Salmonellae are ubiquitous human and animal pathogens, and salmonellosis, a disease that affects an estimated 2 million Americans each year, is common throughout the world.
Salmonella infections that involve invasive serotypes are often life threatening, necessitating appropriate and effective antibiotic therapy.
Salmonellosis includes several syndromes (gastroenteritis, enteric fevers, septicemia, focal infections, and an asymptomatic carrier state).
Gastroenteritis is the most common Salmonella infection worldwide, accounting for 93.8 million cases which result in 155,000 deaths per year
Most non-typhoidal salmonellae enter the body when contaminated food is ingested. Person-to-person spread of salmonellae also occurs. To be fully pathogenic, salmonellae must possess a variety of attributes called virulence factors. These include
(1) the ability to invade cells,
(2) a complete lipopolysaccharide coat,
(3) the ability to replicate intracellularly, and
(4) possibly the elaboration of toxin(s).
After ingestion, the organisms colonize the ileum and colon, invade the intestinal epithelium, and proliferate within the epithelium and lymphoid follicles.
Children below the age of 5 years, elderly people and patients with immunosuppression are more susceptible to Salmonella infection than healthy individuals. Almost all strains of Salmonella are pathogenic as they have the ability to invade, replicate and survive in human host cells, resulting in potentially fatal disease.
Salmonella pathogenesis
