy (NPWT) has displayed significant clinical benefits in the healing of infected wounds. However, the effects of NPWT on bacterial colonisation and infection of traumatic wounds has been controversial. The aim of this study is to evaluate the impact of NPWT treatment in rabbits with a contaminated full‐thickness wound on bacterial behaviour, including colony morphology, spatial distribution, fissional proliferation, and bacterial bioburden. Full‐thickness wounds were created on the back of rabbits, and were inoculated with bioluminescent Staphylococcus aureus. The wounds were treated with sterile gauze dressings and NPWT with continuous negative pressure (−125 mm Hg). Wound samples were harvested on days 0 (6 hours after bacterial inoculation), 2, 4, 6, and 8 at the centre of wound beds before irrigation. Scanning electron microscopy and transmission electron microscopy (TEM) analyses were performed to determine the characteristic bacteriology. Laser scanning confocal microscopy was performed to obtain bioluminescent images, which were used to observe spatial distribution of the GFP‐labelled S. aureus within the tissue and quantify the bacterial bioburden. NPWT resulted in sparse amounts of scattered bacteria on the wound surface or as sparsely spaced single colonies within the tissue. Wound bioburden on day 8 in the NPWT and gauze groups was 34.6 ± 5.5% and 141.9 ± 15.4% of the baseline values (N = 6), respectively (P < .0001). TEM showed a lack of S. aureus active fission within NPWT‐treated tissue. NPWT can impact S. aureus colony morphology and spatial distribution both on the surface and within wound tissue, and reduce S. aureus as early as 48 hours after therapy initiation. Additionally, NPWT inhibits bacterial fissional proliferation in microcolonies.     

Negative pressure wound therapy is associated with up‐regulation of bFGF and ERK1/2 in human diabetic foot wounds

Chronic foot wounds are a leading cause of morbidity and hospitalization for patients with diabetes. Negative pressure wound therapy (NPWT) is known to promote healing of diabetic foot wounds, but the underlying molecular mechanisms remain elusive. We propose to gain molecular insights into the wound healing promoting signals underlying the effects of NPWT on diabetic foot wounds in humans. We assessed 30 patients with diabetic foot ulcers. Of these cases, 15 were treated with NPWT, while 15 patients were treated with traditional gauze therapy. Granulated tissue was harvested before and after treatment in both patient groups and histologically analyzed with hematoxylin & eosin as well as Masson's trichrome staining methods. Immunohistochemistry and Western blot analysis was performed to evaluate expression of basic fibroblast growth factor (bFGF) and extracellular signal‐regulated kinase (ERK)1/2, previously associated with promoting cellular growth and/or wound healing. Unlike controls, the wounds in the NPWT‐treated diabetic patients developed characteristic features of granulated tissue with increased collagen deposition. Immunohistochemical analysis also revealed an increase in bFGF levels in NPWT‐treated patients. Western blot analysis further showed a significant up‐regulation of bFGF and phosphorylated ERK1/2 protein levels in the NPWT‐treated diabetic patients vs. controls. Our studies reveal that NPWT is associated with an up‐regulation of bFGF and ERK1/2 signaling, which may be involved in promoting the NPWT‐mediated wound healing response.     

Evaluation of the use of recombinant human basic fibroblast growth factor in combination with negative pressure wound therapy with instillation and dwell time in porcine full‐thickness wound model

NPWT with instillation and dwell time (NPWTi‐d), which combines NPWT with wound irrigation, has been clinically applied as a more effective treatment than conventional NPWT. Commercially available recombinant human basic fibroblast growth factor (rh‐bFGF) has been demonstrated to be beneficial for use over the wound beds. The objective of this study was to evaluate the effectiveness of combined treatment with NPWTi‐d and rh‐bFGF. Six pigs received 12 full‐thickness excisional skin wounds and were treated with six different treatment groups for each pair. The treatment regimens were composed NPWTi‐d, NPWT, or advanced wound care with or without rh‐bFGF. On day 6, the minimum granulation tissue thickness and blood vessel number of the group of combined treatment with NPWTi‐d and rh‐bFGF spray were significantly greater than that of the control group. Combined treatment with NPWTi‐d and rh‐bFGF spray reads to good granulation tissue formation and vascularization for accelerating wound healing.     

