Bacterial translocation and mortality on rat model of intestinal ischemia and obstruction

Abstract Purpose: To develop an experimental model of intestinal ischemia and obstruction followed by surgical resection of the damaged segment and reestablishment of intestinal transit, looking at bacterial translocation and survival. Methods: After anesthesia, Wistar rats was subject to laparotomy, intestinal ischemia and obstruction through an ileal ligature 1.5cm of ileum cecal valve; and the mesenteric vessels that irrigate upstream of the obstruction site to approximately 7 to 10 cm were ligated. Abdominal wall was closed. Three, six or twenty-four hours after, rats were subject to enterectomy followed by an end to end anastomosis. After 24h, mesenteric lymph nodes, liver, spleen and lung tissues were surgically removed. It was studied survival rate and bacterial translocation. GraphPadPrism statistical program was used. Results: Animals with intestinal ischemia and obstruction for 3 hours survived 24 hours after enterectomy; 6hx24h: survival was 70% at 24 hours; 24hx24h: survival was 70% and 40%, before and after enterectomy, respectively. Culture of tissues showed positivity on the 6hx24h and negativity on the 3hx24h. Conclusion: The model that best approached the clinic was the one of 6x24h of ischemia and intestinal obstruction, in which it was observed bacterial translocation and low mortality rate.

Post-splenectomy infections in chronic schistosomiasis as a consequence of bacterial translocation

INTRODUCTION : Bacterial translocation is the invasion of indigenous intestinal bacteria through the gut mucosa to normally sterile tissues and internal organs. Schistosomiasis may cause alterations in the immune system and damage to the intestines, portal system and mesenteric lymph nodes. This study investigated bacterial translocation and alterations in the intestinal microbiota and mucosa in schistosomiasis and splenectomized mice. METHODS : Forty female 35-day-old Swiss Webster mice were divided into the following four groups with 10 animals each: schistosomotic (ESF), splenectomized schistosomotic (ESEF), splenectomized (EF) and control (CF). Infection was achieved by introduction of 50 Schistosoma mansoni (SLM) cercariae through the skin. At 125 days after birth, half of the parasitized and unparasitized mice were subjected to splenectomy. Body weights were recorded for one week after splenectomy; then, the mice were euthanized to study bacterial translocation, microbiota composition and intestinal morphometry. RESULTS : We observed significant reductions in the weight increases in the EF, ESF and ESEF groups. There were increases of at least 1,000 CFU of intestinal microbiota bacteria in these groups compared with the CF. The EF, ESF and ESEF mice showed decreases in the heights and areas of villi and the total villus areas (perimeter). We observed frequent co-infections with various bacterial genera. CONCLUSIONS : The ESEF mice showed a higher degree of sepsis. This finding may be associated with a reduction in the immune response associated with the absence of the spleen and a reduction in nutritional absorption strengthened by both of these factors (Schistosoma infection and splenectomy). .

Mesenteric lymph reperfusion after superior mesenteric artery occlusion shock exacerbates endotoxin translocation in brain

PURPOSE: To determine the role of mesenteric lymph reperfusion (MLR) on endotoxin translocation in brain to discuss the mechanism of brain injury subjected to superior mesenteric artery occlusion (SMAO) shock. METHODS: Twenty-four rats were randomly assigned to MLR, SMAO, MLR+SMAO and sham groups. MLR was performed by clamping the mesenteric lymph duct (MLD) for 1 h and then allowing reperfusion for 2 h in the MLR group; SMAO involved clamping the superior mesenteric artery (SMA) for 1 h, followed by reperfusion for 2 h in the SMAO group; occlusion of both the SMA and MLD for 1 h was followed by reperfusion for 2 h in the MLR+SMAO group rats. RESULTS: SMAO shock induced severe increased levels of the endotoxin, lipopolysaccharide receptor, lipopolysaccharide-binding protein, intercellular adhesion molecule-1 and tumor necrosis factor-α. Concurrently, MLR after SMAO shock further aggravates these deleterious effects. CONCLUSION: Mesenteric lymph reperfusion exacerbated the endotoxin translocation in brain; thereby increased inflammatory response occurred, suggesting that the intestinal lymph pathway plays an important role in the brain injury after superior mesenteric artery occlusion shock. .

