Bacterial translocation in cirrhotic rats. Its role in the development of spontaneous bacterial peritonitis

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 translocation 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 x 10(9) 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.

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 translocation 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 x 10(9) 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.

Lack of portosystemic bacterial translocation in patients with liver cirrhosis after placement of transjugular shunt

The purpose of this study was to clarify whether bacteria are transferred from the portal venous system into central venous blood during the placement of a transjugular portosystemic stent shunt (TIPSS). TIPSS was created in 30 consecutive cirrhotic patients for recurrent variceal bleeding ( n=12), refractory ascites ( n=16), or hepatorenal syndrome ( n=2). Microbiological analysis was performed prospectively on central venous blood before and on portal venous blood immediately after puncture of the portal vein. Twenty minutes after the placement of TIPSS, another sample of central venous blood was obtained. None of the first two sets of blood cultures showed bacterial growth, so that no bacterial transfer was seen at the time of TIPSS placement. Four of the third sets of blood samples showed skin and mouth flora, interpreted as iatrogenic contamination.

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 ^99mTc-DTPA excretion and intestinal transit by measurement of the distribution of ⁵¹Cr 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 ^99mTc-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.

Two cases of spontaneous epidural abscess in patients with cirrhosis

Medical conditions predisposing to epidural abscess include diabetes, intravenous drug use, alcoholism, and other immunocompromised states. Although cirrhosis is associated with an increased risk of infection in general it has not previously been identified as a condition predisposing to epidural abscess. We describe two cirrhotic patients with spinal epidural abscesses. We speculate that the underlying immune defects associated with cirrhosis increase the risk of spontaneous epidural abscess and should raise concern for this infection when cirrhotic patients present with fever and back pain.

Oral bile acids reduce bacterial overgrowth, bacterial translocation, and endotoxemia in cirrhotic rats

Experiments were performed to test whether conjugated bile acid administration would decrease bacterial overgrowth, bacterial translocation, and endotoxemia in ascitic cirrhotic rats. Cholylsarcosine, a deconjugation-dehydroxylation resistant and cholylglycine, a deconjugation-dehydroxylation susceptible bile acid were used. Rats with CCl(4)-induced cirrhosis and ascites were fed cholylsarcosine, cholylglycine (both at 70 mg/kg/d), or placebo for 2 weeks. Healthy rats, as controls, were treated similarly. In cirrhotic rats receiving placebo, bile secretion from an acute biliary fistula was lower than in healthy rats (27.2 +/- 6.5 vs. 53.0 +/- 3.1 microL/kg/min; mean +/- SE, P<.05). The administration of conjugated bile acids to cirrhotic rats normalized bile secretion (cholylsarcosine, 51.8 +/- 6.29; cholylglycine, 52.72 +/- 8.9 microL/kg/min). Total ileal bacterial content was 6-fold higher in ascitic cirrhotic rats than in healthy rats. Conjugated bile acid administration reduced bacterial content to normal levels. Bacterial translocation was less in cirrhotic animals receiving conjugated bile acids (cholylsarcosine, 33%; cholylglycine, 26%) than in animals receiving placebo (66%). Endotoxemia was decreased in cirrhotic rats by conjugated bile acid feeding (cholylsarcosine, 0.098 +/- 0.002; cholylglycine 0.101 +/- 0.007 EU/mL) compared with placebo (0.282 +/- 0.124, P <.001). Survival was greater in animals receiving conjugated bile acids (cholylsarcosine, 10/15; cholylglycine, 11/15; placebo, 5/15). In conclusion, the administration of conjugated bile acids to ascitic cirrhotic rats increased bile acid secretion, eliminated intestinal bacterial overgrowth, decreased bacterial translocation, decreased endotoxemia, and increased survival. Oral conjugated bile acids may be useful in preventing bacterial translocation, endotoxemia, and spontaneous bacterial perotonitis in cirrhotic patients.

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.

Effect of Lactobacillus johnsonii La1 and antioxidants on intestinal flora and bacterial translocation in rats with experimental cirrhosis

BACKGROUND/AIMS

Probiotics and antioxidants could be alternatives to antibiotics in the prevention of bacterial infections in cirrhosis. The aim of the present study was to determine the effect of Lactobacillus johnsonii La1 and antioxidants on intestinal flora, endotoxemia, and bacterial translocation in cirrhotic rats.

METHODS

Twenty-nine Sprague-Dawley rats with cirrhosis induced by CCl(4) and ascites received Lactobacillus johnsonii La1 10(9)cfu/day in vehicle (antioxidants: vitamin C+glutamate) (n=10), vehicle alone (n=11), or water (n=8) by gavage. Another eight non-cirrhotic rats formed the control group. After 10 days of treatment, a laparotomy was performed to determine microbiological study of ileal and cecal feces, bacterial translocation, endotoxemia, and intestinal malondialdehyde (MDA) levels as index of intestinal oxidative damage.

RESULTS

Intestinal enterobacteria and enterococci, bacterial translocation (0/11 and 0/10 vs. 5/8, P<0.01), and ileal MDA levels (P<0.01) were lower in cirrhotic rats treated with antioxidants alone or in combination with Lactobacillus johnsonii La1 compared to cirrhotic rats receiving water. Only rats treated with antioxidants and Lactobacillus johnsonii La1 showed a decrease in endotoxemia with respect to cirrhotic rats receiving water (P<0.05).

CONCLUSIONS

Antioxidants alone or in combination with Lactobacillus johnsonii La1 can be useful in preventing bacterial translocation in cirrhosis.