Negative pressure wound treatment with computer‐controlled irrigation/instillation decreases bacterial load in contaminated wounds and facilitates wound closure

Microbial wound contamination is known to be a hindrance to wound healing. Negative pressure wound therapy (NPWT) with or without irrigation is known to optimise conditions in problem wounds. The aim of this study was to investigate the influence of computer‐controlled wound irrigation with NPWT on the bacterial load in contaminated wounds. A total of 267 patients were treated with NPWT with automated instillation because of problematic wounds using an antiseptic instillation solution. In 111 patients, a minimum of 4 operative procedures were necessary, and swabs were taken at least at the first and at the fourth operation in a standardised procedure. The number of different bacteria and the amount of bacteria were analysed during the course. In a subgroup of 51 patients, swabs were taken at all 4 operative procedures and analysed separately. In an overall analysis, the number of different bacteria and the amount of bacteria significantly decreased independent of wound localisation and diagnosis. NPWT with automated instillation demonstrates a positive influence in the reduction of bacterial load in problem wounds. Thus, it may help to optimise wound conditions before definite wound closure.     

Novel negative pressure wound therapy device without foam or gauze is effective at −50 mmHg

Negative pressure wound therapy (NPWT) promotes healing in acute or chronic wounds. Conventional NPWT devices consist of a filler (such as foam or gauze) that covers the wound and of a permeable membrane and tubing that connects the space under the membrane to a suction pump. The permeable membrane increases airflow and thus increases the required pump capacity that can cause patient discomfort or even ischemia in wounds with compromised vascularity. In addition, foam or gauze may fragment and become colonized with bacteria over time. To mitigate these, negative aspects, we have developed a new impermeable single layer component membrane dressing to deliver NPWT that does not need a foam or gauze to function. Therefore, the purpose of this study was to introduce this novel NPWT system (platform wound device, PWD) and evaluate its usability and effectiveness in the treatment of porcine full‐thickness burns. A total of 48 burn wounds were created across four Yorkshire pigs on the dorsum. Wounds were created on day 0 and continuous NPWT with ?50 mmHg and ? 80 mmHg was initiated immediately. Subsequently, the burns were debrided on day 3 and animals were euthanized on day 7. The efficacy of the PWD on wound healing and reduction of bacterial burden was measured and compared to wounds that did not receive NPWT. The results showed that PWD promoted wound healing by outperforming the wounds that did not receive NPWT and that PWD was efficient at reducing bacteria from the burn eschar and from the wound bed. In conclusion, this study demonstrated that PWD promoted wound healing with a negative pressure as low as ?50 mmHg, which likely benefits healing and avoids potential safety issues.     

Novel insights into negative pressure wound healing from an in situ porcine perspective

Negative pressure wound therapy (NPWT) is used clinically to promote tissue formation and wound closure. In this study, a porcine wound model was used to further investigate the mechanisms as to how NPWT modulates wound healing via utilization of a form of NPWT called the vacuum-assisted closure. To observe the effect of NPWT more accurately, non-NPWT control wounds containing GranuFoam? dressings, without vacuum exposure, were utilized. In situ histological analysis revealed that NPWT enhanced plasma protein adsorption throughout the GranuFoam?, resulting in increased cellular colonization and tissue ingrowth. Gram staining revealed that NPWT decreased bacterial dissemination to adjacent tissue with greater bacterial localization within the GranuFoam?. Genomic analysis demonstrated the significant changes in gene expression across a number of genes between wounds treated with non-NPWT and NPWT when compared against baseline tissue. However, minimal differences were noted between non-NPWT and NPWT wounds, including no significant differences in expression of collagen, angiogenic, or key inflammatory genes. Similarly, significant increases in immune cell populations were observed from day 0 to day 9 for both non-NPWT and NPWT wounds, though no differences were noted between non-NPWT and NPWT wounds. Furthermore, histological analysis demonstrated the presence of a foreign body response (FBR), with giant cell formation and encapsulation of GranuFoam? particles. The unique in situ histological evaluation and genomic comparison of non-NPWT and NPWT wounds in this pilot study provided a never-before-shown perspective, offering novel insights into the physiological processes of NPWT and the potential role of a FBR in NPWT clinical outcomes.     

