AGAR MEDIA and BIOCHEMICAL TEST FOR ID OF BACTERIA

Blood Agar Plate (BAP)

Used as an isolation medium and for detection of hemolysis

Brilliant Green Agar

Used for the isolation of Salmonella species

• the dye indicator inhibits gram-positive bacteria, gram-negative bacteria, and other enteric bacteria

Brilliant Green Agar

Sucrose and lactose negative Salmonellae form white to reddish colonies with a red zone around colonies on this agar

Brilliant Green Agar

Sucrose and lactose fermenters form yellow-green colonies with a yellow-green zone on this agar

Salmonella

Bacteria that will appear yellow-green on BGA with yellow-green halo EXCEPT:

Salmonella

Form white to pinkish red colonies on BGA

Christie-Atkins-Munch-Petersen

CAMP in CAMP Test means

CAMP Test

uses sheep blood agar to identify specific bacteria, mainly Streptococcus agalactiae (Group B Strep) by detecting its _____ factor, which synergistically enhances hemolysis with Staphylococcus aureus beta-lysin

• creates characteristic arrowhead zone where they meet

  • vertical = Staph aureus

  • horizontal/arrow = Strep agalactiae

Eosin-Methylene-Blue Agar (EMB)

inhibits gram-positive bacteria due to the presence of the dyes

• distinguishes non-lactose fermenters (Shigella and Salmonella - transparent or amber colonies) from lactose fermenters (EC - green-metallic colonies, KP and EA - gray-brown center)

Escherichia coli

produces green-metallic colonies on EMB

EA and KP

produces gray-brown center on EMB

CAMP Medium

Mediums used to differentiate lactose from non-lactose fermenters EXCEPT:

Mannitol Salt Agar (MSA)

Selective (for Staphylococci) and differential (Staphylococcus aureus) medium used for the isolation of salt-tolerant bacteria, if it ferments ________, it turns the agar yellow

Mannitol Salt Agar (MSA)

differential media used to isolate pathogenic Staph, Staphylococcus aureus

MacConkey Agar (MCA)

selective and differential microbiological culture medium used to isolate and differentiate Gram-negative bacteria, especially enteric organisms (Enterobacteriaceae) from Gram-positive ones, based on their ability to ferment lactose.

• key ingredients: bile salts, crystal violet, lactose, pH indicator

Salmonella

grow as pink colonies on MacConkey agar (Gram-negative, lactose fermenters) EXCEPT:

Salmonella and Shigella

forms pale to colorless colonies on MacConkey Agar (MCA)

Sabouraud’s Dextrose Agar

Used for isolation and propagation of fungi

• contains high sugar content (4.0%) abd gas a low pH (5.6) which inhibits bacterial growth

Salmonella Shigella (SS) Agar

Used for the isolation of salmonallae and shigellae

• inhibits gram-positive and lactose fermenting and gram negative bacteria due to presence of brilliant green

  • pink to red for lactose fermenters

  • colorless for non-lactose fermenters

  • hydrogen sulfide production (black centers)

Salmonella and Proteus mirabilis

forms pink colonies with black centers on SS agar

Barbour Stoenner-Kelly Medium

Media for identifying borreliae culture

Brachyspira hyodysenteriae

Shows strong beta hemolysis on BAP

• “ring phenomenon”

MALDI-TOF

Confirmatory procedure used to identify yeast

• protein profiling

BD Phoenix Yeast ID

Yeast identification using biochemical instrument

• panel contains 47 wells with dried biochemical substrates for fermentation, oxidation, degredation, and hydrolysis in combination with chromogenic and fluorogenic substrates along with carbon sources for identification

Biolog

Yeast identification by biochemical profiling

• test reactions performed within a 96 well microplate, 71 different carbon compounds including sugars, carboxylic acids, amino acids, and peptides to provide a wealth of discriminating biochemical characterizations

Vitex

Yeast identification by biochemical profiling

• ID test cards composed of microwells containing carbon assimilation substrates and enzymes activity (64 tests). Inoculum (test yeast) is inoculated into a well by apparatus integrated into the machine

1. Commercial identification kits

2. Automated identification system

Confirmatory yeast identification using biochemical profiling can be (2)

Sugar Assimilation Test

Example of commercial identification test kit

Germ tubes

Method to differentiate Candida sp

India Ink

Method used to detect Cryptococcus neoformans which has capsule, non-myecilated, non-fermenting

Escherichia coli

Produces yellow colonies on XLD (lactose fermenter)

Salmonella

produces black colonies on XLD