Mannitol Salt Agar (MSA) is used as a selective and differential medium for the isolation and identification of Staphylococcus aureus from clinical and non-clinical specimens. It encourages the growth of a group of certain bacteria while inhibiting the growth of others.
D-Mannitol : Only Carbohydrate source present in the medium; Sodium Chloride Phenol Red (Indicator) Agar; Final pH: 7.4 ± 0.2 at 25 o C (Remember the ingredients in Bold letters) You can purchase prepared Mannitol Salt Agar from the commercial suppliers or get the Mannitol Salt Agar Powder and prepare the media in your laboratory.
Those staphylococci that do not ferment mannitol show a purple or red zone around the colonies. Mannitol Salt Agar (MSA) is recommended by the American Public Health Association for the enumeration of staphylococci in food and dairy products. (9,10) FORMULA. Ingredients per liter of deionized water:*
What is Mannitol Salt Agar. A mannitol salt agar test is used to isolate and identify the presence of Staphylococcus aureus in a clinical specimen, which makes it both a selective, differential, and indicator medium.
Mannitol Salt 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.
Staphylococci have the unique ability of growing on a high salt containing media (2). Isolation of coagulase-positive staphylococci on Phenol Red Mannitol Agar supplemented with 7.5% NaCl was studied by Chapman (3). The resulting Mannitol Salt Agar Base is recommended for the isolation of coagulase-
THE PROCEDURE. Each pair presently has an unknown bacterium. Both of the table's unknown bacteria should fit on 1 agar plate. Pick up one mannitol salt agar plate and divide in half. Inoculate both organisms on the one plate---either a straight line or a zig-zag. Be sure not to get the 2 bacteria too close together.
In case of coagulase positive staphylococci (like Staphylococcus aureus), the mannitol salt agar test results show a change of color to yellow.Coagulase positive bacteria are found to grow as large yellow colonies. In general, coagulase negative staphylococci are found as a part of normal flora in the human body.
L007389 1 of 2 BBL™ Mannitol Salt Agar L007389 • Rev. 08 • November 2015 QUALITY CONTROL PROCEDURES (Optional) I INTRODUCTION Mannitol Salt Agar is a selective and differential medium for the detection and enumeration of staphylococci from clinical and nonclinical specimens.