| 1. |
- Bark, Tor, et al.
(författare)
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Bacterial translocation after non-lethal hemorrhage in the rat
- 1993
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Ingår i: Circulatory Shock. - : John Wiley & Sons. - 0092-6213. ; 41:1, s. 60-65
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Tidskriftsartikel (refereegranskat)abstract
- Translocation of enteric bacteria has been suggested to compromise patients in severe catabolic stress. Mechanisms for this route of infection are not known. In this study, ratswere subjected to hemorrhage without reinfusion during 60 min, total blood loss was 3.28 +/- 0.14 ml/100 g BW. Control groups consisted of sham-operated animals without bleeding, and rats not operated at all. The mean number of viable bacteria found in mesenteric lymph nodes (MLN) of bled animals was 168 +/- 45 colony forming units (c.f.u./MLN), significantly higher compared to sham operated (5 +/- 3 c.f.u./MLN) and not operated (0 +/- 0 c.f.u./MLN) controls (P < 0.01). Cultures from MLN were positive in 7/9 rats after bleeding, in 3/9 of sham operated, and in 0/6 of non-instrumented control animals. No positive blood cultures were isolated. Escherichia coli was the dominant species found in MLN. A biochemical fingerprinting method (the PhP system) was used to identify translocating strains of E. coli among strains found in cecum. The method was also used to compare translocating strains between different animals. Our findings reveal that bacteria translocate to MLN after hemorrhage. Some phenotypes of E. coli strains translocate more frequently than others, suggesting that they have properties facilitating translocation.
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| 2. |
- Bark, Tor, et al.
(författare)
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Food deprivation increases bacterial translocation after non-lethal haemorrhage in rats
- 1995
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Ingår i: European Journal of Surgery. - : Taylor & Francis Scandinavia. - 1102-4151 .- 1741-9271. ; 161:2, s. 67-71
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE:To investigate whether brief fasting before the induction of hypotension by non-lethal haemorrhage may induce translocation of enteric bacteria to mesenteric lymph nodes or blood in rats.DESIGN:Laboratory experiment.SETTING:University departments of surgery and microbiology, Sweden.MATERIAL:39 Male Sprague-Dawley rats.INTERVENTIONS:20 animals were fasted for 24 hours, all 39 then underwent controlled haemorrhage for 60 minutes that reduced the blood pressure to 55 mm Hg.MAIN OUTCOME MEASURES:Differences in blood loss, blood glucose concentrations, and packed cell volume; and aerobic cultures of mesenteric lymph nodes and blood.RESULTS:Fasted rats (n = 20) lost 2.3% of blood volume compared with 2.8% in fed rats(p < 0.001). Packed cell volume dropped by 11.3% in fasted rats and 16.5% in fed rats (p < 0.001). Glucose concentrations rose by 7.0 mmol/l in fasted rats compared with 21.0 mmol/l in fed rats (p < 0.001). Mesenteric lymph nodes contained enteric bacteria in 14/20 fasted rats compared with 6/19 fed rats (p < 0.05). In 4 fasted rats blood cultures grew pathogenic bacteria compared with no fed rats (p = 0.11). The number of bacteria found in mesenteric lymph nodes was significantly greater in fasted than in fed rats (p = 0.01).CONCLUSIONS:Brief fasting before hypotension caused by non-lethal haemorrhage was associated with significantly increased bacterial translocation compared with fed animals. Increases in blood glucose concentrations and plasma refill may have had a protective effect in fed rats. These experiments may be of clinical relevance as elective operations are usually preceded by overnight fasting.
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| 3. |
- Bark, Tor, et al.
(författare)
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Glutamine supplementation does not prevent bacterial translocation after non-lethal haemorrhage in rats
- 1995
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Ingår i: European Journal of Surgery. - : Taylor & Francis Scandinavia. - 1102-4151 .- 1741-9271. ; 161:1, s. 3-8
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE:To find out whether supplementation of an enteral diet with glutamine would reduce translocation of bacteria to mesenteric lymph nodes or blood after major haemorrhage in rats.DESIGN:Open randomised study.SETTING:University departments of surgery and microbiology, Sweden.MATERIAL:49 Sprague-Dawley rats.INTERVENTIONS:Rats were fed enterally for 7 days on diets supplemented with either glutamine or an isonitrogenous amount of non-essential amino acids. After feeding, 8 experimental and 8 control rats underwent sham operation; 9 and 7, respectively, underwent moderate haemorrhage (to 65 mm Hg); and 9 and 8, respectively, underwent severe haemorrhage (50 mm Hg) without reinfusion.MAIN OUTCOME MEASURES:Microbiological analyses of samples of blood and mesenteric lymph nodes taken 24 hours after haemorrhage.RESULTS:The median (interquartile) number of colony forming units/mesenteric lymph nodes after moderate haemorrhage in animals who were given glutamine supplementation was 11 (0-34) and in control animals 20 (0-178). After severe haemorrhage the corresponding figures were 199 (10-310) and 22 (0-187). No pathogens were isolated from blood cultures.CONCLUSION:Glutamine supplementation before haemorrhage did not reduce bacterial translocation to mesenteric lymph nodes in this rat model.
