Is Shigella flexneri oxidase positive?

shigella species are oxidase negative – oxidase positive samples are non-shigella species.

Is Shigella citrate positive or negative?

Escherichia coli and Shigella dysenteriae are citrate negative.

Is Shigella catalase positive or negative?

Shigella species are facultative anaerobes, are non-motile, oxidase negative, urease negative, do not decarboxylate lysine, and all except S. dysenteriae type 1 are catalase positive1. The species may be differentiated by biochemical tests and serology of their lipopolysaccharides2.

What method is used to identify Shigella?

The type species is Shigella dysenteriae. Isolates from primary culture are identified by colonial appearance, biochemical tests and serology (agglutination with specific antisera).

Is Salmonella oxidase positive or negative?

Salmonella enterica, a Gram-negative, non-sporing, catalase-positive, oxidase-negative facultative anaerobic bacilli is a significant cause of morbidity and mortality in humans and animals, with multidrug-resistant S. enterica serovar Typhimurium being an emerging problem (1–4).

Is Shigella flexneri a lactose fermenter?

Shigella species are Gram-negative, nonmotile, rod-shaped, facultative anaerobes that almost universally are unable to produce hydrogen sulfide, do not ferment lactose or show late lactose fermentation, fail to utilize citrate as a sole carbon source, and do not generate gas from carbohydrate fermentation.

Is Shigella flexneri Gram positive or negative?

Shigellae are Gram-negative, nonmotile, facultatively anaerobic, non-spore-forming rods. Shigella are differentiated from the closely related Escherichia coli on the basis of pathogenicity, physiology (failure to ferment lactose or decarboxylate lysine) and serology.

Is Shigella dysenteriae catalase-negative?

dysenteriae type 1, as well as S. dysenteriae of types 3, 4, 6, 9, 11 and 12 and S. boydii of type 12, were found catalase-negative.

Is Shigella flexneri motile?

Shigella flexneri is a Gram-negative bacterial pathogen that can grow directly in the cytoplasm of infected host cells and uses a form of actin-based motility for intra- and intercellular spread.

How can you tell the difference between Salmonella and shigella?

Salmonella will not ferment lactose, but produce hydrogen sulfide (H2S) gas. The resulting bacterial colonies will appear colorless with black centers. Shigella do not ferment lactose or produce hydrogen sulfide gas, so the resulting colonies will be colorless.

What organisms are oxidase-positive?

Oxidase Positive Organisms: Pseudomonas, Neisseria, Alcaligens, Aeromonas, Campylobacter, Vibrio, Brucella, Pasteurella, Moraxella, Helicobacter pylori, Legionella pneumophila, etc.

Does Shigella grow on MacConkey Agar?

Shigella grows as non-lactose-fermenting colonies on MacConkey agar, although a more selective agar is used for the isolation of Shigella from feces, such as deoxycholate citrate agar and xylose lysine deoxycholate agar.