The Enterobacteriaceae and Other Related Enterobacteria Flashcards
(38 cards)
On MAC:
Typical strong lactose fermenters produce
red colonies surrounded by a zone of precipitated bile
On MAC:
Slow or weak lactose fermenters produce
light pink colonies or colonies that are clear at the periphery and have pink centers
On MAC:
Non-lactose fermenters produce
colorless colonies or transparent colonies
On EMB:
Typical strong lactose fermenters produce colonies that are
green-black with metallic sheen
On EMB:
Slow or weak lactose fermenters produce
pink to purple colonies
On EMB:
Non-lactose fermenters produce
colorless colonies or transparent colonies
On SSA:
Slight growth of lactose fermenters that produce
pink or red colonies
On SSA:
Salmonella and Proteus colonies are
colorless with black centers
On SSA:
Shigella colonies are
colorless with no blackening
- Triple Sugar Iron Agar Reactions
is indicated by the retention of the original red color of
Alkalinization or nonfermentation of the carbohydrates
designates alkaline reaction; designates acidic reaction
“K”; “A”
indicated by a change in the color of the medium from red to yellow and this may be observed in the butt portion only or throughout the medium
Acid production from fermentation of carbohydrates
indicated by gas bubbles or splitting of the agar in the butt portion
Gas production
indicated by a black discoloration of the medium which first appears or remains confined in the butt portion
Hydrogen sulfide (H2S)
alkaline slant and bua, no gas and H2S producTon
K/K
alkaline slant, acid bua, with gas and H2S producTon
K/Ag + H2S
acid slant and bua, with gas, no H2S producTon
A/Ag
INDOLE TEST: Reagent
15 drops of Ehrlich’s (+ 1 ml of xylene or chloroform) or Kovac’s reagent
INDOLE TEST: Positive result
Bright fuschia red color at the interface of the reagent and the broth (or xylene layer)
INDOLE TEST: Negative result
Yellow color or no color change
METHYL RED TEST: Reagent
5 drops of methyl red indicator
METHYL RED TEST: Positive result
Red color on the surface of the medium
METHYL RED TEST: Negative result
Yellow to orange color
VOGES-PROSKAUER TEST: Reagent
- 6 ml of 5% alpha-naphthol
0. 2 ml of 40% KOH
