Burn bacteriology during the last 50 years

Antimicrobial resistance patterns and virulence factors of enterococci isolates in hospitalized burn patients

OBJECTIVE

The objective of this study was to determine the frequency of the antimicrobial resistance and genes encoding virulence factors of enterococci isolated in hospitalized burn patients in a major burn center in Ahvaz, southwest of Iran. A total of 340 bacterial isolates were collected from the burn center from February 2014 to February 2015. The antimicrobial susceptibility and MIC of vancomycin were determined using the disk diffusion and micro-agar dilution techniques. The genus and species-specific genes, potential virulence genes, and vanA and vanB genes were detected by polymerase chain reaction.

RESULTS

According to our results, out of the 340 bacterial isolates, 16.4% (n = 56) were identified as enterococci. Out of the 56 enterococcal isolates, 35 (62.5%) were Enterococcus faecalis and 21 (37.5%) were Enterococcus faecium. More than 20% (n = 5) of E. faecium demonstrated resistance to vancomycin. The gelE and asa genes were the most prevalent virulence genes in E. faecalis (48.5%) and E. faecium (43%) isolates. The emergence of vancomycin resistant E. faecium strains which have several virulence factors should be considered as a major cause of concern for burn centers. Control and management of infections induced by enterococci should be regarded as highly important in burn patients.

Infection in burn patients in a referral center in Colombia

INTRODUCTION

Worldwide, burns are responsible for more than 300,000 deaths annually; infection is a major cause of morbidity and mortality in these patients. Early identification and treatment of infection improves outcome. Toward this end it's necessary to identify the institutions flora and organisms that most frequently produces infection.

OBJECTIVES

To characterize infections developed by burn patients hospitalized at the University Hospital of Santander (HUS).

METHODOLOGY

Burn patients hospitalized in the HUS from January 1 to December 2014 were followed. Medical information regarding infections, laboratory and pathology reports were obtained. Statistical analysis with measures of central tendency, proportions, global and specific incidence density plus overall and specific incidence was obtained. For the microbiological profile proportions were established.

RESULTS

402 burn patients were included, 234 (58.2%) men and 168 (41.8%) women, aged between 6 days and 83 years, median 12.5 years. The burn agents include scald (52.5%), fire (10.0%), gasoline (9.2%), electricity (7.5%), among others. Burn area ranged from 1% to 80% TBS. Cumulative mortality was 1.5%. 27.8% of burned patients had one or more infections. Identified infections include folliculitis (27.0%), urinary tract infection (19.0%), infection of the burn wound (10.4%), pneumonia (8.6%), Central venous catheter (7.4%), bloodstream infection (7.4%) and skin grafts infection (4.3%) among others. Bacteria were responsible for 88.5% of the cases and fungi 11.5%. The most frequently isolated germs were P. aeruginosa, A. baumannii, E. coli, S. aureus and K. pneumoniae. Most gram-negative bacteria were sensitive to Amikacin, gram positive bacteria were sensitive to multiple antibiotics.

CONCLUSION

Burns is a severe trauma that occurs in adult and pediatric patients, has several causative agents and can compromise the patient's life. The burned patient is at risk for a variety of infections. According to the type of infection it is possible to infer the most common causative organisms and their antibiotic sensitivity/resistance which allow a directed early empiric treatment.

What should be the antibiotic prescription protocol for burn patients admitted in the department of burns, plastic and reconstructive surgery

