Selective decontamination of the digestive tract in surgical patients: a systematic review of the evidence

OBJECTIVE: To determine the comparative efficacy of selective decontamination of the digestive tract in critically ill surgical and medical patients, and in selected subgroups of surgical patients with pancreatitis, major burn injury, and those undergoing major elective surgery and transplantation. DATA SOURCES: The MEDLINE database was searched from January 1966 to December 1996 using the terms "decontamination or prophylaxis," "intensive care units," and "antibiotics." The search was limited to English-language studies evaluating the efficacy of selective decontamination of the digestive tract in human subjects. STUDY SELECTION: The primary review was restricted to prospective randomized trials. DATA EXTRACTION: End points of interest included rates of nosocomial pneumonia, bacteremia, urinary tract infection, wound infection, mortality, and length of intensive care unit stay. Methodologic quality of individual studies was assessed using a previously described model. DATA SYNTHESIS: Odds ratios (ORs) together with their (95% confidence interval [Cls]) were reported and determined using the Mantel-Haenszel method. Mortality was significantly reduced with the use of selective decontamination of the digestive tract in critically ill surgical patients (OR, 0.7, 95% CI, 0.52-0.93), while no such effect was demonstrated in critically ill medical patients (OR, 0.91; 95% CI, 0.71-1.18). The greatest effect was demonstrated in studies where both the topical and systemic components of the regimen were used. Rates of pneumonia were reduced in both subsets of patients, while those of bacteremia were significantly reduced only in surgical patients. CONCLUSIONS: Selective decontamination of the digestive tract notably reduces mortality in critically ill surgical patients, while critically ill medical patients derive no such benefit. These data suggest that the use of selective decontamination of the digestive tract should be limited to those populations in whom rates of nosocomial infection are high and in whom infection contributes notably to adverse outcome.     

Selective decontamination of the digestive tract as infection prevention in the critically ill. A level 1 evidence-based strategy

Selective decontamination of the digestive tract (SDD) evolved into evidence-based medicine as a tool to prevent infections in critically ill patients. It significantly reduces mortality, pneumonia, bloodstream infections and the onset of resistance if the full four-component regimen is used. The use of only oral decontamination may reduce the incidence of pneumonia, but it has no significant impact on mortality. Moreover, the full SDD protocol significantly reduces the fecal carriage of multiresistant aerobic Gram-negative bacteria, whereas oral decontamination only is associated with increased carriage of multiresistant aerobic Gram-negative bacilli.     

Selective decontamination of the digestive tract: a stratified, randomized, prospective study in a mixed intensive care unit.

To evaluate the use of selective decontamination of the digestive tract (SDD) (polymyxin, amphotericin, tobramycin, and intravenous cefotaxime) in a mixed intensive care unit, we performed a stratified, randomized, prospective study. The 331 patients were recruited over an 18-month period, with 256 patients remaining more than 48 hours. Stratification by acute physiology and chronic health evaluation (APACHE II) preceded randomization to control (standard antibiotic therapy) or treatment (SDD) groups. Nosocomial infection was significantly reduced in the SDD group (16.7%; 21 of 126 patients) compared with the control group (30.8%; 40 of 130 patients; p = 0.008). No difference was found in overall mortality rate or length of stay between the two groups. Those patients with admission APACHE II scores 10 to 19 demonstrated the most significant reduction in nosocomial infection (23 of 70 control vs 13 of 76 SDD; p = 0.03) and mortality (15 of 70 control vs 8 of 76 SDD; p = 0.07). Emergence of multiresistant microorganisms was not a clinical problem, but a definite change occurred in the ecology of environmental and colonizing bacteria. With the exception of cefotaxime, a reduction was noted in systemic antibiotic usage in the SDD group. We conclude that SDD is useful in selected patients in a mixed intensive care unit.     

