PetriKey

Lab method

CAMP test

Arrowhead synergy = Group B strep / Listeria

kamp

Gram positivegram-positivebeta-hemolyticsynergydifferentiationcocci

High-yield clue

An arrowhead of enhanced hemolysis where the streak meets S. aureus beta-hemolysin marks CAMP-positive Group B strep (S. agalactiae).

Overview

A synergistic-hemolysis concept where CAMP factor enlarges the beta-hemolysis of Staphylococcus aureus, producing a classic arrowhead zone used to flag Group B streptococcus.

Classification

  • Synergistic hemolysis concept
  • Beta-hemolytic identification
  • Arrowhead pattern readout

Lab & identification clues

  • CAMP factor + S. aureus beta-hemolysin = arrowhead
  • Positive: Group B strep (S. agalactiae)
  • Listeria monocytogenes is also CAMP-positive
  • Read against a perpendicular S. aureus streak

Associations

  • Group B strep identification vocabulary
  • Listeria study cross-reference
  • Beta-hemolysis synergy framing

Commonly confused with

  • Bacitracin test
  • Hippurate hydrolysis test

Your notes

Original concept summary for coursework. Sources checked: OpenStax Microbiology 2e and NCBI Bookshelf Medical Microbiology; reviewed 2026-06. Describes vocabulary and interpretation concepts only; not a lab protocol and not for handling specimens or identifying patient isolates.

OpenStax: Microbiology 2e staining, media, and biochemical-test foundationssourceNCBI Bookshelf: Medical Microbiology diagnostic concept foundationssource