Mannitol salt agar or MSA is a commonly used selective and differential growth medium in microbiology. It encourages the growth of a group of certain bacteria while inhibiting the growth of others. This medium is important in medical laboratories as one method of distinguishing pathogenic microbes in a short period of time.
Mannitol Fermentation Test What is the purpose of the test? The purpose is to see if the microbe can ferment the carbohydrate (sugar) mannitol as a carbon source. How is mannitol fermentation determined?. If mannitol is fermented to produce acid end products, the p H of the medium will drop. A p H indicator in the medium changes color to indicate acid production.
Mannitol Salt is a selective bacterial growth medium because it has a very high concentration of NaCl (7.5%). Most bacteria cannot survive in this highly saline, hypertonic environment. But the genus Staphylococcus has a protective slime layerthat protects it in a harsh, salty environment.
Remember this statement: Mannitol Salt Agar (MSA) ... are salt tolerant bacteria. They can ferment mannitol and produce lactic acid, producing yellow colored colonies on MSA. Catalase test can help to differentiate between Enterococcus (-ve) and Staphylococcus (+ve).
For information on how mannitol salt agar is used to determine growth on 7.5% NaCl, refer to the growth on 7.5% NaCl test For information on how mannitol salt agar is used to determine mannitol fermentation for bacteria able to grow on 7.5% NaCl, or on how mannitol fermentation is determined using phenol red mannitol broth, refer to the ...
Staphylococcus aureus and Staphylococcus epidermidis on mannitol salt agar Mannitol salt agar is a commonly used growth medium in microbiology. It encourages the growth of a group of certain bacteria while inhibiting the growth of others.
The mannitol fermentation test is used to test if a microbe can ferment the carbohydrate mannitol as a carbon source. If mannitol has been used by the microbe, acidic byproducts will be produced and the pH of the medium in which the microbe sits will drop. Mannitol is also known as mannite, manna sugar and osmitrol.
o Staphylococcus aureus ferments mannitol o S. aureus changes the color of the medium from pink to yellow due to acid by-products of mannitol fermentation o Staphylococcus epidermidis grows on MSA, but does not ferment mannitol (media remains light pink in color & colonies are colorles
The growth and production of yellow colonies due to the high salt content of media and fermentation of mannitol is regarded as a presumptive tool for the identification of S. aureus. It is also described as a characteristic for the differentiation of coagulase-positive staphylococci from coagulase-negative staphylococci (CoNS).
Mannitol Salt Agar (MSA) is used to determine if the bacteria is halophilic (salt loving) and if the bacteria can ferment mannitol. If the bacteria is able to grow then it is a halophilic bacteria, due to it's ability to grow in a high salt environment. A positive result for mannitol fermentation would be the formation of a yellow halo around ...