• Salmonella are moderately-sized Gram-negative bacilli.
• Possess a peritrichous (def) arrangement of flagella.
• Facultative anaerobes (def).

Habitat

• The intestinal tract in humans and animals.

Source

• Human or animal feces containing Salmonella; transmitted by the fecal-oral route. Since many different animals carry Salmonella in their intestinal tract, people usually become infected from ingesting improperly refrigerated, uncooked or undercooked poultry, eggs, meat, or dairy products contaminated with animal feces.

Epidemiology

• Around 50,000 cases of salmonellosis are reported annually in the U.S. but most cases go unreported. An estimated 2,000,000 - 3,000,000 people a year in the U.S. become infected with Salmonella and at least 500 die.
• The majority of Salmonella cause diarrhea, but one species, S. typhi, frequently disseminates into the blood and causes a severe form of salmonellosis called typhoid fever. In 1998, 375 cases of typhoid fever were reported in the U.S. but most of these cases were acquired during foreign travel

Clinical Disease

• Enteritis (def) is the most common form of salmonellosis. Symptoms generally appear 6-48 hours after ingestion of the bacteria and include vomiting, nausea, nonbloody diarrhea, fever, abdominal cramps, myalgias (def), and headache. Symptoms generally last from 2 days to 1 week followed by spontaneous resolution.
• All species of Salmonella can cause bacteremia (def) but S. typhi, S. paratyphi, and S. choleraesuis are the most common species to cause bacteremia.

From Salmonellosis, by Michael Zapor, MD, PhD, Fellow, Infectious Disease Section, Department of Medicine, Walter Reed Army Medical Center and David P Dooley, MD, Chief, Associate Fellowship Director, Department of Medicine, Infectious Disease Service, Brooke Army Medical Center; Associate Professor, Department of Medicine, University of Texas at San Antonio.