This is a prospective study with the aim to determine specific patterns of burn wound bacterial colonisation and antimicrobial resistance profiles. There is a high incidence of infections and septicaemia in post-burn patients, which, in turn, are associated with high morbidity and mortality, a fact that compelled us to undertake this study. The study was conducted over a period 11 months, from 1 August 2014 to 30 June 2015, in 50 burn patients admitted in our burn unit. Wound cultures were taken after 72 hours of admission from all the patients, and then, empirical systemic antibiotics were administered. For wound cultures; 1 cubic cm tissue was taken and placed in aerobic and anaerobic culture vials and transported to the microbiology lab under all aseptic precautions as soon as possible. At the time of fever any time after 72 hours of admission, 16 ml of blood was drawn under all aseptic precautions. Both aerobic and anaerobic blood culture vials were filled with 8 ml of blood each and transported to the microbiology lab. The results of culture and sensitivity reports of 50 patients were recorded. The data obtained was analysed using appropriate statistical analytical tests. The most common organism responsible for bacteraemia is Pseudomonas (43%). Most of the strains of organisms isolated were resistant to commonly used antibiotics in the hospital; Pseudomonas was found 100% resistant to a combination of ampicillin + sulbactum, ceftriaxone and was most often sensitive to imipenem, amikacin and vancomycin. Methicillin-resistant Staphylococcus aureus (MRSA) was also found resistant to commonly used antibiotics like ceftriaxone, ampicillin + sulbactum and ceftazidime + calvulanic acid. Linzolid and vancomycin were effective in 83% and 100% cases, respectively. We conclude that similar institution-specific studies should be conducted, and such studies will be helpful in providing useful guidelines for choosing effective empirical therapy that will have a great impact on the prevention of infection and its complications in burn patients because of bacteraemia.

Pseudomonas aeruginosa bacteremia after burn injury: the impact of multiple-drug resistance

To evaluate the clinical impact of multiple-drug resistance in burn patients with Pseudomonas aeruginosa (Pa) bacteremia. A retrospective cohort study in a 10-bed burn intensive care unit (BICU) was performed. Univariate and multivariate analyses were used to analyze the influence of multiple-drug resistance on mortality and length of BICU stay in Pa bacteremic patients. During a 21-year study period (1989-2009), 87 patients with Pa bacteremia were identified; 45 patients had multiple-drug resistant (MDR) strains and 42 susceptible strains. On comparison of the two populations, one with multiple-drug resistant strains and the other with the susceptible strains, the following parameters were found to be significantly different in the univariate analysis: age (32.7 vs 43.6 years; P = .013), sex (males: 91.1 vs 66.7%; P = .005), intubation status on admission (75.6 vs. 54.8%; P = .041), escharotomy (57.8 vs 33.3%; P = .022), burn size (51.0 vs 35.3% of TBSA; P = .002) and Abbreviated Burn Severity Index score (9.2 vs 8.1; P = .048). In terms of outcome parameters, multiple-drug resistance was not significantly related to mortality (adjusted odds ratio 1.076; 95% confidence interval [CI] 0.356-3.254; P = .897) and length of BICU stay after Pa bacteremia (Kaplan-Meier analysis log-rank test P = .945; Cox's proportional hazards regression hazards ratio, 0.994; 95% CI 0.513-1.925; P = .985) in the univariate and multivariate analyses. The data from this study suggest that multiple-drug resistance is not associated with significant increases in mortality and length of BICU stay among burn patients with Pa bacteremia.

Bloodstream infection as a predictor for mortality in severe burn patients: an 11-year study

In this study we collected and analysed data of the severe burn patients at our institution over an 11-year period in order to shed light on the controversial role of bloodstream infection (BSI) as a predictive factor for mortality in this burn population. The factors examined were age, total body surface area, smoke inhalation, presence of BSI, and BSI with resistant bacteria. In total 1081 burn patients were hospitalized from 2001 to 2011, of whom 4% died. We focused here on 158 severe burn patients, 74 of whom developed BSI, and 35 who died. Using univariate analysis, it appeared that the BSI group had a threefold greater chance of mortality compared to the non-BSI group. Patients with a Ryan score 3 had a 100% chance of mortality and those with a score 0 had 0%. Thus, focusing only on Ryan score 1 and score 2 patients, BSI did not contribute to mortality, nor was it shown to contribute to mortality in a multivariate analysis in which the score and BSI were included together. When BSI did occur, it predicted longer hospitalization periods. We conclude that BSI predicts longer length of hospitalization stay but does not contribute to the prediction of mortality beyond that offered by the Ryan score in a severe burn population.

