Mechanisms of colonization and survival of Salmonella within the EGG

Human salmonellosis infections are usually acquired via the food chain as a result of the ability of Salmonella serovars to colonize and persist within the gastrointestinal tract of food-producing animals and the avian reproductive tract, being able to contaminate, survive and grow inside eggs. This review gives an overview of the cellular and molecular processes involved in the colonization of hen's eggs and in Salmonella persistence in the harsh conditions of the egg albumen with special focus on serovar Enteritidis, which shows a particular tropism and ability to persist in chicken oviducts and ovaries and to contaminate, survive and grow inside eggs. The trans-ovarian (also referred to as vertical transmission) and the trans-shell (referred to as horizontal transmission) routes of colonization of the egg are briefly described. In addition, several gene candidates involved in bacterial survival in the egg albumen are identified as potential biomarkers, appropriate for the design of ambitious strategies for the prevention of salmonellosis.