Abstract
A case of septicaemia due to Yersinia enterocolitica serotype 3, biotype 4, in a non-compromised host is described. The patient showed severe signs of gram-negative septicaemia. Treatment with sulphamethoxazole-trimethoprim (Bactrim®) was unsuccessful in spite of full sensitivity, bactericidal and synergistic effects in vitro. Tetracycline gave full restitution.