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An agar plate – an example of a bacterial growth medium*: Specifically, it is a streak plate; the orange lines and dots are formed by bacterial colonies.. A growth medium or culture medium is a solid, liquid, or semi-solid designed to support the growth of a population of microorganisms or cells via the process of cell proliferation [1] or small plants like the moss Physcomitrella patens. [2]
MacConkey agar is a selective and differential culture medium for bacteria. It is designed to selectively isolate gram-negative and enteric (normally found in the intestinal tract) bacteria and differentiate them based on lactose fermentation. [1] Lactose fermenters turn red or pink on MacConkey agar, and nonfermenters do not change color.
TSA plates support growth of many semifastidious bacteria, including some species of Brucella, Corynebacterium, Listeria, Neisseria, and Vibrio. Xylose-lysine-deoxycholate agar is used for the culture of stool samples and contains two indicators. It is formulated to inhibit Gram-positive bacteria, while the growth of Gram-negative bacilli is ...
For example, MH agar may be used in the laboratory for the rapid presumptive identification of C. albicans, as an alternative method for germ tube test (Mattie. As, 2014). The medium is also free of inhibitors that could interfere with bacterial growth, making it a reliable and consistent substrate for bacterial cultures.
Selective media is used to distinguish organisms by allowing for a specific kind of organism to grow on it while inhibiting the growth of others. For example, eosin methylene blue (EMB) may be used to select against Gram-positive bacteria, most of which have hindered growth on EMB, and select for Gram-negative bacteria, whose growth is not ...
Koser’s agar, developed by Stewart A. Koser in 1923, is a clear, colorless agar that allows the observation of bacterial growth by turbidity. [6] With a colorless agar, misinterpreting negative results as positives is more common, which can be reduced by Simmons’ modification of adding bromothymol blue.
As there are many bacteria that also look like Salmonella on DCA, it is widely recommended that more selective agars are used for the identification of Salmonella, namely xylose lysine deoxycholate (XLD) agar. This growth medium is heat-sensitive and should be poured and cooled as soon as possible after addition of the deoxycholate, otherwise ...
Bile salts are the selective ingredient, while esculin is the differential component. Enterococcus hydrolyze esculin to products that react with ferric citrate in the medium to produce insoluble iron salts, resulting in the blackening of the medium. Test results must be interpreted in conjunction with gram stain morphology.