Role of intestinal bacterial overgrowth and intestinal motility in bacterial translocation in experimental cirrhosis.

BACKGROUND: Intestinal bacterial overgrowth (IBO) is related to small bowel motility and has been involved in the pathogenesis of bacterial translocation (BT) in experimental models, and both overgrowing gut flora and translocating bacteria to mesenteric lymph nodes are common features in cirrhosis. OBJECTIVES: The aims of this study were to analyze cecal aerobic bacteria and intestinal transit in cirrhotic rats, and their relationship with BT, evaluating the role of intestinal bacterial overgrowth and small bowel dismotility in the development of BT in experimental cirrhosis. MATERIAL AND METHODS: We included twenty-seven male Sprague-Dawley rats with carbon tetrachloride-induced cirrhosis without ascites and ten controls. Cultures of mesenteric lymph nodes (MLN), peripheral and portal blood, liver, spleen and cecal samples were carried out. Small intestinal transit was determined in ten cirrhotic rats and in ten control rats. RESULTS: The prevalence of bacterial translocation was 56%. Total cecal aerobic bacteria count was significantly higher in cirrhotic rats than in control rats (p < 0.001). Cirrhotic rats with translocated bacteria had higher total aerobic intestinal counts than culture-negative MLN bacteria (p < 0.05). The prevalence of total intestinal bacterial overgrowth in cirrhotic animals was 67%, and 0% in control animals (p < 0.001). According to BT, total IBO was more frequent in cirrhotic rats with BT versus those without BT (93 vs. 33%) (p < 0.001). Of the translocating bacteria, 95.6% were found to be overgrown in the cecum. The small-intestinal transit was slower in cirrhotic rats (60.5 +/- 12.7 cm vs. 81.2 +/- 5.7 cm) than in control animals (p < 0.001). CONCLUSIONS: These results suggest that the increase of intestinal aerobic bacteria in experimental cirrhosis is associated with translocation. In addition, IBO is frequent in cirrhotic rats, and is supposed to play an important role in the development of BT. Impaired motility of the small intestine is a common feature in cirrhosis and may be implicated in the pathogenesis of IBO.     

Effect of propranolol on the factors promoting bacterial translocation in cirrhotic rats with ascites

Bacterial translocation appears to be an important mechanism in the pathogenesis of spontaneous infections in cirrhosis. Cirrhotic patients are commonly treated with beta-adrenoceptor blockers, but the impact of this treatment in the factors promoting bacterial translocation has not been investigated. This study was aimed at investigating in cirrhotic rats with ascites the effect of propranolol on intestinal bacterial load, transit, and permeability of the bowel and on the rate of bacterial translocation. Bacterial translocation to mesenteric lymph nodes and intestinal bacterial overgrowth, permeability (urinary excretion of (99m)Tc-diethylenetriaminepentaacetic acid [(99m)Tc-DTPA]), and transit (geometric center ratio of (51)Cr) were assessed in 29 rats with carbon tetrachloride (CCl(4)) cirrhosis and 20 controls. These variables were then measured in 12 placebo- and in 13 propranolol-treated ascitic cirrhotic rats. Bacterial translocation was present in 48% of the cirrhotic rats and in none of the controls. Cirrhotic rats with intestinal bacterial overgrowth had a significantly higher rate of translocation and slower intestinal transit than those without it. Among the 15 rats with overgrowth and a (99m)Tc-DTPA excretion greater than 10%, 15 had translocation and 2 had bacterial peritonitis. Only 1 of the 14 rats with either intestinal overgrowth or a (99m)Tc-DTPA excretion greater than 10% presented translocation. Compared with the placebo group, propranolol-treated animals had significantly lower portal pressure, faster intestinal transit, and lower rates of bacterial overgrowth and translocation. In ascitic cirrhotic rats, bacterial translocation results from intestinal overgrowth and severe damage to gut permeability. In this setting, intestinal overgrowth is associated with intestinal hypomotility. Propranolol accelerates the intestinal transit, decreasing the rates of bacterial overgrowth and translocation.     

