Direct metagenomics investigation of non-surgical hard-to-heal wounds: a review.

BACKGROUND: Non-surgical chronic wounds, including diabetes-related foot diseases (DRFD), pressure injuries (PIs) and venous leg ulcers (VLU), are common hard-to-heal wounds. Wound evolution partly depends on microbial colonisation or infection, which is often confused by clinicians, thereby hampering proper management. Current routine microbiology investigation of these wounds is based on in vitro culture, focusing only on a limited panel of the most frequently isolated bacteria, leaving a large part of the wound microbiome undocumented. METHODS: A literature search was conducted on original studies published through October 2022 reporting metagenomic next generation sequencing (mNGS) of chronic wound samples. Studies were eligible for inclusion if they applied 16 S rRNA metagenomics or shotgun metagenomics for microbiome analysis or diagnosis. Case reports, prospective, or retrospective studies were included. However, review articles, animal studies, in vitro model optimisation, benchmarking, treatment optimisation studies, and non-clinical studies were excluded. Articles were identified in PubMed, Google Scholar, Web of Science, Microsoft Academic, Crossref and Semantic Scholar databases. RESULTS: Of the 3,202 articles found in the initial search, 2,336 articles were removed after deduplication and 834 articles following title and abstract screening. A further 14 were removed after full text reading, with 18 articles finally included. Data were provided for 3,628 patients, including 1,535 DRFDs, 956 VLUs, and 791 PIs, with 164 microbial genera and 116 species identified using mNGS approaches. A high microbial diversity was observed depending on the geographical location and wound evolution. Clinically infected wounds were the most diverse, possibly due to a widespread colonisation by pathogenic bacteria from body and environmental microbiota. mNGS data identified the presence of virus (EBV) and fungi (Candida and Aspergillus species), as well as Staphylococcus and Pseudomonas bacteriophages. CONCLUSION: This study highlighted the benefit of mNGS for time-effective pathogen genome detection. Despite the majority of the included studies investigating only 16 S rDNA, ignoring a part of viral, fungal and parasite colonisation, mNGS detected a large number of bacteria through the included studies. Such technology could be implemented in routine microbiology for hard-to-heal wound microbiota investigation and post-treatment wound colonisation surveillance.

Bacterial Contamination Control with Sodium Hypochlorite and Jet Lavage Irrigation in a Severe Stage 4 Pelvic Pressure Injury: A Case Report.

ABSTRACT: This case report reviews the effect of combining a 250-cc bottle of standard antimicrobial, buffered sodium hypochlorite with a surgical method, low-pressure jet lavage irrigation in the outpatient setting to control difficult wound contamination. A 73-year-old man had been in treatment for over 8 years, undergoing at least 18 surgical wound debridement procedures for an extensive undermined pelvic pressure injury involving the sacrum, ischium, and greater trochanter. Cultures and polymerase chain reaction diagnostics revealed a multibacterial presence. Autofluorescent imaging (AFI) was used in 21 examinations performed after a 72-hour delay over a long weekend. The AFI contamination exceeded log 4 colony-forming units/g of tissue in all pretreatment examinations and was reduced to less than log 2 colony-forming units in 6 of 21 examinations, with the remaining 15 showing an estimated 80% or higher removal of the bacterial porphyrin "red" appearance. A total of 54 AFI examinations were performed using the combination treatment, and no adverse reactions were encountered. Treatment paradigms can be improved with a multifactorial approach.

The skin microbiome of infected pressure ulcers: A review and implications for health professionals.

BACKGROUND: Pressure ulcers (PUs) are injuries resulting from ischaemia caused by prolonged compression or shear forces on the skin, adjacent tissues and bones. Advanced stages of PUs are associated with infectious complications and constitute a major clinical challenge, with high social and economic impacts in health care. GOALS: This study aims to identify and describe the relationship between PU risk factors, stages and anatomical locations, and the relevance of microbial cohabitation and biofilm growth. METHODS: The narrative review method to advocating a critical and objective analysis of the current knowledge on the topic was performed. Indexed databases and direct consultation to specialized and high-impact journals on the subject were used to extract relevant information, guided by co-authors. The Medical Subject Headings of pressure ulcer (or injury), biofilms, infection and other analogues terms were used. RESULTS: Development of PUs and consequent infection depends on several direct and indirect risk factors, including cutaneous/PU microbiome, microclimate and behavioural factors. Infected PUs are polymicrobial and characterized by biofilm-associated infection, phenotypic hypervariability of species and inherent resistance to antimicrobials. The different stages and anatomical locations also play an important role in their colonization. The prevention and monitoring of PUs remain crucial for avoiding the emergence of systemic infections and reducing health care-associated costs, improve the quality of life of patients and reduce the mortality-associated infected PUs.

