Characterisation of strains of Salmonella serotype Livingstone by multiple typing

Isolates of Salmonella serotype Livingstone (6,7:d:1,w) from man, water and various animals and animal products in Canada, England, France, Israel and Scotland were examined for ribotype, biotype and plasmid profile. Analysis by these methods indicated that an epidemic strain of Livingstone of ribotype 1/biotype 8/plasmid-type 6 was responsible for the major upsurge of Livingstone infection that occurred in man in Tayside (Scotland) between 1989 and 1991; that type was also isolated from spring water, animal feed and poultry. Livingstone isolates of ribotype 1/biotype 8 with plasmid profiles other than type 6 were also present in Scotland, England and France at that same time. Among representative Livingstone isolates from England, a strain of ribotype 2/biotype 1 was predominant in man and poultry products between 1988 and 1992, although strains of other ribotypes (1, 3 and 4) were also present. Strains of ribotype 3 of different biotypes were obtained from poultry and animal feed sources in Canada. A strain of ribotype 5/biotype 3 caused human infections in Israel between 1968 and 1992. Ribotyping, biotyping and plasmid profile analysis used together have helped to trace the sources and extent of spread of human infections caused by Salmonella Livingstone.