chocolate agar

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Related to chocolate agar: MacConkey agar

choc·o·late a·gar

blood agar heated until the blood turns brownish, used especially to isolate Haemophilus, Neisseria, and other species for which unheated blood is inhibitory.
Blood agar that has been heated to open the pyrrole ring, forming hemin, a required growth factor for bacteria lacking hemolysins. Chocolate agars are usually incubated in a microaerophilic—3–10% CO2—environment, providing ideal growth conditions for H influenzae, Neisseria spp, and fastidious anaerobes


a dried hydrophilic, colloidal substance extracted from various species of red algae. When suspended in a liquid medium and heated to 212°F (100°C), the agar dissolves. When it is allowed to cool to 110°F (43°C) the medium becomes a solid gel. It is used in culture media for bacteria and other microorganisms, in making emulsions, and as a supporting medium for immunodiffusion and immunoelectrophoresis. Because of its bulk it is also used in medicines to promote peristalsis and relieve constipation.

birdseed agar
one containing Guizotia abyssinicia (Niger) seed and creatinine, used for growing Cryptococcus neoformans. Called also Niger agar.
bismuth sulfite agar
a special preparation used for isolation of salmonellae from food.
blood agar
a culture medium used for the growth of bacteria. Consists of agar and intact erythrocytes.
brain heart infusion agar
used for cultivating the yeast phase of dimorphic fungi.
brilliant green agar
used to cultivate salmonellae.
chocolate agar
an enriched agar for the growth of Hemophilus, some Actinobacillus, and Taylorella spp. A molten agar and blood mixture is held at 122°F (50°C) prior to pouring plates. The additional nutrients supplied are hemin and NAD.
agar diffusion test
see antimicrobial sensitivity test.
eosin-methylene blue (EMB) agar
used for the identification of Eschericha coli.
agar gel immunodiffusion test
see immunodiffusion tests.
MacConkey agar
contains bile salts, lactose and neutral red indicator for isolation of enterobacteria.
mannitol salt agar
selective for staphylococci.
milk agar
contains skim milk and used to demonstrate casein digestion.
Niger seed agar
see birdseed agar (above).
nutrient agar
the basic growth medium for bacteria, composed of beef extract and peptone.
potato dextrose agar
used in cultivating fungi; promotes sporulation and pigmentation.
Sabouraud's dextrose agar
one used for isolation of fungi. See also dermatophyte test medium.
agar sausage
see medium sausage.
xylose lysine (XLD) agar
used to differentiate Enterbacteriaceae.
References in periodicals archive ?
influenzae isolates (N=194) were simultaneously grown on chocolate agar (CA) with and without isovitalex (IVX).
Burkholderia mallei Polymyxin B or colistin resistant; arginine-positive, nonfermenter Burkholderia Polymyxin B or colistin resistant; pseudomallei arginine-positive, nonfermenter (1) Abbreviations: MAC, MacConkey agar, EMB, eosin methylene blue, BAP, 5% sheep blood agar, CHOC, chocolate agar.
The lack of growth on blood and chocolate agar is also consistent with ssp.
After 48 hours of incubation, creamy, yeast-like colonies grew on chocolate agar (bio-Merieux, Marcy l'Etoile, France), but not on Sabouraud agar containing gentamicin and chloramphenicol (Becton Dickinson).
Because of the remoteness of the outbreak site, samples for bacterial culture were collected on locally available blood agar enriched with rabbit serum without antimicrobial drug-selective agents, rather than on the recommended chocolate agar enriched with horse serum and bacitracin (1).
The CSF culture grew small [alpha]-hemolytic colonies on blood agar and chocolate agar.
Isolates of nonlactose fermenting, small, gram-negative rods were recovered from BAL fluid by using trypticase soy agar supplemented with 5% sheep blood, chocolate agar, and MacConkey agar incubated at 35[degrees]C in 5% C[O.
A slow-growing bacterium was recovered on both blood agar and chocolate agar after 2-day incubation at 35oC with 5% C[O.
Culture on chocolate agar showed scarce growth of small, colorless mucoid colonies that showed positive reactions in oxidase and catalase tests.
For fastidious microorganisms, chocolate agar can be added to the MacConkey agar and the plates incubated in 5% C[O.