CAMP test

This is an example of a positive CAMP test indicated by the formation of an arrowhead where the Strep group B (Streptococcus agalactiae) meets the Staphylococcus aureus (white middle streak).

The CAMP test is a test to identify Group B β-streptococci[1][2] based on their formation of a substance (CAMP factor[3]) that enlarges the area of hemolysis formed by β-hemolysin from Staphylococcus aureus. It is frequently used to identify Group B Strep (Streptococcus agalactiae).

CAMP factor

Although usually used to identify group "B", there is some evidence that the CAMP factor gene is present in several groups of streptococci, including group "A".[4]

A similar factor has been identified in Bartonella henselae.[5]


It can be used to identify Streptococcus agalactiae. Though not strongly beta-hemolytic on its own,[6] it presents with a wedge-shape in the presence of Staphylococcus aureus.[7]


CAMP is an acronym for "Christie–Atkins–Munch-Petersen",[8][9][10] for the three researchers who discovered the phenomenon.[11]

It is often incorrectly reported as the product of four people (counting Munch-Petersen as two people).[12] The true relationship (three people) is the reason for two en dashes and then one hyphen in "Christie–Atkins–Munch-Petersen".

The name has no relationship to cyclic adenosine monophosphate (cAMP).


  1. Phillips EA, Tapsall JW, Smith DD (August 1980). "Rapid tube CAMP test for identification of Streptococcus agalactiae (Lancefield group B)". J. Clin. Microbiol. 12 (2): 135–7. PMC 273541Freely accessible. PMID 7014603.
  2. Wilkinson HW (July 1977). "CAMP-disk test for presumptive identification of group B streptococci". J. Clin. Microbiol. 6 (1): 42–5. PMC 274694Freely accessible. PMID 328534.
  3. "Laboratory Demonstrations". Archived from the original on September 28, 2008. Retrieved 2008-12-12.
  4. Gase K, Ferretti JJ, Primeaux C, McShan WM (September 1999). "Identification, cloning, and expression of the CAMP factor gene (cfa) of group A streptococci". Infect. Immun. 67 (9): 4725–31. PMC 96801Freely accessible. PMID 10456923.
  5. Litwin CM, Johnson JM (July 2005). "Identification, cloning, and expression of the CAMP-like factor autotransporter gene (cfa) of Bartonella henselae". Infect. Immun. 73 (7): 4205–13. doi:10.1128/IAI.73.7.4205-4213.2005. PMC 1168562Freely accessible. PMID 15972511.
  6. "Microbiology Primer: Hemolysis". Retrieved 2008-12-12.
  7. "Streptococcaceae Answers". Retrieved 2008-12-12.
  8. Ratner HB, Weeks LS, Stratton CW (August 1986). "Evaluation of spot CAMP test for identification of group B streptococci". J. Clin. Microbiol. 24 (2): 296–7. PMC 268893Freely accessible. PMID 3528214.
  9. Nsagha DS, Bello CS, Kandakai-Olukemi YT (January 2000). "Hippurate hydrolysis and Christie, Atkins, Munch-Peterson tests as epidemiological diagnostic tools for Streptococcus agalactiae carriage in pregnancy". East Afr Med J. 77 (1): 34–6. doi:10.4314/eamj.v77i1.46373. PMID 10944837.
  10. Valanne S, McDowell A, Ramage G, et al. (May 2005). "CAMP factor homologues in Propionibacterium acnes: a new protein family differentially expressed by types I and II". Microbiology (Reading, Engl.). 151 (Pt 5): 1369–79. doi:10.1099/mic.0.27788-0. PMID 15870447.
  11. Christie, R., Atkins, NE and Munch-Petersen, E. (1944). A note on a lytic phenomenon shown by group B streptococci. Aust. J. Exp. Biol. Med. Sci. 22, 197-200
  12. "Streptococci". Retrieved 2008-12-12.

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