SPaCE Swab: Point-of-Care Sensor for Simple and Rapid Detection of Acute Wound Infection.

Wound infection is commonly observed after surgery and trauma but is difficult to diagnose and poorly defined in terms of objective clinical parameters. The assumption that bacteria in a wound correlate with infection is false; all wounds contain microorganisms, but not all wounds are clinically infected. This makes it difficult for clinicians to determine true wound infection, especially in wounds with pathogenic biofilms. If an infection is not properly treated, pathogenic virulence factors, such as rhamnolipids from Pseudomonas aeruginosa, can modulate the host immune response and cause tissue breakdown. Life-threatening sepsis can result if the organisms penetrate deep into host tissue. This communication describes the sensor development for five important clinical microbial pathogens commonly found in wounds: Staphylococcus aureus, P. aeruginosa, Candida albicans/auris, and Enterococcus faecalis (the SPaCE pathogens). The sensor contains liposomes encapsulating a self-quenched fluorescent dye. Toxins, expressed by SPaCE infecting pathogens in early-stage infected wounds, break down the liposomes, triggering dye release, thus changing the sensor color from yellow to green, an indication of infection. Five clinical species of bacteria and fungi, up to 20 strains each (totaling 83), were grown as early-stage biofilms in ex vivo porcine burn wounds. The biofilms were then swabbed, and the swab placed in the liposome suspension. The population density of selected pathogens in a porcine wound biofilm was quantified and correlated with colorimetric response. Over 88% of swabs switched the sensor on (107-108 CFU/swab). A pilot clinical study demonstrated a good correlation between sensor switch-on and early-stage wound infection.

Lack of a standardised UK care pathway resulting in national variations in management and outcomes of paediatric small area scalds.

INTRODUCTION: There is a paucity of evidence guiding management of small area partial thickness paediatric scalds. This has prevented the development of national management guidelines for these injuries. This research aimed to investigate whether a lack of evidence for national guidelines has resulted in variations in both management and outcomes of paediatric small area scalds across England and Wales (E&W). METHODS: A national survey of initial management of paediatric scalds ≤5% Total Body Surface Area (%TBSA) was sent to 14 burns services in E&W. Skin graft rates of anonymised burns services over seven years were collected from the international Burns Injury Database (iBID). Average skin grafting rates across services were compared. Length of stay and proportion of patients receiving general anaesthesia for dressing application at each service were also compared. RESULTS: All 14 burns services responded to the survey. Only 50% of services had a protocol in place for the management of small area burns. All protocols varied in how partial thickness paediatrics scalds ≤5% TBSA should be managed. There was no consensus as to which scalds should be treated using biosynthetic dressings. Data from iBID for 11,917 patients showed that the average reported skin grafting rate across all burns services was 2.3% (95% CI 2.1, 2.6) but varied from 0.3% to 7.1% (P<0.001). Service provider remained associated with likelihood of skin grafting when variations in the %TBSA case mix seen by each service were controlled for (χ(2)=87.3, P<0.001). The use of general anaesthetics across services varied between 0.6 and 35.5% (P<0.001). The median length of stay across services varied from 1 to 3 days (P<0.001). DISCUSSION: A lack of evidence guiding management of small-area paediatric scalds has resulted in variation in management of these injuries across E&W. There is also significant variation in outcomes for these injuries. Further research is indicated to determine if care pathways and outcomes are linked. An evidence-based national policy for the management of small area paediatric scalds would ensure that high quality, standardised care is delivered throughout E&W and variations in outcome are reduced.

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.

Development of a prototype wound dressing technology which can detect and report colonization by pathogenic bacteria.