Alterations in intestinal motility and microflora in experimental acute pancreatitis

Summary Conclusion A delay in intestinal transit time appears as an early event in acute pancreatitis, preceding intestinal bacterial overgrowth and translocation. Background Septic complications, primarily caused by bacteria of enteric origin, are frequent in severe acute pancreatitis. Impairment in intestinal motility probably plays a pathophysiological role in the development of bacterial overgrowth and ensuing translocation. Methods In the present study, the influence of acute pancreatitis on intestinal motility was evaluated by measuring small intestinal transit time in the rat. Acute pancreatitis was induced by the retrograde intraductal infusion of 0.2 mL taurodeoxycholate. Intestinal transit time was studied by intraduodenal injection of Krebs’ phosphate-buffered solution labeled with Na₂ ⁵¹CrCO₄, and 1 h small intestinal transit was measured at 1, 3, 12, and 24 h, after induction of pancreatitis. Bacterial overgrowth was evaluated by measuringEscherichia coli counts in the colon and distal small intestine, and bacterial translocation to mesenteric lymph nodes, the liver, spleen, and pancreas was determined. Results A delayed small intestinal transit time was noted from 3 h on after induction of acute pancreatitis, with most of the radioactivity retained in the first two intestinal segments. Overgrowth ofE. coli was noted 12 h after induction of pancreatitis in both the colon and distal small intestine, and at the same time-point, a significant increase in the incidence of bacterial translocation to mesenteric lymph nodes was seen.     

Effect of Lactobacillus-fermented diets on bacterial translocation and intestinal flora in experimental prehepatic portal hypertension

Spontaneous bacterial infections in cirrhosis and portal hypertension have been attributed to trans- location of gut-derived bacteria, a process promoted by intestinal bacterial overgrowth and disruption of the gut mucosal barrier. Bacteriotherapy with Lactobacillus has been reported to correct bacterial overgrowth, stabilize mucosal barrier function, and decrease bacterial translocation in rat models of acute liver injury and failure. In this study we investigated the effect of Lactobacillus-supplemented diets on intestinal flora and on bacterial translocation rate in portal vein ligated rats. Lactobacillus-fermented milk (yogurt) containing at least 2 × 10⁹ colony forming units/ml or placebo (water) was adminstrated by gavage twice daily (2 ml) for 9 days. Portal vein ligation was performed on day 7 of treatment. Bacterial translocation to mesenteric lymph nodes and quantification of intestinal flora was assessed by standard bacteriological cultures. Bacterial translocation was not significantly different between animals that received yogurt (82%) and those that received placebo (75%). Yogurt did not induce any significant changes in intestinal flora, whether it was produced with Lactobacillus acidophilus or Lactobacillus GG. In conclusion, in acute prehepatic portal hypertension, bacteriotherapy with Lactobacillus was unable to induce changes in bacterial translocation probably because it was unable to induce changes in bacterial flora.     

Hyperbaric oxygen prevents bacterial translocation in rats with obstructive jaundice

This study was designed to demonstrate bacterial translocation following bile duct ligation and investigate preventive effects of hyperbaric oxygen on obstructive jaundice-related bacterial translocation in an animal model. Hyperbaric oxygen treatment significantly reduced the endogenous colony counts in distal ileum of normal rats both in the short (two days) and long (seven days) term. Endogenous bacteria in distal ileum significantly increased in bile duct ligated rats in the short and long term, and presence of bacterial translocation was proven by bacterial growth in mesenteric lymph nodes, liver, spleen, and blood. Short- and long-term hyperbaric oxygen treatments significantly reduced the intestinal colony counts and prevented the bacterial translocation almost completely in rats with bile duct ligation. It is concluded that obstructive jaundice causes bacterial overgrowth and translocation, and hyperbaric oxygen treatment can prevent both bacterial overgrowth and translocation effectively.     

Failure of Lactobacillus spp. to prevent bacterial translocation in a rat model of experimental cirrhosis

