Effect of Probiotic Supplementation on Bacterial Translocation in Thermal Injury

The role of thermal injury on intestinal bacterial translocation and the mitigating role of probiotics: A review of animal and human studies

INTRODUCTION

Burn patients represent a combination of nutritionally deplete and calorically demanding individuals who are susceptible to morbidity and mortality. A source of sepsis in thermal injury patients is the gastrointestinal tract with its interaction of normal and potentially pathogenic bacteria. The normal flora of the intestines maintains the equilibrium of the gut and prevents bacterial translocation (BT) through numerous mechanisms, all of which are disrupted as a consequence of thermal injury. Probiotic supplements with varying strains of bacteria have the potential to stabilize the integrity of the gut lining and decrease the incidence of BT after thermal injury.

METHODS

A literature review was conducted for animal and human studies in English addressing probiotic therapy in thermal injury. Keywords, "probiotics," "thermal injury" and "burn" were utilized. Reference lists for each analyzed article were also examined to ensure completeness of literature search. Each article was reviewed for methodology, results and conclusions.

RESULTS

Eleven and six unique articles were identified addressing probiotics in thermal injury in animal and human studies, respectively. Heterogeneity between studies and limited demographic and outcome reporting prevented meta-analysis and comprehensive recommendations to be formalized.

CONCLUSION

While heterogeneity did not allow for meta-analysis, the results overall suggest a preventative, if not therapeutic, potential for probiotics in patients after thermal injury. Despite initial concern that probiotic therapy could lead to systemic infection in immune compromised individuals, this was not observed in the analyzed studies. Numerous unanswered questions exist in regards to optimizing probiotic therapy in patients after thermal injury.

Pretreatment with arginine preserves intestinal barrier integrity and reduces bacterial translocation in mice

OBJECTIVE

To evaluate the effects of arginine on intestinal barrier integrity and bacterial translocation (BT) in mice undergoing intestinal obstruction.

METHODS

Mice were divided into 3 groups, treated for 7 d before surgical intervention with isocaloric and isoprotein diets. The ARG group received a diet containing 2% arginine, the IO (intestinal obstruction) and Sham groups, standard chow diet. On the eighth day of treatment, all animals received diethylenetriamine pentaacetic acid (DTPA) solution labeled with 99mTechnetium (99mTc-DTPA) by gavage for intestinal permeability analysis. After 90 min, the animals were anesthetized and the terminal ileum ligated. The Sham group only underwent laparotomy. After 4, 8, and 18 h, blood was collected for radioactivity determination. Samples of ileum were collected 18 h after surgery for histological analysis. In another set of animals, BT was evaluated. After 7 d of treatment, all animals received 10(8) CFU/mL of 99mTc-E.coli by gavage; 90 min later they were submitted to the surgical procedure described above. BT was determined by the uptake of 99mTc-E.coli in blood, mesenteric lymph nodes, liver, spleen, and lungs, assessed 18 h after the surgery.

RESULTS

The intestinal permeability and BT were higher in the IO group when compared with the Sham group (P < 0.05). Arginine supplementation reduced intestinal permeability and BT to physiologic levels. Histological analysis showed mucosal ileum preservation in animals treated with arginine.

CONCLUSION

Arginine was able to preserve barrier integrity, thus reducing BT.

Mesenteric microcirculatory dysfunctions and translocation of indigenous bacteria in a rat model of strangulated small bowel obstruction

PURPOSE

Bacterial translocation has been shown to occur in critically ill patients after extensive trauma, shock, sepsis, or thermal injury. The present study investigates mesenteric microcirculatory dysfunctions, the bacterial translocation phenomenon, and hemodynamic/metabolic disturbances in a rat model of intestinal obstruction and ischemia.

METHODS

Anesthetized (pentobarbital 50 mg/kg, i.p.) male Wistar rats (250-350 g) were submitted to intestinal obstruction or laparotomy without intestinal obstruction (Sham) and were evaluated 24 hours later. Bacterial translocation was assessed by bacterial culture of the mesenteric lymph nodes (MLN), liver, spleen, and blood. Leukocyte-endothelial interactions in the mesenteric microcirculation were assessed by intravital microscopy, and P-selectin and intercellular adhesion molecule (ICAM)-1 expressions were quantified by immunohistochemistry. Hematocrit, blood gases, lactate, glucose, white blood cells, serum urea, creatinine, bilirubin, and hepatic enzymes were measured.

RESULTS

About 86% of intestinal obstruction rats presented positive cultures for E. coli in samples of the mesenteric lymph nodes, liver, and spleen, and 57% had positive hemocultures. In comparison to the Sham rats, intestinal obstruction induced neutrophilia and increased the number of rolling (approximately 2-fold), adherent (approximately 5-fold), and migrated leukocytes (approximately 11-fold); this increase was accompanied by an increased expression of P-selectin (approximately 2-fold) and intercellular adhesion molecule-1 (approximately 2-fold) in the mesenteric microcirculation. Intestinal obstruction rats exhibited decreased PaCO2, alkalosis, hyperlactatemia, and hyperglycemia, and increased blood potassium, hepatic enzyme activity, serum urea, creatinine, and bilirubin. A high mortality rate was observed after intestinal obstruction (83% at 72 h vs. 0% in Sham rats).