Survival benefit in critically ill burned patients receiving selective decontamination of the digestive tract: a randomized, placebo-controlled, double-blind trial

OBJECTIVE: To evaluate whether selective digestive decontamination (SDD) reduces mortality from any cause, and the incidence of pneumonia among patients with severe burns. SUMMARY BACKGROUND DATA: SDD is a prophylactic strategy to reduce infectious morbidity and mortality in critically ill patients. Two meta-analyses and a recent randomized controlled trial demonstrated a mortality reduction varying between 20% and 40%. But this technique has never been properly evaluated in severely burned patients. METHODS: The design of this single-center trial was randomized, double blind, placebo controlled. Patients with burns > or =20% of total body surface and/or suspected inhalation injury were enrolled and assigned to receive SDD or placebo for the total duration of treatment in the burn intensive care unit (ICU). RESULTS: One hundred seventeen patients were randomized and 107 were analyzed (53 in the SDD group and 54 in the placebo group). The ICU mortality was 27.8% in the placebo group and 9.4% in the SDD group in the burn ICU. Treatment with SDD was associated with a significant reduction in mortality both in the burn ICU (risk ratio 0.25; 95% CI 0.08 to 0.76) and in the hospital (risk ratio 0.28; 95% CI 0.10 to 0.80), following adjustment for predicted mortality. The incidence of pneumonia was significantly higher in the placebo group: 30.8 and 17.0 pneumonias per 1000 ventilation days (P = 0.03) in placebo and SDD group, respectively. CONCLUSIONS: Treatment with SDD reduces mortality and pneumonia incidence in patients with severe burns.     

Use of selective decontamination of the digestive tract in United Kingdom intensive care units*

The use of selective decontamination of the digestive tract (SDD) remains controversial despite several large randomised‐controlled trials and meta‐analyses. A postal survey of intensive care units in the United Kingdom was conducted to document current use of SDD, and to identify factors influencing this practice. The response rate was 71%. The vast majority (182 units, 95%) do not use SDD mainly because practising clinicians do not believe it works or that there is not enough evidence (51%), and because of concerns about antibiotic resistance (47%). Of the 10 units using SDD, three apply it to all intubated patients and five do not use intravenous antibiotics in their protocol.     

Frequency of colonization and pneumonia and development of resistance in long-term ventilated intensive-care patients subjected to selective decontamination of the digestive tract

Colonization of the oropharynx with potentially pathogenic microorganisms (PPM) is a highly significant factor in the pathogenesis of bacterial pneumonia in intensive care patients. Via colonization of the oropharynx, bacteria pass into the tracheobronchial tree, where they can give rise to pneumonia after overcoming pulmonary resistance mechanisms. By a new, prophylactic antibiotic treatment schedule consisting in selective decontamination of the digestive tract (SDD) with locally applied nonabsorbable antibiotics, Stoutenbeek achieved drastic lowering of the colonization and infection rate in trauma patients. In the present study, we wanted to check whether this new prophylactic antibiotic schedule can be applied on a surgical intensive care ward in all patients with long-term ventilation, irrespective of the diagnosis, and whether it affords advantages over a conventional antibiotic schedule. MATERIALS AND METHODS. All patients on a surgical intensive care ward in whom it was expected that mechanical ventilation would be necessary for more than 4 days were included in the study. During the first 6 months 83 patients were investigated, in whom antibiotics were only administered when the presence of infection had been confirmed, in accordance with generally accepted guidelines (control group). In the second 6-month period, 82 patients were selectively decontaminated with 4 x 100 mg polymyxin E, 4 x 80 mg tobramycin and 4 x 500 mg amphotericin B, administered through the gastric tube and in an antimicrobial paste in the oropharynx (SDD group). The SDD schedule entailed systemic administration of cefotaxime in the first 3-4 days. RESULTS. In the control group, enterobacteria/Pseudomonas spp. were isolated significantly more frequently than in the SDD group (P less than 0.001): in the pharyngeal smear in up to 53%, in the tracheal secretion up to 36%, and in the rectal smear in up to 93% of the patients In the SDD group in the 1 week the frequency of gram-negative aerobic bacteria in the pharynx decreased from 33% to 5%, in the tracheal secretion from 23% to 14% and in the rectum from 86% to 52% (24% in the second week). However, the decrease in gram-negative microorganisms was accompanied by significant increase in the frequency of Staphylococcus epidermidis and enterococci. The SDD schedule proved to be effective with regard to the rate of infection. In the control group, 35 patients developed pneumonia (42%) as against 5 patients receiving SDD prophylaxis (6%). The duration of mechanical ventilation in the patients with pneumonia was 5 days longer than in patients without pneumonia.(ABSTRACT TRUNCATED AT 400 WORDS)     

Selective decontamination of the digestive tract as infection prevention in the critically ill. Does it lead to resistance?