Detection and identification of bacterial DNA in patients with cirrhosis and culture-negative, nonneutrocytic ascites

The current pathogenic theory of spontaneous bacterial peritonitis (SBP) in patients with cirrhosis and ascites suggests that repeated episodes of bacterial translocation (BT) from intestinal lumen to mesenteric lymph nodes followed by systemic seeding are the key steps for the final development of infectious events. However, most of the episodes of systemic bacterial circulation remain undetected. Therefore, we investigated the hypothetical presence of bacteria in blood and/or ascitic fluid (AF) from patients with cirrhosis and sterile (culture negative) AF by means of bacterial DNA (bactDNA) detection and identification. Twenty-eight consecutively admitted patients with cirrhosis and presence of AF were included in the study. BactDNA was detected using a polymerase chain reaction (PCR)-based method. The corresponding bacteria were identified by nucleotide sequencing of purified PCR products. BactDNA was detected simultaneously in blood and AF in 9 patients (32.1%). DNA sequencing allowed the identification of Escherichia coli (n = 7) and Staphylococcus aureus (n = 2). In all cases, the similarity between the sequence found in AF and blood indicated that the bactDNA present in both locations originated from a single clone (single translocation event). Child-Pugh score and basic hemodynamic, clinical, endoscopic, and biochemical characteristics were similar among patients with or without the presence of bactDNA. In conclusion, we have detected bactDNA in serum and AF in 32% of all patients studied, and this likely represents single clone episodes of translocation and systemic seeding. E. coli is the most frequently identified bacteria.

Why do bacteria reach ascitic fluid?

Spontaneous bacterial peritonitis (SBP) is the most common and serious infection that develops in cirrhotic patients. Translocation of bacteria from their intestinal origin, alterations in immune defence mechanisms and deficiencies in the ascitic fluid antimicrobial activity seem to represent the main steps in the pathogenesis of SBP in cirrhosis. Among the factors determining the development of bacterial translocation, intestinal bacterial overgrowth (mainly related to decreased intestinal motility) and changes in the intestinal barrier appear to play an outstanding role. In conclusion, greater understanding of the pathogenesis of SBP will allow better identification of patients at high risk of developing this complication and contribute to the search for new strategies for its prevention.

Review article: spontaneous bacterial peritonitis--diagnosis, treatment and prevention

Spontaneous bacterial peritonitis is a serious complication of cirrhotic ascites, arising most frequently in those with advanced liver disease. Its development leads to a further reduction in the effective arterial blood volume, and it has a mortality rate equivalent to that of a variceal bleed. However, problems remain with regard to the identification and optimal treatment of spontaneous bacterial peritonitis. Several important studies and consensus documents on the condition have recently been published which aid in the identification of patients at risk and help to guide therapy. In this review, we discuss these publications and address the issues of diagnosis, treatment and both primary and secondary prophylaxis of spontaneous bacterial peritonitis in the light of recent data.

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 microg/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.

Intestinal dysfunction in liver cirrhosis: Its role in spontaneous bacterial peritonitis

Spontaneous bacterial peritonitis is a common illness in patients with cirrhosis and ascites that occurs without any apparent focus of infection. Bacterial translocation plays an important role in spontaneous bacterial peritonitis and it is evident from a variety of studies that the gut is a major source of this bacteria. Gut motility alterations, along with bacterial overgrowth and changes in intestinal permeability, probably play a role in this bacterial translocation. The present review looks at the role of the intestine in spontaneous bacterial peritonitis induced by liver cirrhosis and the factors influencing bacterial translocation in this disease.

Time course of spontaneous bacterial translocation from gastrointestinal tract and its relationship to intestinal microflora in conventionally reared infant rats

Whereas the developed gut mucosal barrier prevents luminal bacteria from invading the host, bacterial translocation appears to be facilitated in the neonate. The aim of this study was to determine the extent to which bacteria spontaneously translocate from the gut to extraintestinal organs during the neonatal period and to relate translocation to the evolving intestinal flora in the rat. Newborn Sprague-Dawley rats suckled ad libitum and ate regular chow after weaning. A total of 167 rats were killed either immediately or at 1, 9, 14, 21, 26, or 42 days after delivery. Mesenteric lymph nodes (MLN), liver, heart blood, and the terminal ileal loop were harvested under sterile conditions and analyzed for aerobic and facultatively anaerobic bacteria by standard microbiologic procedures. Bacterial translocation to the MLN and liver began soon after birth and peaked during the second week. On day 14, translocation to any organ was present in 85% of rats. All cultures from the liver were sterile after day 26. By contrast, the fall in translocation to the MLN was incomplete, as 50% of pups still had positive MLN on day 42. Blood cultures were positive in three of the 167 rats. The intensity of translocation as determined by the number of organs infected significantly increased with the number of gram-negative enterics and gram-positive cocci in the gut and was negatively correlated with the percentage of lactobacilli from the total measured intestinal flora (P < 0.0001). In conclusion, bacterial translocation from the gut is a physiological and age-dependent phenomenon in the neonatal rat. Translocation appears to be facilitated when intestinal concentrations of gram-negative enterics and gram-positive cocci are high and when the concentration of lactobacilli is low.

Spontaneous fungal peritonitis (Candida glabrata) in a patient with cirrhosis

We report a case of spontaneous fungal peritonitis in a patient with cirrhosis. A 70-year-old woman with cirrhosis secondary to autoimmune hepatitis was admitted with fever and abdominal distention. Paracentesis revealed neutrocytosis, and despite appropriate antibacterial coverage, no clinical improvement was noted and the ascitic fluid white cell count increased on repeat paracentesis. Two consecutive ascitic fluid cultures grew Candida glabrata, and antifungal therapy with amphotericin was initiated, pending sensitivity of the isolate. Because of worsening renal function, amphotericin was discontinued and itraconazole was started, as sensitivity of the isolate was then available. Antifungal therapy resulted in resolution of ascitic fluid neutrocytosis and culture negativity. However, the patient's renal function continued to deteriorate, necessitating hemodialysis. Despite multiple courses of antibiotics, she died of fulminant sepsis and multiorgan failure.