The broad landscape of immune interactions with Staphylococcus aureus: from commensalism to lethal infections

Staphylococcus aureus is a gram-positive bacterium that is present in the nostrils of a quarter of the general population without causing any apparent disease. However, S. aureus can also act as a pathogen to cause severe infections. The factors determining the balance between its commensal and pathogenic states are not understood. Emerging evidence suggests that S. aureus, in addition to inducing a pro-inflammatory response, may have the capacity to modulate the host immune system. The latter is in part the result of recognition of specific molecules embedded in the peptidoglycan layer of the staphylococcal cell wall that bind to TLR2 on host antigen-presenting cells and induce a strong IL-10 response that down regulates the adaptive T cell response. This mechanism can partially explain the duality of interactions between S. aureus and the human immune system by favoring nasal colonization instead of staphylococcal diseases. In this review, we discuss the molecular and cellular basis of this mechanism and explore its clinical implications.

Infection control in the burn unit

The survival rates for burn patients have improved substantially in the past few decades due to advances in modern medical care in specialized burn centers. Burn wound infections are one of the most important and potentially serious complications that occur in the acute period following injury. In addition to the nature and extent of the thermal injury influencing infections, the type and quantity of microorganisms that colonize the burn wound appear to influence the future risk of invasive wound infection. The focus of medical care needs to be to prevent infection. The value of infection prevention has been acknowledged in organized burn care since its establishment and is of crucial importance. This review focuses on modern aspects of the epidemiology, diagnosis, management, and prevention of burn wound infections and sepsis.

Infection in patients with severe burns: causes and prevention thereof

The better understanding of burn pathophysiology has resulted in effective fluid resuscitation in the acute stage, but the morbidity and mortality of burn patients are mostly linked to the burn wound consequences. Once the initial acute phase is over, the burn wound becomes the source of virtually all ill effects, local and systemic. The dysfunction of the immune system, a large cutaneous bacterial load, the possibility of gastrointestinal bacterial translocation, prolonged hospitalization, and invasive diagnostic and therapeutic procedures all contribute to infectious complications. Wound infection may lead to septicemia that may not only consume additional resources but is associated with significant morbidity and mortality despite the advances in burn care.

Update on the Use of Antibiotics in Cutaneous Surgery

BACKGROUND

Antibiotics are often prescribed in perioperative settings, including dermatologic surgery. Given the continued evolution in the breadth and complexity of cutaneous procedures performed and inevitable localized or distant infections that occasionally occur, it seems prudent to periodically evaluate findings and recommendations from the literature regarding the use of antibiotics in cutaneous surgery.

MATERIALS AND METHODS

Literature review from English-language sources from the past 30 years, especially focusing on sources from the past 5 to 10 years. Data were examined for a variety of cutaneous surgical procedures, routes of antibiotic administration, and consideration of both cutaneous and distant infections.

RESULTS

The literature suggests that, for most routine skin procedures, antibiotic use is probably not warranted for the prevention of surgical wound infection, endocarditis, and late prosthetic joint infections. During prolonged Mohs procedures, delayed repairs, grafts, takedowns of interpolation flaps, or any procedure that breaches a mucosal surface, the evidence is less clear, and decisions should be made on a case-by-case basis. Topical antibiotics are probably overused, although silver sulfadiazine may have an undeserved negative reputation among dermatologists. Systemic prophylactic antibiotics for laser resurfacing and liposuction appear not to be routinely necessary, although patients with known prior herpes infection likely should receive antiviral prophylaxis. The overall reported infection rates and infectious complications remain low in dermatologic surgery, and antibiotic therapy may be prescribed excessively or inappropriately as a result. CONCLUSION.: Antibiotics continue to be widely used, and through varying routes of administration, in the setting of dermatologic surgery. Prudent use of these agents is indicated in high-risk patients, certain anatomic locations, and the presence of overt infection. Additional studies may help clarify the most appropriate indications, and in which patient populations, in the future.

