Comparison of surface swab cultures and quantitative tissue biopsy cultures to predict sepsis in burn patients: a prospective study

This study aimed at evaluating the possibility of predicting septicemia in burn patients by using wound surface and tissue culture techniques as well as blood cultures. Fifty patients with full-thickness burn wounds covering at least 10% of the total body surface area were included. Signs of septicemia were noted in 21 patients (42%) and 29 patients died (58%). The bacterial colonization of the burn wounds consisted mainly of Staphylococcus aureus and Pseudomonas aeruginosa. Sepsis was better correlated to quantitative burn tissue biopsy cultures than surface swab cultures but the time needed for processing limits its predictive and therapeutic value.     

A survey of wound monitoring and topical antimicrobial therapy practices in the treatment of burn injury

A survey was done to determine how burn wound microbial monitoring is performed and how topical antimicrobial agents are employed. The survey was sent to 90 burn-care facilities, which comprised most of the major burn centers in the United States. The survey contained questions concerning frequency and techniques of wound monitoring, personnel involved in monitoring, as well as questions about how decisions were made to initiate topical antimicrobial therapy, which agents were selected, and how they were administered. Sixty of 90 facilities (66%) responded to the survey. Although there were few areas of unanimous agreement, several trends did emerge. Most facilities monitored burn wounds for microbes (92%). Wound monitoring was typically done at least twice weekly by either surface swab or quantitative biopsy. Nursing staff played a significant role in specimen collection in 69% of facilities and were solely responsible for obtaining biopsy specimens in 29% of facilities that used biopsies exclusively. All responding facilities used topical antimicrobial agents; silver sulfadiazine was the most popular (95%). Only 33% of facilities surveyed had their own laboratory for microbial monitoring. Rapid techniques for early diagnosis of wound sepsis were used in 20% of units, and topical antimicrobial testing was used in 17% of facilities surveyed.     

Precise diagnosis of infection in burn wound biopsy specimens. Combination of histologic technique, acridine orange staining, and culture

This study developed a rapid manual histologic technique on burn wound biopsy specimens for an early diagnosis of infection. A total of 86 biopsy specimens were processed using this rapid manual method, acridine orange fluorescent staining for the detection of microorganisms, and a quantitative culture for the identification and counting of bacteria in adjacent homogenized biopsy specimens. Use of these three techniques has shown their complementarity for the evaluation of sepsis in burn wound patients. The histologic study allowed a classification of the depth of bacterial involvement 4 hours after specimen collection, whereas the acridine orange fluorescent staining was useful for quantitative evaluation of infection in the same delay. Thus a rapid therapeutic decision can be made while waiting for the results of quantitative culture and sensitivity tests, which require 24 to 48 hours. We propose routine monitoring of burned patients consisting of these three tests performed simultaneously on each biopsy specimen.     

Water-Jel in the treatment of burns. A bacteriologic study

In a previous study the Water-Jel system (dressings) was found to protect the burn wound from microbial contamination and to have excellent analgesic and cooling effects when used as the first-aid dressing. In an extensive bacteriologic study in vitro, both semiquantitative and qualitative, Water-Jel was bactericidal in all 15 microorganisms tested, including yeasts. All 15 microorganisms were from the Ostrava Burn Unit. Water-Jel was used successfully in three surgical, nonburned patients with very contaminated, dilacerated wounds. It was superior to all the selective antibiotics used systemically. After its 3-day application, the wounds became sterile; the skin grafting was successful.     

Comparative evaluation of zinc sulfadiazine and silver sulfadiazine in burn wound infection

One percent silver sulfadiazine has been commonly used as a topical antimicrobial agent after a burn injury. Incidence of burn wound colonization by Staphylococcus aureus in patients treated with silver sulfadiazine has spurred research for other agents. A topical preparation that contains zinc and sulfadiazine (Zad-G) was evaluated for in vitro antibacterial spectrum and in vivo efficacy. Muscle biopsy specimens of rats treated with Zad-G appear to have fewer colonies of S. aureus than groups treated with silver sulfadiazine. Topical therapy with Zad-G for patients with burns was comfortable, reduced wound infection, and was comparable to therapy with silver sulfadiazine. A topical Zad-G preparation that contains zinc sulfadiazine appears to be an effective alternative to silver sulfadiazine in the treatment of burn wounds.     

