Bacterial translocation and wasting in stressed mice

The effects of strees immunity and on the bacterial translocation from intestine to mesenteric lymph nodes, liver, and spleen were studied in a group of newborn CD1 mice. Animals were separated into three experimental groups. Mice from group I were stressed by intraperitoneal (IP) injections of heatkilled staphylococci for 4 weeks. Mice from group II were IP injected with saline solution only. The remaining mice, group III, were not injected. The clinical condition, presence of bacteria in abdominal organs, mitochondrial activity in splenic cells, lymphocyte proliferative response to Concanavalin-A and in vitro antibody production were evaluated in each mouse. Results showed that prolonged IP stressor challenge causes severe weight loss and immunodeficiency. The splenic lymphocytes from stressed mice exhibited a significant depression of both proliferative response to Concanavalin-A stimulation and anti-erythrocytes antibody synthesis. Instead, cultured in basal conditions, the splenic cells from stressed mice have an increased capacity to reduce the tetrazolium salts. Bacterial dissemination from intestine to mesenteric lymphoid nodes was also confirmed in the same group of mice. In contrast, mice in groups II and III presented no weight loss and immunodeficiency. Results suggest that chronic biological stress induced in newborn mice could facilitate the translocation of Gramnegative bacteria. Probable pathogenic mechanisms are commented upon and a correlation is proposed between the bacterial dissemination and the wasting development

Traslocación bacteriana en un modelo de autotrasplante de intestino delgado en perros / Bacterial translocation in a small intestine auto transplantation model in dogs

Sepsis is the commonest complication of small bowel transplantation. These infections are presumibly caused by bacterial translocation, due to splachnic ischemia. To study bacterial translocation in the inmediate postoperative period after small bowel transplantation in dogs and to relate it to splanchnic ischemia. Three groups of dogs were studied. In group A (n=6) spontaneous episodes of splanchnic schemia were monitored in the first 18 hrs of the postoperative period. In group B (n=5) a 60 min ischemia was induced by superior mesenteric artery occlusion, 2 hours after small bowel transplantation. In group C (n=5) a 60 min ischemia was induced by occlusion of mesenteric vein, 2 hrs after transplantation. Bacterial translocation was assessed through bacterial cultures from the mesenteric vein and splanchnic ischemia with intramucosal pH measurement (a pH<7.2 was considered indicative of ischemia). 28 of 83 cultures were positive, specially for Gram negative bacilli. The incidence of positive cultures was 14 percent for group A, 17 percent for group B and 79 percent for group C (p<0.01 cpmpared to groups A and b). The higher incidence of bacterial translocation occurred during the first 2 hours after transplantation, when the lower intramucosal pH recording were obtained. The percentage of positive cultures was 39 percent during periods of ischemia, compared to 24 percent during periods without ischemia (p=NS). Bacterial translocation occurs during the first 2 hours after intestinal transplantation in concomitance with the lower intramucosal pH readings