Salmonellosis

Salmonellosis remains the second most common form of bacterial food-poisoning in the UK and in most of the developed economies. Although the number of isolations per annum has declined since 2000, over 10,000 laboratory-confirmed cases are recognised each year in England and Wales, and over 150,000 in Europe. Most of infections are associated with contaminated food, particularly of poultry origin, but also may originate from cattle and pigs, and to a lesser extent, sheep. The most common serovars from cases of human infection is Enteritidis, followed by Typhimurium. Contact with pets, particularly reptiles and amphibians is becoming an increasing problem and infections can be severe, particularly in children. Accurate and reproducible methods of identification and subtyping are crucial for meaningful epidemiological investigations, and traditional phenotypic methods of typing are now being supplemented by DNA- based methods such as pulsed-field gel electrophoresis, variable number of tandem repeats analysis, and multilocus sequence typing. The use of such methods in combination with phenotypic methods has been invaluable for outbreak control at the international level. The occurrence of resistance to antimicrobial drugs is an increasing problem, particularly in relation to the development of resistance to antimicrobials regarded as ‘critically-important’ for last resort therapy in humans. Control measures such as vaccination of poultry flocks appear to have had a substantial impact on the number of infections with Salmonella Enteritidis. Nevertheless good hygiene practices in both catering establishments and the home remain essential for the control of infections at the local level.