MODULATION OF INFLAMMATORY REACTIONS BY PREVIOUS CONTACT WITH ESCHERICHIA-COLI IN RATS

Objective: To find out if contact with Escherichia coli had any effect on a subsequent inflammatory reaction induced by the same micro-organ ism. Design: Controlled laboratory study. Setting: University laborato ry. Material. Male white Wistar rats divided into groups of 6 to 10. I nterventions: Pretreatment with sponges soaked in 1 x 10(9) heat kille d E. coli inserted either subcutaneously into the back or intraperiton eally into the right hypochondrium, and 14 days later repeat challenge . Controls received sponges soaked either in saline with penicillin an d streptomycin or with carrageenan lambda. Pretreatment with live or h eat killed E. coli or E. coli endotoxin injected intradermally or intr aperitoneally (controls were given saline). Main outcome measures: Num ber of white cells present in the inflammatory infiltrate and the peri toneal cavity, and titres of anti-E. coli antibody. Results: Pretreatm ent of Wistar rats with heat-killed or live E. coli (ATCC 25922) was f ollowed by increase in the cellular infiltrates at the site of subsequ ent challenge with the same micro-organism. The effect was not related to the synthesis of anti-E. coli antibodies. Conclusion: Surgical pat ients have commonly been in previous contact with E. coli; this might affect their inflammatory reactions if they came into contact with the organism after operation. Further studies are needed to clarify the p recise mechanisms and clinical relevance of these findings.