What type of organism is Salmonella enterica?

Salmonella enterica is classified as a Gram-negative rod. This classification is based on its cell wall structure, which consists of a thin peptidoglycan layer surrounded by an outer membrane containing lipopolysaccharides. In a Gram stain procedure, the cells of Salmonella enterica do not retain the crystal violet dye, resulting in a pink coloration after the application of a counterstain. This characteristic is typical of Gram-negative bacteria, distinguishing them from Gram-positive organisms, which retain the crystal violet dye and appear purple.

Additionally, Salmonella enterica is known for its pathogenicity, as it is one of the leading causes of foodborne illness in humans. Understanding its Gram-negative nature is important for clinical microbiology and helps in determining appropriate antibiotic treatment, since many antibiotics are more effective against Gram-positive bacteria. The rod shape is also significant in identifying the bacterium and assessing its behavior, such as motility and growth patterns in cultures.