Several meta-analysis showed the efficacy of selective decontamination of the digestive tract (SDD) in the reduction of infections in critically ill patients, particularly for ventilator associated pneumonia and bloodstream infections, thereby reducing mortality and morbidity. The principle of SDD is that by means of application of non-absorbable antibiotics in the intestinal canal and oropharyngeal cavity, potentially pathogenic microorganisms are eliminated, thereby reducing the incidence of organ site infections. The endogenous anaerobic flora is preserved as a factor contributing to defence against colonization. The potential induction of antibiotic resistance (AR) due to SDD is a major concern in ICU. This review evaluates the onset of clinically relevant AR after SDD. The results of a recent meta-analysis and of several studies, which confirmed the virtual absence of any reported AR with SDD and that did not find AR after stopping SDD, are presented. The eradication of the reservoir of abnormal bacteria located in the gut by topical non-absorbable antibiotics appears to significantly reduce morbidity, mortality and resistance. Using only systemic antibiotics in ICU may contribute to maintain an abnormal population of bacteria among which AR is encouraged.     

Enteral vancomycin controls methicillin-resistant Staphylococcus aureus endemicity in an intensive care burn unit: a 9-year prospective study

OBJECTIVE: The aim of this study was to assess the efficacy and safety of enteral vancomycin in controlling MRSA endemicity in an intensive care burn unit. SUMMARY BACKGROUND DATA: MRSA is a serious clinical and epidemiologic problem. It is not uncommon that the traditional maneuvers, detection and isolation of carriers, fail to control endemicity due to MRSA. METHODS: All patients admitted to an Intensive Care Burn unit from January 1995 to February 2004 have been included in this prospective cohort study comprised 2 different periods. During period 1 (January 1995 to January 2000), barrier and isolation measures were enforced. During period 2 (February 2000 to February 2004), patients received enteral vancomycin 4 times daily in addition to selective digestive decontamination. RESULTS: A total of 777 patients were enrolled into the study: 402 in period 1, and 375 in period 2. There were no significant differences in the characteristics of patients between the 2 periods, except for the total body surface burned area, 30.3% in period 1 and 25.61% in period 2 (P = 0.009). There was a significant reduction in the incidence of patients who acquired MRSA from 115 in period 1 to 25 in period 2 (RR, 0.22; 95% confidence interval [CI], 0.15-0.34). Similar reductions were observed in the number of patients with wound (RR, 0.20; 95% CI, 0.12-0.32), blood (RR, 0.13; 95% CI, 0.04-0.35), and tracheal aspirate (RR, 0.07; 95% CI, 0.03-0.19), samples positive for MRSA. There was no emergence of either vancomycin-resistant enterococci or Staphylococcus aureus with intermediate sensitivity to glycopeptides in period 2. CONCLUSIONS: Enteral vancomycin is an effective and safe method to control MRSA in intensive care burn units without VRE.     

Antibiotic resistance in the intensive care unit: a primer in bacteriology

The clinical use of potent, well-tolerated, broad-spectrum antibiotics has been paralleled by the development of resistance in bacteria, and the prevalence of highly resistant bacteria in some intensive care units is despairingly commonplace. The intensive care community faces the realistic prospect of untreatable nosocomial infections and should be searching for new approaches to diagnose and manage resistant bacteria. In this review, we discuss some of the relevant underlying biology, with a particular focus on genetic transfer vehicles and the relationship of selection pressure to their movements. It is an attempt to demystify the relevant language and concepts for the anaesthetist and intensivist, to explain some of the reasons for the emergence of resistance in bacteria, and to provide a contextual basis for discussion of management approaches such as selective decontamination and antibiotic cycling.     

