[Epidemiology of Salmonella typhimurium biotype 6 strains, isolated in Belgium from 1969 to 1982].

Strains of S. typhimurium biotype 6 possess neither tetrathionate reductase nor arginine dihydrolase; they use trehalose, but not inositol and glycerol. Most are multi-resistant to antibiotics and are responsible for numerous outbreaks of salmonellosis. They have been divided into four groups. Groups I includes strains of phage type 207, and was predominant in Belgium from 1969 to 1976. Group II includes strains of a classical variety belonging to phage types 49, 193 and 204. Group III includes strains of the copenhagen variety belonging to the same phage types. Strains of groups II and III are generally resistant to trimethoprim. They have predominated in Belgium since 1978 (mainly phage type 193). Group IV contains a few strains of various phage types, generally non-resistant, which have caused no epidemics.