Selective Gut Decontamination Research Articles

Use of selective gut decontamination in critically ill children: protocol for the Paediatric Intensive Care and Infection Control (PICnIC) pilot study

IntroductionHealthcare-associated infections (HCAIs) are a major cause of morbidity and mortality in critically ill children. In critically ill adults, there are data that suggest the use of Selective Decontamination of...

Role of the Environment in Transmission of Multiresistant Enterobacter cloacae in a Hematology-Oncology Department

Background: The patient environment is increasingly considered a major source of transmission of nosocomial bacteria to patients. In May 2019, a cluster of 3 patients with multiresistant Enterobacter cloacae was discovered in the hematology-oncology department of the Maastricht University Medical Center (built in 1991). The strains had an identical antibiogram: ESBL-positive, ciprofloxacin R, cotrimoxazole R, meropenem S, and colistin S. One neutropenic patient had a positive blood culture for this strain, resistant to the empiric treatment with piperacillin-tazobactam, but the patient recovered after switching the antibiotic regimen to meropenem. All strains were determined to be identical by amplified-fragment length polymorphism and whole-genome multi-locus sequencing typing (genotype A). New cases occurred, despite the introduction of contact isolation of positive and contact patients. Therefore, weekly point-prevalence screening was introduced, in which more newly colonized patients were identified in the subsequent weeks. Attention to hand hygiene was enforced, and the hypothesis of contamination from “wet” environmental locations was tested by performing cultures of sinks and shower drains. In June and July, 47 of 241 environmental cultures (19.5%) were positive for E. cloacae with an identical antibiogram, among which some were typed as genotype A. To diminish the environmental contamination, all siphons of sinks were replaced, and disinfection of sinks and shower drains was intensified using chlorine and soda on a daily basis. Replacement of shower drains was not possible. After this intervention, the incidence of newly colonized patients declined gradually. A change in the regimen of selective gut decontamination in hematology patients was considered as an alternative intervention, but with the decrease in new patient cases, this was not implemented. A final round of environmental cultures at the end of August revealed 8 positive cultures, of which 5 were positive for genotype A. In retrospect, this finding could be explained by the fact that the cleaning team did not follow the intensified instructions for disinfection. From week 29, genotype A E. cloacae was no longer cultured in weekly patient screenings. Based on this observation, it is important that in (re)building plans for hospitals, a master plan for the prevention of nosocomial transmission from environment to patients is incorporated.Funding: NoneDisclosures: None

Dynamics of the Gut Microbiota in Children Receiving Selective or Total Gut Decontamination Treatment during Hematopoietic Stem Cell Transplantation.

Bloodstream infections and graft-versus-host disease are common complications after hematopoietic stem cell transplantation (HSCT) procedures, associated with the gut microbiota that acts as a reservoir for opportunistic pathogens. Selective gut decontamination (SGD) and total gut decontamination (TGD) during HSCT have been associated with a decreased risk of developing these complications after transplantation. However, because studies have shown conflicting results, the use of these treatments remains subject of debate. In addition, their impact on the gut microbiota is not well studied. The aim of this study was to elucidate the dynamics of the microbiota during and after TGD and to compare these with the dynamics of SGD. In this prospective, observational, single-center study fecal samples were longitudinally collected from 19 children eligible for allogenic HSCT (TGD, n=12; SGD, n=7), weekly during hospital admission and monthly after discharge. In addition, fecal samples were collected from 3 family stem cell donors. Fecal microbiota structure of patients and donors was determined by 16S rRNA gene amplicon sequencing. Microbiota richness and diversity markedly decreased during SGD and TGD and gradually increased after cessation of decontamination treatment. During SGD, gut microbiota composition was relatively stable and dominated by Bacteroides, whereas it showed high inter- and intraindividual variation and low Bacteroides abundance during TGD. In some children TGD allowed the genera Enterococcus and Streptococcus to thrive during treatment. A gut microbiota dominated by Bacteroides was associated with increased predicted activity of several metabolic processes. Comparing the microbiota of recipients and their donors indicated that receiving an SCT did not alter the patient's microbiota to become more similar to that of its donor. Overall, our findings indicate that SGD and TGD affect gut microbiota structure in a treatment-specific manner. Whether these treatments affect clinical outcomes via interference with the gut microbiota needs to be further elucidated.