The Persistence of Staphylococcus aureus in Pressure Ulcers: A Colonising Role.

Decubitus pressure ulcers (PU) are a major complication of immobilised patients. Staphylococcus aureus is one of the most frequently detected microorganisms in PU samples; however, its persistence and role in the evolution of these wounds is unknown. In this study, we analysed S. aureus strains isolated from PU biopsies at inclusion and day 28. Eleven S. aureus (21.1%) were detected in 52 patients at inclusion. Only six PUs (11.5%) continued to harbour this bacterium at day 28. Using a whole genome sequencing approach (Miseq®, Illumina), we confirmed that these six S. aureus samples isolated at D28 were the same strain as that isolated at inclusion, with less than 83 bp difference. Phenotypical studies evaluating the growth profiles (Infinite M Mano, Tecan®) and biofilm formation (Biofilm Ring Test®) did not detect any significant difference in the fitness of the pairs of S. aureus. However, using the Caenorhabditis elegans killing assay, a clear decrease of virulence was observed between strains isolated at D28 compared with those isolated at inclusion, regardless of the clinical evolution of the PU. Moreover, all strains at inclusion were less virulent than a control S. aureus strain, i.e., NSA739. An analysis of polymicrobial communities of PU (by metabarcoding approach), in which S. aureus persisted, demonstrated no impact of Staphylococcus genus on PU evolution. Our study suggested that S. aureus presented a colonising profile on PU with no influence on wound evolution.

LimpiAD foam and the potential control of the pressure ulcers onset.

Pressure ulcers development is an undesirable event that often worsens the clinical condition of patients already affected by severe pathologies. Since the aetiology of this clinical complication is unclear yet, at current the primary approach to treat the problem is the adoption of suitable patients' assistance procedures. At the same time, the research focuses on finding medicaments or treatment strategies that could prevent the lesions and/or accelerate their healing. The international market's wide range of cosmetic/pharmaceuticals products is mainly topical preparations based on emollient agents to preserve or restore skin homeostasis. On the other hand, the skin microbiome's implication in the pressure ulcers occurrence is mainly unknown. Based on these assumptions, here we tested an innovative preparation, the LimpiAD foam, as a potential preventive strategy of pressure ulcers onset. The active component of this product is composed of hyaluronic acid conjugated with a bacterial cell wall fragment of C. acnes DSM 28251. For LimpiAD foam, we hypothesised a combined action of the two components on the skin tissue, an emollient effect due to the hyaluronic acid properties together with a modulatory effect on the skin microbiota carried out by the component of bacterial derivation. Our results supported the hypothesis and suggested a potential role of LimpiAD foam in pressure ulcers prevention.

Pressure ulcers microbiota dynamics and wound evolution.

Bacterial species and their role in delaying the healing of pressure ulcers (PU) in spinal cord injury (SCI) patients have not been well described. This pilot study aimed to characterise the evolution of the cutaneous microbiota of PU in SCI cohort. Twenty-four patients with SCI from a French neurological rehabilitation centre were prospectively included. PU tissue biopsies were performed at baseline (D0) and 28 days (D28) and analysed using 16S rRNA gene-based sequencing analysis of the V3-V4 region. At D0, if the overall relative abundance of genus highlighted a large proportion of Staphylococcus, Anaerococcus and Finegoldia had a significantly higher relative abundance in wounds that stagnated or worsened in comparison with those improved at D28 (3.74% vs 0.05%; p = 0.015 and 11.02% versus 0.16%; p = 0.023, respectively). At D28, Proteus and Morganella genera were only present in stagnated or worsened wounds with respectively 0.02% (p = 0.003) and 0.01% (p = 0.02). Moreover, Proteus, Morganella, Anaerococcus and Peptoniphilus were associated within the same cluster, co-isolated from biopsies that had a poor evolution. This pathogroup could be a marker of wound degradation and Proteus could represent a promising target in PU management.