BACKGROUND/AIMS: Prophylaxis of spontaneous bacterial peritonitis in cirrhotic patients with norfloxacin is associated with emergence of quinolone-resistant Enterobacteriaceae. We investigated whether an alternative strategy with Lactobacillus prevents bacterial translocation and ascitic fluid infection in cirrhotic rats. METHODS: CCl(4)-induced cirrhotic rats with ascites (n=34) were allocated to treatment with oral Lactobacillus strain GG at 1-2 x 10(9) cfu/day for 8-10 days (group LGG) or milk (group MILK). In addition, 20 cirrhotic rats were given a single dose of 15 mg norfloxacin orally and then allocated to Lactobacillus (group NOR-LGG) or milk (group NOR-MILK). Ten healthy rats served as control. After sacrifice the cecal flora were analyzed and the prevalence of bacterial translocation and ascitic fluid infection assessed. RESULTS: Cecal colonization with Lactobacillus was achieved in 90% of treated rats. The prevalence of bacterial translocation to mesenteric lymph nodes was 10% in control rats and 93, 84, 70 and 100% in groups MILK, LGG, NOR-MILK and NOR-LGG, respectively (P>0.1 for comparison of treatment groups), the prevalence of ascitic fluid infection was 60, 32, 40 and 40% (P>0.1). Bacterial translocation of Lactobacillus was observed in 24% of rats treated. CONCLUSION: Lactobacilli fail to prevent bacterial translocation and ascitic fluid infection in experimental cirrhosis in spite of successful intestinal colonization.     

Effects of pentoxifylline on intestinal bacterial overgrowth, bacterial translocation and spontaneous bacterial peritonitis in cirrhotic rats with ascites

BackgroundProphylaxis of spontaneous bacterial peritonitis with norfloxacin has been associated to development of antibiotic resistance. We investigated whether pentoxifylline compared to norfloxacin reduces bacterial translocation and spontaneous bacterial peritonitis in rats with CCl₄-induced cirrhosis and ascites.MethodAfter development of cirrhosis and ascites, animals were randomly allocated to receive pentoxifylline (16 mg/kg/d every 8 h, oral route, n = 13) or placebo (n = 12) for 15 days. An additional group of 8 cirrhotic rats was given norfloxacin (5 mg/kg/d for 15 days). Six healthy rats served as controls. Cecal flora and the prevalence of bacterial translocation and spontaneous bacterial peritonitis were analysed. Serum and ascitic fluid levels of TNF-alpha and cecal levels of malondialdehyde were also measured.ResultsPentoxifylline in comparison to placebo reduced intestinal bacterial overgrowth (21% vs. 67%, p = 0.04), bacterial translocation to cecal lymph nodes (23% vs. 75%, p = 0.03) and prevented spontaneous bacterial peritonitis (0% vs. 33%, p = 0.04) by Enterobacteriaceae. Norfloxacin administration induced similar results. Pentoxifylline (0.18 ± 0.10 nmol/mg), but not norfloxacin (0.25 ± 0.13; p = 0.02), significantly reduced cecal mucosal levels of malondialdehyde compared to placebo (0.33 ± 0.16; p = 0.03).ConclusionIn cirrhotic rats with ascites: (a) pentoxifylline as well as norfloxacin reduced intestinal bacterial overgrowth and bacterial translocation and prevented spontaneous bacterial peritonitis; (b) pentoxifylline, but not norfloxacin, reduced oxidative stress in cecal mucosal.     

The effects of sodium deoxycholate, lactulose and glutamine on bacterial translocation in common bile duct ligated rats

BACKGROUND/AIMS: Sepsis is a major cause of post-operative morbidity and mortality in obstructive jaundice as a result of bacterial translocation from the gut. This study was conducted to investigate the effects of glutamine, lactulose, and the bile salt Na deoxycholate in preventing bacterial translocation in an animal model where obstructive jaundice was developed by common bile duct ligation. METHODOLOGY: Fifty Wistar albino rats were divided into 5 groups of 10 animals each. The animals in groups I-IV underwent common bile duct ligation and received, respectively, either saline, Na deoxycholate, lactulose or glutamine, orally. Group V had sham ligation and received saline orally. The animals were sacrificed at the end of the 7th day, and serum concentrations of bilirubin, aspartate aminotransferase (ALT), alanine aminotransferase (ALT), and alkaline phosphatase (AP) were measured. In addition, mesenteric lymph nodes were removed and cultured together with cecal content. Histopathologic examination of terminal ileum specimens was made. RESULTS: Na deoxycholate, lactulose and glutamine all reduced bacterial translocation rates to mesenteric lymph nodes (p<0.05), with glutamine causing the greatest effect. Na deoxycholate and lactulose prevented bacterial translocation by causing a decrease in cecal intraluminal bacterial content (p<0.001), while glutamine exerted its effect by preserving intestinal mucosal integrity. CONCLUSIONS: The integrity of the intestinal mucosal barrier is of paramount importance in preventing bacterial translocation, and the measures taken to protect mucosal integrity reduce bacterial translocation to a greater extent than those taken to decrease the number of bacteria in the gut.     