Comprehensive preoperative regime of selective gut decontamination in combination with probiotics, and smectite for reducing endotoxemia and cytokine activation during cardiopulmonary bypass: A pilot randomized, controlled trial.

Background:Both selective digestive decontamination (SDD) and probiotics have been reported to reduce endotoxemia. However, the available results are conflicting and few studies have investigated the combined effect of SDD and probiotics. This study aimed to examine the effectiveness of a comprehensive preoperative regimen of SDD in combination with probiotics and smectite on perioperative endotoxemia and cytokine activation in patients who underwent elective cardiac surgery with cardiopulmonary bypass (CPB) in a pilot, prospective, randomized, controlled trial.Methods:Patients who underwent elective Aortic Valve Replacement or Mitral Valve Replacement surgery from July 2010 to March 2015 were included. In total, 30 eligible patients were randomly assigned to receive either the comprehensive preoperative regimen (n = 15) (a combination of preoperative SDD, probiotics, and smectite) or the control group (n = 15) who did not receive this treatment. The levels of endotoxin, IL-6, and procalcitonin were measured at the time before anesthesia induction, immediately after cardiopulmonary bypass (CPB), 24 hours after CPB, and 48 hours after CPB. The primary outcomes were changes in endotoxin, IL-6, and procalcitonin concentrations after CPB.Results:The mean levels of change in endotoxin levels after CPB in patients receiving the comprehensive preoperative regimen was marginally significantly lower than those in control group (F = 4.0, P = .0552) but was not significantly different for procalcitonin (F = .14, P = .7134). An interaction between group and time for IL-6 was identified (F = 4.35, P = .0231). The increase in IL-6 concentration immediately after CPB in the comprehensive preoperative group was significantly lower than that in the control group (P = .0112). The changes in IL-6 concentration at 24 hours and 48 hours after CPB were not significant between the comprehensive preoperative group and control group.Conclusion:The present pilot, prospective, randomized, controlled study in patients undergoing cardiac surgery with CPB demonstrated that 3 days of a comprehensive preoperative regime of SDD in combination with probiotics and smectite may reduce the endotoxin and IL-6 levels after CPB compared with the control group.

The ectonucleotidase ENTPD1/CD39 limits biliary injury and fibrosis in mouse models of sclerosing cholangitis.

The pathogenesis of primary sclerosing cholangitis (PSC) and the mechanistic link to inflammatory bowel disease remain ill‐defined. Ectonucleoside triphosphate diphosphohydrolase‐1 (ENTPD1)/clusters of differentiation (CD) 39, the dominant purinergic ecto‐enzyme, modulates intestinal inflammation. Here, we have explored the role of CD39 in biliary injury and fibrosis. The impact of CD39 deletion on disease severity was studied in multidrug resistance protein 2 (Mdr2)–/– and 3,5‐diethoxycarbonyl‐1,4‐dihydrocollidine mouse models of sclerosing cholangitis and biliary fibrosis. Antibody‐mediated CD8+ T‐cell depletion, selective gut decontamination, experimental colitis, and administration of stable adenosine triphosphate (ATP) agonist were performed. Retinoic acid‐induced gut imprinting on T cells was studied in vitro. Over half of Mdr2–/–;CD39–/– double mutants, expected by Mendelian genetics, died in utero. Compared to Mdr2–/–;CD39+/+, surviving Mdr2–/–;CD39–/– mice demonstrated exacerbated liver injury, fibrosis, and ductular reaction. CD39 deficiency led to a selective increase in hepatic CD8+ T cells and integrin α4β7, a T‐cell gut‐tropism receptor. CD8+ cell depletion in Mdr2–/–;CD39–/– mice diminished hepatobiliary injury and fibrosis. Treatment with antibiotics attenuated, whereas dextran sulfate sodium‐induced colitis exacerbated, liver fibrosis in Mdr2–/– mice. Colonic administration of αβ‐ATP into CD39‐sufficient Mdr2–/– mice triggered hepatic CD8+ cell influx and recapitulated the severe phenotype observed in Mdr2–/–;CD39–/– mice. In vitro, addition of ATP promoted the retinoic acid‐induced imprinting of gut‐homing integrin α4β7 on naive CD8+ cells. CD39 expression was relatively low in human normal or PSC livers but abundantly present on immune cells of the colon and further up‐regulated in samples of patients with inflammatory bowel disease. Conclusion: CD39 deletion promotes biliary injury and fibrosis through gut‐imprinted CD8+ T cells. Pharmacological modulation of purinergic signaling may represent a promising approach for the treatment of PSC. (Hepatology Communications 2017;1:957–972)