Bacterial translocation of enteric organisms in patients with cirrhosis

BACKGROUND/AIMS

The aim of the study was to investigate the prevalence and associated risk factors for bacterial translocation in patients with cirrhosis, a mechanism involved in the pathogenesis of bacterial infections in experimental cirrhosis.

METHODS

Mesenteric lymph nodes were obtained for microbiological culture from 101 patients with cirrhosis and from 35 non-cirrhotic patients.

RESULTS

Enteric organisms were grown from mesenteric lymph nodes in 8.6% of non-cirrhotic patients. In the 79 cirrhotic patients without selective intestinal decontamination, the prevalence of bacterial translocation significantly increased according to the Child-Pugh classification: 3.4% in Child A, 8.1% in Child B and 30.8% in Child C patients (chi2 = 6.106, P < 0.05). However, translocation by Enterobacteriaceae, the organisms commonly responsible for spontaneous bacteremia and peritonitis in cirrhosis, was only observed in 25% of the cases. The prevalence of bacterial translocation in the 22 cirrhotic patients undergoing selective intestinal decontamination, all Child-Pugh class B and C, was 4.5%. The Child-Pugh score was the only independent predictive factor for bacterial translocation (odds ratio 2.22, P = 0.02).

CONCLUSIONS

Translocation of enteric organisms to mesenteric lymph nodes is increased in patients with advanced cirrhosis and is reduced to the level found in non-cirrhotic patients by selective intestinal decontamination.

Diagnosis, treatment and prevention of spontaneous bacterial peritonitis

Spontaneous bacterial peritonitis (SBP) is a frequent complication in cirrhotic patients with ascites. Diagnosis of SBP is established by a polymorphonuclear cell count in ascitic fluid > or =250 cells/mm(3). The organism responsible for the infection is isolated in 60-70% of the cases. The remaining cases are considered to have a variant of SBP (culture-negative SBP) and are treated in the same way as those with a positive culture. The SBP resolution rate ranges between 70 and 90%, and hospital survival between 50 and 70%. An early diagnosis and the use of a more adequate antibiotic therapy are the most probable reasons for the improvement in prognosis for SBP in recent decades. Despite the resolution of the infection, SBP may trigger severe complications such as renal impairment, gastrointestinal bleeding and accentuation of hepatic insufficiency which are responsible for the associated mortality. Patients recovering from an episode of SBP should be considered as potential candidates for liver transplantation.

Short- and long-term outcome of severe alcohol-induced hepatitis treated with steroids or enteral nutrition: a multicenter randomized trial

Steroids are recommended in severe alcohol-induced hepatitis, but some data suggest that artificial nutrition could also be effective. We conducted a randomized trial comparing the short- and long-term effects of total enteral nutrition or steroids in these patients. A total of 71 patients (80% cirrhotic) were randomized to receive 40 mg/d prednisolone (n = 36) or enteral tube feeding (2,000 kcal/d) for 28 days (n = 35), and were followed for 1 year or until death. Side effects of treatment occurred in 5 patients on steroids and 10 on enteral nutrition (not significant). Eight enterally fed patients were prematurely withdrawn from the trial. Mortality during treatment was similar in both groups (9 of 36 vs. 11 of 35, intention-to-treat) but occurred earlier with enteral feeding (median 7 vs. 23 days; P =.025). Mortality during follow-up was higher with steroids (10 of 27 vs. 2 of 24 intention-to-treat; P =. 04). Seven steroid patients died within the first 1.5 months of follow-up. In contrast to total enteral nutrition (TEN), infections accounted for 9 of 10 follow-up deaths in the steroid group. In conclusion, enteral feeding does not seem to be worse than steroids in the short-term treatment of severe alcohol-induced hepatitis, although death occurs earlier with enteral nutrition. However, steroid therapy is associated with a higher mortality rate in the immediate weeks after treatment, mainly because of infections. A possible synergistic effect of both treatments should be investigated.

Effect of cisapride on intestinal bacterial overgrowth and bacterial translocation in cirrhosis

Deranged intestinal motility, which occurs in cirrhosis, may facilitate the development of intestinal bacterial overgrowth (IBO), which can lead to bacterial translocation (BT). To assess the effect of cisapride on IBO and BT in cirrhosis, cirrhotic rats received cisapride or a placebo for 7 days, and measurements of jejunal bacterial content and BT studies were performed. In addition, jejunal fluid from 46 cirrhotic patients was obtained for quantitative bacterial culture. Those patients in whom gram-negative IBO was detected were randomized to receive or not to receive cisapride (20 mg twice per day) for 1 week. Cisapride significantly reduced IBO in cirrhotic rats. In addition, no BT was documented in treated animals, whereas it occurred in 40% in nontreated cirrhotic rats. Total IBO was documented in 23 of 46 cirrhotic patients, which was caused by gram-negative organisms in 10 cases. Orocecal transit time (OCT) significantly decreased after cisapride therapy, and was associated with the abolishment of bacterial overgrowth caused by gram-negative organisms in 4 out of 5 treated patients, whereas it persisted in nontreated cases. Cisapride administration to cirrhotic rats resulted in a reduction of the IBO, which is associated with a marked decrease in BT. On the other hand, cisapride facilitates the abolition of IBO caused by gram-negative organisms in cirrhotic patients.

