In most of the salmonellosis outbreaks resulted from poultry products consumption, Enteritidis and Typhimurium serovars have been isolated.
In the late 1990s, Salmonella enterica serovar Typhimurium (Salmonella Typhimurium) serogroup B and Salmonella enterica serovar Enteritidis (Salmonella Enteritidis) serogroup D were the most frequently isolated serotypes, accounting for ∼50% of isolates from patients in the United States. Notable recent outbreaks of Salmonella infection have been linked to eggs, cheese, dry cereal, ice cream premix, a variety of fresh sprouts, juice, cantaloupes, and other fresh vegetables.
Salmonella Enteritidis has been the major cause of the food-borne salmonellosis pandemic in humans over the last 30 years, during which contaminated hen’s eggs were the most important vehicle of the infection. Eggs can be contaminated on the outer shell surface and internally. Internal contamination can be the result of penetration through the eggshell or by direct contamination of egg contents before oviposition, originating from infection of the reproductive organs.
Vertical transmission is very important especially in poultry related Salmonella infection caused by the serovar Enteritidis that has a special affinity for the reproductive system of chickens. In this case, transmission to progeny occurs by transovarian infection when the parent birds have systemic infection leading to infection of the ovary and developing eggs in the oviducts.
Human illness caused by Salmonella enterica serovar Enteritidis (Salmonella Enteritidis) has drastically increased worldwide, and by the 1980’s Salmonella Enteritidis had replaced Salmonella enterica serovar Typhimurium (Salmonella Typhimurium) as the primary cause of salmonellosis globally.
Salmonella enterica serovar Enteritidis