The effect of interleukin-6 on bacterial translocation in acute canine pancreatitis

Summary Background. Bacterial translocation from the gut to mesenteric lymph nodes and other extraintestinal sites is an important source of infection in acute pancreatitis. Impaired host immunity is known to promote bacterial translocation. Interleukin-6 (IL-6) is a multifunctional cytokine that regulates the immune response, acute phase reaction, and hematopoiesis. Methods. Twenty-four mongrel dogs (18–29 kg) were studied in four equal groups. In Groups I and II, acute pancreatitis was induced by direct pressure injection of 4% taurocholate and trypsin into the pancreatic duct at laparotomy. Groups III and IV had only laparotomy. Group I and III dogs were given IL-6 (50 μg/kg/d, sq) daily starting 24 h after operation and Group II and IV dogs received an equal volume of saline administered at similar time. All animals had blood drawn for culture, complete blood count (CBC), platelets, erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), and amylase on d 0, 1, 4, and 7. On d 7, mesenteric lymph nodes (MLN), spleen, liver, pancreas, and cecum were harvested for pathology study and for cultures of aerobic and anaerobic bacteria. Quantitative cecal cultures of aerobic and anaerobic bacteria were obtained. Results. All Group I and Group II dogs had severe pancreatitis. The increase of plasma CRP in Group I was sustained throughout treatment (1.3±0.3 on d 0 vs 3.1±0.3*, 3.0±0.3*, and 2.9±0.3* and d 1,4, and 7, respectively). Plasma CRP was increased in Group II on d 1 and d 4 (1.3±0.3 mg/dL on d 0 vs 3.6±0.3* mg/dL on d 1, and 3.1±0.3* on d 4, *p<0.05). There were no differences in white blood cell (WBC) count, differential, platelets, and ESR between Groups I and II. Bacterial translocation to MLN was lower in Group I (1/6) than in Group II (6/6) (p<0.05). All 6 dogs in Group II had bacterial spread to distant sites compared to 2 of 6 dogs in Group I (p=0.066). Both MLN and other distant organ cultures were negative in Group III and only 1 of 6 MLN cultures was positive in Group IV. Conclusions. IL-6 treatment decreases bacterial translocation to MLN and may be beneficial in reducing septic complications in acute pancreatitis.     

Gut decontamination prevents bronchoscopy-induced bacterial translocation. An experimental study in rats

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.     

Effect of selective bowel decontamination with norfloxacin on spontaneous bacterial peritonitis,translocation, and survival in an animal model of cirrhosis

Selective bowel decontamination with the orally administered quinolone antibiotic, norfloxacin, has been shown to suppress gut gram-negative bacteria and help prevent gram-negative infections in cirrhotic patients who are at high risk of bacterial infection. Because this drug does not eradicate gram-positive organisms, it is conceivable that gram-positives could replace the suppressed gram-negatives in the gut and lead to subsequent infection. Also the effect of norfloxacin on translocation (as defined by culture positivity of mesenteric lymph nodes) has received little attention. In this study, the effect of oral norfloxacin on translocation, bacterial peritonitis, and survival was investigated in an animal model of carbon tetrachloride—induced cirrhosis and ascites. Treated rats received daily doses of orally administered norfloxacin from the onset of cirrhosis until they died or were killed. Controls received no antibiotic. Norfloxacin led to a reduction in bacterial peritonitis from 70% in untreated cirrhotic controls to 28% in treated cirrhotic rats; these data were statistically significant (P = .012). There was no effect on overall translocation rate (28% with norfloxacin vs. 50% without norfloxacin) (P > .1). Gram-positives were isolated in 100% of the bacterial peritonitis episodes and in 71.4% of culture-positive mesenteric lymph nodes in treated animals compared with only 25% of peritonitis episodes and 10% of culture-positive mesenteric lymph nodes of untreated cirrhotic controls (P < .01 for peritonitis and P < .05 for translocation). The survival rate was not different between groups (P > .1). Although norfloxacin was associated with a 60% reduction in the overall rate of peritonitis, this drug increased the risk of gram-positive translocation and gram-positive peritonitis, and did not prolong survival in this animal model.     

