Salt Mannitol agar (SMA)

Hello everyone.

Today we made it to 50 followers. Yippie. Thanks to all the readers.You guys help me a lot, to stay motivated and keep working. 

Let's target for a 100 now :D

Anyways, let's go back to the subject for now.

Today's topic for media made easy is SMA.

First thing first. Salt mannitol agar is also called as Mannitol salt agar. This is a very important and crucial fact so, you must never forget it....Nah, just kidding. But it is a fact.

SMA as the name suggests, contains very high amounts of salt (Around 7% - 10%). Such high concentrations of salt makes the media selective for Staphylococcal species.

Indicator present in the media is Phenol red, which turns yellow in acidic conditions.

The media is also differential because it helps differentiate between coagulase positive and coagulase negative Staphylococcal species, as coagulase negative Staph do not grow on the media.

It also helps us to differentiate the pathogenic species from the non - pathogenic ones. Pathogenic Staphylococci like S.aureus, ferment mannitol and produce yellow colonies, whereas non - pathogenic ones grow on meat extract and do not ferment mannitol thus giving colorless or pink colonies. 

One advantage of this media is, that due to its high selectivity, you can easily test the specimens which have high microbial load.

One disadvantage is, that any other organism that can stand the high salt concentration will grow on this media, Hence doing a coagulase test for confirmation for Staphylococci is advisable.

That's all for this one.

This media, is the easiest one as compared to other selective and differential media.

Agree?

Hope this helps.

High six.

Staph :D