Identification of Causative Organisms and Role of Ceftriaxone in Spontaneous Bacterial Peritonitis (SBP) Secondary to Decompensated Liver Disease

Background There is increasing trend of gram positive organism present in ascetic fluid culture as a result of selective gut decontamination of gram negative organisms by prophylactic antibiotics for SBP and due to different invasive procedures. Objectives to identify causative organisms in ascetic fluid culture of patients with spontaneous bacterial peritonitis secondary to decompensated liver disease and their sensitivities to ceftriaxone as an empiric therapy. Methods A Cross sectional study was conducted at Department of Gastroenterology, Shifa International Hospital, Islamabad. Aseptic technique was adopted to aspirate ascetic fluid. At least 10 ml of ascetic fluid was inoculated in blood culture bottle at bed side before starting ceftriaxone. Result Total 97 patients were included in this study. Among them 57 (58.8%) were male and 40 40(41.2 %) were female. The most common organism was E. coli with a frequency of 42(43.2 %) almost half were ESBL strains 20(20.6%) followed by Klebsiella 15(15.4%) among which 5(5.2%) were ESBL strains while Pseudomonas aeruginosa was 12(12.3%). Conclusion No increasing trend of gram positive pathogens was observed, however ESBL strains are emerging pathogens. Gram negative organisms are still the common pathogens of SBP.

Effect of selective gut decontamination in regulation of inflammatory reaction in patients with systemic inflammatory response syndrome

To explore the effect of selective gut decontamination in regulation of inflammatory reaction compared with rhubarb and glycerine enema for catharsis in patients with systemic inflammatory response syndrome ( SIRS ), and to discuss its mechanisms. A prospective randomized controlled trial was conducted. Fifty-seven patients with SIRS admitted to Department of General Surgery of Aviation General Hospital from June 2009 to June 2014 were enrolled. The patients were randomly divided into rhubarb decontaminate group, traditional decontaminate group and blank control group, with 19 cases in each group. Besides the treatment for primary disease, including anti-infection, operation, alleviate pain, nutritional support, and maintaining water and electrolyte balance, the patients in rhubarb decontaminate group received aqueous extract from rhubarb 15-20 g by gastric tube, enema, or peros, twice a day; and those in traditional decontaminate group received glycerine enema or glycerol enema, twice a day; while no gavage or enema was prescribed in blank control group. Peripheral blood was collected before and 72 hours after treatment. Enzyme linked immunosorbent assay (ELISA) was used to determine the concentration of lipopolysaccharide (LPS) and inflammatory mediators. Compared with blank control group and traditional decontaminate group, the levels of interleukins (IL-1, IL-8), LPS, platelet activating factor (PAF), tumor necrosis factor-α (TNF-α), and γ- interferon (IFN-γ) before treatment was similar to that of rhubarb decontaminate group [IL-1 (ng/L): 53.154±5.783, 50.564±5.771, 51.082±6.403, F=0.994, P=0.377; IL-8 (ng/L): 70.492±6.146, 68.376±6.112, 68.673±8.384, F=0.514, P=0.601; LPS (μg/L): 11.630±2.449, 10.858±2.307, 10.463±2.145, F=1.261, P=0.291; PAF (μg/L): 4.173±0.395, 4.051±0.362, 4.078±0.487, F=0.446, P=0.642; TNF-α (ng/L): 132.498±10.772, 129.735±12.881, 127.207±11.514, F=0.963, P=0.388; IFN-γ (μg/L): 45.645±4.558, 43.692±5.578, 43.767±5.028, F=0.904, P=0.411]. The above parameters after treatment were significantly lower than those before treatment in three groups. The effect on the LPS and pro-inflammatory factors of the rhubarb decontaminate group was more obvious than that of the blank control group and traditional decontaminate group [LPS(μg/L): 7.571±1.113 vs. 9.008±1.904, 8.874±1.808, F=4.416, P=0.017; IL-1 (ng/L): 45.309±3.563 vs. 48.731±4.466, 46.112±4.322, F=3.557, P=0.035; IL-8 (ng/L): 60.492±5.346 vs. 65.553±5.384, 63.437±5.462, F=4.213, P=0.020; PAF (μg/L): 3.519±0.250 vs. 3.832±0.356, 3.766±0.309, F=5.450, P=0.007; TNF-α (ng/L): 114.988±8.772 vs. 123.230±10.433, 118.534±9.519, F=3.525, P=0.036; IFN-γ (μg/L): 38.683±3.190 vs. 41.831±4.122, 39.161±3.972, F=3.820, P=0.028]. The usage of selective gut decontamination can inhibit the release of endotoxin and inflammatory mediators in patients with SIRS, and it will get a better effect using rhubarb, and the mechanism may be related to the protection of intestinal mucosal barrier function.

