What is the Gram stain morphology of Salmonella?

What is the Gram stain morphology of Salmonella?

Salmonella is a Gram-negative facultative rod-shaped bacterium in the same proteobacterial family as Escherichia coli, the family Enterobacteriaceae, trivially known as “enteric” bacteria.

Can Salmonella be Gram stained?

(B) Salmonella typhimurium L forms are negative Gram stain and filamentous bacillus.

What is the gram reaction and shape of Salmonella?

Salmonella enterica is a Gram-negative rod-shaped enterobacterium. The size of the rods ranges from 0.7–1.5 μm to 2.2–5.0 μm; Salmonella produces colonies of approximately 2–4 mm in diameter. They have peritrichous flagella, although they are sometimes nonmotile. They are facultative anaerobic chemoorganotrophs.

Is Typhoid Gram-negative bacilli?

Typhoid fever is a systemic disease caused by the gram-negative bacterium Salmonella enterica serotype Typhi (S. Typhi). Symptoms are high fever, prostration, abdominal pain, and a rose-colored rash.

What stain is used for Salmonella typhi?

A photomicrograph of Salmonella typhosus bacteria using a Flagellar stain technique. Also known as Eberthella typhi and Bacillus typhosus, is the cause of Typhoid fever.

Is bacillus gram positive or negative?

Bacillus species are rod-shaped, endospore-forming aerobic or facultatively anaerobic, Gram-positive bacteria; in some species cultures may turn Gram-negative with age.

What color is Salmonella bacteria?

Typical Salmonella appear as blue-green to blue colonies with black centers. Many Salmonella cultures have large glossy black centers or may appear as almost completely black colonies. ➢ H2S negative Salmonella appear as blue-green to blue colonies without black centers.

Is Salmonella Gram positive or negative?

Salmonella species are Gram-negative, flagellated facultatively anaerobic bacilli characterized by O, H, and Vi antigens. There are over 1800 known serovars which current classification considers to be separate species.

Is Salmonella typhi viral or bacterial?

Typhoid fever is caused by dangerous bacteria called Salmonella typhi. Salmonella typhi is related to the bacteria that cause salmonellosis, another serious intestinal infection, but they aren’t the same.

What is the color of Salmonella typhi?

S. Typhimurium colonies grown on HE agar are blue-green in color indcating that the bacterium does not ferment lactose However it does produce hydrogen sulfide, (H2S), as indicated by black deposits in the centers of the colonies. (CDC).