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.

A tungsten supplemented diet attenuates bacterial translocation in chronic portal hypertensive and cholestatic rats: role of xanthine dehydrogenase and xanthine oxidase

BACKGROUND

Bacterial translocation (BT) plays a major role in the pathophysiological process of spontaneous infections in portal hypertension (PH) and cholestatic jaundice. The major mechanisms promoting BT in experimental animal models are the disruption of the intestinal ecological equilibrium and disruption of the intestinal mucosal barrier. The enzymes xanthine dehydrogenase (XD) and xanthine oxidase (XO) are often implicated as a significant source of oxidants which have a major impact on the impairment of intestinal barrier function.

AIM

To investigate the incidence of BT in rats with PH and obstructive jaundice, and to evaluate the impact of XD and XO.

METHODS

Animals were subjected to sham laparotomy (SL), PH by calibrated stenosis of the portal vein, and common bile duct ligation (CBDL). They were fed either a standard pellet diet or a tungsten supplemented molybdenum-free diet. Four weeks after the operative procedure, intestinal colonisation and BT to portal vein, vena cava, mesenteric lymph nodes, liver, and spleen were determined. Intestinal XD and XO activity were measured enzymatically and histochemically.

RESULTS

Significant (p<0.01) intestinal bacterial overgrowth was present in all PH and CBDL groups compared with the SL group. In normally fed animals after SL, BT occurred in 12%. In PH and after CBDL, the rate of BT increased significantly (p<0.05) to 28% and 54% respectively. In the jejunum of normally fed animals subjected to PH or CBDL, a significant increase in XO was observed (p<0.01). Animals fed a tungsten supplemented diet showed a significant attenuation of BT to 14% in PH and 22% after CBDL (p<0. 05). Tungsten treatment completely suppressed jejunal XD and XO activities.

CONCLUSIONS

Significant intestinal bacterial overgrowth, BT, and XD to XO conversion occurred in PH and after CBDL. XD and XO inactivation by a tungsten supplemented molybdenum-free diet significantly reduced the incidence of BT without affecting intestinal bacterial overgrowth. These data strongly support the hypothesis that increased XD to XO conversion may contribute to intestinal barrier failure in PH and after CBDL.

Bacterial translocation in cirrhotic rats stimulates eNOS-derived NO production and impairs mesenteric vascular contractility

Nitric oxide (NO) has been implicated in the arterial vasodilation and associated vascular hyporesponsiveness to vasoconstrictors observed in liver cirrhosis. Bacteria, potent activators of NO and TNF-alpha synthesis, are found in the mesenteric lymph nodes (MLNs) of ascitic cirrhotic rats. Here, we investigated the impact of bacterial translocation (BT) to MLNs on TNF-alpha production, vascular NO release, and contractility in the mesenteric vasculature of ascitic cirrhotic rats. Vascular response to the alpha-adrenoagonist methoxamine, which is diminished in the superior mesenteric arterial beds of cirrhotic rats, is further blunted in the presence of BT. BT promoted vascular NO release in cirrhotic rats, an effect that depended on pressure-induced shear stress and was blocked by the NO inhibitor N(omega)-nitro-L-arginine. Removing the endothelium had the same effect. Endothelial NO synthase (eNOS), but not the inducible isoform (iNOS), was present in mesenteric vasculature of cirrhotic rats with and without BT, and its expression was enhanced compared with controls. TNF-alpha was induced in MLNs by BT and accumulated in parallel in the serum. This TNF-alpha production was associated with elevated levels of tetrahydrobiopterin (BH(4)), a TNF-alpha-stimulated cofactor and enhancer of eNOS-derived NO biosynthesis and NOS activity in mesenteric vasculature. These findings establish a link between BT to MLNs and increased TNF-alpha production and elevated BH(4) levels enhancing eNOS-derived NO overproduction, further impairing contractility in the cirrhotic mesenteric vasculature.

Granulocyte elastase in cirrhotic patients with spontaneous bacterial peritonitis

Granulocyte elastase (GE) is a powerful proteolytic enzyme that is released by PMNs when degranulated in infectious processes. The aim of this study was to measure GE in ascites and plasma of cirrhotic patients with spontaneous bacterial peritonitis (SBP). We studied 29 cirrhotic patients, 17 of them having SBP (group A). Twelve patients with noninfected ascites formed the control group (group B). At the time of diagnosis of SBP, GE levels in ascites (183.17 +/- 86.11 microg/liter) and plasma (114.6 +/- 35.99 microg/liter) were higher in group A than in group B (27.41 +/- 11.54 microg/liter, P < 0.00001 and 82.54 +/- 20.52 microg/liter, P = 0.01, respectively). Levels of GE in ascites had a high value for discriminating between patients with and without SBP. In the patients who responded to the initial antibiotic treatment, these values significantly decreased in ascites (67.69 +/- 54.22 microg/liter, P = 0.003) and plasma (67 +/- 22.39 microg/liter, P = 0.01) 48 hr after therapy was started, in parallel with the decrease of PMN in ascites. In patients who did not respond, the production of GE remained elevated. Patients who developed renal insufficiency following SBP had more marked elevation of GE in plasma (144.8 +/- 33.43 microg/liter) than those with normal renal function (99.5 +/- 27.53 microg/liter, P = 0.02). These results suggest that the measurement of GE may be helpful for the diagnosis of SBP in patients with cirrhosis and for assessing the efficacy of therapy. In addition, the release of GE into plasma may contribute to the impairment of renal function that follows SBP in some patients.