Oral Supplementation with Non-Absorbable Antibiotics or Curcumin Attenuates Western Diet-Induced Atherosclerosis and Glucose Intolerance in LDLR−/− Mice – Role of Intestinal Permeability and Macrophage Activation

Association between circulating lipopolysaccharide (LPS) and metabolic diseases (such as Type 2 Diabetes and atherosclerosis) has shifted the focus from Western diet-induced changes in gut microbiota per se to release of gut bacteria-derived products into circulation as the possible mechanism for the chronic inflammatory state underlying the development of these diseases. Under physiological conditions, an intact intestinal barrier prevents this release of LPS underscoring the importance of examining and modulating the direct effects of Western diet on intestinal barrier function. In the present study we evaluated two strategies, namely selective gut decontamination and supplementation with oral curcumin, to modulate Western-diet (WD) induced changes in intestinal barrier function and subsequent development of glucose intolerance and atherosclerosis. LDLR−/− mice were fed WD for 16 weeks and either received non-absorbable antibiotics (Neomycin and polymyxin) in drinking water for selective gut decontamination or gavaged daily with curcumin. WD significantly increased intestinal permeability as assessed by in vivo translocation of FITC-dextran and plasma LPS levels. Selective gut decontamination and supplementation with curcumin significantly attenuated the WD-induced increase in plasma LPS levels (3.32 vs 1.90 or 1.51 EU/ml, respectively) and improved intestinal barrier function at multiple levels (restoring intestinal alkaline phosphatase activity and expression of tight junction proteins, ZO-1 and Claudin-1). Consequently, both these interventions significantly reduced WD-induced glucose intolerance and atherosclerosis in LDLR−/− mice. Activation of macrophages by low levels of LPS (50 ng/ml) and its exacerbation by fatty acids is likely the mechanism by which release of trace amounts of LPS into circulation due to disruption of intestinal barrier function induces the development of these diseases. These studies not only establish the important role of intestinal barrier function, but also identify oral supplementation with curcumin as a potential therapeutic strategy to improve intestinal barrier function and prevent the development of metabolic diseases.

Global survey of polymyxin use: A call for international guidelines.