Cultured epidermal autograft and the treatment of the massive burn injury.

As a rule, adult and pediatric patients with thermal injuries that involve more than 90% total body surface area (TBSA) burn have poor prognoses. Even for patients who are 5 to 34 years old with a 70% TBSA burn, the mortality rate is 80%. Lack of autologous donor skin, which is essential for permanent wound closure, is the major problem. Recent advances in growth of cultured epidermal autograft (CEA) have allowed closure of full- and partial-thickness burns; in approximately 3 weeks, a 2 cm2 biopsy specimen will produce enough CEA to cover a pediatric patient. Since 1989, we have used this product on nine patients; the average age was 39, and the average TBSA burn was 70% (range, 44% to 93%). We report our approach to use of CEA in six of these patients, including topical applications of 1% silver sulfadiazine and excision of full- and deep partial-thickness wounds within 2 weeks of injury. Temporary closure was achieved with cadaver allograft. "Take" of the allograft forecasted take of CEA. The total operative time of CEA placement was decreased by a two-step technique that obviates repeating debridement: the technique consists of debriding and grafting with allograft, then removing it at the time of CEA placement. CEA take is best on early granulation tissue or freshly excised wounds. Early excision of burn eschar, temporary wound closure with cadaveric allograft and Biobrane (Winthrop Pharmaceuticals, Wound Care Div., Fountain Valley, Calif.), and permanent closure with CEA may improve survival rates among patients with massive burn wounds. CEA is a tremendous asset to the management of massive burn injuries.     

68例烧伤患者血清PA和CRP的检测及其临床意义

目的探索烧伤患者血清前白蛋白（PA）与C-反应蛋白（CRP）的变化及其临床意义。方法68例烧伤患者按烧伤总面积大小分为小于15％组38例和大于50％组30例，健康对照组30例。伤后第一天，采用透射免疫比浊法分别测定3组人群血清CRP及PA的浓度。结果烧伤面积大于50％组CRP水平明显高于面积小于15％组，而PA水平烧伤面积大于50％组明显低于面积小于15％组，与CRP水平呈负相关。结论PA水平随着烧伤面积的增加而降低，PA作为烧伤后的炎症程度指标，有十分重要的意义。     

药物气管垫在烧伤患者气管切开护理中的应用

目的 改变应用传统气管垫加重气管切开周围创面感染的局面，探索适用于烧伤患者气管切开护理需要的气管垫，以防止套管周围创面感染，减少呼吸道并发症的发生。方法 普通气管垫分别用庆大霉素、丁胺卡那霉素、磺胺嘧啶银混悬剂、碘伏浸泡后制作成药物气管垫，应用于烧伤患者气管切开护理，分别间隔4、8、12h，更换气管垫，更换时于气管切开口周围取样培养，所得数据行χ^2检验。结果 庆大霉素组间隔4、8、12h取样各26例次，细菌培养全部为阳性；丁胺卡那霉素组间隔各时间段分别取样30例次，阳性率80％～90％，各时间段之间无显著差异；磺胺嘧啶银组各时间段的细菌培养阳性率70％～80％，各间隔时间比较差异不显著；碘伏组4、8、12h各时间段的阳性率分别为6．25％、18．75％、50％，4、8、12h结果比较阳性率差异显著，而4、8h结果比较阳性率差异不显著。结论 烧伤患者气管切开护理中，应首选碘伏气管垫。     

Effect of indomethacin and Impact liquid diet administration on inflammatory mediator production by murine splenocytes after burn injury.

Production of prostaglandin E2 (PGE2) and tumor necrosis factor-alpha (TNF-alpha) by various cells is increased after injury, and these mediators are implicated in the downregulation of immune responses. We attempted to modulate the production of immune suppressive mediators by inhibiting prostaglandin production in a murine model that had a burn covering 25% of the total body surface area. Two treatments were performed. One was the intraperitoneal administration of indomethacin after burn injury at 2 mg/kg day for 10 days. The control group received saline solution injections. The other treatment was the ad libitum administration of a commercial diet after burn injury for 10 days. This diet contained mixed fats, including omega-3 and omega-6 fatty acids. The control group received standard mouse food. On days 1, 5, and 10 after burn injury, spleens were removed aseptically, and splenocyte cultures were established and stimulated with phytohemagglutinin. TNF-alpha and PGE2 concentrations were determined in culture supernatants at 48 hours with the use of commercial enzyme-linked immunosorbent assay kits. Splenocytes from burned animals produced elevated levels of both mediators in culture supernatants, reaching significant levels of TNF-alpha on day 10 after burn injury and of PGE2 on days 5 and 10 after burn injury. Neither the administration of indomethacin for 10 days nor the administration of the commercial diet for 10 days decreased production of these mediators in culture. However, cells in culture may escape the in vivo regulating effects of biologic modifying agents.     