Effect of long-term trimethoprim-sulfamethoxazole prophylaxis on ascites formation, bacterial translocation, spontaneous bacterial peritonitis, and survival in cirrhotic rats

Selective intestinal decontamination with norfloxacin is useful in preventing spontaneous bacterial peritonitis in cirrhotic patients and also in cirrhotic rats. The emergence of norfloxacin-resistant infections in these patients warrants a search for alternative therapies. The aim of this study was to evaluate the effect of long-term trimethoprim-sulfamethoxazole administration on carbon tetrachloride (CCl4) -induced cirrhosis in rats with specific attention to intestinal flora, bacterial translocation, spontaneous bacterial peritonitis (SBP), and survival. Male Sprague-Dawley rats received CCl4 administered weekly by gavage. After eight weeks of CCl4 administration rats were randomly allocated into two groups. Group I received daily overnight trimethoprim-sulfamethoxazole diluted in phenobarbital water during follow-up and group II did not. The rats were killed when gravely ill, and a laparotomy was performed to culture samples of cecal stool, mesenteric lymph nodes, and portal and inferior vena caval blood. There was a trend toward a reduction in the incidence of bacterial translocation (8/17 vs 11/14, respectively) and SBP (5/17 vs 7/14, respectively) in treated rats that were killed just before death compared to untreated rats. A decrease in the incidence of bacterial translocation caused by gram-negative bacilli was observed in group I (17.6% vs 78.6%, P < 0.01). The development of ascites was delayed in group I (P < 0.05) and survival was prolonged in group I (P < 0.05), despite a higher CCl4 dose in this group (P < 0.05). In conclusion, long-term prophylactic trimethoprim-sulfamethoxazole administration in CCl4-induced cirrhosis in rats delayed the development of ascites, prolonged survival, and reduced the incidence of gram-negative bacterial translocation but not of SBP, without increasing gram-positive episodes. These data suggest that trimethoprim-sulfamethoxazole might be a good alternative to norfloxacin for preventing gram-negative bacterial translocation.

Nutritional support in alcoholic cirrhotic patients improves host defenses

BACKGROUND

Malnutrition is usual in patients with alcoholic liver disease and is associated with a poor outcome. Nutritional support decreases nutrition-associated complications.

AIM

To demonstrate that nutritional support in ambulatory alcoholic cirrhotic patients improves host defenses.

METHODS

Thirty-one male outpatients with alcoholic cirrhosis CHILD-PUGH B or C were included. Twenty-five subjects completed six months consuming daily a nutritional supplement (Ensure, 1000 Kcal and 35 g protein), in addition to their regular diet. At entrance and every three months, a clinical assessment, nutritional evaluation and indirect calorimetry were performed. Liver function tests and LPS-induced monocyte production of cytokines, salivary secretory IgA, lactulose/mannitol ratio and breath hydrogen tests were also measured in these intervals. Delayed cutaneous hypersensitivity and IgG and IgM antibody response to endotoxin were assessed at entrance and at the end of the study.

RESULTS

Patients drank 85% of the provided supplement as an average. REE, total body fat and serum albumin increased, basal breath hydrogen decreased and cellular immunity improved significantly during the follow up period (p< or =0.03). All the other parameters remained unchanged throughout the study. Six patients (16.2%) died during the study, five due to upper gastrointestinal bleeding.

CONCLUSION

Nutritional support in alcoholic cirrhotic patients improves nutritional status and cell mediated immunity.

Infections caused by Escherichia coli resistant to norfloxacin in hospitalized cirrhotic patients

Selective intestinal decontamination with norfloxacin is useful to prevent bacterial infections in several groups of cirrhotic patients at high risk of infection. However, the emergence of infections caused by Escherichia coli resistant to quinolones has recently been observed in cirrhotic patients undergoing prophylactic norfloxacin. Our aim is to determine the characteristics of the infections caused by E. coli resistant to norfloxacin in hospitalized cirrhotic patients. One hundred and six infections caused by E. coli in 99 hospitalized cirrhotic patients were analyzed and distributed into two groups: group I (n = 67), infections caused by E. coli sensitive to norfloxacin, and group II (n = 39), infections caused by E. coli resistant to norfloxacin. The clinical and analytical characteristics at diagnosis of the infection were similar in both groups. Previous prophylaxis with norfloxacin was more frequent in group II (15/67, 22.4% vs. 32/39, 82%, P <.0001), as a result of a higher number of patients submitted to continuous long-term prophylaxis in this group, whereas previous short-term prophylaxis was similar in both groups. Infections were more frequently nosocomial-acquired in group II than in group I (17/67, 25.3% vs. 20/39, 51.2%, P =.01). The type of infections was similar in both groups: urinary tract infections 38 in group I and 24 in group II, spontaneous bacterial peritonitis 8 and 2, spontaneous bacteremia 4 and 4, and bacterascites 1 and 0, respectively (pNS). Mortality during hospitalization was similar in the two groups (4/67, 5.9% vs. 5/39, 12.8%, pNS). None of the E. coli resistant to norfloxacin were also resistant to cefotaxime and only one of them was resistant to amoxicillin-clavulanic acid. Prophylaxis with norfloxacin, usually continuous long-term prophylaxis, favors the development of infections caused by norfloxacin-resistant E. coli. Long-term antibiotic prophylaxis should therefore be restricted to highly selected groups of cirrhotic patients at high-risk of infection. Infections caused by E. coli resistant to norfloxacin show a severity similar to those caused by sensitive E. coli. No significant associated resistance between norfloxacin and the antibiotics most frequently used in the treatment of bacterial infections in cirrhotic patients has been observed.