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| 4. |
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| 5. |
- Katouli, Mohammad, et al.
(författare)
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Composition and diversity of intestinal coliform flora influence bacterial translocation in rats after hemorrhagic stress
- 1994
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Ingår i: Infection and Immunity. - : American Society for Microbiology. - 0019-9567 .- 1098-5522. ; 2:11, s. 4768-4774
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Tidskriftsartikel (refereegranskat)abstract
- Coliform bacteria are the most frequently reported bacteria to translocate afterhemorrhage. We investigated the correlation between composition and diversity of the cecal coliform flora and the degree of translocation in a rat model of hemorrhagic stress. Two groups of nine rats each were bled to 60 and 50 mm Hg mean arterial blood pressure, respectively. A sham-operated group without bleeding (n = 9) and a noninstrumented group (n = 6) served as controls. From each rat, 40 coliform isolates from the cecum and up to 16 from positive mesenteric lymph node (MLN) cultures were tested with an automated biochemical fingerprinting method. The phenotypic diversity of coliforms in each cecal sample was calculated as Simpson's diversity index (DI), and similarities between bacterial types in different samples were calculated as population similarity coefficients. Three rats in the sham-operated group and seven in each of the bled groups showed bacterial translocation. Of the different biochemical phenotypes (BPTs) found in the cecum of bled rats (mean, 6.5 BPTs), only a few were detected in MLNs (mean, 1.9 BPTs per MLN), with Escherichia coli being the dominant species. The translocating E. coli strains were mainly of two BPTs. Rats showing no translocation either did not carry these strains or had a high diversity of coliforms in the cecum. Furthermore, translocation of these coliform types was independent of their proportion in the cecum. In bled rats, the diversityof coliforms (mean DI, 0.53) was significantly higher than that in control groups (mean DI, 0.30; P = 0.004), suggesting that hemorrhage stimulates an increase in diversity of cecal coliforms. Rats with similar coliform flora and subjected to the same treatment showed similar patterns of translocation. Our results suggest that the composition of the coliformflora is an important factor in translocation and that certain coliform strains have the ability to translocate and survive in MLNs more easily than others.
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| 6. |
- Katouli, Mohammad, et al.
(författare)
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Selective translocation of coliform bacteria adhering to caecal epithelium of rats during catabolic stress
- 1997
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Ingår i: Journal of Medical Microbiology. - : The Microbiology Society. - 0022-2615 .- 1473-5644. ; 46:7, s. 571-578
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Tidskriftsartikel (refereegranskat)abstract
- Adult conventional rats were starved for 48 h with or without haemorrhage at 24 h, and translocation of caecal coliforms to mesenteric lymph nodes (MLNs) was measured. Translocation was detected in three of 11 rats without haemorrhage, in 6 of 11 starved and sham-operated rats and in 12 of 22 rats after haemorrhage. In contrast, only one of 13 non-instrumented and fed control rats showed translocation. Translocation was associated with more coliforms adhering to caecal epithelium in rats. Coliform isolates from caecum, caecal epithelium and MLNs were characterised and grouped into different biochemical phenotypes (BPTs) by a biochemical fingerprinting method. Of 291 BPTs detected in the caecum of all rats, 108 were also found on caecal epithelium; 36 BPTs were detected in MLNs, of which 17 were not detected either in the caecum or on the caecal epithelium of the corresponding rats. One isolate from each of these 36 BPTs was selected and compared to the others. Four common (C) BPTs (i.e., C1-C4) were identified among them. Strains of C1 formed the majority of isolates from the caecum (79%), caecal epithelium(71%) and MLNs (91%). In contrast, C2-C4 had a significantly lower incidence both in the caecum and on the caecal epithelium, but not in the MLNs. These findings indicate that not all caecal coliforms adhere to the epithelium during catabolic stress and that for translocation to occur, other bacterial properties besides adhesion are needed. It is also concluded that coliforms with a low incidence in the caecum can translocate with the same efficiency as those with a high incidence.
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| 7. |
- Nettelbladt, Carl Gustaf, et al.