Randomized controlled trial comparing the combination of a polymeric membrane dressing plus negative pressure wound therapy against negative pressure wound therapy alone: The WICVAC study

Negative pressure wound therapy (NPWT) is the treatment of choice for chronic wounds; yet, it is associated with considerable workload. Prompted by its nonadhesive and wound‐healing properties, this study investigated the effect of an additional polymeric membrane interface dressing (PMD; PolyMem WIC) in NPWT. From October 2011 to April 2013, 60 consecutive patients with chronic leg wounds or surgical site infections after revascularization of lower extremities were randomly allocated to either treatment with conventional NPWT (control arm) or NPWT with an additional PMD (intervention arm). The primary outcome was wound healing achieved within 30 days, the secondary endpoints included: number of days between dressing changes, wound‐related pain, cost efficiency, and occurrence of adverse events ( ClinTrials.gov Identifier: NCT02399722). Forty‐seven patients completed follow‐up. No difference in wound healing was observed (p > 0.05) between both study arms. The additional PMD allowed significantly longer wearing times (days) between dressing changes (intervention: 8.8 ± 0.5, control: 4.8 ± 0.2; p < 0.001). Pain was slightly higher in patients randomized to NPWT alone (VAS score: 4.8 ± 2.9) compared to NPWT + PMD (VAS score: 3.0 ± 2.9, p = 0.063). No wound infections were observed. Costs were reduced by 34% per patient in the intervention arm. These results suggest that the combination of NPWT and an additional interface PMD is a safe and economic method for the treatment of chronic wounds, which requires significantly fewer dressing changes for a comparable wound healing.     

Clinical recommendations and practical guide for negative pressure wound therapy with instillation

Effective wound management involves a comprehensive assessment of the patient and the wound to determine an optimal wound treatment plan. It is critical to identify and address factors that may impair wound healing, prior to selecting the most appropriate therapy for each patient. Negative pressure wound therapy (NPWT) is a well‐established advanced therapy that has been successful in adjunctive management of acute and chronic wounds. In recent years, the introduction of topical wound solution delivery in combination with NPWT has provided further benefits to wound healing. A commercially available system now offers automated, volumetric control of instilled topical wound solutions with a dwell time in combination with NPWT (NPWTi‐d; V.A.C. VeraFlo? Therapy, KCI, an Acelity company, San Antonio, TX). This NPWTi‐d system differs from other instillation systems in that a timed, predetermined volume of topical wound solution is intermittently delivered (versus continuously fed) and allowed to dwell in the wound bed (without NPWT), for a user‐selected period of time before NPWT is resumed. This added accuracy and process simplification of solution delivery in tandem with NPWT have prompted use of NPWTi‐d as first‐line therapy in a wider subset of complex wounds. However, considerably more research is required to validate efficacy of NPWTi‐d in various wound types. The purpose of this review is to provide a relevant overview of wound healing, describe current literature supporting the adjunctive use of NPWTi‐d, propose a clinical approach for appropriate application of NPWTi‐d and conclude with case studies demonstrating successful use of NPWTi‐d. Based on this review, we conclude that either a large case series examining effects of NPWTi‐d on different wound types or possibly a large prospective registry evaluating NPWTi‐d with real‐world topical wound solutions versus immediate debridement and closure would be valuable to the medical community in evaluating the efficacy of this promising therapy.     

