Burkholderia Pseudomallei

Catalase test: The catalase test is used to differentiate some bacterial species. The test is done by placing a drop of hydrogen peroxide on a microscope slide. Using an applicator stick, a small portion of a colony is then added to a drop of hydrogen peroxide drop.

If bubbles or froth forms, the organism is said to be catalase-positive.
Staphylococci and microcci are catalase-positive
If no bubbles form, the organism is catalase-negative. Streptococci and Enterococci are catalase-negative

Oxidase: The oxidase test is used to determine if a bacterium produces certain cytochrome c oxidases. The reagent, tetramethyl-p-phenylenediamine is used as a redox indicator. The reagent turns dark blue when oxidized (oxidase positive). The reagent is colorless when reduced (oxidase-negative). Pseudomonas species and Aeromonas species are gram-negative bacilli that are oxidase-positive. Neisseria species are gram-negative cocci that are oxidase positive.

Gram stain: The Gram stain, is a laboratory staining technique that distinguishes between two groups of bacteria that have differences in the structure of their cell walls. Standard bacterial taxonomy makes a distinction between Gram-negative bacteria, which stain red/pink and the Gram-positive bacteria, which stain blue/purple. Different antimicrobial agents are directed specifically at gram-positive bacteria and gram-negative bacteria.

MacConkey: MacConkey agar is a selective medium that inhibits the growth of Gram-positive bateria due to the presence of crystal violet and bile salts. Most Gram-negative bacteria grow well on MacConkey. MacConkey agar also contains neutral red (a pH indicator) and lactose (a disaccharide). Lactose fermenting bacteria or Lactose + bacteria on MacConkey will appear as bright pink colonies. Non-lactose fermenting bacteria will be colorless (or, if they have any color, will be their natural color rather than pink).

BAP or SBA: An abbreviation for blood agar plate or sheep blood agar. Blood agar contains mammalian blood (usually sheep, rabbit or horse), typically at a concentration of 5-10%. Blood agar is an enriched media used to isolate bacteria and to detect hemolytic activity.

Characteristic	B. pseudomallei	B. cepacia	P. stutzeri
Wrinkled colony	+	–	Later
Gas from Nitrate	+	–	+/-
Arginine dihydrolase	+	–	–
Musty odor	+	–	–