Metabolic Profiling of VOCs Emitted by Bacteria Isolated from Pressure Ulcers and Treated with Different Concentrations of Bio-AgNPs.

Considering the advent of antibiotic resistance, the study of bacterial metabolic behavior stimulated by novel antimicrobial agents becomes a relevant tool to elucidate involved adaptive pathways. Profiling of volatile metabolites was performed to monitor alterations of bacterial metabolism induced by biosynthesized silver nanoparticles (bio-AgNPs). Escherichia coli, Enterococcus faecalis, Klebsiella pneumoniae and Proteus mirabilis were isolated from pressure ulcers, and their cultures were prepared in the presence/absence of bio-AgNPs at 12.5, 25 and 50 µg mL-1. Headspace solid phase microextraction associated to gas chromatography-mass spectrometry was the employed analytical platform. At the lower concentration level, the agent promoted positive modulation of products of fermentation routes and bioactive volatiles, indicating an attempt of bacteria to adapt to an ongoing suppression of cellular respiration. Augmented response of aldehydes and other possible products of lipid oxidative cleavage was noticed for increasing levels of bio-AgNPs. The greatest concentration of agent caused a reduction of 44 to 80% in the variety of compounds found in the control samples. Pathway analysis indicated overall inhibition of amino acids and fatty acids routes. The present assessment may provide a deeper understanding of molecular mechanisms of bio-AgNPs and how the metabolic response of bacteria is untangled.

Effects of cefazolin-containing niosome nanoparticles against methicillin-resistant Staphylococcus aureus biofilm formed on chronic wounds.

The ability of biofilm formation in methicillin-resistant Staphylococcus aureus (MRSA) causes significant mortality and morbidity in wound infections. Nanoparticles because of the drug concentration increment at the point of contact of nanoparticles and bacteria, and slower release of the drug at the desired location are considered as proper tools to overcome the therapeutic problem of antimicrobial-resistant infections. This study was aimed to evaluate the anti-biofilm activity of cefazolin-loaded nanoparticles against MRSA isolates. The 27 clinical isolates of MRSA were collected from patients with pressure sores and diabetic ulcers referred to Loghman Hospital in Tehran-Iran. MRSA isolates were detected by polymerase chain reaction (PCR) and biochemical tests. Cefazolin-loaded niosome was synthesized using the thin-film hydration method and were characterized by zeta potential measurement and transmission electron microscopy (TEM). The round-shaped cefazolin-loaded niosomes had a diameter of 100 nm and a -63 mV zeta potential. The cefazolin-containing niosomes removed 1, 3, and 5 d old biofilms at the concentration of 128 µg ml-1, 128 µg ml-1, and 256 µg ml-1, respectively. Histological results indicated that BALB/c mice receiving cefazolin-loaded niosomes were treated effectively faster than those treated by cefazolin or untreated group. In conclusion, the cefazolin-loaded niosome could be considered as a promising candidate for the treatment of biofilm-mediated infections of MRSA.

Evaluation of ebselen in resolving a methicillin-resistant Staphylococcus aureus infection of pressure ulcers in obese and diabetic mice.

Pressure ulcers (PUs) are a source of morbidity in individuals with restricted mobility including individuals that are obese or diabetic. Infection of PUs with pathogens, including methicillin-resistant Staphylococcus aureus (MRSA), impairs ulcers from healing. The present study evaluated ebselen as a topical antibacterial to treat MRSA-infected PUs. Against two different S. aureus strains, including MRSA USA300, resistance to ebselen did not emerge after 14 consecutive passages. Resistance to mupirocin emerged after only five passages. Additionally, ebselen was found to exert a modest postantibiotic effect of five hours against two MRSA strains. Ebselen was subsequently evaluated in MRSA-infected PUs in two models using obese and diabetic mice. In obese mice, topical ebselen (89.2% reduction) and oral linezolid (84.5% reduction) similarly reduced the burden of MRSA in infected PUs. However, in diabetic mice, topical ebselen (45.8% reduction in MRSA burden) was less effective. Histopathological evaluation of ulcers in diabetic mice determined that ebselen treatment resulted in fewer bacterial colonies deep within the dermis and that the treatment exhibited evidence of epithelial regeneration. Topical mupirocin was superior to ebselen in reducing MRSA burden in infected PUs both in obese (98.7% reduction) and diabetic (99.3% reduction) mice. Ebselen's antibacterial activity was negatively impacted as the bacterial inoculum was increased from 105 CFU/mL to 107 CFU/mL. These results suggest that a higher dose of ebselen, or a longer course of treatment, may be needed to achieve a similar effect as mupirocin in topically treating MRSA-infected pressure ulcers.

