Pseudomonas pyocyanin inhibits wound repair by inducing premature cellular senescence : role for p38 mitogen-activated protein kinase

Pseudomonas aeruginosa is an important nosocomial pathogen of burn wounds. Pyocyanin, a virulence factor produced by the bacterium, induces persistent intracellular oxidative stress and premature senescence in mammalian cells. Our aims were to evaluate pyocyanin levels in infected wound dressings and the potential of the toxin to influence wound repair. Surgical dressings from infected burn patients were examined for pyocyanin and normal primary human diploid fibroblasts (HDFs) were treated with comparable concentrations and their replicative ability examined. Pyocyanin was detected in the exudate of infected wound dressings in amounts up to 5.3 μg/g (mean: 2.0 ± 2.3 μg/g). HDFs exposed to pyocyanin (1–50 μM; 0.2–10.5 μg/ml) underwent growth arrest at all concentrations and developed morphological characteristics associated with cellular senescence, including expression of senescence-associated β-galactosidase. Using an in vitro wound repair model, a single exposure to pyocyanin inhibited wound repair in a concentration-dependent manner. Prior treatment with a specific p38MAPK inhibitor allowed cells to maintain their replicative ability and pre-senescent morphology indicating pyocyanin operates through the Erk/p38MAPK senescence pathway. These data support the hypothesis that bacterial virulence factors capable of inducing persistent low-level oxidative stress play a pivotal role in modulating the tissue repair response to infection by inducing premature cellular senescence

Ablative fractional resurfacing in acute care management of facial burns: a new approach to minimize the need for acute surgical reconstruction

Current evidence suggests awaiting for scars to fully mature before engaging surgical reconstruction unless acute indications to prevent secondary damage, such as microstomia and eyelid ectropion are apparent. To evaluate the efficacy of ablative fractional CO laser intervention early in the acute treatment of panfacial burn injury. A 39-year-old Asian male with 60% TBSA flame burns including panfacial involvement was developing microstomia and upper and lower eyelid ectropion early proceeding epithelialization. At 6-weeks postinjury, ablative fractional CO laser treatment was commenced while still in the intensive care unit, and subsequently delivered at regular intervals. Nonsurgical scar contracture management was provided concurrently as per site specific standard protocols. Measurements and photographic data relative to deficits in eye and mouth competence were obtained at rest, as well as maximal opening at baseline and routinely until scar stabilization was reached. The outcomes were subsequently compared with facial burn patient historical data within our facility. No significant difference was identified in the functional ROM for mouth and eye regions; treatment duration was, however, shorter and aesthetic outcomes were considered superior to their surgical reconstruction counterparts in the historical cohort. This case report reveals that early ablative fractional CO resurfacing treatment, coalesced with nonsurgical scar management is an efficacious interventional approach to abate contractures to the face, accelerates and enhances scar maturation processes and may alleviate the need for surgical scar reconstructions. Moreover, optimal aesthetic outcomes may be achieved compared with traditional reconstructive methods

Orofacial contracture management: current patterns of clinical practice in Australian and New Zealand adult burn units

Burn injury to the face can lead to scarring and contractures that may impair oral competence for articulation, feeding, airway intubation access, oral/dental hygiene, aesthetics, and facial expression. Although a range of therapy interventions has been discussed for preventing contracture formation, there is minimal information on current practice patterns. This research examined patterns of clinical practice for orofacial burns management during a 4-year period to determine the nature and extent of clinical consistency in current care. Allied health clinicians involved in orofacial contracture management in Australia and New Zealand were surveyed at two time points (2010 and 2014). Twenty and 23 clinicians, respectively, across a range of allied health professions completed the surveys. Both surveys revealed multiple allied health disciplines, predominantly occupational therapy, speech language pathology, and physiotherapy, were involved orofacial burn management. A high degree of variation was observed across clinical practices in the 2010 survey. In the 2014 survey, although, greater consistency in practice patterns was observed with more clinicians commencing intervention earlier, with greater treatment intensity observed and more treatment modalities being used. Furthermore, in 2014, there was an increased use of assessment tools and clinical indicators to guide patient treatment. Agreement regarding clinical practice pathways for orofacial contracture rehabilitation is still emerging, and treatment continues to be predominantly guided by clinical experience. There is an urgent need for treatment efficacy research utilizing validated outcome measure tools to inform clinical consensus and practice guidelines

The speech-language pathologist's role in multidisciplinary burn care: an international perspective

Purpose: To explore international practices of speech-language pathology (SLP) within burn care in order to provide direction for education, training and clinical practice of the burns multidisciplinary team (MDT)

