Which Gram-negative bacteria are oxidase-positive?

Gram-negative, rod-shaped, oxidase-positive bacteria, such as Aeromonas and Pseduomonas, are widespread in the environment. Aeromonas are emerging human pathogens associated with extraintestinal and opportunistic infections.

What organisms are gram-positive diplococci?

Streptococcus pneumoniae is a gram-positive, encapsulated, lancet-shaped diplococci, most commonly causing otitis media, pneumonia, sinusitis, and meningitis.

Which Gram-negative cocci is positive for oxidase test?

The Gram-negative diplococci Neisseria and Moraxella are oxidase-positive. Many Gram-negative, spiral curved rods are also oxidase-positive, which includes Helicobacter pylori, Vibrio cholerae, and Campylobacter jejuni.

Is diplococcus Gram-positive or negative?

* As mentioned, there are both Gram-positive and Gram-negative diplococcus bacteria. Gram-negative diplococci like Moraxella catarrhalis will appear pale pink in color.

Why is Pseudomonas aeruginosa oxidase positive?

In the oxidase test, artificial electron donors and acceptors are provided. When the electron donor is oxidized by cytochrome oxidase it turns a dark purple. This is considered a positive result. In the picture below the organism on the right (Pseudomonas aeruginosa) is oxidase positive.

What Gram-negative bacteria is oxidase negative?

Thirty-five strains of oxidase-negative nonfermenting Gram-negative bacteria were identified as Acinetobacter anitratus (21 strains), Moraxella lwoffi (11 strains) and Pseudomonas maltophilia (3 strains).

What is gram neg diplococci?

Examples of gram-negative diplococci are Neisseria spp. and Moraxella catarrhalis. Examples of gram-positive diplococci are Streptococcus pneumoniae and Enterococcus spp. Presumably, diplococcus has been implicated in encephalitis lethargica.

Is Streptococcus pneumoniae gram-positive diplococci?

Streptococcus pneumoniae is a gram-positive, α-hemolytic, lancet-shaped diplococcus and is bile soluble and optochin sensitive.

Can diplococci be gram-negative?

Types. Examples of gram-negative diplococci are Neisseria spp. and Moraxella catarrhalis. Examples of gram-positive diplococci are Streptococcus pneumoniae and Enterococcus spp.

Which Pseudomonas is oxidase negative?

Pseudomonas luteola and P. oryzihabitans typically exhibit rough, wrinkled, adherent colonies or, more rarely, smooth colonies. They can both be distinguished from other pseudomonads by their negative oxidase reaction and production of non-diffusible yellow pigment.

Are all Pseudomonas oxidase positive?

Clinical Pseudomonas isolates are oxidase-positive (except for Pseudomonas luteola and Pseudomonas oryzihabitans) and catalase-positive. On MacConkey agar, Pseudomonas spp. are identified as nonlactase fermenters.