◉ Results : A positive test CAMP appears as an area of arrowhead hemolysis adjacent to where the two lines of streaks come together. A lack of enhanced hemolysis near the colony being tested is a negative CAMP test
☰ Summary :
CAMP test has been widely used since its discovery, Christie et al 1944, in diagnostic microbiology for the presumptive identification of Streptococcus agalactiae (an important cause of neonatal infections).
The CAMP reaction is a phenomenon of co-hemolysis which consists of a zone of strong hemolysis which is observed when S. agalactiae, which produces the CAMP factor, is streaked next to Staphylococcus aureus, which secretes sphingomyelinase, on sheep blood agar.
CAMP is an acronym for the authors of this test (Christie, Atkinson, Munch, Peterson).
Red blood cells (erythrocytes) of sheep are rich in sphingomyelin, their sphingomyelin content being up to 51%, erythrocytes of different mammalian species support the CAMP reaction to varying degrees depending on the sphingomyelin content of their cell membranes.
The proteins responsible for the CAMP reaction are S. aureus sphingomyelinase and CAMP factor, a protein secreted by S. agalactiae. Sphingomyelinase initially hydrolyzes sphingomyelin to ceramide, which renders erythrocytes sensitive to the lytic activity of factor CAMP.
This synergistic reaction results in a zone of reinforced and very visible hemolysis in the region between the two cultures.
Note : The CAMP test can also be performed with discs impregnated with beta-lysine. the organism to be identified is inoculated in a straight line within 5 mm of the disc.
CAMP test
The CAMP test is performed on standard dishes of sheep blood agar or trypticase soy agar +5% sheep blood.
◉ Results : A positive test CAMP appears as an area of arrowhead hemolysis adjacent to where the two lines of streaks come together. A lack of enhanced hemolysis near the colony being tested is a negative CAMP test
In 1962, Fraser, G. was the first to observe the synergistic lysis of sheep red blood cells by L. monocytogenes and S. aureus or Rhodococcus equi.
The CAMP test can be used to differentiate hemolytic Listeria species; L. monocytogenes, L. ivanovii and L. seeligeri.
Hemolysis by L. monocytogenes and to a lesser degree L. seeligeri is enhanced in the vicinity of S. aureus and hemolysis by L. ivanovii is enhanced in the vicinity of the R. equi streak (cholesterol oxidase). Listeria factors responsible for synergistic lysis of red blood cells with S. aureus and Rhodococcus. equi are respectively PLC and LLO (Listeriolysin O).
Note : The CAMP test has been reviewed for its applicability and it has been shown that sometimes it cannot properly differentiate between L. monocytogenes and L. ivanovii
◉ Results : A CAMP test positive appears as a smaller, less obvious rectangular area of hemolysis
A reverse CAMP reaction is a reaction whereby hemolysis by beta-hemolysin of Staphylococcus aureus (or S. intermedius) is inhibited by the production of phospholipase D (or phospholipase C).
◉ Results : A positive reverse CAMP test appears as An arrow without hemolysis forms at the junction of the test organism with staphylococci. Ex : Corynebacterium pseudotuberculosis , Corynebacterium ulcerans , Arcanobacterium haemolyticum , Mycoplasma hyorhinis , C. perfringens
CAMP test positive(S.agalactiae, Listeria.spp, A.haemolyticum)
Reference