CAMP test


The CAMP test is a test to identify group B β-hemolytic streptococci based on their formation of a substance that enlarges the area of hemolysis formed by the β-hemolysin elaborated from Staphylococcus aureus.

CAMP factor

Although the test is usually used to identify group B streptococcus, there is some evidence that the CAMP factor gene is present in several groups of streptococci, including group A.
A similar factor has been identified in Bartonella henselae.

Uses

The CAMP test can be used to identify Streptococcus agalactiae. Though not strongly beta-hemolytic on its own, group B strep presents with wedge-shaped colonies in the presence of Staphylococcus aureus.
It can also be used to identify Listeria monocytogenes which produces a positive CAMP reaction.

Setup

  1. Streak a beta-lysin–producing strain of aureus down the center of a sheep blood agar plate.
  2. The test organism streak should be 3 to 4 cm long.
  3. Streak test organisms across the plate perpendicular to the S. aureus streak within 2 mm..
  4. Incubate at 35°-37°C in ambient air for 18-24 hours.
  5. Wedge shaped pattern radiating from the test organism near the S. aureus indicates positivity

    History

CAMP is an acronym for "Christie–Atkins–Munch-Petersen", for the three researchers who discovered the phenomenon.
It is often incorrectly reported as the product of four people. The true relationship is the reason for two en dashes and then one hyphen in Christie–Atkins–Munch-Petersen.
The name of the test bears no relationship to the name of the second messenger cyclic adenosine monophosphate.