Salmonella are bacteria. The Salmonella consist of a range of very closely related bacteria, many of which cause disease in humans and animals. The word Salmonella refers to a group or family of bacteria that variously cause illness in humans. Salmonella serotype typhimurium and Salmonella serotype Enteritidis are the most common in the United States. Salmonella javiana is the fifth most common serotype in the United States and accounted for 3.4% of Salmonella isolates reported to the CDC during 2002 according to studies.