Host-Microbiome Interactions in Alcoholic Liver Disease

Alcoholic liver disease is a leading cause of morbidity and liver-related death worldwide. Intestinal bacterial overgrowth and dysbiosis induced by ethanol ingestion play an important role in the pathogenesis of alcoholic liver disease. After exposure to alcohol in the lumen, enteric bacteria alter their metabolism and thereby disturb intestinal homeostasis. Disruption of the mucosal barrier results in the translocation of microbial products that contribute to liver disease by inducing hepatic inflammation. In this review, we will discuss the effects of alcohol on the intestinal microbiome, and in particular, its effects on bacterial metabolism, bacterial translocation and ecological balance. A better understanding of the interactions among alcohol, the host and the microbiome will reveal new targets for therapy and lead to new treatments.

Typical and atypical enteropathogenic Escherichia coli bacterial translocation associated with tissue hypoperfusion in rats

Although enteropathogenic Escherichia coli (EPEC) are well-recognized diarrheal agents, their ability to translocate and cause extraintestinal alterations is not known. We investigated whether a typical EPEC (tEPEC) and an atypical EPEC (aEPEC) strain translocate and cause microcirculation injury under conditions of intestinal bacterial overgrowth. Bacterial translocation (BT) was induced in female Wistar-EPM rats (200-250 g) by oroduodenal catheterization and inoculation of 10 mL 10(10) colony forming unit (CFU)/mL, with the bacteria being confined between the duodenum and ileum with ligatures. After 2 h, mesenteric lymph nodes (MLN), liver and spleen were cultured for translocated bacteria and BT-related microcirculation changes were monitored in mesenteric and abdominal organs by intravital microscopy and laser Doppler flow, respectively. tEPEC (N = 11) and aEPEC (N = 11) were recovered from MLN (100 percent), spleen (36.4 and 45.5 percent), and liver (45.5 and 72.7 percent) of the animals, respectively. Recovery of the positive control E. coli R-6 (N = 6) was 100 percent for all compartments. Bacteria were not recovered from extraintestinal sites of controls inoculated with non-pathogenic E. coli strains HB101 (N = 6) and HS (N = 10), or saline. Mesenteric microcirculation injuries were detected with both EPEC strains, but only aEPEC was similar to E. coli R-6 with regard to systemic tissue hypoperfusion. In conclusion, overgrowth of certain aEPEC strains may lead to BT and impairment of the microcirculation in systemic organs.

Translocación bacteriana e infecciones en un modelo experimental de cirrosis en la rata / Bacterial translocation and infections in an experimental model

In summary the carbon tetrachloride/phenobarbital of cirrhosis in rats mimics human cirrhosis very closely, with development of ascites and SBP. This model shows us that bacterial overgrowth occurs as cirrhosis progresses and that bacterial translocation from the gut to extra-intestinal sites is part of the early pathogenesis of SBP. SID with norfloxacin dramatically reduced translocation and SBP at the expense of grampositive overgrowth and infection with gram-positives and colonization with strange gram negatives. SID with TMP-SMZ actually delayed development of ascites and prolonged survival.

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

PRUPOSE: Bacterial translocation has been shown to occur in critically ill patients after extensive trauma, shock, sepsis, or thermal injury. The present study investigates mesenteric microcirculatory dysfunctions, the bacterial translocation phenomenon, and hemodynamic/metabolic disturbances in a rat model of intestinal obstruction and ischemia. METHODS: Anesthetized (pentobarbital 50 mg/kg, i.p.) male Wistar rats (250-350 g) were submitted to intestinal obstruction or laparotomy without intestinal obstruction (Sham) and were evaluated 24 hours later. Bacterial translocation was assessed by bacterial culture of the mesenteric lymph nodes (MLN), liver, spleen, and blood. Leukocyte-endothelial interactions in the mesenteric microcirculation were assessed by intravital microscopy, and P-selectin and intercellular adhesion molecule (ICAM)-1 expressions were quantified by immunohistochemistry. Hematocrit, blood gases, lactate, glucose, white blood cells, serum urea, creatinine, bilirubin, and hepatic enzymes were measured. RESULTS: About 86 percent of intestinal obstruction rats presented positive cultures for E. coli in samples of the mesenteric lymph nodes, liver, and spleen, and 57 percent had positive hemocultures. In comparison to the Sham rats, intestinal obstruction induced neutrophilia and increased the number of rolling (~2-fold), adherent (~5-fold), and migrated leukocytes (~11-fold); this increase was accompanied by an increased expression of P-selectin (~2-fold) and intercellular adhesion molecule-1 (~2-fold) in the mesenteric microcirculation. Intestinal obstruction rats exhibited decreased PaCO2, alkalosis, hyperlactatemia, and hyperglycemia, and increased blood potassium, hepatic enzyme activity, serum urea, creatinine, and bilirubin. A high mortality rate was observed after intestinal obstruction (83 percent at 72 h vs. 0 percent in Sham rats). CONCLUSION: Intestinal obstruction and ischemia in rats is a relevant model for ...

