exotoxins produced by gram-positive cocci species
able to destroy red blood cells & hemoglobin
Blood agar is sometimes called? why?
Sheep blood agar
because it contains 5% sheep blood in tryptic soy agar base
3 major types of hemolysis are:
complete destruction of RBC's and hemoglobin, results in a clearing of the medium around the colonies
pratial destruction of RBC's and produces a greenish discoloration of the agar around the colonies
non-hemolysis and appears as simple growth with no change to the medium
hemolysins produced by sreptococci are called? what are their 2 forms?
: O & S
expresses maximal activity under anaerobic conditions
express itself optimally under anearobic conditions
streak stab technique:
easiest method of providing an enviroment favorable for streptolysisns on blood agar
plate is streaked for isolation and stabbed
stab encourages streptolysin activity because of the reduced oxygen concntration of the subsurface enviro
blood agar is used for isolation and cultivation of many types of? differentiates?
based on hemolytic characteristics, especilly w/in streptococcus, enterococcus and aerococcus.
Blood Agar Results:
clearing around growth
greening around growth
No change in the medium
organisms hemolyzes RBC's completely (beta)
organism hemolyzes RBC's partially (alpha)
Organism does not hemolyze RBC's (gamma)