A cost analysis of long term antibiotic prophylaxis for spontaneous bacterial peritonitis in cirrhosis

OBJECTIVE

The aim of this study was to perform a cost analysis of different strategies of long term antibiotic prophylaxis for spontaneous bacterial peritonitis (SBP) in patients with cirrhosis and ascites. The study involved a cost analysis using a decision analysis model and patients with cirrhosis and ascites who are at risk for developing SBP.

METHODS

Two different strategies of antibiotic prophylaxis were compared with a "no prophylaxis" strategy in patients with cirrhosis and ascites using a decision analysis model. In strategy I, antibiotic prophylaxis was administered in all patients with cirrhosis and ascites and in strategy II, patients were stratified into a low risk and a high risk group on the basis of serum bilirubin and ascitic fluid protein levels; only patients in the high risk group received antibiotic prophylaxis. The cost per patient treated for 1 yr was the outcome measure compared in the different strategies. Clinical input probabilities and ranges used were obtained by searching the MEDLINE database for English language articles. Cost estimates were obtained from a university hospital setting. Cost analysis was done with a societal perspective, and only direct costs were taken into account. Sensitivity analyses were performed to evaluate the effect of variations in the key clinical probabilities and cost estimates ranging from a best case to a worst case scenario on the outcome measure.

RESULTS

The estimated cost per patient treated in strategy I, strategy II, and strategy III (the strategy of "no prophylaxis") were $1311, $1123, and $3509, respectively. Over a broad range of clinical and cost variables, the strategy of risk stratification and restriction of antibiotic prophylaxis to the subgroup of patients with cirrhosis and ascites who were at high risk for SBP (as identified by serum bilirubin >2.5 mg/dl and ascitic fluid protein <1 g/dl) was the most favored strategy. However, when the cost of prophylaxis was low or the probability of a primary episode of SBP was at the lower end of the range reported in the literature, administering antibiotic prophylaxis to all patients with cirrhosis and ascites was the least costly strategy.

CONCLUSION

This cost analysis indicates that antibiotic prophylaxis particularly when restricted to a subgroup of patients who, by simple laboratory parameters, are identified to be at high risk for SBP, is very cost-effective in the prevention of SBP in patients with cirrhosis and ascites.

Translocated intestinal bacteria cause spontaneous bacterial peritonitis in cirrhotic rats: molecular epidemiologic evidence

BACKGROUND/AIMS

Intestinal bacterial translocation is common in cirrhotic rats with spontaneous bacterial peritonitis, and it is thought to play a major pathogenic role. There has so far been no evidence for clonality between bacteria isolated from intestine and ascites. This study aimed to use molecular epidemiology techniques to show that spontaneous bacterial peritonitis is due to translocated intestinal bacteria.

METHODS

Samples of ascitic fluid, portal blood, mesenteric lymph nodes and ileal contents from healthy (n=10) and ascitic cirrhotic rats with (n=12) or without (n=15) spontaneous bacterial peritonitis were cultured. In six infected rats, DNA macrorestriction fragments of 30 bacterial isolates [Escherichia coli (n=13), Enterococcus faecalis (n=12) and Proteus mirabilis (n=5)] from ascites (n=8), mesenteric lymph nodes (n=7), portal blood (n=6), and ileal flora (n=9) were compared.

RESULTS

Bacterial translocation was more frequent in animals with (58%) than in those without spontaneous bacterial peritonitis (20%, p=0.049) or controls (10%, p=0.026). The same bacterial strain was simultaneously isolated in ascites and in mesenteric lymph nodes and/or ileum in 7/8 (87%) instances. The identity rate for bacteria present in both ascites and mesenteric lymph nodes was 80% (4/5). Likewise, identity was demonstrated in 3/4 instances of bacteria found in both ascites and portal blood.

CONCLUSIONS

These results indicate that spontaneous bacterial peritonitis in cirrhotic rats is mainly due to intestinal bacteria translocated to mesenteric lymph nodes. Portal blood could be a less frequent route.

Intestinal bacterial overgrowth and bacterial translocation in cirrhotic rats with ascites

BACKGROUND/AIMS

Translocation of indigenous bacteria from the gut lumen of cirrhotic animals to mesenteric lymph nodes appears to be an important step in the pathogenesis of spontaneous bacterial peritonitis. However, the sequence of events leading to translocation remains unclear. One of the most predictable risk factors for translocation is overgrowth of gut bacterial flora. The present study was designed to compare the intestinal aerobic bacterial flora of cecal stools at the time of sacrifice between cirrhotic and normal rats and to evaluate the role of intestinal aerobic bacterial overgrowth in bacterial translocation in cirrhotic rats.

METHODS

Thirty-five male Sprague-Dawley rats with carbon tetrachloride-induced cirrhosis and ascites and 10 normal rats were included in this study. Cirrhotic rats were sacrificed when ill and samples of ascitic fluid, mesenteric lymph nodes and cecal stool were taken for detecting quantitatively aerobic bacteria.

RESULTS

Total intestinal aerobic bacterial count in cecal stool at the time of sacrifice was significantly increased in cirrhotic rats with bacterial translocation with or without spontaneous bacterial peritonitis compared to cirrhotic rats without bacterial translocation (p<0.001 and p<0.001, respectively) and to normal rats (p<0.001 and p<0.001, respectively). Of the 42 species of bacteria translocating to the mesenteric lymph nodes, 41 (97.6%) were found in supranormal numbers in the stool at the time of sacrifice.

CONCLUSIONS

Carbon tetrachloride-induced cirrhotic rats with bacterial translocation have increased total intestinal aerobic bacteria count, and intestinal bacterial overgrowth appears to play an important role in bacterial translocation in this experimental model of cirrhosis in rats.