Bacterial and fungal colonization of burn wounds

A prospective study of fungal and bacterial flora of burn wounds was carried out from February 2004 to February 2005 at the Burns Unit of Hospital Regional da Asa Norte, Brasília, Brazil. During the period of the study, 203 patients were treated at the Burns Unit. Wound swab cultures were assessed at weekly intervals for four weeks. Three hundred and fifty four sampling procedures (surface swabs) were performed from the burn wounds. The study revealed that bacterial colonization reached 86.6% within the first week. Although the gram-negative organisms, as a group, were more predominant, Staphylococcus aureus (28.4%) was the most prevalent organism in the first week. It was however surpassed by Pseudomonas aeruginosa form third week onwards. For S. aureus and P. aeruginosa vancomycin and polymyxin were found to be the most effective drugs. Most of the isolates showed high level resistance to antimicrobial agents. Fungi were found to colonize the burn wound late during the second week postburn, with a peak incidence during the third and fourth weeks. Species identification of fungi revealed that Candida tropicalis was the most predominant, followed by Candida parapsilosis. It is crucial for every burn institution to determine the specific pattern of burn wound microbial colonization, the time-related changes in the dominant flora, and the antimicrobial sensitivity profiles. This would enable early treatment of imminent septic episodes with proper empirical systemic antibiotics, without waiting for culture results, thus improving the overall infection-related morbidity and mortality.

Transient cutaneous adenoviral gene therapy with human host defense peptide hCAP-18/LL-37 is effective for the treatment of burn wound infections

Host defense peptides (HDP) are naturally occurring effector molecules of the innate immune system, which might be an alternative to currently used antibiotics. The objective of this study was to investigate the efficiency of transient cutaneous adenoviral transfection with human cathelicidin hCAP-18/LL-37 in infected burn wounds. Specific transgene expression was analyzed in vitro on mRNA and protein level using real-time PCR and Western-blot. Male Sprague-Dawley rats (n=40) received a second degree scald burn on both flanks (5% BSA), which were inoculated with 10(8) colony-forming units (CFU) Pseudomonas aeruginosa. Two days later, rats were randomized into the following groups: (1) adenoviral delivery of LL-37 (Ad5-hCAP-18, n=10), (2) synthetic host defense peptide LL-37 (1 mg; n=10), (3) carrier control (PBS, n=10) and (4) empty-virus control (Ad5-LacZ, n=10). Agents were injected intradermally and subcutaneously into both flanks. After either 2 or 7 days, skin samples were harvested and homogenized. CFU per gram tissue were determined. The hCAP-18/LL-37 expression was confirmed by real-time PCR and localized using in situ hybridization. In vitro transfection of cutaneous cells delivered a specific response on mRNA production. Western blot analysis revealed protein expression of hCAP-18/LL-37 in conditioned medium and cell pellet. The host defense peptide LL-37 was detectable after cleavage of the inactive pro-form hCAP-18/LL-37 with human elastase. Ad5-hCAP-18 showed a significant bacterial inhibition of approximately 10 000 fold compared to the control group (P<0.001) and 1000-fold (P<0.001) compared to the synthetic HDP LL-37 7 post-transfection. No inhibition was observed for the carrier or empty-virus control. Real-time PCR and in situ hybridization confirmed expression of hCAP-18/LL-37. In conclusion, transient cutaneous adenoviral delivery of the host defense peptide hCAP-18/LL-37 is significantly more effective than administration of synthetic host defense peptides and might be a potential adjunct for wound treatment in the near future.