Exploding power: a statewide review of lithium battery related burns

**Introduction**: With the increase of lithium battery devices, including electronic cigarettes and battery power banks, there has been a steady rise in burn injuries secondary to device malfunction. These devices may cause chemical or flame burns. Our aim was to identify and classify epidemiological trends of explosions from lithium battery devices across the state of New South Wales (NSW), Australia. **Methods**: A review of the NSW Burn Injury Service (SBIS) database from January 2005–December 2019, together with medical records from the burns units at the Children’s Hospital at Westmead (CHW), the Concord Repatriation General Hospital (CRGH) and the Royal North Shore Hospital (RNSH) was conducted. All patients who suffered a burn secondary from a lithium battery device were included and data was extracted on mechanism of injury, severity of injury and management. This study was approved by the ethics committees of CHW, RNSH and CRGH [2020/PID00179]. **Results**: Of the 24 patients identified, six were paediatric and 18 were adults. The majority were male (7:1) with a mean age of 29.0 (± 16.6 years). The mean total body surface area burnt was 2.5 per cent   (± 0.9) [range 0.1–21.0%]. The majority occurred after 2014 and involved spontaneous explosions. Their injuries ranged from partial to full thickness burns with flame being the most common type (n=15). Three quarters of the cases (n=18) occurred in a home setting. **Conclusions**: Lithium battery device explosions can result in a mix of burn depth injuries from flame, contact and electrical, or chemical burns. Consumers need to be made more aware of the potential risks associated with use of lithium battery powered devices

Dysphagia in older persons following severe burns: burn location is irrelevant to risk of dysphagia and its complications in patients over 75 years

Background: Management of burns in older persons is complex with evidence indicating advanced age is associated with elevated risk for morbidity and mortality. Dysphagia and its sequelae may further increase this risk. Aims: (1) Determine the prevalence, and (2) identify risk factors for dysphagia in patients admitted with severe burn injury over 75 years. Methods: All patients >75 years admitted to Concord Repatriation General Hospital with severe burn injury over a 4-year period (2013–2017) were assessed for dysphagia on presentation and continually monitored throughout their admission. Burn injury, demographic and nutritional data were captured and analysed for association with and predictive value for dysphagia. Results: Sixty-six patients (35 male; 31 female) aged 75–96 years (median 82 years) were recruited. Dysphagia was identified in 46.97% during their hospital admission. Dysphagia was significantly associated with burn size, pre-existing cognitive impairment, mechanical ventilation, duration of enteral feeding, hospital length of stay, in-hospital complications and mortality. No association was identified between burn location, burn mechanism, surgery and dysphagia. Burn size and Malnutrition Screening Tool score were found to be independent predictors for dysphagia. Conclusions: Dysphagia prevalence is high in older persons with burns and is associated with increased morbidity and mortality, regardless of burn location

Microbiological findings in burn patients treated in a general versus a designated intensive care unit: Effect on length of stay

BACKGROUND: Infection is one of the most common causes of mortality and morbidity in burn patients. The incidence and frequency of microbiological micro-organisms are known to vary across different models of intensive care units. To date, no study has attempted to describe the different findings in burn patients treated in an open, general intensive care unit (GICU) versus a dedicated burns intensive care unit (BICU). Only limited data is available on the effect of these microbiological micro-organisms on patients' length of stay. AIM: To characterize and compare the microbiological flora and antibiotic resistance patterns encountered in two different models of burn intensive care and to determine the effect of specific microbiological types on length of intensive care unit (ICU) and overall stay. METHODS: A retrospective case-control study of 209 burn patients treated in two highly specialized, Western burn referral centres between September 2009 and March 2014. RESULTS: 9710 culture results were analysed, of which 2590 (26.7%) yielded positive results (1537 in the GICU and 1050 in the BICU). Gram-positive cultures were more frequently found in the GICU, whereas Gram-negative and yeast cultures were more prevalent in the BICU. The most frequently encountered micro-organisms in both units were similar and included Staphylococcus aureus, Pseudomonas aeruginosa, coagulase-negative staphylococci (CoNS) and Candida albicans. Significantly more resistant bacteria were detected in the BICU. Testing positive across all types of microbiological isolates, as well as for both Gram-positive and -negative bacteria significantly prolonged patient length of stay. This effect was even more pronounced if the micro-organisms were resistant to antimicrobial therapy. CONCLUSION: There are notable differences in the microbiological isolate and antibiotic resistance patterns between burn patients treated in a GICU compared to a designated BICU. In both units, testing positive for resistant microbiological micro-organisms is significantly associated with longer hospital stay

Tropoelastin incorporation into a dermal regeneration template promotes wound angiogenesis

Severe burn injury results in substantial skin loss and cannot be treated by autografts. The Integra Dermal Regeneration Template (IDRT) is the lead- ing synthetic skin substitute because it allows for wound bed regeneration and wound healing. However, all substitutes suffer from slow blood vessel ingrowth and would benefi t considerably from enhanced vascularization to nurture tissue repair. It is shown here that by incorporating the human elastic protein tropoelastin into a dermal regeneration template (TDRT) we can pro- mote angiogenesis in wound healing. In small and large animal models com- prising mice and pigs, the hybrid TDRT biomaterial and IDRT show similar contraction to autografts and decrease wound contraction compared to open wounds. In mice, TDRT accelerates early stage angiogenesis by 2 weeks, as evidenced by increased angiogenesis fl uorescent radiant effi ciency in live ani- mal imaging and the expression of endothelial cell adhesion marker CD146. In the pig, a full thickness wound repair model confi rms increased numbers of blood vessels in the regenerating areas of the dermis closest to the hypo- dermis and immediately below the epidermis at 2 weeks post-surgery. It is concluded that including tropoelastin in a dermal regeneration template has the potential to promote wound repair through enhanced vascularization