A pilot study exploring quality of life experienced by patients undergoing negative‐pressure wound therapy as part of their wound care treatment compared to patients receiving standard wound care

The use of negative pressure wound therapy (NPWT) has been widely documented as a technique to help heal complex wounds. This article presents the findings of a preliminary study which aimed to explore quality of life (QoL) experienced by patients undergoing NPWT as part of their wound care treatment in comparison to that of patients with a wound using traditional (standard) wound care therapies. A quasi‐experimental study was undertaken, with patients treated in wound care/vascular clinics with chronic/acute wounds. QoL impact was measured using the Cardiff Wound Impact Schedule and administered post‐consent at timed intervals. Our results identified that there were no real differences in QoL scores recorded by patients over the 12‐week period. Although there was no overall interaction between the therapies used for wound healing, NPWT did have an effect on social life: during the first 2 weeks of the application of therapy, patients in the NPWT group reported an increase in the social life domain. The authors conclude that true QoL can only be elicited if an accurate baseline is established or if data is collected over a long enough period to allow comparison of scores over time.     

Negative-pressure wound therapy using gauze or open-cell polyurethane foam: Similar early effects on pressure transduction and tissue contraction in an experimental porcine wound model

Negative-pressure wound therapy (NPWT), also known as topical negative-pressure therapy, is widely used to manage wounds and accelerate healing. NPWT has so far been delivered mainly via open-cell polyurethane foam, but increasing interest has been directed toward delivering NPWT via gauze. In the present study, the early effects of NPWT on pressure transduction and wound contraction were examined in wounds filled with either polyurethane foam or gauze. An experimental setup of a porcine wound model was used, in which the animals were anesthetized for 12–14 hours. Negative pressures between −50 and −175 mmHg were applied in −25 mmHg increments. Wound bed pressure was measured using a saline filled catheter sutured to the bottom of the wound. The contraction of the wound edges was also determined. The recordings were performed upon reaching steady state, which typically occurred within 1 minute. For both fillers, wound bed negative pressure increased linearly with delivered vacuum with little deviation from set pressure (correlation coefficient 0.99 in both cases). Similar tissue contraction was observed when using foam and gauze. The most prominent contraction was observed in the range of 0 to −50 mmHg with greater vacuum only producing minor further movement of the wound edge. In conclusion, the present experimental study shows that gauze and foam are equally effective at delivering negative pressure and creating mechanical deformation of the wound.     

A PEGylated fibrin hydrogel‐based antimicrobial wound dressing controls infection without impeding wound healing

Combat injuries are associated with a high incidence of infection, and there is a continuing need for improved approaches to control infection and promote wound healing. Due to the possible local and systemic adverse effects of standard 1% cream formulation (Silvadene), we had previously developed a polyethylene glycol (PEGylated) fibrin hydrogel (FPEG)‐based wound dressing for the controlled delivery of silver sulfadiazine (SSD) entrapped in chitosan microspheres (CSM). In this study, we have evaluated the antimicrobial and wound healing efficacy of SSD‐CSM‐FPEG using a full‐thickness porcine wound infected with Pseudomonas aeruginosa. Infected wounds treated with a one‐time application of the SSD‐CSM‐FPEG wound dressing demonstrated significantly reduced bacterial bioburden over time (99·99% of reduction by day 11; P < 0·05) compared with all the other treatment groups. The epithelial thickness and granulation of the wound bed was significantly better on day 7 (150·9 ± 13·12 µm), when compared with other treatment groups. Overall, our findings demonstrate that the SSD‐CSM‐FPEG wound dressing effectively controls P. aeruginosa infection and promotes wound healing by providing a favourable environment that induces neovascularisation. Collectively, sustained release of SSD using fibrin hydrogel exhibited enhanced benefits when compared with the currently available SSD treatment, and this may have significant implications in the bacterial reduction of infected wounds in military and civilian populations.     