The effect of essential oils on methicillin-resistant Staphylococcus aureus using a dressing model

Patchouli, tea tree, geranium, lavender essential oils and Citricidal (grapefruit seed extract) were used singly and in combination to assess their anti-bacterial activity against three strains of Staphylococcus aureus: Oxford S. aureus NCTC 6571 (Oxford strain), Epidemic methicillin-resistant S. aureus (EMRSA 15) and MRSA (untypable). The individual essential oils, extracts and combinations were impregnated into filter paper discs and placed on the surface of agar plates, pre-seeded with the appropriate strain of Staphylococcus. The effects of the vapours of the oils and oil combinations were also assessed using impregnated filter paper discs that were placed on the underside of the Petri dish lid at a distance of 8mm from the bacteria. The most inhibitory combinations of oils for each strain were used in a dressing model constructed using a four layers of dressings: the primary layer consisted of either Jelonet or TelfaClear with or without Flamazine; the second was a layer of gauze, the third a layer of Gamgee and the final layer was Crepe bandage. The oil combinations were placed in either the gauze or the Gamgee layer. This four-layered dressing was placed over the seeded agar plate, incubated for 24h at 37 degrees C and the zones of inhibition measured. All experiments were repeated on three separate occasions. No anti-bacterial effects were observed when Flamazine was smeared on the gauze in the dressing model. When Telfaclear was used as the primary layer in the dressing model compared to Jelonet, greater zones of inhibition were observed. A combination of Citricidal and geranium oil showed the greatest-anti-bacterial effects against MRSA, whilst a combination of geranium and tea tree oil was most active against the methicillin-sensitive S. aureus (Oxford strain). This study demonstrates the potential of essential oils and essential oil vapours as antibacterial agents and for use in the treatment of MRSA infection.

Effects of burn wound excision on bacterial colonization and invasion

Rates of survival after thermal injury have improved in the past two decades, and rates of wound infections and sepsis have decreased during the same period. Early excision has been advocated as one of the major factors, but its safety and efficacy and the exact timing of burn excision are still under debate. It was hypothesized that acute burn wound excision (in the first 24 hours after burning) would be superior to conservative treatment and delayed excision in preventing bacterial colonization and invasion. Twenty consecutive patients with thermal injuries were studied. Twelve patients underwent acute burn wound excision, and eight patients underwent conservative treatment and delayed excision. The second group of patients received topical treatments in another facility and underwent delayed excision after transfer to our service, on postburn day 6. Quantitative bacteriological assessments of the excised wound and biopsy samples of the wound bed, obtained before autografting and/or homografting, were performed. The effects of time on bacterial counts, differences between superficial and deep biopsy samples, and the effects of early versus late debridement were studied. Patients admitted early exhibited bacterial counts of less than 10 bacteria per gram of tissue. Patients in this group did not experience infection or graft loss. Patients admitted late exhibited counts of more than 10 bacteria (p = 0.001, compared with early admission). Three patients in the late excision group experienced infection and graft loss (p < 0.05, compared with the early excision group). Burn wound excision significantly decreased bacterial colonization for all patients (p < 0.001). Greater bacterial colonization and higher rates of infection were correlated with topical treatment and late excision (p < 0.001). It is concluded that burn wound excision significantly reduces bacterial colonization. Patients who undergo topical treatment and delayed burn wound excision exhibit greater bacterial colonization and increased rates of infection. Acute burn wound excision should be considered for all full-thickness burns.

Cronología de la colonización bacteriana en grandes quemados: ¿es el aislamiento estricto necesario?

INTRODUCTION

Infection is still one of the main causes of mortality in severe burn patients. Strict isolation has been used for the prevention of infection, but the efficacy of this measure is debatable. The aim of this study was to determine the timing of bacterial colonization in these patients and to ascertain whether strict isolation is indicated.

METHODS

Thirty consecutive children with severe burns were studied. Patients were only barrier-nursed during dressing changes. On admission and twice weekly over the entire hospital stay, burn, sputum, gastric aspirates, feces, and blood samples were obtained for culture. All isolates were tested for specific biotypes. Results were studied with linear regression and repeated measures ANOVA to determine the timing of colonization and cross-colonization between patients.

RESULTS

On admission, normal cutaneous flora were isolated from burn cultures of all patients. The remaining cultures were negative. After one week, gastric aspirates were found to be colonized by gram-negative bacteria and fungi. This was followed by colonization of feces, burn, and sputum cultures. Biotype identification showed unidirectional colonization from the gastrointestinal tract to burns and upper airway. There were no cross infections between patients.

