it inhibits the growth of Gram positive bacteria
MacConkey agar is designed to grow Gram-negative bacteria and also contains crystal violet dye which inhibits the growth of Gram-positive bacteria. Since S. aureus is Gram-positive it should not grow on MacConkey agar. No. MacConkey agar inhibits MOST of the Gram-positive bacteria. There are some Gram-positive bacteria that can tolerate bile-salt are able to grow in MacConkey agar. Enterococcus and some species of Staphylococcus are able to grow in MacConkey. (lack citation though)
Yes, Enterobacter cloacae typically cannot grow on mannitol salt agar because it does not ferment mannitol. Mannitol salt agar is selective for salt-tolerant Staphylococci species that can ferment mannitol, producing acid and turning the agar yellow.
Bacillus subtilis typically does not ferment acid from mannitol salt agar as it lacks the enzymes needed for fermentation. Mannitol salt agar is mostly used to differentiate Staphylococcus species, which are capable of fermenting mannitol.
Selective media are specifically designed to promote the growth of certain microorganisms while inhibiting the growth of others. Examples of selective media include MacConkey agar and Mannitol salt agar, which can help in isolating specific pathogens by suppressing the growth of unwanted bacteria.
Mannitol Salt Agar Complex is a synthetic medium because it is prepared from pure chemical substances and the exact composition of the medium is known.
MacConkey agar is designed to grow Gram-negative bacteria and also contains crystal violet dye which inhibits the growth of Gram-positive bacteria. Since S. aureus is Gram-positive it should not grow on MacConkey agar. No. MacConkey agar inhibits MOST of the Gram-positive bacteria. There are some Gram-positive bacteria that can tolerate bile-salt are able to grow in MacConkey agar. Enterococcus and some species of Staphylococcus are able to grow in MacConkey. (lack citation though)
Staphylococcus aureus does not typically grow on MacConkey agar, as this medium is selective for Gram-negative bacteria, particularly Enterobacteriaceae, due to its bile salts and crystal violet dye that inhibit Gram-positive organisms. However, if S. aureus is observed on MacConkey agar, it may be due to contamination or the presence of certain strains that can tolerate the inhibitory conditions. Generally, for the isolation of S. aureus, media such as mannitol salt agar is more appropriate since it is selective for staphylococci.
So here is the deal, same use different recipies different results to do the same thing. I'll just post some lecture notes and hope that helps:MacConkey's Agar (enterics)Selective for gram negativeCrystal violet and bile salts prevent non-entericsDifferential for lactose fermentationNon-fermenter --> white/clear coloniesFermenter--> red/pink coloniesEosin Methylene Blue (EMB) (Weakly selective for intestinal pathogens)Selective for gram negativeEosin and methylene blue inhibit gram positive growthDifferential for lactose fermentationLactose fermenters produce a green-metallic sheenNon-fermenters do notNOTE: EMB Agar is not in common use anymore
Well, Macconkey Agar II plates have Gram Crystal Violet in them so there are a number of bacterial species that can absorb it and turn "very pink." The way to narrow it down is to identify whether it grows in chains or clusters. But other than that, it is hard to tell.
Two media that include elevated concentrations of sodium chloride for preventing growth of most bacteria are mannitol salt agar and Thiosulfate-Citrate-Bile Salts-Sucrose (TCBS) agar. These media are selective for certain types of bacteria, such as Staphylococcus species in the case of mannitol salt agar, and Vibrio species in the case of TCBS agar.
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Bile salts are compounds produced in the liver from cholesterol and stored in the gallbladder. They help in the digestion and absorption of fats by emulsifying lipids in the small intestine to aid in their breakdown by enzymes. Bile salts also play a role in the elimination of waste and toxins from the body.
Yes, Enterobacter cloacae typically cannot grow on mannitol salt agar because it does not ferment mannitol. Mannitol salt agar is selective for salt-tolerant Staphylococci species that can ferment mannitol, producing acid and turning the agar yellow.
Proteus vulgaris typically does not grow well on Mannitol Salt Agar (MSA) because it is a non-fermenter of mannitol and cannot utilize this substrate. MSA is selective for salt-tolerant organisms like Staphylococcus species, which can ferment mannitol, resulting in a pH decrease and color change. Proteus vulgaris is more commonly found on media like MacConkey agar.
bile salt
Bacillus subtilis typically does not ferment acid from mannitol salt agar as it lacks the enzymes needed for fermentation. Mannitol salt agar is mostly used to differentiate Staphylococcus species, which are capable of fermenting mannitol.
In the gallbladder.