Would removal of sodium chloride from msa?

Asked by: Bruce Harris  |  Last update: 29 June 2021
Score: 4.2/5 (72 votes)

Yes, the removal of sodium chloride from MSA will alter the medium's sensitivity or specificity to a great extent.

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Simply so, What would be the likely consequences of removing the NaCl from MSA?

What would be the likely consequences of omitting the NaCl in Mannitol Salt Agar? Why? Non-staphylococcus bacteria would be able to grow on the media. This may lead to false positives for Non-staphylococcus that can ferment mannitol.

Keeping this in mind, What is the role of NaCl in MSA?. Sodium chloride is used in MSA to provide the essential fermentation substrate. It limits the growth of most organisms apart from bacteria in mixed...

Just so, What is the role of NaCl in mannitol salt agar and how does it work?

Mannitol salt agar is selective in allowing bacteria capable of growth in 7.5% NaCl while preventing the growth of salt sensitive microbes. ... Mannitol salt agar is thus selective in prohibiting the growth of bacteria unable to tolerate 7.5% NaCl and differential in the use of mannitol by those that can grow.

What is the application of mannitol salt agar A What is the purpose of NaCl in this medium?

It contains a high concentration (about 7.5–10%) of salt (NaCl) which is inhibitory to most bacteria - making MSA selective against most Gram-negative and selective for some Gram-positive bacteria (Staphylococcus, Enterococcus and Micrococcaceae) that tolerate high salt concentrations.

24 related questions found

What bacteria Cannot grow on MSA?

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.

What does a red color symbolize in a MSA plate?

MSA also contains the sugar mannitol and the pH indicator phenol red. If an organism can ferment mannitol, an acidic byproduct is formed that will cause the phenol red in the agar to turn yellow. Most pathogenic staphylococci, such as Staphylococcus aureus, will ferment mannitol.

What is the purpose of the high sodium chloride content in MSA and how does it work?

The sodium chloride in MSA ensures that only Staphylococci species survive due to the high salt concentration. This eliminates all other gram-positive microbes. Further, we can confidently identify Staphylococcus aureus in MSA because it is the only type of Staphylococci species that can ferment mannitol in MSA.

What ingredient makes MSA differential?

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.

How does the NaCl IN MSA kill organisms?

What does the NaCl contained in MSA do? Makes the medium selective because its concentration is high enough to dehydrate and kill most bacteria.

What does MSA plate test for?

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.

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.

How is MSA differential?

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.

Does Micrococcus luteus grow on MSA?

When grown on mannitol salt agar some species of Micrococcus (Micrococcus is a normal flora of human skin, mucosa, and oropharynx), such as M. luteus (yellow) can produce yellow colonies. ... They can ferment mannitol and produce lactic acid, producing yellow-colored colonies on MSA.

What does an MSA plate select for quizlet?

selective for gram (+) organisms. salt (NaCl) inhibits nonhalophiles. inhibits non staph organisms, gram (-) organisms, and nonhalophiles. 7 things needed to know for the MSA plate: differential. pH indicator = phenol red.

What is the purpose of phenol red in MSA?

Phenol red is a pH indicator and change the color from red to yellow if mannitol is fermented and acid products are produced. Typical pathogenic staphylococci (coagulase-positive staphylococci) ferment mannitol and form yellow colonies with yellow zones around the colonies.

What do you expect to see on the MSA and Na plates?

Growth on the MSA and NA plates was recorded as "good growth", "poor growth" or "no growth". These are qualitative and, at least for the first two, subjective terms. ... This means that bacteria that are sensative to salt would grow on the NA, but not on the MSA.

How do you perform an MSA test?

Obtain at least 10 random samples of parts manufactured during a regular production run. Choose three operators that regularly perform the particular inspection. Have each of the operators measure the sample parts and record the data. Repeat the measurement process three times with each operator using the same parts.