Disinfection capabilities of a 222 nm wavelength ultraviolet lighting device: a pilot study.

OBJECTIVE: To demonstrate the efficacy of the SafeZone UVC (Ushio Inc., Japan) 222 nm ultraviolet C (UVC) light to reduce bacterial burden in pressure ulcers (PUs) in human patients. This research is the first human clinical trial using 222 nm UVC in eradicating bacteria in human wounds. METHOD: Patients with Stage 2 or 3 (as defined by the revised National Pressure Ulcer Advisory Panel Pressure Injury Staging System) sacral or gluteal pressure ulcers (PUs) were subjected to four sessions of 222 nm UVC light therapy over two weeks. Pre- and post-UVC therapy, wound cultures were taken and quantitative analysis of bacterial colony forming units (CFU) were performed. RESULTS: A total of 68 UV light sessions across 16 different patients were conducted. Of these sessions, 59 (87.0%) sessions showed a reduction in CFU counts, with 20 (29.4%) showing complete eradication of bacteria. Bacteria identified included meticillin-resistant Staphylococcus aureus, Pseudomonas aeruginosa and Klebsiella Pneumoniae. The overall median reduction in CFU of the 68 sessions was 78.9%. No adverse events were reported in any of the UV sessions. CONCLUSION: In this study, 222 nm UVC light was safe and effective in reducing bacterial CFU counts in sacral and gluteal PUs across numerous different species of bacteria.

Diagnostic Accuracy of Point-of-Care Fluorescence Imaging for the Detection of Bacterial Burden in Wounds: Results from the 350-Patient Fluorescence Imaging Assessment and Guidance Trial.

Objective: High bacterial load contributes to chronicity of wounds and is diagnosed based on assessment of clinical signs and symptoms (CSS) of infection, but these characteristics are poor predictors of bacterial burden. Point-of-care fluorescence imaging (FL) MolecuLight i:X can improve identification of wounds with high bacterial burden (>104 colony-forming unit [CFU]/g). FL detects bacteria, whether planktonic or in biofilm, but does not distinguish between the two. In this study, diagnostic accuracy of FL was compared to CSS during routine wound assessment. Postassessment, clinicians were surveyed to assess impact of FL on treatment plan. Approach: A prospective multicenter controlled study was conducted by 20 study clinicians from 14 outpatient advanced wound care centers across the United States. Wounds underwent assessment for CSS followed by FL. Biopsies were collected to confirm total bacterial load. Three hundred fifty patients completed the study (138 diabetic foot ulcers, 106 venous leg ulcers, 60 surgical sites, 22 pressure ulcers, and 24 others). Results: Around 287/350 wounds (82%) had bacterial loads >104 CFU/g, and CSS missed detection of 85% of these wounds. FL significantly increased detection of bacteria (>104 CFU/g) by fourfold, and this was consistent across wound types (p < 0.001). Specificity of CSS+FL remained comparably high to CSS (p = 1.0). FL information modified treatment plans (69% of wounds), influenced wound bed preparation (85%), and improved overall patient care (90%) as reported by study clinicians. Innovation: This novel noncontact, handheld FL device provides immediate, objective information on presence, location, and load of bacteria at point of care. Conclusion: Use of FL facilitates adherence to clinical guidelines recommending prompt detection and removal of bacterial burden to reduce wound infection and facilitate healing.

Skin Physiology and its Microbiome as Factors Associated with the Recurrence of Pressure Injuries.

