The CAMP test (Christie–Atkins–Munch-Peterson) is a test to identify group B β-hemolytic

streptococci ''Streptococcus'' is a genus of gram-positive ' (plural ) or spherical bacteria that belongs to the family Streptococcaceae, within the order Lactobacillales (lactic acid bacteria), in the phylum Bacillota. Cell division in streptococci ...

(''

Streptococcus agalactiae ''Streptococcus agalactiae'' (also known as group B streptococcus or GBS) is a gram-positive coccus (round bacterium) with a tendency to form chains (as reflected by the genus name ''Streptococcus''). It is a beta-hemolytic, catalase-negative, a ...

'') based on their formation of a substance (CAMP factor) that enlarges the area of

hemolysis Hemolysis or haemolysis (), also known by several other names, is the rupturing (lysis) of red blood cells (erythrocytes) and the release of their contents (cytoplasm) into surrounding fluid (e.g. blood plasma). Hemolysis may occur in vivo o ...

formed by the β-

hemolysin Hemolysins or haemolysins are lipids and proteins that cause lysis of red blood cells by disrupting the cell membrane. Although the lytic activity of some microbe-derived hemolysins on red blood cells may be of great importance for nutrient acqu ...

elaborated from ''

Staphylococcus aureus ''Staphylococcus aureus'' is a Gram-positive spherically shaped bacterium, a member of the Bacillota, and is a usual member of the microbiota of the body, frequently found in the upper respiratory tract and on the skin. It is often posit ...

''.

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 Group A is a set of motorsport regulations administered by the FIA covering production derived vehicles intended for competition, usually in touring car racing and rallying. In contrast to the short-lived Group B and Group C, Group A vehicles w ...

. A similar factor has been identified in ''

Bartonella henselae ''Bartonella henselae'', formerly ''Rochalimæa henselae'', is a bacterium that is the causative agent of cat-scratch disease (bartonellosis). ''Bartonella henselae'' is a member of the genus ''Bartonella'', one of the most common types of bacte ...

''.

Uses

The CAMP test can be used to identify ''

''. Though not strongly beta-hemolytic on its own, group B strep presents with wedge-shaped colonies in the presence of ''

''. It can also be used to identify ''

Listeria monocytogenes ''Listeria monocytogenes'' is the species of pathogenic bacteria that causes the infection listeriosis. It is a facultative anaerobic bacterium, capable of surviving in the presence or absence of oxygen. It can grow and reproduce inside the hos ...

'' which produces a positive CAMP reaction.

Setup

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

History

''CAMP'' is an acronym for "Christie–Atkins–Munch-Peterson", for the three researchers who discovered the phenomenon.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 It is often incorrectly reported as the product of ''four'' people (counting Munch-Petersen as two people). The true relationship (three people) is the reason for two

en dashes The dash is a punctuation mark consisting of a long horizontal line. It is similar in appearance to the hyphen but is longer and sometimes higher from the baseline. The most common versions are the endash , generally longer than the hyphen b ...

and then one

hyphen The hyphen is a punctuation mark used to join words and to separate syllables of a single word. The use of hyphens is called hyphenation. ''Son-in-law'' is an example of a hyphenated word. The hyphen is sometimes confused with dashes ( figur ...

in Christie–Atkins–Munch-Petersen. The name of the test bears no relationship to the name of the

second messenger Second messengers are intracellular signaling molecules released by the cell in response to exposure to extracellular signaling molecules—the first messengers. (Intercellular signals, a non-local form or cell signaling, encompassing both first m ...

cyclic adenosine monophosphate Cyclic adenosine monophosphate (cAMP, cyclic AMP, or 3',5'-cyclic adenosine monophosphate) is a second messenger important in many biological processes. cAMP is a derivative of adenosine triphosphate (ATP) and used for intracellular signal transd ...

(commonly referred to as cAMP).

References

Medical tests Microbiology techniques {{Med-diagnostic-stub