A new methodology for detecting the microbiological state of a wound dressing in terms of its colonization with pathogenic bacteria such as Staphylococcus aureus or Pseudomonas aeruginosa has been developed. Here we report how stabilized lipid vesicles containing self-quenched carboxyfluorescein dye are sensitive to lysis only by toxins/virulence factors from P. aeruginosa and S. aureus but not by a non-toxic Escherichia coli species. The development of the stabilized vesicles is discussed and their response to detergent (triton), bacterial toxin (α-hemolysin) and lipases (phospholipase A(2)). Finally, fabrics with stabilized vesicles attached via plasma deposited maleic anhydride coupling are shown visibly responding to S. aureus (MSSA 476) and P. aeruginosa (PAO1) but not E. coli DH5α in a prototype dressing.

Preventing venous thrombosis in critically ill children: what is the right approach?

BACKGROUND: The incidence of venous thromboembolic (VTE) events in children has increased in recent years (J Neurosurg, 101, 2004, 32; J Thromb Haemost, 1, 2003, 1443) yet there is currently no consensus as to what VTE prophylaxis, if any, should be applied to the pediatric population. OBJECTIVES/AIMS: Our aim was to audit current practice in pediatric VTE prophylaxis across England and Wales and to advocate simple measures for prevention. We illustrate the importance of the condition with a series of cases from the South West Paediatric Burns and Neurosurgical Services based in Bristol. METHODS: Every pediatric intensive care unit (PICU) and burns center admitting children in England and Wales was invited to participate in a structured telephone questionnaire designed to find out how VTE in children were being prevented. We performed a literature review of specific risk factors and management of these factors. RESULTS: Only one of the 24 units surveyed had written guidelines specific for children. Four other units used modified adult guidelines in older children. In the remaining 19 units that had no written guidelines, decisions regarding prophylaxis were based on individual cases and consultant-led. CONCLUSION: There is no consensus in England and Wales as to which VTE prophylactic measures should be applied in patients <18 years of age. The National Institute for Health and Clinical Excellence (NICE) guidelines apply to adults only. Given the rarity of VTE events in children, it is unlikely that randomized controlled trials will provide the answer. We therefore propose that simple empirical measures be formally implemented in critically ill children to reduce the risk of developing this important but under-recognized condition.

Severe staphylococcal scalded skin syndrome in children.

Staphylococcal scalded skin syndrome (SSSS) is a rare toxin-mediated condition caused by Staphylococcus aureus, which causes blistering and desquamation of the skin. Between November 2005 and April 2006, four children were admitted to critical care beds in the South West Regional Paediatric Burns Unit because of SSSS affecting more than 50% of the body surface area. Details of these cases are presented, highlighting the potential severity of the condition. The cases also illustrate that fluid overload is a common complication of the condition, despite hypovolaemia being the more obvious risk, and that both hyponatraemia and leukopenia are frequent findings. These summaries clearly demonstrate the need for paediatric critical care in a tertiary burns unit for children with SSSS affecting a large proportion of the body surface area. The cluster of admissions prompted us to write a management protocol for children with severe SSSS and a summary of this is provided. Most children with SSSS will initially present to general paediatric units, where mild cases will be managed, but severe cases should be promptly referred to a tertiary paediatric burns unit for multi-disciplinary care in a critical care environment.

Early diagnosis and treatment of toxic shock syndrome in paediatric burns.

Young children with burns are at risk of developing toxic shock syndrome (TSS), which is an exotoxin mediated disease usually caused by Staphylococcus aureus (S. aureus). The diagnosis of TSS is difficult because in the early stages the signs and symptoms resemble other common childhood illnesses such as scarlet fever. If the condition is not treated promptly it has a high mortality. The South West Regional Paediatric Burns Unit at Frenchay Hospital admits 150-200 burns per year. We have designed a protocol to facilitate the early diagnosis and treatment of TSS. We report our experience over a 3-year period in which almost one quarter of cases of TSS were admitted from home or another hospital. During this period all children with TSS survived and none needed ventilatory support. Typical cases presented within 2 days of thermal injury, in a child under 2 years old with a burn of less than 10% of body surface area (BSA).