BIOL 3052 Lecture Notes - Lecture 5: Meat Extract, Osmoregulation, Mannitol
27 Jan 2017
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Document Summary
Mannitol salt agar for the isolation of staphylococcus aureus. 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. It is a selective medium prepared according to the recommendations of chapman for the isolation of presumptive pathogenic staphylococci. Mannitol salt agar contains peptones and beef extract, which supply nitrogen, vitamins, minerals and amino acids essential for growth. The 7. 5% concentration of sodium chloride results in the partial or complete inhibition of bacterial organisms other than staphylococci. Sodium chloride also supplies essential electrolytes for transport and osmotic balance. Mannitol is the fermentable carbohydrate, fermentation of which leads to acid production, detected by phenol red indicator, aids in the differentiation of staphylococcal species.
