Infection control in burn patients: are fungal infections underestimated?

Microbial infections in burn patients

Polymicrobial infections are the leading causes of complications incurred from injuries that burn patients develop. Such patients admitted to the hospital have a high risk of developing hospital-acquired infections, with longer patient stays leading to increased chances of acquiring such drug-resistant infections. Acinetobacter baumannii, Klebsiella pneumoniae, Pseudomonas aeruginosa, and Proteus mirabilis are the most common multidrug-resistant (MDR) Gram-negative bacteria identified in burn wound infections (BWIs). BWIs caused by viruses, like Herpes Simplex and Varicella Zoster, and fungi-like Candida spp. appear to occur occasionally. However, the preponderance of infection by opportunistic pathogens is very high in burn patients. Variations in the causative agents of BWIs are due to differences in geographic location and infection control measures. Overall, burn injuries are characterized by elevated serum cytokine levels, systemic immune response, and immunosuppression. Hence, early detection and treatment can accelerate the wound-healing process and reduce the risk of further infections at the site of injury. A multidisciplinary collaboration between burn surgeons and infectious disease specialists is also needed to properly monitor antibiotic resistance in BWI pathogens, help check the super-spread of MDR pathogens, and improve treatment outcomes as a result.

Infections in Burn Patients

Infections are the leading cause of mortality in burn patients who survive their initial resuscitation. Burn injury leads to immunosuppression and a dysregulated inflammatory response which can have a prolonged impact. Early surgical excision along with support of the multidisciplinary burn team has improved mortality in burn patients. The authors review diagnostic and therapeutic challenges as well as strategies for management of burn related infections.

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Local or general fungal infection remain a very serious event in burns. Burns have numerous risk factors for such, infections associated with depressed immunity. Candida, Aspergillus and mucor fungi prevail in wound infections. The two latest are especially serious and impairing. Diagnosis is based on anatomo-pathological and mycological examination of skin samples. Treatment is mainly surgical. Medical therapy depends on antifungal susceptibility. Most fungemias are candidemias. Diagnosis is difficult and often based on clinical suspicion. Treatment uses echinocandin and fluconazole.

Design and development of a topical dosage form for the convenient delivery of electrospun drug loaded nanofibers

Nanofibers dispersed in gel facilitated the convenient administration of drug loaded nanofibers.

Infection control in severely burned patients

In the last two decades, much progress has been made in the control of burn wound infection and nasocomial infections (NI) in severely burned patients. The continiually changing epidemiology is partially related to greater understanding of and improved techniques for burn patient management as well as effective hospital infection control measures. With the advent of antimicrobial chemotherapeutic agents, infection of the wound site is now not as common as, for example, urinary and blood stream infections. Universal application of early excision of burned tissues has made a substantial improvement in the control of wound-related infections in burns. Additionally, the development of new technologies in wound care have helped to decrease morbidity and mortality in severe burn victims. Many examples can be given of the successful control of wound infection, such as the application of an appropriate antibiotic solution to invasive wound infection sites with simultaneous vacuum-assisted closure, optimal preservation of viable tissues with waterjet debridement systems, edema and exudate controlling dressings impregnated with Ag (Silvercel, Aquacell-Ag). The burned patient is at high risk for NI. Invasive interventions including intravenous and urinary chateterization, and entubation pose a further risk of NIs. The use of newly designed antimicrobial impregnated chateters or silicone devices may help the control of infection in these immunocomprimised patients. Strict infection control practices (physical isolation in a private room, use of gloves and gowns during patient contact) and appropriate empirical antimicrobial therapy guided by laboratory surveillance culture as well as routine microbial burn wound culture are essential to help reduce the incidance of infections due to antibiotic resistant microorganisms.

Fungal infections in burns: Diagnosis and management

Burn wound infection (BWI) is a major public health problem and the most devastating form of trauma worldwide. Fungi cause BWI as part of monomicrobial or polymicrobial infection, fungaemia, rare aggressive soft tissue infection and as opportunistic infections. The risk factors for acquiring fungal infection in burns include age of burns, total burn size, body surface area (BSA) (30-60%), full thickness burns, inhalational injury, prolonged hospital stay, late surgical excision, open dressing, artificial dermis, central venous catheters, antibiotics, steroid treatment, long-term artificial ventilation, fungal wound colonisation (FWC), hyperglycaemic episodes and other immunosuppressive disorders. Most of the fungal infections are missed owing to lack of clinical awareness and similar presentation as bacterial infection coupled with paucity of mycology laboratories. Expedient diagnosis and treatment of these mycoses can be life-saving as the mortality is otherwise very high. Emergence of resistance in non-albicans Candida spp., unusual yeasts and moulds in fungal BWI, leaves very few fungi susceptible to antifungal drugs, leaving many patients susceptible. There is a need to speciate fungi as far as the topical and systemic antifungal is concerned. Deep tissue biopsy and other relevant samples are processed by standard mycological procedures using direct microscopy, culture and histopathological examination. Patients with FWC should be treated by aggressive surgical debridement and, in the case of fungal wound infection (FWI), in addition to surgical debridement, an intravenous antifungal drug, most commonly amphotericin B or caspofungin, is prescribed followed by de-escalating with voriconazole or itraconazole, or fluconazole depending upon the species or antifungal susceptibility, if available. The propensity for fungal infection increases, the longer the wound is present. Therefore, the development of products to close the wound more rapidly, improvement in topical antifungal therapy with mould activity and implementation of appropriate systemic antifungal therapy guided by antifungal susceptibility may improve the outcome for severely injured burn victims.

Ultraviolet-C light for treatment of Candida albicans burn infection in mice

Burn patients are at high risk of invasive fungal infections, which are a leading cause of morbidity, mortality, and related expense exacerbated by the emergence of drug resistant fungal strains. In this study, we investigated the use of UVC light (254 nm) for the treatment of yeast Candida albicans infection in mouse third degree burns. In vitro studies demonstrated that UVC could selectively kill the pathogenic C. albicans compared with a normal mouse keratinocyte cell line in a light exposure dependent manner. A mouse model of chronic C. albicans infection in non-lethal third degree burns was developed. The C. albicans strain was stably transformed with a version of the Gaussia princeps luciferase gene that allowed real-time bioluminescence imaging of the progression of C. albicans infection. UVC treatment with a single exposure carried out on day 0 (30 min postinfection) gave an average 2.16-log(10)-unit (99.2%) loss of fungal luminescence when 2.92 J cm(-2) UVC had been delivered, while UVC 24 h postinfection gave 1.94-log(10)-unit (95.8%) reduction of fungal luminescence after 6.48 J cm(-2). Statistical analysis demonstrated that UVC treatment carried out on both day 0 and day 1 significantly reduced the fungal bioburden of infected burns. UVC was found to be superior to a topical antifungal drug, nystatin cream. UVC was tested on normal mouse skin and no gross damage was observed 24 h after 6.48 J cm(-2). DNA lesions (cyclobutane pyrimidine dimers) were observed by immunofluorescence in normal mouse skin immediately after a 6.48 J cm(-2) UVC exposure, but the lesions were extensively repaired at 24 h after UVC exposure.