Aztreonam pharmacokinetics in burn patients.

The pharmacokinetics of aztreonam in eight adult patients with severe burn injuries (total body surface area burn, 49% +/- 21% [mean +/- standard deviation]) were studied. The time of initiation of study following burn injury was 7.0 +/- 1.4 days. Four patients at first dose and at steady state were studied. Aztreonam concentrations were measured by high-performance liquid chromatography, and a two-compartment model was used to fit the data. No significant differences in any pharmacokinetic parameters between first dose and steady state were observed. Volume of distribution of the central compartment after first dose (0.14 liters/kg) and volume of distribution at steady state (0.31 liters/kg) were approximately 30% higher than those reported for other patient populations. Total drug clearance and renal drug clearance when normalized to creatinine clearance (CLCR) were similar to those previously reported for other critically ill patients. CLCR was strongly correlated with renal drug clearance (r = 0.94) and total drug clearance (r = 0.95). The extent and degree of burn (percent second or third degree burn) were poorly correlated with all pharmacokinetic parameters with the exception of the volume of distribution at steady state, which was correlated with both total body surface area burn (r = 0.95) and percent second degree burn (r = 0.83). Aztreonam pharmacokinetics are altered as a result of thermal injury; however, CLCR can be used to assess the clearance of aztreonam in burn patients.     

Vagal nerve stimulation blocks peritoneal macrophage inflammatory responsiveness after severe burn injury

ABSTRACT: Large surface area burn injuries lead to activation of the innate immune system, which can be blocked by parasympathetic inputs mediated by the vagus nerve. We hypothesized that vagal nerve stimulation (VNS) would alter the inflammatory response of peritoneal macrophages after severe burn injury. Male BALB/c mice underwent right cervical VNS before 30% total body surface area steam burn and were compared with animals subjected to burn alone. Peritoneal macrophages were harvested at several time points following injury and exposed to lipopolysaccharide (LPS) in culture conditions. The inflammatory response of peritoneal macrophages was measured by analyzing changes in nuclear factor κB p65 phosphorylation using flow cytometry. We found that peritoneal macrophages isolated from mice subjected to burn injury were hyperresponsive to LPS challenge, suggesting burn-induced macrophage activation. We identified a protective role for VNS in blocking peritoneal macrophage activation. Analysis of the phosphorylation state of nuclear factor κB pathway mediator, p65 Rel A, revealed a VNS-mediated reduction in p65 phosphorylation levels after exposure to LPS compared with burn alone. In combination, these studies suggest VNS mediates the inflammatory response in peritoneal macrophages by affecting the set point of LPS responsiveness.     

癌-睾丸抗原基因在神经胶质瘤干细胞中的表达

背景：癌-睾丸抗原基因在胶质瘤干细胞表达还不甚清楚。目的：检测癌-睾丸抗原基因在神经胶质瘤干细胞中的表达。方法：通过神经球培养的方法而分离干细胞。以半定量PCR及实时荧光定量PCR检测癌-睾丸抗原基因在母细胞、干细胞与分化细胞中的表达。结果与结论：以神经球培养方式从胶质瘤细胞系中可分离出肿瘤球,将肿瘤球培养在含血清的培养基中,它的形态呈贴壁分化,且与母细胞没有区别。半定量PCR及实时荧光定量PCR检测发现与母细胞和分化细胞相比,癌-睾丸抗原基因在干细胞中的表达最高。提示癌-睾丸抗原基因可能为肿瘤干细胞的表面抗原。     

Diagnostic value of PCR for detection of Borrelia burgdorferi DNA in clinical specimens from patients with erythema migrans and Lyme neuroborreliosis.