Pathophysiology, complications, and treatment of ascites

In the past few years, there have been important advances in the field of pathogenesis and management of ascites and spontaneous bacterial peritonitis in cirrhosis. A new pathogenic theory of ascites and renal dysfunction in cirrhosis has been presented, and previously ill-defined conditions, such as refractory ascites and hepatorenal syndrome, have been defined precisely. The reintroduction of therapeutic paracentesis has modified markedly the way in which patients hospitalized for ascites are treated. The use of potent and safe antibiotics has improved the resolution rate and survival of patients with spontaneous bacterial peritonitis, and the use of oral antibiotics will simplify the management of this condition in the near future. Finally, prophylactic antibiotic regimens represent a major step forward in the prevention of spontaneous bacterial peritonitis in subsets of cirrhotic patients with a great risk of developing this complication.

Insulin-like growth factor 1 has beneficial effects, whereas growth hormone has limited effects on postoperative protein metabolism, gut integrity, and splenic weight in rats with chronic mild liver injury

BACKGROUND

Both growth hormone (GH) and insulin-like growth factor 1 (IGF-1) improve protein metabolism after surgical insult in subjects without liver disease. However, these effects in chronic liver injury, in which the GH-IGF-1 axis is impaired, have not been investigated. We examined the anabolic effects of GH and IGF-1 after gastrectomy in rats with chronic mild liver injury.

METHODS

Rats with chronic mild liver injury induced by thioacetamide were used. After gastrectomy, the rats were randomized into vehicle control, GH, and IGF-1 groups. In the latter two groups, 0.8 IU/kg/d of GH or 4 mg/kg/d of IGF-1 was infused for 72 hours. Anabolic effects were assessed by body weight change, 3-methylhistidine (3-MH) excretion, nitrogen excretion, and whole-body protein turnover. Organ weights, plasma levels of glucose, insulin, and IGF-1, tissue IGF-1 levels, hepatic messenger RNA (mRNA) content, and intestinal structure were also determined.

RESULTS

Both GH and IGF-1 decreased nitrogen excretion. IGF-1, but not GH, increased postoperative body weight, whole-body protein turnover, and splenic weight. IGF-1 reduced atrophy of the intestinal mucosa. GH treatment increased hepatic IGF-1-mRNA and the plasma IGF-1 level, whereas IGF-1 treatment increased the plasma IGF-1 level with no change in the hepatic IGF-1-mRNA content. There were no significant differences in plasma glucose or insulin levels among the three groups. Neither GH nor IGF-1 affected the gastrocnemius muscle IGF-1 level.

CONCLUSIONS

IGF-1 has beneficial effects, whereas GH has only limited effects on post-operative protein metabolism, gut integrity, and splenic weight in chronic mild liver injury.

Spontaneous bacterial peritonitis in patients with cirrhosis undergoing selective intestinal decontamination. A retrospective study of 229 spontaneous bacterial peritonitis episodes

BACKGROUND/AIMS

Selective intestinal decontamination with norfloxacin is widely used to prevent spontaneous bacterial infections in cirrhosis. The study was performed to compare the spontaneous bacterial peritonitis occurring in patients with and without prophylactic norfloxacin.

METHODS

Two hundred and twenty-nine consecutive episodes of spontaneous bacterial peritonitis, (193 in patients without (Group A) and 36 in patients with norfloxacin prophylaxis (Group B)), were retrospectively analyzed. In 100 episodes (86 and 14, respectively), the responsible organism was isolated in ascitic fluid.

RESULTS

Clinical and laboratory data at diagnosis were comparable in both groups. There were marked differences (p < 0.001) between group A and B in the frequency of peritonitis caused by gram-negative (67.4% vs. 14.3%) and gram-positive (30.2% vs. 78.6%) bacteria. There were three polymicrobial episodes. Bacteria resistant to cefotaxime and gram-negative bacilli resistant to quinolones were isolated in ascitic fluid in nine (seven in Group A and two in Group B) and three episodes (all in Group A), respectively. No differences in the course of infection and patient survival were observed between groups.

CONCLUSIONS

Spontaneous bacterial peritonitis in patients with and without prophylaxis with norfloxacin are not different in clinical features, response to treatment and prognosis. Spontaneous bacterial peritonitis caused by gram-negative organisms resistant to quinolones is extremely uncommon in patients with cirrhosis receiving prophylactic norfloxacin.

Allopurinol reduces bacterial translocation, intestinal mucosal lipid peroxidation, and neutrophil-derived myeloperoxidase activity in chronic portal hypertensive and common bile duct-ligated growing rats

