A systematic review of intervention studies demonstrates the need to develop a minimum set of indicators to report the presence of burn wound infection.

INTRODUCTION: Burn wound infections result in delayed healing and increased pain, scarring, sepsis risk and healthcare costs. Clinical decision making about burn wound infection should be supported by evidence syntheses. Validity of evidence from systematic reviews may be reduced if definitions of burn wound infectionvary between trials. This review aimed to determine whether burn wound infectionis defined, and whether there is variation in the indicators used to define burn wound infectionacross studies testing interventions for patients with burns. METHOD: Searches were carried out in four databases (Ovid Medline, Ovid Embase, Cinahl, Cochrane Register of Trials) to identify studies evaluating interventions for patients with burns and reporting a burn wound infection outcome. Pre-defined inclusion and exclusion criteria were systematically applied to select relevant studies. Data were systematically extracted and reported narratively. RESULTS: 2056 studies were identified, of which 72 met the inclusion criteria, comprising 71 unique datasets. 52.1% of studies were randomised controlled trials. Twenty-eight (38.0%) studies reporting a burn wound infection outcome did not report how they had defined it. In the methods of included studies, 59 studies (83.1%) reported that they planned to measure burn wound infection as an outcome. Of these, 44 studies (74.6%) described how they had defined burn wound infection; 6 studies (13.6%) reported use of a previously developed consensus-informed definition of burn wound infection, and 41 studies (69.5%) described the specific indicators used to define it. Studies used between one (11 studies; 26.8%) and nine indicators (2 studies; 4.9%) to define burn wound infection (median = 3, inter-quartile range = 2). The most commonly used indicator was presence of bacteria in the wound (61.0% of studies). Only 13 studies (31.7%) defined burn wound infection using the same indicators as at least one other study. DISCUSSION AND CONCLUSIONS: Within intervention studies reporting burn wound infection outcomes, a definition of this outcome is commonly not provided, or it varies between studies. This will prevent evidence synthesis to identify effective treatments for patients with burn injuries. Since there is no objective method for assessing burn wound infection, expert consensus is needed to agree a minimum set of indicators (Core Indicator Set) reported in all trials reporting burn wound infection as an outcome.

Consensus demonstrates four indicators needed to standardize burn wound infection reporting across trials in a single-country study (ICon-B study).

INTRODUCTION: Evidence-based interventions are needed to treat burn wound infection (BWI). Evidence syntheses have been limited by heterogeneity of indicators used to report BWI across trials. Consistent reporting of BWI would be facilitated by an agreed minimum set of indicators. The Infection Consensus in Burns study aimed to achieve expert consensus about a core indicator set (CIS) for BWI. METHODS: The CIS was established through development of a long list of BWI indicators identified from a systematic review and expert input. In a Delphi survey, UK expert participants rated the indicators according to use in everyday practice, importance for diagnosis and frequency of observation in patients with BWI. Indicators were included in the CIS if ≥75% of participants agreed it was important for diagnosis and used in everyday practice, and ≥50% of participants rated it as frequently observed in patients with BWI. RESULTS: One hundred and ninety-five indicators were identified from the systematic review and reduced to 29 survey items through merging of items with the same meaning. Seventy-five UK experts participated in the Delphi survey. Following a single survey round and a consensus meeting with an expert panel, four items were included in the CIS: pyrexia, spreading erythema, change in white cell count, and presence of pathogenic microbes. DISCUSSION AND CONCLUSIONS: To facilitate evidence synthesis, a single-country systematic, expert-informed approach was taken to develop a CIS to be reported consistently across trials reporting BWI as an outcome. Future work requires verification of the CIS with international experts.

The SPaCE diagnostic: a pilot study to test the accuracy of a novel point of care sensor for point of care detection of burn wound infection.

