Burn Wound Infections Treatment & Management

The goal of medical care is to prevent infection. Early excision and grafting is the current standard of care and the primary surgical method for reducing infection risk and length of hospital stay and increasing graft take. ^[10] A 2015 meta-analysis of all available randomized controlled studies found that early excision reduced mortality rates in all burned patients who did not have an inhalation injury. ^[33] A fast and permanent closure of full-thickness burns can be obtained with autografts (a split-thickness skin graft from an uninjured donor site on the same patient). ^[10] Nonetheless, donor sites are painful and impose their own wound-healing burden on the patient. ^[10] If donor sites are insufficient owing to an extensive burn area, allografts, xenografts, skin substitutes, or a dermal analog should be considered. ^[10]

Wound care should be directed at thoroughly removing devitalized tissue, debris, and previously placed topical antimicrobials. A broad-spectrum surgical antimicrobial topical scrub such as chlorhexidine gluconate should be used along with adequate analgesia and preemptive anxiolytic in order to permit adequate wound care.

For analgesia, the use of opiates is debated, as these medications induce tolerance and addiction and may promote pain, a phenomenon known as opioid-induced hyperalgesia. ^[34] Multimodal pain management should therefore be considered. Opioid-sparing agents include acetaminophen, ketamine, and alpha-adrenergic agonists such as clonidine and dexmedetomidine. ^[34] Nonsteroidal anti-inflammatory agents should be avoided, as they impair wound healing ^[10] and increase the risk of acute kidney injury and bleeding.

Topical antimicrobials for the prevention and treatment of burn wound infection include mafenide acetate, silver sulfadiazine, silver nitrate solution, and silver-impregnated dressings. These various therapies differ in their ability to penetrate eschars, antimicrobial activities, and adverse-event profiles. ^{[35, 36]}

The method of antimicrobial delivery may also affect results. A clinical trial comparing silver sulfadiazine as a cream or as a powdered spray showed the latter formulation achieved higher rates of infection prevention and sterilization. ^[37] Silver formulations may be associated with drug pressure, resulting in infections with resistant bacteria or fungus. A 2013 meta-analysis showed a statistically significant increase in burn wound infections and a longer length of stay in patients treated with silver sulfadiazine than in patients receiving wound dressing or skin substitutes. Of note, the included trials were at a high or unclear risk of bias. ^[38]

In the event of a localized MRSA burn wound infection, fusidic acid and gentamycin sulfate can be used as topical treatment. Topical vancomycin is also available and has been demonstrated to be more effective than the systemic formulation with a lower adverse effect rate. ^[37]

Antibiotic prophylaxis at the time of wound manipulation has also been studied in patients with burns. Only a few studies have supported this use of systemic antibiotics during acute burn surgery. Antibiotics appear to be of no value in the preoperative setting; ^[38] however, surgical prophylaxis in patients with burns of more than 40% TBSA appears to reduce the rate of burn wound infections, although it does not affect mortality. ^[33] In nonsurgical patients, systemic antibiotic prophylaxis does not affect the incidence of burn wound infection or sepsis. ^[38]

Treatment of airway colonization is not recommended, as local airway antibiotic prophylaxis does not influence sepsis or mortality rates. ^[38] Furthermore, selective decontamination of the digestive tract with nonabsorbable antibiotics plus cefotaxime significantly increases the risk of MRSA infection. ^[38]

When an infection is identified, antimicrobial therapy should be directed at the pathogen recovered on culture. In the setting of invasive infection or evidence of sepsis, empiric therapy should be initiated. The incidence of bacteremia in critically ill adult patients with burn wounds is reported to be 4%. The most frequent pathogens in North American burn centers include S aureus and P aeruginosa ^[34] ; therefore, these microorganisms should be considered when choosing empiric therapy. It is important to remember that gram-negative pathogens isolated from burn centers (ie, P aeruginosa, A baumannii, Enterobacter species, K pneumoniae, E coli,Proteus species) do not differ significantly among burn centers worldwide. ^[39] A local burn facility's antibiogram should also be established to help direct empirical therapy.