CONCLUSIONS

Microbial colonization in severe burn patients was endogenous in nature and there were no cross infections. Thus, strict isolation is not necessary in burn centers, except during outbreaks of multi-resistant microorganisms.

Multi-resistant Acinetobacter baumannii on a burns unit--clinical risk factors and prognosis

Burns patients are highly susceptible to infection, and preventing and treating infection are integral to the successful management of severe burns.Multi-resistant Acinetobacter baumannii (MR-AB) strains are becoming increasingly important in nosocomial infections. We conducted a retrospective study of all adult admissions to the Singapore General Hospital (SGH) National Burns Center over an 18-month period. The only independent risk factors for the acquisition of MR-AB were the APACHE II score on admission and the number of intravascular lines placed. The only independent predictor of infection with MR-AB was the number of intravascular lines placed. The only independent predictors of longer length of stay were the total number of operations required and infection with MR-AB. The only independent predictor of mortality was the APACHE II score. This is in contrast to other studies that have suggested that the acquisition of MR-AB is an independent risk factor for mortality.

Microbiologic aspects of predominant bacteria isolated from the burn patients in Korea

The risk of infection in burns is well-known. In recent decades, the antimicrobial resistance of bacteria isolated from burn patients has increased. For this reason, we have carried out a study of the predominant bacterial profiles and antimicrobial resistance patterns of isolates from a burn center in Korea. A retrospective study was undertaken at Hallym University, Hangang Sacred Heart Hospital to examine the bacterial isolates from the burn patients and to compare the antibiograms of the predominant bacteria isolated from these patients with those of the other wards over a period of 3 years. Pseudomonas aeruginosa was the most common (n=2997, 45.7%) isolate from the burn patients followed by Staphylococcus aureus (n=21261, 19.2%) and Acinetobacter baumannii (n=878, 13.4%). These bacteria, isolated from the burn patients, were almost all higher in antimicrobial resistance rate than those in the non-burn patients (P<0.05). Because these bacteria showed very high resistant rates, they must be avoided in order to control a hospital-acquired infection. Our results seem helpful in providing useful guidelines for choosing effective empiric antimicrobial therapy against bacteria isolated from the burn patients in Korea.

Beta-haemolytic Streptococcus infection in burns

Group A beta haemolytic Streptococcus has been one of the most serious infections in the burn patients resulting in severe cellulitis and sepsis. Penicillin has been used ever since its introduction as prophylaxis against these conditions. Penicillin prophylaxis was used in our burn unit as well without any serious evaluation until December 1992. This prospective study was therefore, undertaken to evaluate the incidence of beta haemolytic Streptococcus infection in burn patients, and its clinical outcome over a period of 5 years in the absence of prophylaxis with penicillin. 14 of the 1213 burn patients admitted to the Al-Babtain Centre for Plastic Surgery and Burns from January 1993 to December 1997 had either colonization or infection with Streptococcus spp. Their mean age was 15 years (range 1 month to 52 years) and the mean burn surface area was 20% (range 5 to 90%). Streptococci were isolated from burn wounds in 10 patients, throat in 3 and blood culture in 1. Group A Streptococcus was found in 5, group C in 3 and group D in 6 patients. In all patients except one the organisms were isolated > or =72 h post burn. The infections were successfully controlled by antibiotic and no detrimental effect was observed either on wound healing or skin graft take. There was no mortality amongst these 14 patients. The study showed that only 1.1% of the burn patients in our unit acquired Streptococcus of which only one third comprised of group A. This study thus demonstrates that the practice of penicillin prophylaxis during the first five post burn days may not be of any value and therefore, deserves discontinuation in units where the incidence of this organism is minuscule.