Intestinal mucosal oxidative damage and bacterial translocation in cirrhotic rats

BACKGROUND: Bacterial translocation plays an important role in the pathogenesis of spontaneous bacterial peritonitis mainly due to intestinal bacterial overgrowth. Alterations in the functional integrity of the intestinal barrier caused by an increased production of free radical metabolites as a consequence of portal hypertension could also facilitate bacterial translocation in cirrhotic rats. OBJECTIVE: The aim of the study was to determine intestinal mucosal lipid peroxidation and neutrophil infiltration and their relationship with portal hypertension and bacterial translocation in cirrhotic rats. DESIGN: Eighteen male Sprague-Dawley rats with cirrhosis induced by carbon tetrachloride, administered by gavage, and eight control rats were included in the study. METHODS: Samples of jejunum, ileum and caecum were obtained by laparotomy for the determination of malondialdehyde and myeloperoxidase as indexes of lipid peroxidation and neutrophil infiltration, respectively. Samples of ascitic and pleural fluids, mesenteric lymph nodes and ileal stools were obtained for the culture of microoganisms. RESULTS: The concentration of malondialdehyde was significantly higher in ileal and caecal, but not in jejunal mucosa, in cirrhotic rats, mainly in those with ascites (P< 0.01), as compared to control rats (P< 0.01), and in cirrhotic rats with bacterial translocation compared to those without bacterial translocation (P< 0.01). No differences between groups were observed in the concentrations of myeloperoxidase in jejunum, ileum or caecum. A direct correlation between ileal malondialdehyde and portal pressure was observed (P< 0.01). CONCLUSIONS: Cirrhotic rats, particularly those with ascites and bacterial translocation, show increased malondialdehyde levels in ileal and caecal mucosa. These results suggest that mucosal oxidative damage in ileum and caecum could favour bacterial translocation in cirrhotic rats.     

Bacterial translocation to mesenteric lymph nodes is increased in cirrhotic rats with ascites

Cirrhotic patients are predisposed to develop spontaneous bacteremias and/or peritonitis, mainly caused by enteric bacteria. The aim of this study was to investigate if bacterial translocation, which is the passage of bacteria from the intestinal lumen to regional lymph nodes and/or the systemic circulation, is increased in a rat model of cirrhosis. Rats were studied after 12–16 weeks of CCl₄ inhalation, when samples of mesenteric lymph nodes, blood, liver, and spleen for standard bacteriologic cultures and a fragment of colon and liver for histology were obtained. Immunostaining of the cecum was performed using a polyclonal anti-Escherichia coli antibody. A significantly greater proportion of rats with cirrhosis and ascites (5 of 9; 56%) had positive mesenteric lymph node cultures compared with cirrhotics without ascites (0 of 9) and normal controls (0 of 12) (P < 0.01). In one cirrhotic rat, E. coli was isolated from both mesenteric lymph nodes and ascites. Rats with cirrhosis and ascites had significantly greater cecal submucosal edema and inflammation than rats with no ascites and controls. Immunoreactivity with E. coli was present in the cecal wall in 3 of 5 animals with E. coli translocation to mesenteric lymph nodes. In cirrhotic rats, bacterial translocation is increased after the development of ascites and may be a major factor in the development of spontaneous infections in cirrhosis.     

Hyperbaric oxygen ameliorates bacterial translocation in rats with mechanical intestinal obstruction