Bacterial translocation in rats nonfunctioning diverted distal colon

PURPOSE: To investigate whether the alterations of the diverted colon segment mucosa, evidenced in fecal colitis, would be able to alter Bacterial Translocation (BT). METHODS: Sixty-two Wistar male rats ranging from 220 to 320 grams of weight, were divided in two groups: A (Colostomy) and B (Control), with 31 animals each one. In group A, all animals underwent end colostomy, one stoma, in ascending colon; and in the 70th POD was injected in five rats, by rectal route diverted segment - 2ml of a 0.9 percent saline solution in animals (A1 subgroup); in eight it was inoculated, by rectal route, 2ml of a solution containing Escherichia coli ATCC 25922 (American Type Culture Collection), in a concentration of 10(8) Colony Forming Unit for milliliters (CFU/ml) - A2 Subgroup; in ten animals the same solution of E. coli was inoculated, in a concentration of 10(11) CFU/ml (A3 Subgroup); and in eight it was collected part of the mucus found in the diverted distal colonic segment for neutral sugars and total proteins dosage (A4 subgroup). The animals from the group B underwent the same procedures of group A, but with differences in the colostomy confection. In rats from subgroups A1, A2, A3, B1, B2, and B3 2ml of blood were aspirated from the heart, and fragments from mesenteric lymphatic nodule, liver, spleen, lung and kidney taken for microbiological analysis, after their death. This analysis consisted of evidencing the presence of E. coli ATCC 25922 CFU. Mann-Whitney and ANOVA Tests were applied as analytic techniques for association of variables. RESULTS: The occurrence of BT was evidenced only in those animals in which inoculated concentration of E. coli ATCC 25922, reached levels of 10(11)CFU/ml, i.e. in Subgroups A3 and B3, although, being significantly greater (80 percent) in those animals without colostomy (subgroup B3) when compared to the ones with colostomy (20 percent) from the subgroup A3 (P <0.05). Lung, liver and mesenteric lymphatic...

OBJETIVO: Investigar se as alterações do cólon desfuncionalizado, evidenciadas na colite de derivação fecal, seriam capazes de permitir Translocação Bacteriana (TB), ou se a mucosa intestinal atrofiada permitiria a passagem de bactérias para órgãos à distância. MÉTODOS: Foram utilizados 62 ratos Wistar, machos, pesando entre 220 e 320 gramas, divididos em dois grupos: A (Colostomia) e B (Controle), contendo cada um 31 animais. No grupo A, os animais foram submetidos à colostomia, terminal boca única, em cólon ascendente. A partir do 70° dia de observação os seguintes procedimentos foram adotados: em cinco ratos foi injetado por via retal no segmento desfuncionalizado - 2ml de uma solução salina 0,9 por cento nos animais (subgrupo A1); em oito inoculou-se, por via retal, uma solução de 2ml contendo Escherichia coli ATCC 25922 (American Type Culture Collection), na concentração de 10(8) Unidades Formadoras de Colônias por mililitros (UFC/ml) - Subgrupo A2; em dez animais inoculava-se a mesma solução de E. coli, na concentração de 10(11)UFC/ml (Subgrupo A3); e em oito colhia-se o muco do segmento colônico distal desfuncionalizado, para dosagens de açúcares neutros e proteínas totais (subgrupo A4). Os animais do grupo B foram submetidos aos mesmos procedimentos do grupo A, e não foram submetidos à colostomia. Nos animais dos subgrupos A1, A2, A3, B1, B2, e B3, após serem mortos, realizou-se punção cardíaca para coleta de 2ml de sangue e retiraram-se fragmentos de tecidos de linfonodo do mesocólon, fígado, baço, pulmão e rim, para análise microbiológica. Essa análise consistia em evidenciar a presença de UFC de Escherichia coli ATCC 25922. Os testes de Mann-Whitney e Anova foram aplicados como técnicas investigativas para associação das variáveis. RESULTADOS: A ocorrência de TB, só foi evidenciada nos animais em que a concentração inoculada de Escherichia coli ATCC 25922, atingia níveis de 10(11)UFC/ml, ou seja, nos Subgrupos A3 e B3, no entanto,...

