The use of a new model for the investigation of sepsis

Abstract

The purpose of the investigation was to induce the clinical form of sepsis in rats by inoculation of pure cultures of certain species of microorganisms into the ligated caecum. The experiments were performedon 104 Wistar strain male rats of 190-240 goody weight. The rats were divided into four groups three of which contained 28 animals each and one control group of 20 animals. In order to monitor the development of sepsis, rats were killed at 12,24, 72 and 120hafterthe surgical intervention. Clinically apparent sepsis in two groups of rats was induced in the following way: the previously emptied, tied off and washed out caecum was inoculated with pure cultures of Escherichia coli or Staphylococcus aureus. In the third group, sepsis was produced by the caecal content of the tied off and punctured caecum (a mixed culture of microorganisms). A false surgical intervention was performed in the control group by opening the abdomen. Clinically manifest symptoms of sepsis, such as higher body temperature, diarrhoea, anorexia, tachycardia tachypnoea, changes in appearance and behaviour, were observed in all the rats, from 24 to 120 h after surgery. Bacteriological findings in the blood and parenchyma! organs of the investigated rats, in the model of sepsis induced by the gram-negative bacterium E.coli, showed the presence of E.coli at all times from 12-120 h after inoculation. In the model of sepsis caused by Staphylococcus aureus this gram-positive bacterium was detected in the blood and tissue samples from 12 to 72 h after inoculation. In the model of sepsis induced by mixed bacterial cultures (E.coli, Proteus mirabilis Enterococcus spp) only E.coli was detected in the blood and parenchyma! organ samples at all the monitored time.s from 12 to 120 h, whereas P. mirabilis and Enterococcus spp. were detected only during the first 24 h of the experiment