CONCLUSION

Intestinal obstruction and ischemia in rats is a relevant model for the in vivo study of mesenteric microcirculatory dysfunction and the occurrence of bacterial translocation. This model parallels the events implicated in multiple organ dysfunction (MOD) and death.

The effect of Lactobacillus bacteria supplement on sepsis and its complications in patients with acute burns

Sepsis as a result of bacterial translocation from the gastrointestinal tract (GIT) is a known associate of morbidity and mortality in patients with severe burns. This translocation is influenced by the GIT flora. Oral consumption of Lactobacillus bacteria was previously shown to reduce translocation. We conducted a retrospective cohort study on a series of 56 patients with burns admitted to Soroka University Medical Center in Beer-Sheva, Israel. Those 56 patients included 28 who were given lactobacillus supplements and 28 who were not. The parameters that were compared between the groups evaluated the level of sepsis and its complications. The parameters of morbidity during hospitalization were significantly higher in the treatment group; however, their mortality was lower. That difference in mortality between the groups was not significant as a whole (p=0.071), but it was significant in the subgroup analysis of 41-70% total body surface area burned. In that subgroup there were zero cases of death in the treatment group versus five cases in the control group (p=0.005). Our findings suggest that in acute burns, lactobacillus bacteria food additives may be clinically beneficial in patients with total burned body surface area of 41-70%.

Saccharomyces cerevisiae strain 905 reduces the translocation of Salmonella enterica serotype Typhimurium and stimulates the immune system in gnotobiotic and conventional mice

Previous results in the laboratory of the authors showed that Saccharomyces cerevisiae strain 905, isolated during 'cachaça' production, was able to colonize and survive in the gastrointestinal tract of germ-free and conventional mice, and to protect these animals against oral challenge with Salmonella enterica serotype Typhimurium or Clostridium difficile. In the present work, the effects of S. cerevisiae 905 on the translocation of Salm. Typhimurium (mesenteric lymph nodes, Peyer's patches, spleen, liver) as well as on the immune system (number of Küpffer cells, immunoglobulin production, clearance of Escherichia coli B41) were evaluated in gnotobiotic and/or conventional mice. The treatment with the yeast reduced significantly the translocation of Salm. Typhimurium to liver in gnotobiotic animals and to all the organs tested in conventional mice. The number of Küpffer cells per 100 hepatocytes in liver was significantly higher (P<0.05) in yeast mono-associated mice (52.9+/-15.7) than in germ-free controls (38.1+/-9.0). Probably as a consequence, clearance of E. coli B41 from the bloodstream was more efficient in yeast mono-associated animals when compared to germ-free mice. Higher levels (P<0.05) of secretory IgA in intestinal content and of IgA and IgM in serum were observed in yeast mono-associated mice when compared to germ-free group. Concluding, the protection against pathogenic bacteria observed in a previous study was probably due to a modulation of both local and systemic immunity of mice treated with S. cerevisiae 905.

Effects of various enteral nutrition solutions on bacterial translocation and intestinal morphology during the postoperative period

Bacterial translocation is the passage of bacteria or endotoxins from the gastrointestinal tract to extraintestinal sites, such as mesenteric lymph nodes, liver, spleen, and bloodstream. In this study, the investigators examined the effects of various enteral nutrients on bacterial translocation and intestinal morphology during the postoperative period. Sixty rats were randomly divided into 5 groups, each of which included 12 animals; cecal mobilization was performed in all groups. Group I rats were fed rat chow and water; group II was given standard enteral nutrients; group III, high-energy enteral nutrients; group IV, enteral nutrients supplemented with fiber; and group V, immunonutrients. Bacterial translocation was detected in mesenteric lymph nodes, spleen, liver, and blood cultures. Changes in the terminal ileum were scored from 0 to 4 with the morphologic scoring system. Bacterial translocation was predominantly detected in mesenteric lymph nodes. Rats fed immunonutrients (group V) showed a significant reduction in bacterial translocation compared with other groups. Although minor morphologic alterations in the villi were observed in groups IV and V, the histologic scores of these groups were not statistically different from the scores of control group members. In the present study, investigators evaluated the effects of various enteral nutritional solutions on bacterial translocation and intestinal morphology during the postoperative period. Enteral diets supplemented with arginine, nucleotides, and omega-3 fatty acids were found to reduce bacterial translocation. The investigators concluded that this effect might be related to improvement in immune function resulting from the use of immunonutrients.