Effects and safety of atmospheric low‐temperature plasma on bacterial reduction in chronic wounds and wound size reduction: A systematic review and meta‐analysis

The use of atmospheric low‐temperature plasma (AP) on chronic wounds and its effect on microbial bioburden in open wounds has not been explored with a systematic review and meta‐analysis. PRISMA guidelines were followed and PubMed, Embase, CENTRAL, and CINAHL databases searched for randomised controlled trials (RCTs), which compared AP with no AP for the management of open, chronic wounds. The primary outcomes of reduction of bioburden or wound size were included. Meta‐analyses were performed; odds ratio (OR) and 95% confidence intervals (CIs) were extracted and pooled in a random effects model. Four RCTs investigated the effect of AP on chronic wound healing. Chronic wounds treated with AP did not show a significant improvement in healing (AP vs control: OR = 1.46; 95% CI = 0.89‐2.38; P = 0.13). Five further RCTs investigated the reduction of bioburden in wounds, but AP demonstrated no significant reduction of bioburden (AP vs control: OR = 0.85; 95% CI = 0.45‐1.62; P = 0.63). All nine RCTs recorded the presence of any severe adverse events (SAEs) in the 268 patients studied, with only one unrelated SAE identified in each group (AP vs control: OR = 1.00; 95% CI = 0.05‐19.96; P = 1.00). Use of AP in wound care is safe, but the retrieved evidence and meta‐analysis show that there is no clinical benefit of AP in chronic open wounds using currently available AP device settings.     

An inexpensive method of negative pressure wound therapy for extremities

Negative pressure wound therapy (NPWT) is an established method for the faster wound healing of chronic non‐healing wounds. It is also used for laparostomy wounds and healing of split skin grafts. The commercially available machine and the consumables for NPWT are very expensive and economically not feasible in developing and underdeveloped countries. So, we devised a NPWT system for wounds of the extremity using inexpensive, readily available materials in any hospital. The materials used are sterile glove, autoclaved sponge, Foley catheter, and a wall suction unit. The sponge was placed over the wound, and a sterile glove was pulled over it. A Foley catheter was placed over the sponge and taken out through one of the fingers of the glove. Adhesive plaster was used to air‐seal the glove. The Foley catheter was fixed with silk ties and connected to wall suction. Granulation and wound healing was faster in this system. This system was safe and inexpensive for the treatment of wounds of the extremity.     

Factors associated with positive outcomes in 131 patients treated with gauze-based negative pressure wound therapy

Negative Pressure Wound Therapy (NPWT) is commonly used in many surgical specialties to improve wound management and healing outcomes. This study reports the ability of gauze-based NPWT to address several treatment goals commonly defined at the onset of therapy. A prospective, multi-center, non-comparative clinical investigation was carried out using gauze-based NPWT in chronic and acute wounds. 131 patients including traumatic, post-surgical and chronic wounds were assessed. Weekly percentage reductions in wound area, depth and volume were 8.3%, 15.8% and 20.5% respectively (p < 0.001). A reduction in exudate level was observed from baseline to treatment discontinuation (p < 0.001). An increase (p = 0.007) in red granulation tissue and a decrease (p < 0.001) in non-viable tissue was observed. Baseline wound characteristics associated with slower rates of progress included chronic wound aetiologies, longer wound duration prior to NPWT and presence of diabetes as a co-morbidity. Important indicators of wounds which had improved sufficiently and no longer required NPWT included reduction in volume and exudate levels. Gauze-based NPWT can be used to address many of the treatment goals commonly defined at the onset of therapy including reduction in wound volume, management of exudate and infection status, and improvement in wound bed quality.     

Use of negative-pressure wound therapy in orthopaedic trauma

Negative-pressure wound therapy (NPWT) has become an important adjunct to the management of traumatic wounds and surgical incisions related to musculoskeletal trauma. On the battlefield, this adjunct therapy allows early wound management and safe aeromedical evacuation. NPWT mechanisms of action include stabilization of the wound environment, reduction of wound edema, improvement of tissue perfusion, and stimulation of cells at the wound surface. NPWT stimulates granulation tissue and angiogenesis and may improve the likelihood of primary closure and reduce the need for free tissue transfer. In addition, NPWT reduces the bacterial bioburden of wounds contaminated with gram-negative bacilli. However, an increased risk of colonization of gram-positive cocci (eg, Staphylococcus aureus) exists. Although NPWT facilitates wound management, further research is required to determine conclusively whether this modality is superior to other management options. Ongoing research will continue to define the indications for and benefits of NPWT as well as establish the role of combination therapy, in which NPWT is used with instillation of antibiotic solutions, placement of antibiotic-laden cement beads, or silver-impregnated sponges.     

