Brucella

Pathogen in blood, lymph nodes, bone marrow
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).
Non-hemolytic (γ-hemolysis): If an organism does not induce any hemolysis on a blood agar plate, it is said to display gamma or no hemolysis. The agar under and around the colony is unchanged.
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.
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.
Indole test: The indole test is a biochemical test performed on bacterial species to determine the ability of the organism to split indole form the amino acid tryptophan. The results of an indole test are indicated by a change in color following a reaction after the addition of Kovacs reagent. A positive result is shown by the presence of a red color. A negative result appears yellow. The Indole test is a key test for separating Proteus mirabilis (indole-negative) and Proteus vulgaris (indole-positive) and Klebsiella pneumoniae (indole negative) and K. pneumoniae oxytoca (indole-positive).
Urease: Urease is an enzyme that catalyzes the hydrolysis of urea into carbon dioxide and ammonia. Urease is found in certain bacteria and yeast. Cryptococcus is urease-positive and Candida is urease-negative.

 - Do not grow on MacConkey

 - Non-hemolytic, slow-growing colonies

 - Catalase positive

 - Oxidase positive  

 - Indole negative

 - Rapid positive urease

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.

 Gram – or Gram variable short rod. Tends to stain  Gram positive in original  samples.
@ Ellen Jo Baron 2007

 

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.
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).

 Colonies resemble Enterobacteriaceae on BAP

 but do not grow on MacConkey

Pasteurella multocida

Pathogen in bite wounds, blood

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.
 - Regular Gram-negative rod

 - Do not grow on MacConkey

 - Non-hemolytic, good growth on BAP

 - Catalase positive

 - Oxidase positive

 - Indole positive - rapid

 - Urease negative

 - Smells like bleach