Bacterial translocation (BT) from the gastrointestinal tract has been thought to play a role in the pathogenesis of septic complications in patients with chronic portal hypertension (PH) and obstructive jaundice. The purpose of this study was to investigate the incidence of BT and to assess the role of intestinal mucosal malondialdehyde (MDA) levels as an indicator of lipid peroxidation and polymorphonuclear neutrophil-derived myeloperoxidase (MPO) in chronic portal hypertensive and common bile duct-ligated rats. Twenty male rats were subjected to sham laparotomy (SL), 20 rats to calibrated portal vein constriction (PH), 20 rats to common bile duct ligation (CBDL), and 10 rats served as a nonoperated control group (NOP). After 4 wk, 10 animals of each operated group received 50 mg/kg allopurinol intraperitoneally, at 24 h, and again 2 h prior to estimation of BT, intestinal mucosal MDA, and MPO activities. In the NOP and SL groups, BT to the mesenteric lymph nodes (MLN) and spleen was present. In PH and in CBDL rats, BT to liver, portal vein, peritoneum, and caval vein occurred. Allopurinol treatment attenuated the frequence of BT in PH and decreased BT in CBDL rats significantly (p < 0.05). Ileal mucosal MDA levels (nanomoles/g) in untreated rats increased from 45.1 +/- 7.9 in SL to 98.2 +/- 9.1 in PH and to 102.2 +/- 11 in CBDL rats (p < 0.01). In the allopurinol groups the increase of MDA to 49.1 +/- 1.3 in PH, and 66.2 +/- 2.2 in CBDL was significantly lower (p < 0.01). MPO activity (units/g) in the ileal mucosa increased in untreated rats from 319 +/- 129 after SL to 866 +/- 104 after PH and to 1016 +/- 104 after CBDL (p < 0.01). Allopurinol significantly attenuated MPO activity to 369 +/- 44 in PH, and to 372 +/- 60 in CBDL animals (p < 0.01). In PH and CBDL rats significant BT, intestinal mucosal lipid peroxidation, and polymorphonuclear neutrophil-derived MPO activity occurred. Allopurinol reduced BT and improved intestinal mucosal MDA and MPO activities, suggesting that there might be an association between BT and intestinal mucosal lipid peroxidation.

Allopurinol and glutamine attenuate bacterial translocation in chronic portal hypertensive and common bile duct ligated growing rats

BACKGROUND

Spontaneous bacterial infections and septicaemia result in morbidity and mortality in patients with portal hypertension and obstructive jaundice.

AIM

The aim of this study in rats was to investigate the incidence of bacterial translocation in portal hypertension and obstructive jaundice, and to evaluate the effects of allopurinol and glutamine.

METHODS

Rats were subjected to sham laparotomy (SL), portal hypertension (PH) by calibrated stenosis of the portal vein, and common bile duct ligation (CBDL). Animals of each group were either treated with allopurinol (50 mg/kg twice a week), glutamine (1 g/kg/d), and allopurinol and glutamine.

RESULTS

After four weeks, significant bacterial translocation in the untreated PH and CBDL rats occurred. Intestinal mucosal malondialdehyde concentrations (MDA), as an indicator for lipid peroxidation, and myeloperoxidase activity (MPO) released from activated neutrophils were also significantly increased (p < 0.01). Allopurinol and glutamine in PH and CBDL rats improved bacterial translocation, and decreased MDA and MPO values (p < 0.01).

CONCLUSION

In PH and CBDL rats significant bacterial translocation, ileal mucosal lipid peroxidation, and neutrophil derived MPO activity occurred. Allopurinol and glutamine significantly reduced bacterial translocation, as well as ileal mucosal MDA and MPO activities.

Bacterial translocation in chronic portal hypertensive and common bile duct-ligated growing rats

Spontaneous bacteremias and infectious complications occur in patients with chronic portal hypertension (PH) and obstructive jaundice, and most of these infections are caused by indigenous intestinal bacteria translocating to regional lymph nodes and the systemic circulation. The aim of this study was to investigate bacterial translocation (BT) at two stages: (1) isolated chronic PH; and (2) obstructive jaundice. Four-week-old male rats were either subjected to sham laparotomy (SL) or to pH or common bile duct ligation (CBDL). After 4 weeks, animals were weighed and the portal pressure was measured. Samples from the portal vein (PV), vena cava, liver, spleen, mesenteric lymph nodes (MLN), and ileum were obtained for bacteriologic cultures. Specimens from the liver, jejunum, and ileum were taken for histologic examination. Portal pressure increased from 7.4±0.3 to 20.5±0.6 mmHg in PH and CBDL animals (P <0.01). Bacterial cultures obtained from the ileum showed significant bacterial overgrowth (P <0.01) in pH and CBDL rats (1.3±0.8 × 10(4) after SL; 1.2±0.6 × 10(5) in PH and 1.9±0.6 × 10(6) in CBDL). BT occured in 10% of SL animals to the MLN and spleen. In PH animals 23% positive cultures were found, almost all due to BT to the PV, vena cava, and liver. CBDL resulted in a BT rate of 47%, mainly by translocation to the PV, liver, and MLN (P <0.05 vs. SL). Histomorphologically, the jejunum and ileum were normal in all three groups. These results suggest that in growing PH and CBDL rats intestinal bacterial overgrowth with significant BT occurs, and the incidence of BT seems to be related to the amount of bacteria colonizing the intestinal tract.

Effect of early nutritional deprivation and diet on translocation of bacteria from the gastrointestinal tract in the newborn rat

The gastrointestinal (GI) barrier function is immature in the preterm neonate and might thus facilitate translocation of enteric bacteria and gut-derived septicemia. Circumstantial evidence suggests that bacterial uptake from the intestine may be further enhanced by an alteration of the host nutritional status. To test this hypothesis, neonatal rats were fed normal or restricted amounts of either breast milk or of a rat milk-simulated formula for 3-5 d. At the end of the study, various sections of the GI tract, mesenteric lymph nodes, liver, spleen, and blood were analyzed for bacteria using standard microbiologic procedures. Normal breast feeding was associated with bacterial translocation to mesenteric lymph nodes and in some cases to liver or spleen in 27% of rats, whereas all bacterial cultures were negative in a control group killed immediately after birth. Restricted breast feeding did not increase translocation compared with normal breast feeding. By contrast, feeding normal or restricted amounts of formula increased the numbers of gut bacteria by 2-3 logs, altered the morphology of the small intestinal mucosa, and resulted in ample bacterial translocation to the mesenteric lymph nodes and to systemic organs including the blood. Bacterial translocation may normally occur in suckling neonatal rats and is not increased by food restriction. Artificial feeding dramatically enhances translocation of gut bacteria.