The use of iodine as an antiseptic agent

A review of the discovery, uses and evolution of iodine and its compounds as antiseptics and the development of povidone-iodine

Burn septicaemia: an analysis of 79 patients

Out of 943 patients treated from June 92 to May 96 at the burns unit of the Al-Babtain Centre for Plastic Surgery and Burns, Kuwait, 280 (30%) required admission to the burns intensive care unit (ICBU) and were studied retrospectively. Seventy-nine (28.2%) developed clinically and microbiologically proven septicaemia. Forty-four (56%) were males, 35 (44%) females with a mean age of 26 years (range 45 days to 75 years) and mean total body surface area burn (TBSA) of 46% (range 10-90%). Sixty-two had flame burns, 16 a scald and one had an electric burn. These 79 patients had a total of 118 septicaemic episodes. Sixty (76%) had only one and 19 (24%) had multiple episodes of septicaemia. Fifty-four (68%) had their first episode within 2weeks, though the maximum number of episodes was between 6 and 10 days postburn. Septicaemia was also observed in 13% of patients within 3 days postburn. Out of the 118 episodes, 48 were due to methicillin resistant Staphylococcus aureus (MRSA), 17 due to methicillin resistant Staphylococcus epidemidis (MRSE), 15 to Pseudomonas, 12 to Acinetobacter, four to Streptococcus, another four to Enterococci, two to Klebsiella, one due to Serratia and 15 to more than one organism. Once the septicaemia was diagnosed appropriate therapy was instituted. Fifty-six (71%) patients had 143 sessions of skin grafting and the mortality was low in operated patients. Twenty-three (29.1%) patients died. The low mortality rate was probably due to factors such as continuous clinical and microbiological surveillance leading to quick detection of aetiology, appropriate antibiotic therapy, care for nutrition and early wound cover. This study suggests that flame burn patients are more vulnerable to sepsis. Onset of septicaemia may be as early as 3 days and commonly within 2 weeks. A surface wound is the likely source of entry to the blood stream. Gram positive organisms are dominant in the aetiology. Early detection and appropriate treatment including wound coverage result in a better outcome.

Evidence-based management of patients with burns

A review of the evidence for the management of burn wounds

The role of antimicrobial agents in wound care

This article considers the action of synthetic and natural chemical substances used in the control and destruction of micro-organisms

A comparison of phenotypic properties of Staphylococcus aureus isolated from burned children and other patient groups

This study aimed to determine whether strains of Staph. aureus isolated from children on our paediatric burns unit were different from strains isolated from other patient groups. Of particular interest was the incidence of toxin production amongst the different patient groups and the potential association with toxic shock syndrome (TSS). Wound isolates of Staph. aureus were collected from three patient groups: (1) hospital inpatients, (2) community patients and (3) patients from a regional burns unit. One hundred isolates were collected from each group (n = 300). Each isolate was tested for enterotoxin and TSST-1 production, phage type, antibiogram and tryptophan dependence. The results were compared, to determine whether there were any differences between the isolates from each of these patient groups. There were some variations in antibiotic sensitivity patterns and phage type of the isolates between the different patient groups but there was no significant difference in the incidence of toxin production, which was an important observation. The 100 isolates collected from this burns unit were derived from 58 patients. The colonization patterns of the Staph. aureus showed that 12 patients were colonized by more than one isolate and that these were a mixture of toxin-positive and toxin-negative strains. The medical records were examined for evidence of TSS; there was a higher incidence of toxic episodes in the patients colonized with strains which produced TSST-1 toxin.

Influence of a changed care environment on bacterial colonization of burn wounds

This study investigated the influence of a conditioned care environment per se on bacterial colonization of burn wounds. Two cohorts of burn patients were treated in the successive years 1992 and 1993, the first group in a (permanent) purpose-designed unit and the second in wards of traditional 'open' design, during renovation of the unit. Patients who were admitted to the permanent and temporary units numbered 224 and 231 respectively, the groups being similar in features that generally influence the course and outcome of burn injuries. The principles and practice of treatment by the burn care team remained the same in both years. No significant difference in wound colonization rates was found between the two groups. We conclude that while the other known advantages of managing burn patients in purpose-designed units remain valid, a conditioned care environment per se does not influence bacterial colonization rates of burn wounds.