BACKGROUND: Preventing recurrent pressure injuries (RPIs) is one of the important challenges faced in healthcare, but the risk factors of RPIs have not been fully revealed. This study aims to explore factors associated with RPIs, by focusing on skin physiology and its microbiome as local factors crucial for the health of healed tissue after pressure injury healing. METHODS: This prospective observational study was conducted in a long-term care facility in Japan with patients whose PIs had healed within 1 month. Skin physiology was evaluated by stratum corneum (SC) hydration, pH, and transepidermal water loss. Skin bacteria was collected by tape stripping, followed by 16S ribosomal RNA-based metagenomics analysis. These parameters were evaluated every two weeks over a period of six weeks. RESULTS: A total of 30 patients were included in this study, and 8 patients (26.7%) had an RPI within 6 weeks. In this study, significantly lower SC hydration and a higher rate of Staphylococcus species on the healed site were found in the RPI group. DISCUSSION: A high rate of RPIs (about one in four) points out the necessity of a further care strategy on the healed PIs. Lower skin hydration and/or the increase in Staphylococcus bacteria may have a potential to be used as a biomarker for the prediction of RPIs, or may be an intervention point for the prevention of RPIs by, for example, skin cleansing with moisturizing care.

Caracterización de las úlceras por presión en adultos con gérmenes multirresistentes / Characterization of pressure lesions in adults with multidrug resistant germs / Caracterização das lesões por pressão em adultos portadores de germes multirresistentes

OBJETIVO: Describir las características de las lesiones por presión en pacientes adultos con gérmenes multirresistentes. MÉTODO: Este es un estudio transversal realizado con pacientes hospitalizados en la unidad de pacientes hospitalizados por gérmenes resistentes a múltiples fármacos de un hospital público en el sur de Brasil. Se seleccionaron pacientes con lesión por presión del estadio II. Los datos se recopilaron en 2017 de una muestra de 110 lesiones en 36 pacientes utilizando la Herramienta de evaluación de heridas Bates-Jensen (BWAT). Los datos se analizaron mediante estadísticas descriptivas y analíticas. RESULTADOS: La edad promedio de los individuos fue de 45.4 (± 21.3) años y el 89.1% había sido hospitalizado con una lesión por presión, que ocurrió en el hogar o en otras instituciones de salud. El valor medio de BWAT fue de 35.5 ± 8.9 puntos y hubo una correlación positiva débil (r = 0.228 p = 0.017) con el tamaño de la lesión, correlación positiva moderada con el estadio de la lesión (r = 540 p <0.001). y con el resultado de la escala de Braden (r = 0.44 p = 0.651). CONCLUSIÓN: Los resultados muestran la enfermedad de pacientes jóvenes. Los pacientes con gérmenes multirresistentes presentaron lesiones por presión con una mayor participación de las estructuras, lo que sugiere la necesidad de apoyo en el hogar

OBJECTIVE: To describe the characteristics of the pressure lesions in adult patients with multiresistant germs. METHOD: This is a cross-sectional study conducted with patients admitted to the inpatient unit for multidrug resistant germs in a public hospital in Brazil. Patients with pressure lesions from stage II were selected. Data collection took place in 2017, in a sample of 110 injuries, in patients, through the Pressure Ulcer State Assessment Instrument (Bates-Jensen Wound Assessment Tool - BWAT). RESULTS: The average age of the individuals was 45.4 (± 21.3) years old and 89.1% had already suffered pressure lesions, such as those that occurred at home or in other health institutions. The mean BWAT value was 35.5 ± 8.9 points and there was a weak positive correlation (r = 0.228 p = 0.017) with lesion size, moderate positive correlation with lesion stage (r = 540 p <0.001), and with the result of the Braden scale (r = 0.44 p = 0.651). CONCLUSION: The results indicated the illness of young patients. Patients with multiresistant germs suffered pressure lesions with greater involvement of structures, which suggests the need for home support