Polymyxins (polymyxin B and colistin) are older bactericidal antibiotics that are increasingly used to treat infections caused by multidrug-resistant (MDR) Gram-negative bacteria. However, dosing and clinical use of these drugs vary widely. This survey was undertaken to reveal how polymyxins are used worldwide. Data were collected through a structured online questionnaire consisting of 24 questions regarding colistin usage patterns and indications as well as colistin dosage for adult patients. The questionnaire was disseminated in 2011 to relevant experts worldwide and was completed by 284 respondents from 56 different countries. Respondents from 11/56 countries (20%) had no access to colistin; 58/284 respondents (20.4%) reported that in 2010 they experienced that colistin was not available when needed. Formulations of polymyxins used were reported as: colistimethate sodium (48.6%); colistin sulfate (14.1%); both (1.4%); polymyxin B (1.4%); and unknown. Intravenous formulations were used by 84.2%, aerosolised or nebulised colistin by 44.4% and oral colistin for selective gut decontamination by 12.7%. Common indications for intravenous colistin were ventilator-associated pneumonia, sepsis and catheter-related infections with MDR Gram-negative bacteria. Only 21.2% of respondents used a colistin-loading dose, mainly in Europe and North America. This survey reveals that the majority of respondents use colistin and a few use polymyxin B. The survey results show that colistin is commonly underdosed. Clear guidance is needed on indications, dosing and antibiotic combinations to improve clinical outcomes and delay the emergence of resistance. Colistin should be considered a last-resort drug and its use should be controlled. International guidelines are urgently needed.

PTU-049 Modulation of toll-like receptor genes with selective gut decontamination in cirrhotic animals prevents the development of acute-on chronic liver failure (ACLF)

IntroductionAcute deterioration in the liver function following precipitating illness in patients with cirrhosis often lead to multiple organ failure. Inflammation is thought to be a major contributing factor. We hypothesised...

MODULATION OF TOLL-LIKE RECEPTOR GENES WITH SELECTIVE GUT DECONTAMINATION IN CIRRHOTIC ANIMALS PREVENTS THE DEVELOPMENT OF ACUTE-ON CHRONIC LIVER FAILURE (ACLF)

Introduction Acute deterioration in the liver function following precipitating illness in patients with cirrhosis often lead to multiple organ failure. Inflammation is thought to be a major contributing factor. We hypothesised that toll like receptor9s (TLRs) play a pivotal role in lipopolysaccharide (LPS) mediated cytokine surge in patients with cirrhosis culminating in acute-on-chronic liver failure (ACLF). Selective gut decontamination with Norfloxacin would dampen this inflammatory cascade. Methods Global hepatic gene expression was studied in a rodent model of cirrhosis induced by bile duct ligation (BDL) (Agilent microarray) and compared the results to sham animals. TLR related genes were among the differentially expressed genes in the liver. We validated gene expression in the Liver and Kidney in a second set of experiment in Sham, BDL, BDL+LPS, BDL+Norfloxacin, BDL+Norfloxacin+LPS groups using the quantitative real-time PCR. Cytokines (Becton Dickenson) and biochemistry were measured (COBAS Integra 400). Results Among the several genes with high expression in the BDL group as detected by the microarray, both TLR 4 and 2 had significantly higher expression in liver and Kidney compared with the sham group. We also found a marked upregulation of the C-C motif ligand 2 (CCl2) and C-X-C motif ligand 2(CxCl2) Furthermore, LPS administration in BDL animals accentuated not only the TLRs (4 and 2) expression in both kidney and liver but also the Cxcl2 and CCl2 in both these organs associated with deterioration organ function as suggested with a rise in the liver enzyme, creatinine and a rise in plasma and tissue cytokines. Norfloxacin pre-treatment in BDL group (BDL+Norfloxacin) attenuated the TLR4 and TLR2 expression in both liver and kidney. Selective decontamination with Norfloxacin in BDL +LPS animals limited the upregulation of TLR4 and TLR2 in the Liver and Kidney. It also prevented the upregulation of the CxcL2 and CCl2 in both these organs. This was associated with significant improvement in liver enzymes, creatinine and cytokines. Conclusion This study shows that the liver and kidneys in cirrhotic animals are primed by upregulation of TLR9s and its downstream inflammatory mediators in the Liver and Kidney which make them exquisitely sensitive to the effects of superimposed infection/inflammation leading to organ failure. Selective decontamination with Norfloxacin prevents the progression of ACLF by reducing gene expression of TLR 2 and 4 and its associated inflammatory adaptors. Competing interests None declared.