BACKGROUND: The aim of the study is to evaluate the diagnostic sensitivity of a 16S ribosomal RNA-based PCR on clinical specimens from patients with erythema migrans (EM) and neuroborreliosis and to compare the sensitivities with those obtained by in vitro culture and serological testing. A semiquantitative detection system, representing the input amount of specific DNA and thus the density of spirochetes in clinical specimens, indicated the preferred clinical sample to obtain for PCR testing. METHODS AND RESULTS: Skin biopsy and urine samples from 31 patients with EM and cerebrospinal fluid (CSF) and urine samples from 30 patients with neuroborreliosis were investigated. Borrelia burgdorferi DNA was detected in 71% of the skin biopsy specimens and 13% of the urine samples from patients with EM. Forty-one percent of the patients with EM were found to have B burgdorferi-specific antibodies in serum, and B burgdorferi was cultured in 29% of the EM specimens. For patients with neuroborreliosis, the diagnostic sensitivities in CSF and urine samples were 17% and 7%, respectively. Specific intrathecal antibody production was found in 90% of the patients, and 87% showed elevated B burgdorferi antibodies in serum. In general, PCR of skin biopsy samples yielded very high amounts of amplicons versus low amounts for CSF and urine samples. CONCLUSIONS: PCR of skin biopsy specimens is currently the most sensitive and specific test for the diagnosis of patients with EM, superior to culture and serological testing. For B burgdorferi-specific CSF disgnosis in patients with neuroborreliosis, the measurement of specific intrathecal antibody synthesis is superior to PCR. However, in patients with a short duration of disease (<14 days), PCR may be a useful diagnostic supplement. PCR of urine samples cannot be recommended at the present time for routine diagnosis of patients with EM or neuroborreliosis.     

Comparison of cultured epidermal autograft and massive excision with serial autografting plus homograft overlay.

The chief determinant of mortality in severe burn injuries has been the size and severity of the wound. Early massive excision of the wound has increased the median lethal dose to 98% of total body surface area burn but presents the problem of wound closure. Autograft substitutes must be used for a large burn. We report our experience with early massive excision in the treatment of 47 pediatric patients with burns who had greater than 80% total body surface area burn and greater than 80% full-thickness burn. Four patients died within hours of admission. Fifteen patients died of sepsis and multiorgan failure; the primary source of bacterial contamination was the open wound. The 28 survivors received approximately 2.0 m2 2:1 homograft until autograft became available. A case report of a 10-year-old boy illustrates the use of two types of cultured epidermal autograft, one "homegrown" and one commercially produced.     

The use of blood in burn shock. Clinical and experimental study

We have given whole blood as one of the main constituents of burn shock resuscitation for the past 28 years. To appraise the value of using whole blood, we have summarized the clinical experience of 2630 burn patients. Overall mortality was 4.18%. The lethal area of the burn were 50% of the population is expected to die was 82.8% total body surface area and 57.4% third-degree burns. The incidence of renal failure, pulmonary edema, and gastrointestinal bleeding was 0.9%, 0.4%, and 0.6% respectively. To confirm the advantage of transfusion of whole blood, we have carried out a series of experimental studies. Two groups of 25 dogs with 25% total body surface area full-thickness burns were treated with two resuscitation regimens. Group I was treated with whole blood, and group II with no blood, during the shock phase. After 48 hours, the infusions were stopped. Measurements were made before the burn and 2, 24, 48, 72, and 144 hours after the burn injury. The animals were then killed for histologic studies. From our data, we concluded that whole blood used in burn shock did not increase hemoconcentration or viscosity; it improved anemia, oncotic pressure, hypoproteinemia, acid-base balance, oxygenation, hemodynamics, and myocardial contractility, promoted cardionatrin secretion, reduced edema of tissue, and protected viscera from degenerative changes and bacterial colonization.     

Burn size estimate reliability: a study.