Décontamination digestive sélective chez le malade de réanimation

Nosocomial infections increase morbidity and mortality in hospitalized patients. ICU patients are at high risk of sustaining them, due to the high rate of invasive procedures and their poor health state. Conventional methods for decreasing the incidence of infection in ICU patients include hand-washing, catheter care, strict antibiotic policy, and reduction of environmental sources of infection. Despite these measures, the colonization in these patients is always high, because of the presence of pathogens in the own patients' flora. Nosocomial pneumonia which is a major cause of mortality in ICU patients arises from retrograde colonization of the lung by pathogens originating from oro-pharyngeal and gastric secretions. Since 1984, selective decontamination of the digestive tract (SDD) has been advocated in ICUs to prevent from bacterial and fungal gastrointestinal/oropharyngreal colonization, nosocomial infection, subsequent multiple organ failure (MOF) and death.The SDD regimen is usually an extemporaneously prepared suspension of antimicrobial agents. Appropriate antibiotics for this regimen should ideally be nonabsorbable, to prevent from the development of resistant pathogens and avoid systemic toxicity. They should also be able to selectively eliminate enterobacteriaceae and yeasts, without decreasing the protective anaerobic flora. The most used combination is a suspension of colistin, amphotericin B and aminoglycoside, administered four times day through the nasogastric tube, in association with a paste consisting of 2 p. 100 colistin/amphotericin B/aminoglycoside, applied to the oropharynx. A parenteral antibiotic is also often co-administered during the first four days to prevent from early infections until the SDD regimen reachies its full effect ; cefotaxime is usually used for this. SDD significantly decreases colonization rates in the oropharynx, gastrointestinal (GI) tract and trachea. This effects is primarily attributable to a decrease of Gram-negative bacilli (GNB) and yeasts, although several studies also reported decreased isolates of Gram-positive cocci (GPC). Oropharyngeal and GI colonization significantly decrease after four days of such a regimen, but tracheal decontamination in uncertain. Several studies recognized an emergence of GPC during or after SDD and resistance occurrence in GNB (especially against aminoglycosides). Recolonization occurs rapidly, about 4 to 8 days after the discontinuation of SDD.SDD decreases significantly the nosocomial infections, especially Gram-negative pneumonia. This benefit is most obvious in trauma patients, severely burned patients and after orthopic liver transplantation. Several studies reported a significant decrease in the overall rate of infections, especially extrapulmonary infections, including blood, urinary tract, wounds, abdominal, and catheter related infections. Despite a major decrease in infection rates with SDD, most studies did not show lowered mortality rates. Several studies have reported a reduced mortality rate in selected patient subgroups (trauma patients, ICU stay longer than seven days…). Meta-analyses showed contradictory results. SDD decreases neither the length of stay in the ICU nor the number of days on ventilator. SDD has been used to control nosocomial outbreaks of colonization and infection with multiresistant GNB in ICU, but the results are controversial. In situations leading to MOF and sepsis, as in severe burns, haemorrhagic shock and in endotoxic shock, gut bacteria, especially Enterobacteriaceae, have been demonstrated to translocate into the peritoneal cavity, mesenteric lymph nodes, liver and spleen, finally causing septicaemia. SDD could prevent from gut-originating sepsis by selective elimination of aerobic flora and endotoxin inactivation in the faeces. However these data have been obtained only in rats. The overall cost/effectiveness ratio of SDD use in ICU patients has not been accurately evaluated. In some studies, SDD was associated with a decrease in overall parenteral antibiotic use. In a French multicenter trial, the total costs of antimicrobial agents were 2.2 times higher in ICU patients receiving SDD antibiotics. Therefore additional research is required before SDD regimens can be recommended for routine use in ICU patients. Subpopulations of ICU patients, such as trauma patients may benefit from SDD, but further studies have still to demonstrate the effect of SDD on mortality rate. Research should also be undertaken to determine the effects of SDD on bacterial resistance patterns.     

Selective gut decontamination reduces nosocomial infections and length of stay but not mortality or organ failure in surgical intensive care unit patients.