Prevention of acute kidney injury in a rodent model of cirrhosis following selective gut decontamination is associated with reduced renal TLR4 expression

Superimposed infection and/or inflammation precipitate renal failure in cirrhosis. This study aimed at testing the hypothesis that increased gut bacterial translocation in cirrhosis primes the kidney to the effect of superimposed inflammation by upregulating expression of Toll-like receptor 4 (TLR4), NFκB, and cytokines. A well-characterized bile-duct ligated (BDL) model of cirrhosis, which develops renal failure following superimposed inflammatory insult with lipopolysaccharide (LPS), was used and selective gut decontamination was performed using norfloxacin. Sprague-Dawley rats were studied: Sham, Sham+LPS; BDL, BDL+LPS; an additional BDL and BDL+LPS groups were selectively decontaminated with norfloxacin. Plasma biochemistry, plasma renin activity (PRA) and cytokines and, protein expression of TLR4, NFκB, and cytokines were measured in the kidney homogenate. The kidneys were stained for TLR4, TLR2, and caspase-3. Endotoxemia was measured using neutrophil burst and Limulus amoebocyte lysate (LAL) assays. The groups treated with norfloxacin showed significant attenuation of the increase in plasma creatinine, plasma and renal TNF-α and renal tubular injury on histology. The increased renal protein expression of TLR4, NFκB, and caspase-3 in the untreated animals was significantly attenuated in the norfloxacin treated animals. PRA was reduced in the treated animals and severity of endotoxemia was also reduced. The results show for the first time that kidneys in cirrhosis show an increased expression of TLR4, NFκB, and the pro-inflammatory cytokine TNF-α, which makes them susceptible to a further inflammatory insult. This increased susceptibility to LPS can be prevented with selective decontamination, providing novel insights into the pathophysiology of renal failure in cirrhosis.

Prevention and management of ventilator-associated pneumonia: A survey on current practices by intensivists practicing in the Indian subcontinent

Implementation of evidence-based guidelines to prevent and manage ventilator-associated pneumonia (VAP) in the clinical setting may not be adequate. We aimed to assess the implementation of selected VAP prevention strategies, and to learn how VAP is managed by the intensivists practicing in the Indian Subcontinent. Three hundred 10-point questionnaires were distributed during an International Critical Care Conferenceheld at New Delhi in 2009. A total of 126 (42%) questionnaires distributed among delegates from India, Nepal and Sri Lanka were analyzed. Majority (96.8%) reported using VAP bundles with a high proportion including head elevation (98.4%), chlorhexidine mouthcare (83.3%), stress ulcer prophylaxis (96.8%), heat and moisture exchangers (HME, 92.9%), early weaning (94.4%), and hand washing (97.6%) as part of their VAP bundle. Use of subglottic secretion drainage (SSD, 45.2%) and closed suction systems (CSS, 74.6%) was also reported by many intensivists, whereas use of selective gut decontamination was reported by only 22.2%. Commonest method for sampling was endotracheal suction by 68.3%. Gram negative organisms were reported to be the most commonly isolated. Majority (39.7%) reported using proton pump inhibitors for stress ulcer prophylaxis and 84.1% believed that VAP contributed to increased mortality. De-escalating therapy was considered in patients responding to treatment by 57.9% and 65.9% considered adding empirical methicillin resistant Staphylococcus aureus (MRSA)coverage, while 63.5% considered adding nebulized antibiotics in certain high-risk patients. There was good concordance regarding VAP prophylaxis among the intensivists with a majority adhering to evidence-based guidelines. We could identify certain issues like the choice of agent for stress ulcer prophylaxis, use of HME filters, SSD and CSS, where there still exists some practice variability and opportunities for improvement.

P32 Gut sterilisation with norfloxacin modulates cerebral inflammation in cirrhosis and prevents deterioration in brain oedema and delays coma in cirrhotic rats

IntroductionIn a bile duct ligated (BDL) rodent model of cirrhosis, superimposed infection/inflammation leads to multiorgan failure including cerebral inflammation, worsening oedema and coma. The mechanism of why cirrhotic animals are...