OBJETIVO: Descrever as características das lesões por pressão em pacientes adultos portadores de germes multirresistentes. MÉTODO: Trata-se de um estudo transversal, realizado com pacientes hospitalizados na unidade de internação para portadores de germes multirresistentes de um hospital público do sul do Brasil. Foram selecionados pacientes portadores de lesão por pressão a partir de estágio II. A coleta de dados ocorreu em 2017, em uma amostra de 110 lesões, através do Instrumento de Avaliação do estado da Úlcera por Pressão (Bates-Jensen Wound Assessment Tool - BWAT. Os dados foram analisados através de estatística descritiva e analítica. RESULTADOS: A idade média dos indivíduos foi 45,4 (± 21,3) anos e 89,1% já internaram com lesão por pressão, as quais ocorreram no domicílio ou em outras instituições de saúde. O valor médio da BWAT foi de 35,5 ± 8,9 pontos e houve correlação positiva fraca (r=0,228 p = 0,017) com o tamanho da lesão, correlação positiva moderada com o estágio da lesão (r= 540 p < 0,001) e com o resultado da escala de Braden (r= 0,44 p = 0,651). CONCLUSÃO: Os resultados apontam o adoecimento de pacientes jovens. Pacientes portadores de germes multirresistentes apresentaram lesões por pressão com maior acometimento de estruturas, o que sugere necessidade de aporte domiciliar

Auranofin Rapidly Eradicates Methicillin-resistant Staphylococcus aureus (MRSA) in an Infected Pressure Ulcer Mouse Model.

Pressure ulcers (PUs) frequently occur in individuals with limited mobility including patients that are hospitalized or obese. PUs are challenging to resolve when infected by antibiotic-resistant bacteria, particularly methicillin-resistant Staphylococcus aureus (MRSA). In this study, we investigated the potential of repurposing auranofin to treat pressure ulcers infected with MRSA. Auranofin's in vitro activity against strains of S. aureus (including MRSA) was not affected in the presence of higher bacterial inoculum (107 CFU/mL) or by lowering the pH in standard media to simulate the environment present on the surface of the skin. Additionally, S. aureus did not develop resistance to auranofin after repeated exposure for two weeks via a multi-step resistance selection experiment. In contrast, S. aureus resistance to mupirocin emerged rapidly. Moreover, auranofin exhibited a long postantibiotic effect (PAE) in vitro against three strains of S. aureus tested. Remarkably, topical auranofin completely eradicated MRSA (8-log10 reduction) in infected PUs of obese mice after just four days of treatment. This was superior to both topical mupirocin (1.96-log10 reduction) and oral clindamycin (1.24-log10 reduction), which are used to treat infected PUs clinically. The present study highlights auranofin's potential to be investigated further as a treatment for mild-to-moderate PUs infected with S. aureus.

Development of recurrent pressure ulcers, risk factors in older patients: a prospective observational study.

OBJECTIVE: Prevention of recurrent pressure ulcers (PU) is one of the most important challenges in wound care, furthermore, the risk factors for recurrent PUs are still not fully understood. This study aimed to explore the risk factors for recurrent PU development within two weeks, including biophysical skin properties, pro-inflammatory cytokine (tumour necrosis factor [TNF]-α) levels and bacterial species, in older patients. METHOD: This prospective study was conducted in a long-term care facility with patients whose PU had healed within two months. Biophysical skin properties were evaluated by stratum corneum hydration, pH, sebum content and transepidermal water loss. TNF-α level was measured using skin blotting. Skin bacteria were collected using tape stripping and determined by species-specific gene amplification. These parameters, along with Braden scale and interface pressure, were evaluated every two weeks for a total period of eight weeks. A penalised generalised estimating equation analysis was used to determine the risk factors for recurrent PUs. RESULTS: In total, 20 patients were included in this study, with 57 observations. Of these, recurrent PU was seen in eight observations. Elevation of pH (p=0.049; odds ratio [OR] per 1 unit=3.91, 95% confidence interval [CI]:1.01-15.15), presence of Acinetobacter spp. (p=0.039; OR versus culture-negative=6.28, 95%CI:1.10-35.86) and higher interface pressure (p=0.008; OR per 1 mmHg=1.06, 95%CI:1.01-1.10) on the healed PU were significantly related to the development of recurrent PU. CONCLUSION: Higher pH, existence of Acinetobacter spp. and higher interface pressure on the site of the healed PU were associated with the development of recurrent PUs in older patients undergoing conservative treatments.