PURPOSE: The aim of this study was to demonstrate bacterial translocation after experimentally induced intestinal obstruction as well as investigate the preventive effects of hyperbaric oxygen on obstruction-induced bacterial translocation in rats. METHODS: Forty Wistar-albino male and female rats were used. Although no procedure was done in the control group (n = 8), hyperbaric oxygen treatment under 2.5 atm absolute for 90 minutes daily was applied for two days in the hyperbaric oxygen group (n = 8). In the sham group (n = 8), after laparotomy the small bowel was only handled gently, and tissue sampling was done 48 hours later. In the obstruction group (n = 8) the ileum was ligated by 5-0 polypropylene just 5 cm proximal to the ileocecal valve. In the obstruction and hyperbaric oxygen group (n = 8), after obstruction hyperbaric oxygen treatment was applied. Forty-eight hours after the procedures, tissue samples from small bowel, mesenteric lymph nodes, spleen, and liver were taken and 1 ml of blood from the portal vein was withdrawn. All samples were cultured for microbiologic examination. RESULTS: Hyperbaric oxygen treatment significantly reduced the endogenous bacterial overgrowth in the small intestine of normal rats. Endogenous bacteria in the small intestine were significantly increased in the obstruction group, and the presence of bacterial overgrowth was proven by bacterial presence on mesenteric lymph nodes, spleen, liver, and blood. Hyperbaric oxygen treatment significantly reduced the endogenous bacterial overgrowth in the small intestine and prevented the bacterial translocation almost completely in obstruction-induced rats. CONCLUSIONS: Intestinal obstruction causes bacterial overgrowth and translocation. Hyperbaric oxygen treatment prevents the bacterial translocation effectively.     

Effects of Octreotide on Intestinal Transit and Bacterial Translocation in Conscious Rats with Portal Hypertension and Liver Fibrosis

In cirrhosis, delayed intestinal transit may be responsible for increased endoluminal bacterial overgrowth and increased bacterial translocation. Octreotide has been reported to reduce intestinal transit. Therefore, we evaluated whether octreotide administration influences bacterial translocation in a model of liver fibrosis secondary to dimethylnitrosamine (DMNA) administration. Twenty-nine conscious rats were randomly assigned to three groups (sham rats + placebo as controls, DMNA + placebo, DMNA + octreotide, 1.5 g/kg thrice daily subcutaneously), and including portal pressure, intestinal transit (radioactive method), and bacterial translocation were measured. Three of four variables measuring intestinal transit suggested a significant delay in intestinal transit in DMNA rats compared to controls (eg, cumulated radioactivity 50%: controls: 5.3 ± 1.5, DMNA + placebo: 3.2 ± 1.2, DMNA + octreotide: 2.7 ± 1.9, P < 0.01). This delay tended to be enhanced by octreotide but the effect was only significant with one of the intestinal transit variables. Bacterial translocation was significantly increased in DMNA rats compared to controls but octreotide did not increase translocation [eg, germ count (log) in lymph nodes: controls: 3.1 ± 3.6, DMNA + placebo: 12.3 ± 4.4, DMNA + octreotide: 10.6 ± 6.0, P < 0.001]. There was no significant correlation of portal pressure, intestinal transit, and bacterial translocation in this study. In conclusion, our results show that, although octreotide worsens delayed intestinal transit, it has no influence on the level of bacterial translocation.     

Microbiology of bacterial translocation in humans

Background—Gut translocation of bacteria has beenshown in both animal and human studies. Evidence from animal studiesthat links bacterial translocation to the development of postoperative sepsis and multiple organ failure has yet to be confirmed in humans.
Aims—To examine the spectrum of bacteriainvolved in translocation in surgical patients undergoing laparotomyand to determine the relation between nodal migration of bacteria andthe development of postoperative septic complications.
Methods—Mesenteric lymph nodes (MLN), serosalscrapings, and peripheral blood from 448 surgical patients undergoinglaparotomy were analysed using standard microbiological techniques.
Results—Bacterial translocation was identified in69 patients (15.4%). The most common organism identified wasEscherichia coli (54%). Both enteric bacteria, typical ofindigenous intestinal flora, and non-enteric bacteria were isolated.Postoperative septic complications developed in 104 patients (23%).Enteric organisms were responsible in 74% of patients. Forty one percent of patients who had evidence of bacterial translocation developedsepsis compared with 14% in whom no organisms were cultured(p<0.001). Septic morbidity was more frequent when a greater diversityof bacteria resided within the MLN, but this was not statistically significant.
Conclusion—Bacterial translocation is associatedwith a significant increase in the development of postoperative sepsisin surgical patients. The organisms responsible for septic morbidity are similar in spectrum to those observed in the mesenteric lymph nodes. These data strongly support the gut origin hypothesis of sepsisin humans.

