Human infection in Tayside, Scotland due to Salmonella serotype Livingstone

Livingstone was the third most common salmonella serotype isolated from cases of human salmonellosis in the Tayside region of Scotland in 1989-1991; latterly, it spread to Grampian region. The significant upsurge of Livingstone in these two Scottish regions was not matched by similar increases in its frequency of isolation from human cases of salmonellosis in other regions of Scotland or elsewhere in the UK. Although Salmonella Livingstone is usually associated in the UK with incidents of infection among poultry flocks, our detailed investigations found no clear evidence that poultry, eggs or poultry-related products were responsible for this outbreak. Most cases occurred in the summer months from July to September and many of the patients required hospital treatment. Other than one outbreak among geriatric patients in a long-stay hospital in north Tayside, most of the cases were sporadic. The extent of the outbreak, covering 3 years, was recognised mainly because Livingstone was previously an uncommon serotype in Tayside. There were few Livingstone isolations from non-human sources in Scotland in these same years. Possible sources of infection and predisposing factors among patients are discussed. Livingstone was not isolated in Scotland in 1992.