Suppression of the gut luminal aerobic flora to reduce nosocomial infections was tested in a prospective, randomized, double-blind, placebo-controlled clinical trial in patients in a surgical intensive care unit who had persistent hypermetabolism. Forty-six patients were randomized to receive either norfloxacin, 500-mg suspension every 8 hours, together with nystatin, 1 million units every 6 hours, or matching placebo solutions administered through a nasogastric tube within 48 hours of surgical intensive care unit admission. Selective gut decontamination with the experimental therapy or placebo solutions continued for at least 5 days or until the time of surgical intensive care unit discharge. Patients were monitored with routine surveillance cultures for the development of nosocomial infections, as defined by criteria from the Centers for Disease Control. All other therapy was given as clinically indicated, including systemic antibiotics. The selective gut decontamination group experienced a significant reduction in the incidence of nosocomial infections and a reduced length of stay. However, these results were not associated with a concomitant decrease in progressive multiple organ failure syndrome, adult respiratory distress syndrome, or mortality.     

Basics in microbiology for the patient requiring intensive care

The major aim of the article is to clearly define the basic concepts of carriage, colonization and infection. The individuals defence system consisting of three potent lines of defence against carriage, colonization and infection is described in detail. Surveillance samples of throat and rectum are required to measure carriage defence and are distinguished from diagnostic samples including lower airway secretions and blood for the evaluation of the quality of the last two defence barriers against colonization and infection.Microbes and infections are classified using the concept of the carrier state. Low level pathogens are distinguished from high level pathogens and potentially pathogenic microorganisms. Low level pathogens including viridans streptococci, enterococci and coagulase negative staphylococci only cause morbidity. High level pathogens including Salmonella and potential pathogens such as Streptococcus pneumoniae, Staphylococcus aureus, Klebsiella, Acinetobacter baumannii and Pseudomonas aeruginosa causing pneumonia and/or septicaemia, cause attributable mortality. The concept of the carrier state allows the distinction of primary endogenous from secondary endogenous and exogenous infections. Seven recent studies demonstrate that the major infection problem is primary endogenous due to potential pathogens imported into the unit, varying between 50% and 75% in adult and paediatric units respectively. Nosocomial infections due to intensive care unit (ICU) microbes only include secondary endogenous and exogenous infections. Infection control targets the three types of infection mainly due to potential pathogens. To control primary endogenous infections parenteral antibiotics are administered immediately on admission. Eradication of digestive tract overgrowth by abnormal flora using enteral non-absorbable antibiotics controls secondary endogenous infections besides restoring systemic immunity. A high level of hygiene is required to prevent exogenous infection. Surveillance cultures are indispensable for the evaluation of the efficacy and compliance of this protocol, termed selective decontamination of the digestive tract (SDD) which has been shown to reduce morbidity and mortality by 65% and 20%, respectively.     

Selective bowel decontamination in elective liver transplantation: no improvement in endotoxaemia, initial graft function and post-operative morbidity

Peri-operative endotoxaemia during liver transplantation has been linked to compromised graft function and infection. Selective decontamination of the digestive tract (SDD) could prevent endotoxaemia by eradicating Gram-negative bacteria from the intestine. In a randomized placebo controlled study we investigated the effects of endotoxaemia and the efficacy of SDD to prevent its occurrence. Thirty-one patients undergoing elective orthotopic liver transplantation received either SDD ( n=15) or placebo ( n=16), which was started at least 7 days before transplantation. Endotoxin levels were measured in blood peroperatively. Patients were scored daily for signs of liver dysfunction and infection. Endotoxaemia was neither associated with initial poor function nor any routine liver function test. Infections were more prominent in patients without endotoxaemia. SDD did not prevent endotoxaemia. Endotoxaemia does not affect post-operative graft function or the incidence of post-operative infections. SDD cannot prevent peri-operative endotoxaemia. Translocation of endotoxin may not be relevant in liver transplantation.     

Selective decontamination of the digestive tract in severely burned pediatric patients.

