The principle of the CAMP test lies in detecting the ability of microorganisms to produce a thermostable, extracellular protein called the CAMP factor. This factor enhances the lysis of red blood cells (hemolysis) caused by Staphylococcus aureus beta-lysin.
Here's a breakdown:
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CAMP Factor Production: Certain microorganisms, notably Streptococcus agalactiae (Group B Streptococcus), produce and secrete the CAMP factor.
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Interaction with Staphylococcus aureus Beta-Lysin: When the CAMP factor interacts with beta-lysin produced by Staphylococcus aureus, it synergistically enhances the lysis of red blood cells. Beta-lysin by itself causes only partial lysis.
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Visual Observation: On a blood agar plate, this enhanced hemolysis appears as an arrowhead-shaped zone of clearing where the Streptococcus species' growth nears the Staphylococcus aureus streak.
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Identification: The presence of this distinct arrowhead-shaped zone is a positive result, indicating the production of the CAMP factor and aiding in the identification of the specific microorganism, such as Streptococcus agalactiae.
In essence, the CAMP test leverages the synergistic hemolytic activity between a bacterial CAMP factor and Staphylococcus aureus beta-lysin to identify microorganisms that produce the CAMP factor.
