STARVATION INCREASES THE NUMBER OF COLIFORM BACTERIA IN THE CECUM ANDINDUCES BACTERIAL ADHERENCE TO CECAL EPITHELIUM IN RATS

Objective: To investigate the impact of starvation for 24 and 48 h on the number of coliform bacteria in the caecal contents, on the mucosal adherence of coliform bacteria, and on bacterial translocation in rat s. Design: Open prospective study. Setting: University departments of surgery and microbiology, Sweden. Material: 46 adult male Sprague-Dawl ey rats. Interventions: 19 rats served as controls, and were fed until samples were taken. Six animals were starved for 24 h and another 15 for 48 h, with free access to water, and then anaesthetised before blo od, mesenteric lymph nodes (MLN), caecum, and caecal contents were sam pled. To verify bacterial translocation in this strain of rats, anothe r six rats underwent controlled haemorrhage for 60 min to reduce the b lood pressure to 55 mm Hg mean arterial pressure (MAP). These rats had free access to food and water before haemorrhage but were allowed onl y water until samples were taken 24 h after haemorrhage. Main outcome measures: Presence and number of coliform bacteria in samples taken fr om caecal contents, caecal epithelium, MLN, and blood. Results: Starva tion for 24 h increased the number of coliform bacteria (colony formin g units (CFU)/g) in the caecal contents 25-fold (p < 0.05). Starvation for 48 h further increased the number by a factor of 100. The number of coliform bacteria that adhered to the caecal epithelium increased 3 000 times in rats that had been starved for 48 h (p < 0.001). There wa s no significant difference in translocation (as indicated by cultures from MLN) between rats that had been fed and those that had been star ved for 48 h. In 4 of the 6 rats that were bled and then starved for 2 4 h there were signs of bacterial translocation, which was significant ly more than the 1/19 in fed rats (p < 0.05). Conclusion: Starvation i ncreases the number of bacteria in the caecal contents and increases b acterial adherence to the caecal epithelium. These changes may contrib ute to the previously reported increase in bacterial translocation in starved compared with fed rats that were subjected to stress. The same changes in the gut were observed in animals subjected to haemorrhagic stress in addition to starvation, and in which bacterial translocatio n was evident.