Antimicrobial-resistant bacterial infection among burn patients is associated with prolonged stays in the hospital. Isolates recovered after 7, 14, and 21 days of hospitalization are considerably more likely to be resistant to the antibiotics tested compared with admission-day isolates. Changing resistance patterns throughout hospitalization can significantly affect empirical therapy choices for patients who develop infection weeks after arriving in the hospital. Inadequate initial antimicrobial therapy to treat multidrug-resistant (MDR) infections results in higher mortality rates. ^[11]

If an multidrug-resistant pathogen is isolated, colistin should be considered. ^[40] An evaluation of the antimicrobial activities of colistin against gram-negative bacteria isolates worldwide demonstrated that this medication is still effective with constant resistance levels. It is necessary to remember that this medication has a narrow therapeutic window, with nephrotoxicity and neurotoxicity being the most common adverse effects. Therefore, evaluation of the patient by an expert multidisciplinary group while the antibiotic therapy is underway is required. ^[41]

If fungi are observed on histopathology, culture samples to detect the infecting genus and species are necessary, as the available antifungals have varying activity against different fungi. Amphotericin B was once the agent of choice because of its broad spectrum, but some facilities have seen increased rates of infections with Fusarium species and Aspergillus terreus, which are innately resistant to amphotericin B. In these cases, voriconazole is often used. A newer agent, posaconazole, may have broader antifungal activity. ^{[8, 13]}

In addition to maintaining a hospital antibiogram, many centers monitor individual patient colonization using admission and scheduled (often weekly) cultures of wounds (or other sites). This can be informative despite the low yield, as samples that are positive for resistant pathogens can help tailor the choice of empirical antibiotic therapy if patients subsequently become septic. ^[42]

Hyperglycemia is associated with an increase in inflammatory response and occurs in burned patients because of the increased rate of glucose production and impaired tissue glucose extraction. Tight glucose control has been suggested to improve survival and to reduce the sepsis risk. ^{[9, 43]}

Propranolol has been studied for its potential benefits in burns. It is suggested that this drug may restore glycemic control, reduce peripheral lipolysis, and enhance the immune response to sepsis by modulation of the catecholamine release during severe burn injury. In a prospective, randomized trial of propranolol following injury, decreased healing time and hospital length of stay was noted. ^[9]

A meta-analysis in the use of recombinant growth hormone (rhGH) in burn patients could not find any study reporting burn wound infection as an outcome. It was observed that, among both children and adults with burns larger than 40% TBSA, rhGH hastened burn wound healing and reduced length of hospital stay. An increased risk for hyperglycemia was observed; nonetheless, rhGH treatment did not affect mortality. ^[44]

Patients with burns are also at risk for tetanus. Tetanus vaccination plus anti-tetanus immunoglobulin should be administered to patients who have no history of vaccination with booster tetanus toxoid vaccination given at 4 weeks and 6 months.

This is fundamental to the care of the patient. Systemic and local antibiotics have limited effect in improving morbidity and mortality unless they are used in combination with adequate surgical care.

Consultation with an infectious disease specialist is suggested if multidrug-resistant bacteria are present. ^[45]

After a severe burn injury, a prolonged and persistent hypermetabolic response has been noted (believed to be secondary to elevation of catecholamines, cortisol, and inflammatory mediators). This response augments the metabolic rate, leading to muscle catabolism and immunosuppression. ^{[26, 46]}

The loss of body mass associated with severe burns has been associated with higher infection rates, delayed wound healing, and longer hospital stays; therefore, the initiation of early and aggressive nutritional support is required. ^{[10, 46]} Nutrition assessment should include a complete history and physical examination, evaluating features that may affect nutrition management. ^[26]