O intestino na insuficiência cardíaca: aspectos funcionais, imunológicos e terapêuticos / The intestine in heart failure: functional, immunological and therapeutic aspects

Fundamentos: a translocação intestinal de bactérias e endotoxinas pode contribuir para a ativação de mediadores inflamatórios obsevados em pacientes com insuficiência cardíaca. Alterações na homeostase da barreira intestinal aumentam a translocação. Objetivo: revisar a inter-relação entre os sistemas gastrintestinal e cardiovascular na fisiopatologia da insuficiência cardíaca, com ênfase nos mecanismos imunoinflamatórios como novos alvos terapêuticos. Métodos: foram selecionados pelo método de busca no Medline...

Prevention of bacterial translocation using beta-(1-3)-D-glucan in small bowel ischemia and reperfusion in rats

PURPOSE: To investigate the role of beta-(1-3)-D-glucan on 99mTc labelled Escherichia coli translocation and cytokines secretion in rats submitted to small bowel ischemia/reperfusion injury. METHODS: Five groups (n=10 each) of Wistar rats were subjected to control(C), sham(S), group IR subjected to 45 min of bowel ischemia/60 min of reperfusion(I/R), and group I/R+glucan subjected to 45 min of bowel ischemia/60 min of reperfusion(I/R) and injected with 2mg/Kg intramuscular. Translocation of labelled bacteria to mesenteric lymph nodes, liver, spleen, lung and serum was determined using radioactivity/count and colony forming units/g(CFU/g). Serum TNFalpha, IL-1beta, IL-6, IL-10 were measured by ELISA. RESULTS: CFU/g and radioactivity/count were higher in I/R than in I/R+glucan rats. In C, S and S+glucan groups, bacteria and radioactivity/count were rarely detected. The I/R+glucan rats had enhancement of IL-10 and suppressed production of serum TNFalpha, IL-1beta and, IL-6, compared to I/R untreated animals. CONCLUSION: The beta-(1-3)-D-glucan modulated the production of pro-inflammatory and anti-inflammatory cytokines during bowel ischemia/reperfusion, and attenuated translocation of labelled bacteria.

OBJETIVO: Investigar o papel da beta-(1-3)-D-glucana na translocação de Escherichia coli marcada com 99mTc e na secreção de citocinas em ratos submetidos a isquemia e reperfusão intestinal. MÉTODOS: Cinco grupos (n=10 cada) de ratos Wistar foram denominados controle (C), sham (S), grupo IR submetido a 45 minutos de isquemia do intestino delgado e 60 minutos de reperfusão(I/R), grupo I/R+glucana com 45 minutos de isquemia e 60 minutos de reperfusão(I/R) e tratados com glucana 2mg/Kg intramuscular. Translocação de Escherichia coli marcada com 99mTc, para Linfonodos mesentéricos, fígado, baço, pulmão e soro foi avaliada usando contagem de radioatividade e de unidades formadoras de colônias/g (UFC/g) Dosagem sérica de TNFalfa, IL-1beta, IL-6, IL-10 foi realizada pelo método ELISA. RESULTADOS: CFU/g e contagem de radioatividade foi significantemente maior nos ratos do grupo I/R do que no grupo I/R+glucana. Nos grupos C, S e S+glucana bactérias e contagem radioativa foram raramente detectadas. Os ratos do grupo I/R+glucana tiveram aumento de IL-10 sérica e significante redução da expressão de TNFalfa, IL-1beta e IL-6, quando comparados com os animais não tratados do grupo I/R. CONCLUSÃO: A beta-(1-3)-D-glucana modulou a produção de citocinas pró-inflamatórias e anti-inflamatórias durante a isquemia/reperfusão intestinal e contribuiu para reduzir a translocação de bactérias marcadas.

Açäo do pneumoperitônio com dióxido de carbono na translocaçäo bacteriana em ratos / Action of pneumoperitoneum with carbon dioxide on bacterial tranlocation in rats