Infection is still one of the leading causes of morbidity and mortality in severely burned patients. Evidence suggests that many of the responsible organisms are endogenous. Systemic antibiotic prophylaxis is not effective, and produces resistant strains of microorganisms. SDD has been postulated to be beneficial for controlling and decreasing infections in critically ill patients. Its efficacy in severely burned patients, however, remains controversial. In order to analyze the efficacy of selective decontamination of the digestive (SDD) tract, to decrease the bacterial colonization of the aerodigestive tract and burn wounds, and the incidence of septic complications in severely burned children, 23 pediatric patients affected of severe burns were prospectively randomized in a double-blinded study. Eleven patients received SDD (Polymyxin E, Tobramycin, and Amphotericin B), and 12 placebo. Demographics, hospital course, microbiology results, complications, infectious episodes, and serum levels of IL-1beta, IL-6, IL-10, and TNF-alpha were compared to determine the efficacy of SDD. Colonization rates to the wound, sputum, nasogastric aspirates, and feces were similar. Pneumonia, sepsis and other complications had similar incidence in both groups. Serum levels of all cytokines studied were also comparable, suggesting a similar inflammatory status in all patients, regardless of the treatment received. Patients in the SDD group, however, had a significantly higher incidence of diarrhea (P=0.003). We can conclude that selective decontamination of the digestive tract with Polymixin E, Tobramycin and Amphotericin B is not effective to decrease bacterial colonization and infectious episodes in severely burned pediatric patients.     

Selective digestive tract decontamination in intensive care medicine. Fundamentals and current evaluation

Selective digestive tract decontamination (SDD) is a method where topical non-absorbable antibiotics are applied to the oropharynx and stomach which primarily is aimed at the prevention of ventilator-associated pneumonia. The rationale for SDD is that ventilator associated pneumonia usually originates from the patients'own oropharyngeal microflora. SDD is also used for the prevention of gut-derived infections in acute necrotizing pancreatitis and in liver transplantation. Despite numerous clinical trials and several meta-analyses, SDD is still a controversial topic. It is now commonly accepted that the incidence of pneumonia is reduced,however, the concept of using topical antibiotics has its inherent limitations and the best results have been obtained by combination with a short course of intravenous antibiotics. Several issues surrounding the notorious difficulties in establishing the diagnosis of ventilator-associated pneumonia especially in the presence of antibiotics are an on-going matter of debate.Furthermore, pneumonia is the leading cause of death from nosocomial infections and its prevention was not adequately followed by reduced mortality in most individual trials, however, a benefit was suggested by recalculation of data in meta-analyses.Patients are not well defined by their need for ICU admission and mechanical ventilation and the attributable mortality of infections depends more on the type and severity of the underlying diseases.Recently published trials substantially improved our understanding as to which patients may derive most benefit from SDD.Currently, it seems that an improved survival can be achieved in surgical and trauma patients with severe but salvageable diseases, which might be classified e.g.by calculation of APACHE-II scores on admission.However, the most important drawback of SDD is the development of resistance and an increased selection pressure towards Gram-positive pathogens, especially in institutions with endemic multi-resistant microorganisms.Thus, it appears that "selective" must not only be interpreted as selective suppression of pathogenic bacteria but rather as selection of appropriate groups of patients with respect to underlying diseases and severity of illness. Furthermore, it means selection of ICUs where the endemic resistance patterns might allow the use of SDD at a relatively low risk for selection of resistant microorganisms, which is still the major concern associated with SDD.     

Controlled clinical trial of selective decontamination for the treatment of severe acute pancreatitis.

OBJECTIVE: A randomized, controlled, multicenter trial was undertaken in 102 patients with objective evidence of severe acute pancreatitis to evaluate whether selective decontamination reduces mortality. SUMMARY BACKGROUND DATA: Secondary pancreatic infection is the major cause of death in patients with acute necrotizing pancreatitis. Controlled clinical trials to study the effect of selective decontamination in such patients are not available. METHODS: Between April 22, 1990 and April 19, 1993, 102 patients with severe acute pancreatitis were admitted to 16 participating hospitals. Patients were entered into the study if severe acute pancreatitis was indicated, on admission, by multiple laboratory criteria (Imrie score > or = 3) and/or computed tomography criteria (Balthazar grade D or E). Patients were randomly assigned to receive standard treatment (control group) or standard treatment plus selective decontamination (norfloxacin, colistin, amphotericin; selective decontamination group). All patients received full supportive treatment, and surveillance cultures were taken in both groups. RESULTS: Fifty patients were assigned to the selective decontamination group and 52 were assigned to the control group. There were 18 deaths in the control group (35%), compared with 11 deaths (22%) in the selective decontamination group (adjusted for Imrie score and Balthazar grade: p = 0.048). This difference was mainly caused by a reduction of late mortality (> 2 weeks) due to significant reduction of gram-negative pancreatic infection (p = 0.003). The average number of laparotomies per patient was reduced in patients treated with selective decontamination (p < 0.05). Failure of selective decontamination to prevent secondary gram-negative pancreatic infection with subsequent death was seen in only three patients (6%) and transient gram-negative pancreatic infection was seen in one (2%). In both groups of patients, all gram-negative aerobic pancreatic infection was preceded by colonization of the digestive tract by the same bacteria. CONCLUSION: Reduction of gram-negative colonization of the digestive tract, preventing subsequent pancreatic infection by means of selective decontamination, significantly reduces morbidity and mortality in patients with severe acute necrotizing pancreatitis.     