A study was undertaken to assess any differences between physicians' and nurses' estimates of burn size from drawings of 10 hypothetical patients with burns. Patient drawings were sent to the 199 burn facilities that are listed in the American Burn Association's Burn Care Resources in North America 1989-1990. The mailings were randomized between physicians and nurses. In order to have an even distribution, the cover letter asked the individual who received the forms to fill them out himself or herself rather than to pass them on to someone else. Forty-one nurses and 16 doctors (29%) returned the completed forms. The length of experience in burn care for the nurses averaged 9.3 years (range, 2 to 20 years), and the length of experience in burn care for the physicians averaged 14.7 years (range, 1 to 30 years [p = 0.01]). There were significant differences in the estimate of mean burn size between the physicians and nurses for only the two smallest drawings; in these cases, size may have been hard to translate from the patient to the drawing. There were four smaller burn charts (less than 20% body surface area), and in two (50%) of these, there were significant differences in the estimation of the burn size. For the six larger burn charts (greater than 20% body surface area), there were no differences in the size estimates. With regression analysis, no trend was noted that correlated the size estimates with the length of experience in burn care for either the physicians or the nurses. Additionally, the participants were asked to indicate which method of estimating burn size was used in their units. Thirty-five percent use the Rule of Nines, 33% use the Lund & Browder chart, 5.3% use Berkow's method, 3% use other methods, and 1.75% use a combination of the Lund & Browder chart and the Rule of Nines. Twenty-one percent failed to indicate any preferred method. Estimates of burn sizes with the use of standardized burn forms were consistently the same whether estimates were made by physicians or nurses. Sixty-eight percent of the respondents used the Rule of Nines or the Lund & Browder chart to estimate burn size, but 21% of the respondents failed to answer the question about which method is used in their units. In conclusion, there appears to be little variance in estimation of burn size as made by experienced burn nurses and physicians, and use of these estimates in a centralized data bank should be reliable.     

Semiquantitative cultures of intravascular catheters from cancer patients

Three-hundred seventy-nine catheter tips were prospectively cultured by both a semiquantitative method and by broth culture, over a 2-month period. One hundred eleven of the catheters were culture-positive in broth, and 47 of these were also culture-positive by the semiquantitative method. Clinical signs of infection were reviewed for the 111 culture-positive catheters and for 50 of the 268 culture-negative catheters. Both culture-positive and culture-negative catheters were infrequently associated with local signs of infection (10% and 12%, respectively). Culture-positive catheters, however, were more likely to be associated with systemic signs of infection than were culture-negative catheters (15% and 2%, respectively). Among the culture-positive catheters, those that yielded greater than or equal to 15 colonies on semiquantitative culture were more likely to be associated with septicemias than were those with less than 15 colonies (22% and 6%, respectively). Nevertheless, there were five catheter-related bacteremias that were associated with catheters which were culture-negative on semiquantitative culture but culture-positive in broth. The proportion of patients with culture-positive and culture-negative catheters who were febrile was similar (30% and 42%, respectively). Semiquantitative cultures of catheters from cancer patients are useful, but the result should be interpreted with some caution.     

Return to work after burn injury.

The research literature suggests but does not test the hypothesis that differential factors determine when a patient will return to work after serious burn injury. In this study, factors influencing time before return to work after serious burn injury were investigated prospectively as part of a large burn research project. Sixty-five patients with burns who had returned to work were followed. Several variables were examined, including percent total body surface area burned, total percent of partial-thickness burn, total percent of full-thickness burn, duration of treatment, payment source for treatment, sex, race, type of burn, and age. The most significant predictor of time before return to work was percent total body surface area burned, followed by percent body surface area with full-thickness burns, percent body surface area with partial-thickness burns, and number of weeks of treatment, respectively. Sufficient data were available to develop a regression equation to specifically predict time before return to work. The data presented here are useful in informing patients, families, employers, and health-funding agencies as to the probable delay before return to work that can be expected after serious burn injury. In particular, predictability refinements are possible with the regression equation developed in this study.     

Bedside measurement of D-dimer in the identification of bacteremia in the emergency department

The objective of this pilot study was to determine the clinical utility of the SimpliRed D-dimer bedside assay to identify patients with bacteremia in a university hospital Emergency Department. We tested 265 patients and compared blood culture results with a novel D-dimer semiquantitative whole blood assay. Bacteremia was confirmed in 25/262 patients. Sensitivity of D-dimer assay was 66.7% for Gram-positive bacteremia and 61.5% for Gram-negative bacteremia with negative predictive value of 98% for Gram-positive and 96% for Gram-negative bacteremia patients. Measurement of D-dimer appears to be of value in identifying patients at low risk for bacteremia and can be accomplished rapidly using a whole blood semiquantitative bedside assay. Although increases in D-dimer are not detected in all patients subsequently documented to have bacteremia on a single sampling, the results of this and other earlier studies suggest assay of D-dimer is useful in rapid differentiation of patients with bacteremia from those who have no bacteremia using blood culture positivity as the standard for bacteremia.