Integrated negative pressure wound therapy system with volumetric automated fluid instillation in wounds at risk for compromised healing

Nearly all wounds are at risk for compromised healing due to excessive exudation, oedema, contaminants and presence of inflammatory mediators. Compromised wounds have the potential to develop complications, such as infection, which may lead to delayed wound healing, prolonged hospitalisation and more frequent readmissions. It is generally believed that the wound advances from contamination to colonisation when the bacteria on the wound's surface begin to replicate and increase their metabolic activity. Heavy bacterial bioburden increases the metabolic requirements, stimulates a proinflammatory environment and encourages the in-migration of monocytes, macrophages and leukocytes - all of which can negatively impact wound healing. Bacteria also secrete harmful cytokines which can lead to vasoconstriction and decreased blood flow. Thus, controlling or preventing infections is essential for normal wound healing process to occur. While the mainstay of treating wound infection has historically included intravenous, oral and/or topical antimicrobials in addition to frequent gauze dressing changes, a shift towards wound management with advanced modalities, such as negative pressure wound therapy (NPWT), has occurred during the past decade. This review will provide expert opinion and scientific support for the use of NPWT with instillation (NPWTi; V.A.C. Instill? Wound Therapy and V.A.C. VeraFlo? Therapy, KCI USA, Inc., San Antonio, TX) for the treatment of at-risk and complicated wounds.     

Poly‐N‐acetyl glucosamine nanofibers for negative‐pressure wound therapies

The wound healing promoting effect of negative wound pressure therapies (NPWT) takes place at the wound interface. The use of bioactive substances at this site represents a major research area for the development of future NPWT therapies. To assess wound healing kinetics in pressure ulcers treated by NPWT with or without the use of a thin interface membrane consisting of poly‐N‐acetyl glucosamine nanofibers (sNAG) a prospective randomized clinical trial was performed. The safety of the combination of NPWT and sNAG was also assessed in patients treated with antiplatelet drugs. In the performed study, the combination of NPWT and sNAG in 10 patients compared to NPWT alone in 10 patients promoted wound healing due to an improved contraction of the wound margins (p = 0.05) without a change in wound epithelization. In 6 patients treated with antiplatelet drugs no increased wound bleeding was observed in patients treated by NPWT and sNAG. In conclusion, the application of thin membranes of sNAG nanofibers at the wound interface using NPWT was safe and augmented the action of NPWT leading to improved wound healing due to a stimulation of wound contraction.     

Use of 16S rRNA sequencing and quantitative PCR to correlate venous leg ulcer bacterial bioburden dynamics with wound expansion,antibiotic therapy,and healing

Clinical diagnosis of infection in chronic wounds is currently limited to subjective clinical signs and culture‐based methods that underestimate the complexity of wound microbial bioburden as revealed by DNA‐based microbial identification methods. Here, we use 16S rRNA next generation sequencing and quantitative polymerase chain reaction to characterize weekly changes in bacterial load, community structure, and diversity associated with a chronic venous leg ulcer over the 15‐week course of treatment and healing. Our DNA‐based methods and detailed sampling scheme reveal that the bacterial bioburden of the wound is unexpectedly dynamic, including changes in the bacterial load and community structure that correlate with wound expansion, antibiotic therapy, and healing. We demonstrate that these multidimensional changes in bacterial bioburden can be summarized using swabs taken prior to debridement, and therefore, can be more easily collected serially than debridement or biopsy samples. Overall, this case illustrates the importance of detailed clinical indicators and longitudinal sampling to determine the pathogenic significance of chronic wound microbial dynamics and guide best use of antimicrobials for improvement of healing outcomes.