(författare)
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Bulking fibre prevents translocation of an efficiently translocating Escherichia coli strain in rats
- 1998
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Ingår i: Clinical Nutrition. - : Elsevier. - 0261-5614 .- 1532-1983. ; 17:4, s. 185-190
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Tidskriftsartikel (refereegranskat)abstract
- Background: starvation for 24 h prior to experimental haemorrhage increases bacterial translocation in rats. Forty-eight hours starvation alone causes pronounced microbiological changes in caecal contents and a marked increase in bacterial adherence to caecal epithelium. The aim of the present study was to examine whether bulking fibre prevents these microbiological changes induced by starvation, i.e. mucosal adherence and/or bacterial translocationwith and without haemorrhage in rats. Methods: 32 rats were inoculated with the translocating Escherichia cell strain KI-C1. Groups of these rats were then starved for 48 h with or without access to bulking fibre. An additional group of rats was given bulking fibre and subjected to haemorrhage. A control group was untreated and given regular food. Samples were taken from caecal contents, caecal epithelium, mesenteric lymph nodes and blood. A biochemical fingerprinting method was used to characterize and compare E. coil strains in all samples. Results: ingestion of bulking fibre alone for 48 h significantly reduced the frequency of KI-C1 both in caecal contents and on caecal epithelium and completely prevented translocation of the strain, compared to starvation without bulking fibre for 48 h. Enforced stress (haemorrhage) increased bacterial translocation to the same level as starvation for 48 h. E. coli phenotypes found in mesenteric lymph nodes were also found adhering to the caecal epithelium. Conclusions: the presence of bulking fibre in gut lumen, by unknown mechanisms, reduces the frequency of an inoculated translocating strain of E. coil in caecal contents and on caecal epithelium and prevents its translocationto mesenteric lymph nodes.
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| 8. |
- Nettelbladt, Carl Gustaf, et al.
(författare)
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Hyperosmotic glucose infusion during hemorrhage does not reduce bacterial translocation in 24 hour-starved rats
- 1995
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Ingår i: Shock. - : Lippincott Williams & Wilkins. - 1073-2322 .- 1540-0514. ; 4:2, s. 113-116
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Tidskriftsartikel (refereegranskat)abstract
- Food deprivation 24 h before stress increases bacterial translocation in hemorrhage. Presently it tested whether hyperosmolality, induced by exogenous glucose infusion to improve plasma refill, prevents or reduces bacterial translocation after experimental hemorrhage in 24 h food-deprived rats. Rats were given an i.v. infusion of either 2 mL of 30% glucose (G) or the same volume of .9% NaCl (C) while simultaneously being submitted to a standardized 60 min hemorrhage period, of moderate or more severe hemorrhage. Blood was not reinfused. Despite development of marked hyperglycemia (p < .001, G vs. C) resulting in significantly greater reductions in packed cell volume (p < .001, G vs. C), bacterial translocation was detected similarly in both groups regardless of whether moderate (10/12-G, 9/12-C) or severe (15/19-G, 15/18-C) hemorrhage was inflicted. It was concluded that hyperglycemic hyperosmolality did not prevent bacterial translocation in these models of hemorrhagic stress in 24 h-starved rats.
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| 9. |
- Nettelbladt, Carl-Gustaf, et al.
(författare)
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Orally inoculated Escherichia coli strains colonize the gut and increase bacterial translocation after stress in rats
- 2003
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Ingår i: Shock. - Philadelphia, USA : Lippincott Williams & Wilkins. - 1073-2322 .- 1540-0514. ; 20:3, s. 251-6
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Tidskriftsartikel (refereegranskat)abstract
- Coliforms are the members of the indigenous gut flora that most often translocate to mesenteric lymph nodes. Very few strains of Escherichia coli found in cecal contents of rats are able to translocate. The present study investigated the role of the composition of the gut flora for the occurrence of bacterial translocation. Two strains of E. coli (KI-C1 and KI-C2), previously shown to translocate in rats subjected to stress, were given by oral inoculation to rats lacking these strains. A biochemical fingerprinting method was used to identify bacteria in cecal contents, on cecal epithelium, and in mesenteric lymph nodes. In a challenge study, the inoculated E. coli strains were shown to colonize the rats and persist for up to 75 days in cecum. Subsequently, one group was starved for 24 h and a second group was subjected to experimental hemorrhage and then starved for 24 h before sampling for bacteriological analyses from blood, cecum, and mesenteric lymph nodes. Two parallel groups of rats served as controls and were not inoculated but otherwise received the same treatment before sampling. In the inoculated group, starved for 24 h, seven out of 11 rats showed translocation, whereas in the noninoculated group one of 11 rats showed translocation (P < 0.05). In groups subjected to hemorrhage and then starved for 24 h, 15/22 rats in the inoculated and 5/20 rats in the noninoculated group showed translocation (P < 0.01). These findings show that orally inoculated KI-C1 and KI-C2 strains can colonize the gut and can substantially increase bacterial translocation in rats subjected to mild and severe stress. The composition of the gut flora seems to be an underestimated factor in the pathophysiology of bacterial translocation.
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