microbiology topic hemolysis blood agar and hemolysis beta hemolysis

1. HEMOLYSIS &
BLOOD AGAR
ABHIJITH SP
CVAS POOKODE

2. INTRODUCTION
• Blood agar is a solid growth medium that contains red blood cells.(5% SHEEP BLOOD)
• The medium is used to detect bacteria that produces enzymes to break apart blood cells.
This process is termed as Hemolysis.
• The degree to which blood cells are hemolyzed is used to distinguish bacteria from one
another.
• There are mainly 3 types of hemolysis pattern:
• 1.Alpha Hemolysis
• 2.Beta hemolysis
• 3.Gamma Hemolysis
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4. 1.Beta Hemolysis
• Complete or True lysis of RBCs.
• A clear zone, approaching the color and transparency of base medium,
surrounds the colony.
• E.g.: Staphylococcus aureus, Streptococcus pyogenes
• Complete hemolysis with transparency.
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6. 2.Alpha Hemolysis
• Reduction of RBC hemoglobin to methemoglobin in the medium
surrounding colony.
• This causes greenish brown discoloration in the medium.
• The color can be equated with bruising of cells.
• This is actually not a partial hemolysis or incomplete hemolysis.
• Partial hemolysis without transparency.
• E.g.: Streptococcus pneumoniae, Streptococcus mutans
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8. 3.Gamma Hemolysis
• This is somewhat self contradictory.
• Gamma indicates lack of hemolysis.
• There should be no reaction in the surrounding medium.
• Gamma streptococcus are usually non-hemolytic but after 24hrs of
incubation they produce slight alpha hemolysis.
• E.g.: Enterococcus faecalis
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10. FACTS.
• The Staphylococcus aureus produces 4 types of hemolysin toxin. They are
alpha, beta, gamma, delta.
• But the beta hemolysin here produce partial hemolysis or Hot-Cold
Hemolysis.
• They produce synergistic hemolysis when streaked together with
Streptococcus agalactiae in CAMP Test.
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11. THANK YOU