OP21 The role of Toll like receptor-4 in the pathogenesis of hepatorenal syndrome in a Bile duct ligated model of cirrhosis in the rat

IntroductionHepatorenal syndrome (HRS) is a frequent presenting complication in patients with cirrhosis and usually occurs with a superimposed infection/inflammation. It is associated with high morbidity and mortality. The pathogenesis of...

Toll-Like Receptors 2 and 4 Are Involved in the Induction of Graft-Versus-Host-Disease in Mice.

BACKGROUND: Intestinal Graft-versus-Host disease is a frequent and often lethal complication after allogenic stem cell transplantation. Since NOD2 polymorphisms have been recognized as potential triggers of severe intestinal GvHD in humans, we have developed murine transplantation models to investigate the role of different pattern recognition receptors (PRR) in GvHD and GvL. Here we report our results on the role of TLR2 and TLR4 for the induction of GvHD.METHODS: Severity of GvHD in wildtype (wt) C57B/10 (H-2Db), TLR2−/−, TLR4−/−, and combined TLR2−/−TLR4−/− C57B/10 mice was investigated. Mice received treosulfan 2000 mg/kg from day -3 to -1 and cyclophosphamide 200 mg/kg day -1 prior to injection of 10×10^6 H-2Dd BM cells and 5×10^6 splenocytes (SC). Survival and GvHD score were assessed daily. Engraftment was determined every 2 weeks in pB and at the end of the experiments in bone marrow by flow cytometry. T cell alloreactivity in GvH direction was assessed by MLR using splenocytes as stimulators from PRR-deficient mice or wt as control and CFSE-staining as read-out. The relevance of PRR ligands for the enhancement of GvH alloreactivity was determined by addition of lipid A, lipopetides, or CpG.RESULTS:in vivo data: The transfer of 10×10^6 BMC + 5×10^6 SC induced a severe GvHD in all wt recipients, leading to death of 90% of the animals within 20 days. Recipient mice lacking either TLR2 or TLR4 showed only a slightly and not significantly decreased GvHD lethality. In recipients lacking both PPRs, i.e. TLR2 and TLR4, GvHD was generally milder and the majority (60%) of the animals survived until day 20 (p<0.05). However, the long term survival was not significantly improved. Differences in clinical severity of GvHD were confirmed histologically.In vitro data: Stimulation with cells from TLR2−/− and TLR4−/− mice resulted in a decreased alloreactivity in MLR. A median of 2% of Balb/c CD4+ T cells proliferated in response to C57B/10 stimulators. The addition of the TLR2 and TLR4 ligands lipopeptide, Lipid A and CpG significantly (p<0.05) increased the proliferation of CD4+ T cells in a specific manner more than twofold.CONCLUSION: Our in vivo and in vitro data consistantly show that bacterial components are involved in triggering GvH alloreactivity via different types of PPRs. Binding of bacterial substances to TLR2 and TLR4 leads to activation of the immune system and subsequent induction of GvHD. Our data provide an experimental basis for the development of strategies for modulation of the intestinal gut flora by selective gut decontamination and/or probiotic regimens to prevent GvHD in humans.

Review article: bacterial translocation in the critically ill – evidence and methods of prevention

Delayed sepsis, systemic inflammatory response syndrome (SIRS) and multiorgan failure remain major causes of morbidity and mortality on intensive care units. One factor thought to be important in the aetiology of SIRS is failure of the intestinal barrier resulting in bacterial translocation and subsequent sepsis. This review summarizes the current knowledge about bacterial translocation and methods to prevent it. Relevant studies during 1966-2006 were identified from a literature search. Factors, which detrimentally affect intestinal barrier function, are discussed, as are methods that may attenuate bacterial translocation in the critically ill patient. Methodological problems in confirming bacterial translocation have restricted investigations to patients undergoing laparotomy. There are only limited data available relating to specific interventions that might preserve intestinal barrier function or limit bacterial translocation in the intensive care setting. These can be categorized broadly into pre-epithelial, epithelial and post-epithelial interventions. A better understanding of factors that influence translocation could result in the implementation of interventions which contribute to improved patient outcomes. Glutamine supplementation, targeted nutritional intervention, maintaining splanchnic flow, the judicious use of antibiotics and directed selective gut decontamination regimens hold some promise of limiting bacterial translocation. Further research is required.