Keywords:bacterial translocation; mesenteric lymph nodes; serosal scrapings; enteric bacteria; postoperative sepsis

     

Intestinal transit and bacterial translocation in obstructive pancreatitis

Pancreatic infection from gut-derived bacteria has emerged as the major cause of death in necrotizing pancreatitis. Bacterial overgrowth of indigenous enteric organisms as a consequence of gut stasis (ileus) represents a potential initial event in this process. The present study was designed to examine the interrelationships between intestinal transit, enteric bacteriology, and the translocation of bacteria from the gut lumen to mesenteric lymph nodes and splanchnic viscera during experimentally induced acute pancreatitis. Male rats underwent pancreaticobiliary duct ligation (PBDL) or sham surgery and were sacrificed after 24, 48, or 96 hr. Severity of pancreatitis was assessed with histology, tissue water content, and amylase and lipase levels. Intestinal transit was measured with fluorescent tracers. Blood, mesenteric lymph nodes (MLNs), splanchnic organs, and gut luminal contents were subjected to bacteriologic analysis. PBDL was followed by biochemical and histologic evidence of progressive pancreatic injury at each time interval. Enteric bacteria within the gut and in adjacent MLNs increased as intestinal transit decreased after PBDL-induced pancreatic inflammation. Surprisingly, all parameters returned to control levels by 96 hr in spite of progression of pancreatic inflammation.     

Effect of cisapride on intestinal bacterial and endotoxin translocation in cirrhosis

AIM: To investigate the effects of cisapride on intestinal bacterial overgrowth (IBO), bacterial and endotoxin translocation, intestinal transit and permeability in cirrhotic rats. METHODS: All animals were assessed with variables including bacterial and endotoxin translocation, intestinal bacterial overgrowth, intestinal transit and permeability. Bacterial translocation (BT) was assessed by bacterial culture of MLN, liver and spleen, IBO by a jejunal bacterial count of the specific organism, intestinal permeability by determination of the 24-hour urinary (99m)Tc-DTPA excretion and intestinal transit by measurement of the distribution of (51)Cr in the intestine. RESULTS: Bacterial translocation (BT) and IBO was found in 48 % and 80 % cirrhotic rats respectively and none in control rats. Urinary excretion of (99m)Tc-DTPA in cirrhotic rats with BT (22.2+/-7.8) was greater than these without BT (10.5+/-2.9). Intestinal transit (geometric center ratio) was significantly delayed in cirrhotic rats (0.31+/-0.06) and further more delayed in cirrhotic rats with BT (0.24+/-0.06) than these without BT (0.38+/-0.11). Cirrhotic rats with IBO had significantly higher rates of intestinal bacterial and endotoxin translocation, slower intestinal transit time and higher intestinal permeability than those without IBO. It was also found that BT was closely associated with IBO and the injury of intestinal barrier. Compared with the placebo group, cisapride-treated rats had lower rates of bacterial/endotoxin translocation and IBO, which was closely associated with increased intestinal transit and improved intestinal permeability by cisapride. CONCLUSION: These results indicate that endotoxin and bacterial translocation in cirrhotic rats may be attributed to IBO and increased intestinal permeability. Cisapride that accelerates intestinal transit and improve intestinal permeability might be helpful in preventing intestinal bacterial and endotoxin translocation.     

Effect of glutamine on the non-steroidal anti-inflammatory drug-induced bacterial translocation]

BACKGROUND/AIMS: NSAIDs induce gut damage throughout the entire gastrointestinal tract and bacterial translocation. The aim of this study was to examine if administration of glutamine was able to prevent the NSAID-induced gut damages and bacterial translocation in the animal models. METHODS: Rats were utilized into 5 groups; control group, diclofenac group, and diclofenac with glutamine 0.8, 1.6, and 3.2 g/kg/day group. The animals with glutamine were fed with L-glutamine for 4 days before diclofenac administration. Gut injury was induced by administration of a single dose of diclofenac (80 mg/kg orally). Intestinal permeability (24 hour urinary excretion of phenolsulfonphthalein), enteric aerobic bacterial counts, serum biochemical profiles and bacterial translocation to mesenteric lymph nodes, liver and spleen were measured. RESULTS: Diclofenac caused the increase in intestinal permeability, enteric bacterial count, enteric protein and albumin loss and bacterial translocation. Administration of glutamine reduced the increase in intestinal permeability, protein losing enteropathy, enteric bacterial overgrowth and bacterial translocation induced by diclofenac. CONCLUSIONS: Glutamine may have beneficial effects on NSAID-induced gut damage and bacterial translocation.