5.21: Blood agar Flashcards
In the last century, bacteria have been differentiated and characterized based on their ?? and ?? diversity using ?? tests.
-biochemical
-physiological
-differential
Differential tests identifies the presence or absence of an ?? or multiple ??
-enzyme
-enzymes
Culture media are a mixture of ?? that allow the growth of microorganisms and can be divided into 4 categories:
-nutrients
1. selective media
2. enriched nonselective media
3. Differential media
4. Specialized media
Several species of gram-positive cocci produce exotoxins called ??, which are able to destroy red blood cells and hemoglobins
-hemolysins
Blood agar includes ??% blood (?? blood) in a tryptic soy agar base and allows to differentiate bacteria based on their ability to hemolyze RBCs
-5%
-sheep
There are 3 major types of hemolysis:
-beta(b) hemolysis
-alpha hemolysis
-gamma(y) hemolysis
Beta hemolysis:
-complete destruction of RBCs and hemoglobin
-yellowish color
Alpha hemolysis:
-partial destruction of RBCs
-green color
Gamma hemolysis:
-nonhemolysis
-no change to medium, no color
If an organism that is grown on a Blood Agar plate does not cause any visible change to the blood in the agar, the pattern is called
-gamma hemolysis
After incubation on blood agar plate, the medium surrounding the organism is observed to have a greenish discoloration. The organism would be described as:
-alpha hemolytic
Blood agar is characterized by having:
-5% of red blood cells
Hemolysins are:
-exotoxins
TRUE OR FLASE:
The exotosins that are produced by certain microorganisms and can be specifically detected using blood agar are called hemolysins:
-TRUE
Selective media is a media that:
-Favors the growth of some microorganisms and inhibits others