Antibiofilm activity and cytotoxicity of silk sericin against Streptococcus mutans bacteria in biofilm: an in vitro study.

OBJECTIVE: To investigate the potential of sericin extracted by different methods to inhibit biofilm formation (prevention) and disrupt already formed biofilm (treatment). METHOD: In this in vitro study, sericin was extracted by heat, acid, alkali and urea. Streptococcus mutans bacteria were cultivated in the presence of various concentrations of sericin to evaluate antibiofilm formation using cell density assay (inhibition effect before biofilm formed). Conversely, various concentrations of sericin were added to a biofilm already formed by Streptococcus mutans bacteria, and the viability of bacteria assessed by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay (disruption effects after biofilm formed). Structures of extracted sericin were evaluated using circular dichroism and Fourier-transform infrared spectrometer. RESULTS: The urea-extracted sericin at all concentrations (12.5mg/ml, 25mg/ml, 50mg/ml and 100mg/ml) showed the highest potential antibiofilm activity in terms of both inhibition and disruption effects, compared with sericin extracted by heat, acid or alkali. The heat-extracted and acid-extracted sericin were found to reduce the biofilm formation dose-dependently, while the alkali-extracted sericin did not show either inhibition or disruption effect on the bacterial biofilm. The urea-extracted sericin also killed the bacteria residing within the biofilm, possibly due to its modified structure which may destabilise the bacterial cell wall, leading to membrane disintegration and, finally, cell death. CONCLUSION: Our results demostrated the antibiofilm activity of sericin. This could form the basis of further research on the mechanism and application of sericin as a novel antibiofilm agent.

The cutaneous microbiome in hospitalized patients with pressure ulcers.

This study investigated whether there are differences in the composition of the cutaneous microbiome of the unaffected skin between patients with pressure ulcers compared with those without pressure ulcers. The cutaneous microbiome of the unaffected skin of 15 patients with sacral pressure ulcers compared to 15 patients without pressure ulcers was analysed. It demonstrated that the inter-individual variation in skin microbiota of patients with pressure ulcers was significantly higher (P = 0.01). The abundance of 23 species was significantly different with Staphylococcus aureus and unclassified Enterococcus the most abundant species in patients with pressure ulcers. Random Forest models showed that eight species were associated with pressure ulcers occurrence in 81% of the patients. A subset of four species gave the strongest interaction. The presence of unclassified Enterococcus had the highest association with pressure ulcer occurrence. This study is the first to demonstrate that the cutaneous microbiome is altered in patients with pressure ulcers.

Photobiomodulation by dual-wavelength low-power laser effects on infected pressure ulcers.

The aim of this study was to evaluate the effects of photobiomodulation (PBM) by dual-wavelength low-power lasers on the healing and bacterial bioburden of pressure ulcer (PU) models. Twenty-five male Swiss mice were divided into five equal groups. Ischemia reperfusion cycles were employed to cause PU formation by the external application of magnetic plates. Immediately after wounding, a suspension of Pantoea agglomerans was applied at the base of all the wounds of the infected groups, using a calibrated pipette. PBM (simultaneous emission at 660 and 808 nm, 142.8 J/cm2, in continuous wave emission mode) was applied to the PUs for 14 sessions. The animals were euthanized 14 days after PU induction, and their tissues were analyzed for wound contraction and reepithelialization, epidermis thickness, bacterial survival, and IL-1ß and IL-10 mRNA level evaluations. The PU areas appeared larger in the mice from the infected groups than in those in the laser group 4 days after PU induction and presented incomplete reepithelialization 14 days after PU induction. However, the PBM accelerated the wound healing in the infected + laser group compared with the infected group 11 and 14 days following the PU induction. The infected and irradiated PUs exhibited a thinner neo-epidermis than those in the infected group, and the bacterial survival decreased in the laser group; the relative expression IL-1ß mRNA levels demonstrated an increasing tendency while the relative expression IL-10 mRNA levels demonstrated a decreasing tendency in the infected + laser and laser groups. These results suggest that PBM improves healing by killing or inhibiting bacteria in PUs as well as by accelerating the wound healing, resulting in tissue repair.

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.