Objetivo: Investigar a translocaçäo bacteriana decorrente da açäo do pneumoperitônio com CO Z em ratos normais e em ratos com colite induzida. Métodos: Utilizaram-se 60 ratos distribuídos em seis grupos de 10 animais. No grupo simulaçäo realizou-se laparotomia, manipulaçäo de órgäos abdominais e síntese da parede; os dois grupos pneumoperitônio foram submetidos a pneumoperitônio por uma e três horas, respectivamente; no grupo colite, foi induzida colite e realizada laparotomia, manipulaçäo de órgäos abdominais e síntese da parede; nos dois grupos colite pneumoperitônio induziu-se colite mais pneumoperitônio por uma e três horas, respectivamente. Sacrificados os animais, foram feitas as coletas dos rins, baço, fígado e linfonodos mesentéricos. Nos animais submetidos a colite induzida, foram ressecados 2cm de cólon para análise histológica. Nos órgäos ressecados pesquisou-se a presença de Escherichia coli e Enterococcus faecallis para verificar a translocaçäo bacteriana. Resultados: Näo ocorreram óbitos nos grupos estudados. Näo houve diferença estatisticamente significante nos grupos de animais submetidos a colite. A ocorrência de translocaçäo bacteriana nos diferentes órgäos independe do gênero da bactéria. Näo há incre-mento da translocaçäo bacteriana com relaçäo a duraçäo de pneumoperitônio (1 e 3h) tanto em ratos normais como nos submetidos a colite induzida: Conclusäo: O pneumoperitônio induz a translocaçäo bacteriana em ratos normais e a incrementa em ratos submetidos à colite.

Translocaçäo bacteriana na obstruçäo aguda do cólon esquerdo / Bacterial translocation in the acute obstruction of left colon

O cólon esquerdo é sede freqüente de obstruçäo intestinal e os resultados do tratamento cirúrgico nessa situaçäo estäo associados a maior morbi-mortalidade pós-operatória. O objetivo deste trabalho foi o de investigar experimentalmente a ocorrência de translocaçäo bacteriana na obstruçäo aguda do cólon esquerdo. 26 ratos Wistar foram submetidos a laparotomia mediana sendo obstruídos no cólon esquerdo com um nó de linho a 2,5 cm acima da reflexäo peritoneal (grupo obstruçäo; n=13) ou näo (grupo controle; n=13). 24h após, foram novamente reoperados para coleta dos linfonodos mesentéricos, fígado, baço e de uma amostra de sangue caval. As peças foram homogeneizadas e enviadas para cultura. Observou-se uma maior incidência de culturas positivas nos animais do grupo obstruçäo tanto nos linfonodos (8/10 vs. 3/13; p<0.01) quanto no fígado (7/10 vs. 1/13; p<0.01) e no baço (8/10 vs. 4/13; p<0.05). No sangue, 6 dos 10 ratos obstruídos apresentaram cultura positiva enquanto que isso näo ocorreu em nenhum rato do grupo controle (p<0.01). As bactérias mais freqüentes nas culturas foram a Escherichia coli, Proteus vulgaris e Klebsiella pneumoniae. A obstruçäo aguda do cólon esquerdo neste modelo animal determina a ocorrência de translocaçäo bacteriana

Estudo da transmigração bacteriana na apendicite experimental em coelhos / Study about bacterial transmigration in experimental appendicitis in rabbits

Introdução: A queda extrínseca dos mecanismos de defesa de um hospedeiro é vista classicamente como uma infecção, que resulta na aquisição de um tecido normal, de um novo microorganismo, cuja virulência é fundamental para a sua patogenia.Na década de 50, estudos comprovaram que bactérias e endotoxinas podem ultrapassar a barreira intestinal e atingir a circulação, demonstrando ainda, que a flora intestinal representa uma importante fonte para o desenvolvimento da infecção sistêmica. Objetivo: o presente estudo visa avaliar a ocorrência de transmigração bacteriana em apendicite experimental induzida em coelhos, mediante a oclusão completa do apêndice vermiforme. Métodos: foram utilizados 24 coelhos brancos, da linhagem Nova Zelândia, com peso corporal variando de 2500 a 3000 gramas, sendo então divididos em 2 grupos. Os animais do Grupo I foram submetidos a laparotomia mediana e retirada de fragmentos do baço, rim esquerdo, pulmão direito, linfonodo abdominal, conteúdo da luz do apêndice vermiforme e sangue da veia porta para cultura. Os animais do Grupo II foram submetidos a laparotomia mediana e oclusão completa do apêndice vermiforme para a indução de apendicite e, após 24 horas, realizada a coleta do material nos moldes do Grupo I. Resultados: No Grupo controle (Grupo I), não se observou o crescimento de bactérias nas amostras analisadas. No Grupo experimento (Grupo II), observou-se o crescimento de Escherichia coli em todos os animais. Conclusão: Ocorreu transmigração bacteriana após 24 horas de observação em coelhos com apendicite experimental.