Wound management in burn centres in the United Kingdom

Despite advances in the use of topical and parenteral antimicrobial therapy, and the practice of early tangential excision, infection of the burn wound remains a leading cause of morbidity and mortality. The aim of this study was to survey and compare wound management and antibiotic usage in burn surgery in all UK burn centres. A postal questionnaire was used, followed up by telephone. Answers were obtained from all 39 units treating burns in the UK. A written policy on antibiotic usage was used by 13 centres. Excisions were covered routinely by prophylactic antibiotic therapy in 18 units, and three of these used antibiotic cover during all procedures in which the wound was manipulated. No routine antibiotic cover was given in 21 units. All units obtained surface swab cultures, but only two performed punch biopsy of the wounds. Quantitative bacteriology (counting colony forming units) was employed by three centres. Most units cleaned the burn with saline (17 of 39) or chlorhexidine (eight of 39) but combinations of these and other agents were also used. Nearly half (17 of 37) of those who replied had not seen any cases of proven or suspected toxic shock syndrome in the past 2 years. Four units gave prophylaxis against Staphylococcus aureus, and four gave antibiotics against Streptococcus pyogenes, despite recommendations in the literature. Twenty-nine units gave no prophylaxis. This study has revealed that there is no consensus on antibiotic usage amongst centres treating burns in the UK and that most units rely on surface swab cultures to monitor infection.

Hot water burns in Cape Town

Scalds are common in South Africa and accounted for 21.6 per cent of the admissions to the Burns Unit of the University of Cape Town. Two hundred and forty adult patients (160 males, 80 females) with a mean age of 34.2 years were admitted for treatment of scalds between 1985 and June 1992. One hundred and thirteen sustained their scalds accidentally while 127 patients were assaulted with hot water. Epilepsy accounted for 11 per cent of the accidental burns. The head and neck was involved in 16.8 per cent of accidental burns and in 84.9 per cent of assaults. A quarter of the scalds to the trunk and limbs were caused by assault compared with 75 per cent caused by accidents. Beta haemolytic streptococcus was the second commonest organism isolated from the burn wound (57 patients). In 19 per cent of these patients a weekly course of penicillin and erythromycin did not eradicate the streptococcus and clindamycin was required. Accidental scalds usually affect the lower body and limbs whereas assault with hot water commonly involves the head and neck. Streptococcus is a common organism in the Burns Unit and is becoming more difficult to eradicate.

Dressings and wound infection

Wounds will readily acquire bacteria, unless protective measures are taken. The bacterial protection afforded by conventional absorbent cellulose dressings has been shown to be limited, particularly in the presence of serous exudate that may compromise dressing integrity. In addition, dressings may shed particles that remain in the wound. By contrast, many modern dressings are impermeable to bacteria, are removed completely, have been found to optimize reepithelialization rates and reduce the incidence of wound sepsis. Recently, it has been found that they could also play a role in preventing cross-contamination. Removing conventional cellulosic dressings from bacterially colonized wounds liberates wound bacteria into the air, and the numbers are slow to decline. However, using an in vitro wound model, use of the hydrocolloid dressing Granuflex (ConvaTec, Skillman, NJ) on experimentally colonized wounds resulted in significantly fewer numbers of airborne bacteria. Dispersal from wet conventional dressings was lower than from dry dressings; nevertheless, the numbers of bacteria per liter of air following removal of the hydrocolloid dressing were approximately 20% of those observed for gauze. These findings have also been confirmed in the clinic. To reduce the incidence of complications, wound care in general, and infection control procedures in particular, requires carefully disciplined team work.

Clustering of group A streptococcal infections on a burns unit: important lessons in outbreak management

In a 12-month period 37 patients and four members of staff on a burns unit were infected or colonized by Streptococcus pyogenes (Group A streptococcus). One patient became septicaemic and died. Serotyping revealed five distinct clusters against a low background level of infection. Infection control measures included isolation, screening of patients, staff and environment and the use of prophylactic antibiotics for uninfected patients. We discuss the role of staff and patient carriers and the environment as a continuing source of infection, and the importance of serotyping in outbreak epidemiology.