BACKGROUND: Wound infection in burn patients is common and has an impact on outcomes. There is no objective method to diagnose infection at point of care (PoC). Early diagnosis prevents progression to sepsis. Diagnostic subjectivity supports over-diagnosis, unnecessary hospitalization, and antibiotic overuse. AIM: This pilot study aimed to investigate the accuracy of a novel PoC wound infection diagnostic in burn patients. METHODS: We produced, and in vitro tested, a PoC diagnostic for early wound infection diagnosis. The prototype SPaCE diagnostic uses a patented lipid vesicle suspension into which a clinical swab is placed. The diagnostic delivers a colour-response to Staphylococcus aureus, Pseudomonas aeruginosa, Candida species and Enterococcus faecalis at toxin release. A pilot clinical diagnostic accuracy study was undertaken. The reference standard was a retrospective decision made by an expert clinical panel using routinely available data. FINDINGS: Data was available from 33 of 34 patients. Of these, 52% were considered to have a wound infection, 42% not, and two (6%) were equivocal. The diagnostic results showed 24% were infected, 42% were not and 33% produced intermediate results. Agreement between clinical judgement and diagnostic result, assessed using a weighted Kappa, was 0.591 suggesting moderate agreement. If the intermediate results were excluded, 22 sets of data with definitive results achieved a Kappa statistic of 0.81 suggesting 'almost perfect' agreement. Sensitivity and specificity were 57% (8/14) and 71% (12/17), respectively. CONCLUSION: This pilot study provided evidence that the SPaCE diagnostic could provide valuable and timely data to support clinical decision-making at PoC for wound infection.

Development of an amperometric assay for phosphate ions in urine based on a chemically modified screen-printed carbon electrode.

An amperometric assay for the determination of inorganic phosphate (Pi) in urine has been developed without the need for sample preparation. A screen-printed carbon electrode modified with the electrocatalyst cobalt phthalocyanine (CoPC-SPCE) and covered with a cellulose acetate membrane (CAM) serves as the sensor. The sensor detects hydrogen peroxide (H(2)O(2)), which is produced as a result of the oxidative decarboxylation of pyruvate, catalyzed by pyruvate oxidase (PyOd), in the presence of Pi, oxygen, and cofactors. Following optimization of solution conditions, and in the presence of a urine sample, a linear range was found to exist between the rate of current increase and phosphate concentration over the range of 2.27 x 10(-5) to 1.81 x 10(-4)M, and the limit of detection was found to be 4.27 x 10(-6)M. The assay was applied to the determination of phosphate ions in the urine of a normal subject, and the mean concentration in unspiked urine was found to be 3.40 x 10(-5)M with a coefficient of variation of 8.0% (n=5). The mean recovery of phosphate added to urine samples was 98.7% with a coefficient of variation of 5.5% (n=3). To the authors' knowledge, this is the first report of an amperometric assay for Pi that incorporates a CoPC-SPCE as the sensing device.

Impedimetric approach for quantifying low bacteria concentrations based on the changes produced in the electrode-solution interface during the pre-attachment stage.

This paper describes an approach for quantifying low concentrations of bacteria, particularly Escherichia coli, based on the measurement of the initial attachment of bacteria to platinum surfaces, using impedance spectroscopy. The value of the interface capacitance in the pre-attachment stage (before 1min of attachment) showed correlation with suspended concentration of bacteria from 10(1) to 10(7)CFUmL(-1) (colony forming units per mL). This method was found to be sensitive to the attachment time, to the applied potential and to the size of the counter electrode. The sensor lifetime was also evaluated.

The effect of the ionophore valinomycin on biomimetic solid supported lipid DPPTE/EPC membranes.

Self assembled monolayers and bilayers are produced on a flat glass surface, bound by a thiolipid onto bare gold. 1,2-Dipalmitoyl-sn-Glycero-3-Phosphothioethanol (DPPTE) is used as the molecule binding to the electrode surface. The lipid lambda-alpha-Phosphatidyl-Choline-beta-Oleoyl-g-Palmitoyl (POPC) and the lipid mixture eggphosphatadiylcholine (EPC) are used as spacer lipids with the aim of achieving solid-supported artificial lipid membranes. With the aim of creating and investigating more natural systems, ion carrier proteins such as valinomycin are introduced into the DPPTE/EPC system. The direct influence on the membranes as well as the effects of different ionic solutions on the proteins is shown.

Study into the kinetic properties and surface attachment of a thermostable adenylate kinase.