Evaluation of potential risk factors for early infectious complications after autologous peripheral blood stem cell transplantation in patients with lymphoproliferative diseases

A number of risk factors for the occurrence of neutropaenic fever after haematopoietic stem cell transplantation (HSCT) have been proposed. We were interested in whether these factors remain valid for several early infection-related outcomes when applied to a homogeneous group of patients in uni- and multivariate analyses. Therefore, we analysed 144 consecutive patients with lymphoproliferative disorders receiving autologous peripheral blood HSCT. Variables tested as potential risk factors for the occurrence of fever, documented infection (DI), microbiologically documented infection (MDI) or failure of first-line antimicrobial therapy were sex, conditioning regimen, prolonged neutropaenia, low number of CD34+ cells transplanted, purging, lack of selective gut decontamination, higher age and increased body mass index. In uni- and multivariate analyses, conditioning including total body irradiation was the only risk factor for the occurrence of fever, and neutropaenia >or=10 days was the only factor associated with failure of first-line antimicrobial therapy. None of the variables tested was associated with an increased risk for DI or MDI. This analysis suggests that a number of previously proposed risk factors actually are of minor clinical relevance for early infections in the majority of patients receiving autologous HSCT.

Fulminant hepatic failure

Abstract Analysis of the first 150 cases collected from 73 centers reporting to the Fulminant Hepatic Failure Surveillance Study showed that 80 patients had presumable viral hepatitis, of whom 62 died. Of 41 patients who had recent surgery, 36 died. In 35 patients massive liver necrosis developed less than three weeks after halothane anesthesia, and 27 (77 per cent) of these had multiple exposures to halothane. The risk from halothane is small, but this complication was present in nearly one quarter of the cases reported in our study. When the use of halothane is desired, multiple exposure should be avoided, if possible. Moreover, postoperative fever after exposure to halothane, otherwise "unexplained," is an important warning sign, and should be thoroughly investigated and taken into consideration when further exposure to this anesthetic is contemplated. The physician prescribing halothane must balance need against risk.

Gut Decontamination Prevents Bronchoscopy-Induced Bacterial Translocation

Background: Selective gut decontamination is suggested to suppress the gram-negative bacterial overgrowth in the intestine and consequently to reduce bacterial translocation. Objective: The purpose of the present study is to examine the effects of gut decontamination on bronchoscopy-induced bacterial translocation, and intestinal mucosal injury. Methods: Forty-five rats were assigned into three groups. Group 1 served as control (n = 15). Group 2 (n = 15) and group 3 (n = 15) underwent bronchoscopy. In addition, group 3 underwent gut decontamination. Gut decontamination was performed two days prior to bronchoscopy with erythromycin and neomycin. Twenty-four hours after bronchoscopy, blood, mesenteric lymph nodes, spleen, liver, ileum and cecum were harvested for bacterial determination. The ileum was also assessed and graded histologically according to Chiu’s injury scale. Results: In the bronchoscopy group, bacterial translocation to the mesenteric lymph nodes was found in 7/15 rats (46.7%), compared to none of the controls (p = 0.01). These rats also showed significant evidence of intestinal injury, compared to the controls (mean ranks, 32.7 or 8.5, p < 0.0001). On the other hand, gut decontamination prevented bacterial translocation, compared to the bronchoscopy group (p = 0.011). However, gut decontamination provided no beneficial effect on the intestinal mucosal injury, compared to the bronchoscopy group. These animals also revealed significant intestinal injury, compared to the controls (mean ranks, 27.8 or 8.5, p < 0.0001). Conclusions: Our data shows that despite no amelioration in bronchoscopy-induced intestinal mucosal injury, gut decontamination has a preventive role for bronchoscopy-induced bacterial translocation.