What is the purpose of mannitol salt agar?
Mannitol Salt Agar is used as a selective media for the isolation of pathogenic Staphylococci. It is recommended for the detection and enumeration of coagulase-positive Staphylococci in milk, food and other specimens.
What is the purpose of MSA in microbiology?
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.
What is unique about MSA agar?
Mannitol Salt Agar (MSA) is a selective and differential medium. The high concentration of salt (7.5%) selects for members of the genus Staphylococcus, since they can tolerate high saline levels. Organisms from other genera may grow, but they typically grow very weakly.
Why does mannitol salt agar turn yellow?
The differential ingredient in MSA is the sugar mannitol. Organisms capable of using mannitol as a food source will produce acidic byproducts of fermentation that will lower the pH of the media. The acidity of the media will cause the pH indicator, phenol red, to turn yellow.
What does a positive MSA plate mean?
Mannitol Salt Agar (MSA) is used to determine if the bacteria is halophilic (salt loving) and if the bacteria can ferment mannitol. A positive result for mannitol fermentation would be the formation of a yellow halo around the bacterial colony, this is an indication of acid production from the breakdown of mannitol.
What will turn MSA yellow?
Does E coli grow on MSA?
Gram-negative bacteria like E. coli and P. aeriginosa are not tolerant to salt (not halophilic) and will not grow colonies on MSA (see quadrants II and IV). Staphylococcus aureus is also able to ferment mannitol, because this bacterial species has the enzyme coagulase required for the process.
What type of bacteria grow on MacConkey agar?
Altogether, MacConkey agar only grows gram-negative bacteria, and those bacteria will appear differently based on their lactose fermenting ability as well as the rate of fermentation and the presence of a capsule or not.
What types of bacteria grow on blood agar?
Blood Agar is used to grow a wide range of pathogens particularly those that are more difficult to grow such as Haemophilus influenzae, Streptococcus pneumoniae and Neisseria species. It is also required to detect and differentiate haemolytic bacteria, especially Streptococcus species.
Is E coli MSA positive?
Gram-negative bacteria like E. coli and P. aeriginosa are not tolerant to salt (not halophilic) and will not grow colonies on MSA (see quadrants II and IV). Pathogenic gram-positive Staphylococcus aureus salt-tolerant (halophilic) and will produce colonies on MSA.
From Wikipedia, the free encyclopedia An MSA plate with Micrococcus sp. (1), Staphylococcus epidermidis (2) and S. aureus colonies (3). 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.
What is in MSA agar?
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.
Why is mannitol salt agar used in microbiology?
The purpose of this test was to isolate the Gram positive bacterium. This was possible because Mannitol Salt Agar is a selective medium (along with differential) that only allows for the growth of specific Gram positive bacteria due to its high salt content (McDonald et al., 2011).
What kind of microbes live in MSA medium?
This type of medium is both selective and differential. The MSA will select for organisms such as Staphylococcus species which can live in areas of high salt concentration (plate on the left in the picture below).