To manage the postburn hypermetabolic state and its complications, enteral nutrition is a safe, widely available, and effective measure that should be started within the first 24 hours of admission. Early enteral nutrition has been shown to deliver caloric requirements and diminish the hypermetabolic response, thus reducing complications. Delays in enteral nutrition initiation are associated with gut mucosal damage, decreased absorption, and bacterial translocation, leading to poorer outcomes. ^{[9, 46]} Early enteral nutrition should be started in patients with burns larger than 20% TBSA, even in patients who can be fed orally, as orally fed patients have higher complications and infection rates. ^[47]

Carbohydrate and fat intake must be closely monitored in burn patients, as their excesses can increase the risk of infection and sepsis. ^[10] Carbohydrates should be delivered at a rate of 7 g/kg/day, and fat should comprise less than 25% of the calories obtained from nonprotein sources. ^[48]

Although low albumin levels have been related with poor outcomes (see Laboratory Studies), albumin supplementation to maintain levels higher than 2 g/dL do not affect the length of stay, time to wound healing, or in-hospital mortality rate. ^[49]

A 2013 meta-analysis evaluated the use of glutamine supplementation in severely burned patients, showing a reduction in gram-negative infections and mortality with this intervention. ^[50]

Patients may be as active as they can tolerate. Aggressive physical and occupational therapy of extremity injuries is necessary to prevent long-term morbidity. ^[51]

Burn wound infections are often the source of bacteria responsible for other systemic infections, including bloodstream infections and pneumonia. This can lead to sepsis, multisystem organ failure, and death. ^[22]

Early wound excision is associated with bleeding complications that require transfusions. Given the evidence that increased blood transfusion is associated with higher infection rates in the general trauma population, further data are needed to evaluate the overall utility of early excision, especially since the overall data supporting this technique are limited, although it is considered the standard of care in most burn facilities. ^[24]

The prevention of burn wound infection is a team approach that includes the support of surgeons, nurses, infection-control providers, and infectious disease physicians. Emphasis on early wound care, infection-control practices, and long-term rehabilitative care is necessary to improve the morbidity and mortality associated with burns.

Early removal of full-thickness burned tissue, as well as early definitive wound closure and strict enforcement of infection-control procedures, is necessary to mitigate poor outcomes.

Patients require prolonged occupational and physical therapy support based on the site of the burn. ^[30]

A primary goal during hospitalization is to prevent nosocomial transmission of multidrug-resistant pathogens, especially in patients with a greater percentage of total body surface area (TBSA) burn (approximately 30%) or who are known to be colonized with multidrug-resistant bacteria such as MRSA, vancomycin-resistant Enterococcus species, or gram-negative bacteria known to develop resistance (eg, Pseudomonas, Klebsiella, Acinetobacter species). ^{[6, 11]}

Hand hygiene should be aggressively implemented. Standard precautions should be used in the care of all patients with burn injuries. Patients should be managed in single rooms, if possible, with use of contact precautions. Gowns and gloves should be used when contact with infected material or open wounds is expected. Masks and caps should be implemented based on the presence of multidrug-resistant bacteria. The use of individual-patient equipment should be considered. ^[20]

For catheter insertion, locations distal from the wound are necessary since catheters inserted near or through burn wounds are more frequently associated with infection development and earlier bacterial contamination with higher numbers of colony-forming units than catheters inserted distant from the wound. If a central venous catheter is required, femoral insertion sites are associated with higher infection rates. ^[52]

Routine surveillance cultures may be used in conjunction with isolation precautions for all or those patients with multidrug-resistant bacterial colonization or previous infection. Surveillance cultures, isolation, and hand hygiene, used in conjunction with regular feedback and education and environment control measures, have been shown to control the transmission of resistant pathogens. ^[9]

Aggressive infection-control procedures should be undertaken when transferring patients between facilities because of the risk of transferring multidrug-resistant bacteria.