Colony incompatibility studies among strains of Salmonella typhimurium phage type 199 isolated in connection with one outbreak.

Strains of Salmonella typhimurium phage type 199 from an outbreak of salmonellosis in the Wellington region were investigated by means of the colony incompatibility phenomenon. With the exception of one strain isolated from milk, all outbreak strains were fully compatible, despite differing in antibiotic resistance pattern and plasmid carriage. This suggests that these strains are derived from one clone. Colony incompatibility is considered a useful rapid method of epidemiological assessment of outbreaks of salmonellosis.