A thermostable adenylate kinase (tAK) has been used as model protein contaminant on surfaces, so used because residual protein after high temperature wash steps can be detected at extremely low concentrations. This gives the potential for accurate, quantitative measurement of the effectiveness of different wash processes in removing protein contamination. Current methods utilise non-covalent (physisorbtion) of tAK to surfaces, but this can be relatively easily removed. In this study, the covalent binding of tAK to surfaces was studied to provide an alternative model for surface contamination. Kinetic analysis showed that the efficiency of the enzyme expressed as the catalytic rate over the Michaelis constant (kcat/KM) increased from 8.45±3.04 mM-1 s-1 in solution to 32.23±3.20 or 24.46±4.41 mM-1 s-1 when the enzyme was immobilised onto polypropylene or plasma activated polypropylene respectively. Maleic anhydride plasma activated polypropylene showed potential to provide a more robust challenge for washing processes as it retained significantly higher amounts of tAK enzyme than polypropylene in simple washing experiments. Inhibition of the coupled enzyme (luciferase/luciferin) system used for the detection of adenylate kinase activity, was observed for a secondary product of the reaction. This needs to be taken into consideration when using the assay to estimate cleaning efficacy.

Assessing phage therapy against Pseudomonas aeruginosa using a Galleria mellonella infection model.

The Galleria mellonella infection model was used to assess the in vivo efficacy of phage therapy against laboratory and clinical strains of Pseudomonas aeruginosa. In a first series of experiments, Galleria were infected with the laboratory strain P. aeruginosa PAO1 and were treated with varying multiplicity of infection (MOI) of phages either 2h post-infection (treatment) or 2h pre-infection (prevention) via injection into the haemolymph. To address the kinetics of infection, larvae were bled over a period of 24h for quantification of bacteria and phages. Survival rates at 24h when infected with 10 cells/larvae were greater in the prevention versus treatment model (47% vs. 40%, MOI=10; 47% vs. 20%, MOI=1; and 33% vs. 7%, MOI=0.1). This pattern held true when 100 cells/larvae were used (87% vs. 20%, MOI=10; 53% vs. 13%, MOI=1; 67% vs. 7%, MOI=0.1). By 24h post-infection, phages kept bacterial cell numbers in the haemolymph 1000-fold lower than in the non-treated group. In a second series of experiments using clinical strains to further validate the prevention model, phages protected Galleria when infected with both a bacteraemia (0% vs. 85%) and a cystic fibrosis (80% vs. 100%) isolate. Therefore, this study validates the use of G. mellonella as a simple, robust and cost-effective model for initial in vivo examination of P. aeruginosa-targeted phage therapy, which may be applied to other pathogens with similarly low infective doses.

Enhancement of the antimicrobial properties of bacteriophage-K via stabilization using oil-in-water nano-emulsions.

Bacteriophage therapy is a promising new treatment that may help overcome the threat posed by antibiotic-resistant pathogenic bacteria, which are increasingly identified in hospitalized patients. The development of biocompatible and sustainable vehicles for incorporation of viable bacterial viruses into a wound dressing is a promising alternative. This article evaluates the antimicrobial efficacy of Bacteriophage K against Staphylococcus aureus over time, when stabilized and delivered via an oil-in-water nano-emulsion. Nano-emulsions were formulated via thermal phase inversion emulsification, and then bacterial growth was challenged with either native emulsion, or emulsion combined with Bacteriophage K. Bacteriophage infectivity, and the influence of storage time of the preparation, were assessed by turbidity measurements of bacterial samples. Newly prepared Bacteriophage K/nano-emulsion formulations have greater antimicrobial activity than freely suspended bacteriophage. The phage-loaded emulsions caused rapid and complete bacterial death of three different strains of S. aureus. The same effect was observed for preparations that were either stored at room temperature (18-20°C), or chilled at 4°C, for up to 10 days of storage. A response surface design of experiments was used to gain insight on the relative effects of the emulsion formulation on bacterial growth and phage lytic activity. More diluted emulsions had a less significant effect on bacterial growth, and diluted bacteriophage-emulsion preparations yielded greater antibacterial activity. The enhancement of bacteriophage activity when delivered via nano-emulsions is yet to be reported. This prompts further investigation into the use of these formulations for the development of novel anti-microbial wound management strategies.