Does Staphylococcus aureus grow on mannitol salt agar?
Does Staphylococcus aureus grow on mannitol salt agar?
Most pathogenic staphylococci, such as Staphylococcus aureus, will ferment mannitol. Most non-pathogenic staphylococci will not ferment mannitol. The Staphylococcus aureus ferments mannitol and turns the medium yellow. The Serratia marcescens does not grow because of the high salt content.
Why mannitol salt agar is specific for Staphylococcus?
Principle of Mannitol Salt Agar 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.
Can S.aureus grow on blood agar?
S. aureus can also be cultured and isolated successfully on blood agar – where it produces white or pale haemolytic colonies ( Figure 3 ). It also grows on chocolate agar and MacConkey agar. S. aureus grow aerobically at 35-37 o C. Figure 2.
What is the selective agent found in mannitol salt agar?
MANNITOL SALT AGAR (MSA) Mannitol salt agar is a selective medium used for the isolation of pathogenic staphylococci . The medium contains mannitol , a phenol red indicator, and 7.5% sodium chloride. The high salt concentration inhibits the growth of most bacteria other than staphylococci. On MSA, pathogenic Staphylococcus aureus produces
What color does Staphylococcus appear on nutrient agar?
Staphylococcus aureus produces yellow colonies with yellow zones, whereas other coagulase-negative staphylococci produce small pink or red colonies with no colour change to the medium. If an organism can ferment mannitol , an acidic byproduct is formed that causes the phenol red in the agar to turn yellow.
Does Micrococcus luteus grow in mannitol salt agar?
Some species of Micrococcus, such as M. luteus (yellow) and M. roseus (red) produce yellow or pink colonies when grown on mannitol salt agar. Isolates of M. luteus have been found to overproduce riboflavin when grown on toxic organic pollutants like pyridine. [1]