Salmonella

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Medical Author:

Charles Patrick Davis, MD, PhD

Charles Patrick Davis, MD, PhD

Dr. Charles "Pat" Davis, MD, PhD, is a board certified Emergency Medicine doctor who currently practices as a consultant and staff member for hospitals. He has a PhD in Microbiology (UT at Austin), and the MD (Univ. Texas Medical Branch, Galveston). He is a Clinical Professor (retired) in the Division of Emergency Medicine, UT Health Science Center at San Antonio, and has been the Chief of Emergency Medicine at UT Medical Branch and at UTHSCSA with over 250 publications.

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Medical Editor:

Melissa Conrad Stöppler, MD, Chief Medical Editor

Melissa Conrad Stöppler, MD, Chief Medical Editor

Melissa Conrad Stöppler, MD, is a U.S. board-certified Anatomic Pathologist with subspecialty training in the fields of Experimental and Molecular Pathology. Dr. Stöppler's educational background includes a BA with Highest Distinction from the University of Virginia and an MD from the University of North Carolina. She completed residency training in Anatomic Pathology at Georgetown University followed by subspecialty fellowship training in molecular diagnostics and experimental pathology.

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• Salmonella Overview
• Symptoms of Salmonella Infection
• How Common Are Salmonella Infections?
• How Do Salmonella spp Cause Disease(s)?
• Risk Factors for Salmonella Infection
• When to Seek Medical Care
• Diagnosis of Salmonella Infection
• Treatment of Salmonella Infection
• Complications of Salmonella Infection
• What Is the Prognosis for Patients Infected With Salmonella?
• Prevention of Salmonella Infections
• For More Information
• Synonyms and Keywords
• Author and Editor
• Viewer Comments: Salmonella - Describe Your Symptoms Experienced

Salmonella Overview

Salmonella are a group of closely related rod-shaped, Gram-stained negative bacteria that have flagella (tail-like structures used for movement). Salmonella types are further characterized by specific proteins found on the bacterial and flagellar surface. Each different combination of protein coats is termed a serovar. Serovars are distinguished usually by special laboratories with immunologic tests.

The nomenclature of specific types of Salmonella has changed in recent decades. Currently, many investigators consider the over 2,500 serovars to be members of only two species, S. enterica or S. bongori. However, many serovars were considered to be and named as individual species in the past before more sophisticated genetic methods to characterize separate species were available. Consequently, many of the old serovar names are still seen in the medical literature, such as S. enteritidis, S. typhimurium, S. typhi, and S. choleraesuis. In other cases, doctors simply avoid the name problem and identify all isolates as Salmonella spp (species) since the bacteria of this group are so closely related.

Salmonella infections cause diseases in humans (for example, salmonellosis, gastroenteritis, typhoid fever, and paratyphoid fever), animals, and birds. They are one of the major causes of gastroenteritis in both industrialized and third world countries. Salmonella were first isolated from infected pigs in 1885 by Theobald Smith and were named after his lab director, D. E. Salmon.