选择性消化道脱污染对烫伤大鼠脏器的保护作用

目的 探讨选择性消化道脱污染对烫伤大鼠组织白细胞介素－18mRNA表达的影响及脏器保护作用。方法 采用大鼠30％体表面积Ⅲ度烫伤延迟复苏模型，肠、肺组织IL－18、IFN－γ mRNA含量采用逆转录聚合酶链式反应检测；ELISA法测定IFN－γ含量；同时检测肠、肺功能指标。结果 肠、肺组织IL－18、IFN－γ mRNA表达较伤前有显著升高，烫伤后8h达高峰，且一直持续至伤后24h，给予SDD预治疗后可不同程度抑制IL－18、IFN－γ mRNA的表达；严重烫伤后，出现广泛的脏器功能，预防性SDD处理可不同程度地保护脏器。结论 肠、肺组织IL－18、IFN－γ mRNA表达在烫伤后显著增多，并逐渐升高，后者对脏器具有重要影响。SDD预治疗后可不同程度抑制IL－18 mRNA的表达并保护脏器。     

Impact of selective decontamination of the digestive tract on carriage and infection due to Gram-negative and Gram-positive bacteria: a systematic review of randomised controlled trials

Meta-analyses of randomised controlled trials of selective digestive decontamination have clinical outcome measures, mainly pneumonia and mortality. This meta-analysis has a microbiological endpoint and explores the impact of selective digestive decontamination on Gram-negative and Gram-positive carriage and severe infections. We searched electronic databases, Cochrane Register of Controlled Trials, previous meta-analyses and conference proceedings with no language restrictions. We included randomised controlled trials which compared the selective digestive decontamination protocol with no treatment or placebo. Three reviewers independently applied selection criteria, performed the quality assessment and extracted the data. The outcome measures were carriage and severe infection due to Gram-negative and Gram-positive bacteria. Odds ratios were pooled with the random effect model. Fifty-four randomised controlled trials comprising 9473 patients were included; 4672 patients received selective digestive decontamination and 4801 were controls. Selective digestive decontamination significantly reduced oropharyngeal carriage (odds ratio [OR] 0.13, 95% confidence interval [CI] 0.07 to 0.23), rectal carriage (OR 0.15, 95% CI 0.07 to 0.31), overall infection (OR 0.17, 95% CI 0.10 to 0.28), lower respiratory tract infection (OR 0.11, 95% CI 0.06 to 0.20) and bloodstream infection (OR 0.35, 95% CI 0.21 to 0.67) due to Gram-negative bacteria. Reduction in Gram-positive carriage was not significant. Gram-positive lower airway infections were significantly reduced (OR 0.52, 95% CI 0.34 to 0.78). Gram-positive bloodstream infections were not significantly increased (OR 1.03, 95% CI 0.75 to 1.41). The association of parenteral and enteral antimicrobials was superior to enteral antimicrobials in reducing carriage and severe infections due to Gram-negative bacteria. This meta-analysis confirms that selective digestive decontamination mainly targets Gram-negative bacteria; it does not show a significant increase in Gram-positive infection.     

Digestive decontamination in burn patients: A systematic review of randomized clinical trials and observational studies

Objective

The objective of this systematic review is to assess the effect of selective digestive decontamination (SDD) or non-absorbable enteral antibiotics (EA) on mortality, the incidence of infection and its adverse effects in burn patients.