It would allow growth of Gram-positive cocci.
Staphylococcus will not grow on Mac since crystal violet inhibits the growth of Gram positivesfmchinea: Actually some species of staphylococcus grow on MacConkey's plate including Staphylococcus aureus.
Staphylococcus epidermidis is a gram-positive bacterium and does not ferment lactose. Therefore, on a MacConkey agar plate, S. epidermidis would appear as colorless, indicating a negative result for lactose fermentation. Additionally, there would not be any pink or red colonies representing acid production.
Most gram positive bacteria cannot grow on MacConkey Agar because the agar contains crystal violet and bile salts that inhibit the growth of gram positive organisms. Additionally, the agar is designed to selectively isolate and differentiate gram negative bacteria based on their ability to ferment lactose, producing pink colonies.
Scanning about the microbiologic community, a few references to Gram pos bacteria growing on MacConkey's showed up. One reports a Gram positive rod of unspecified species (see links). Another article says some forms of Enterococcus and Staphylococcus can grow in spite of the bile salts that make this medium so antagonistic to Gram positives. But just as many articles opine that, if this happens, the medium may not have been properly prepared.
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.
MacConkey's agar refers to a culture medium that is designed to selectively grow Gram-negative bacteria. It contains crystal violet dye, which inhibits certain Gram-positive bacteria.
Staphylococcus will not grow on Mac since crystal violet inhibits the growth of Gram positivesfmchinea: Actually some species of staphylococcus grow on MacConkey's plate including Staphylococcus aureus.
Lac+ bacteria is acid base color indicator that lowers the pH of the MacConkey agar. The MacConkey agar contains neutral red dye, lactose, peptone, and crystal violet dye.
Enterococcus faecalis typically does not grow on MacConkey agar as this selective and differential medium is primarily used for isolating and differentiating members of the Enterobacteriaceae family, which are mostly gram-negative bacteria. Enterococcus species are gram-positive bacteria and do not ferment lactose, the key ingredient in MacConkey agar that allows for differentiation.
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)
Macconkey agar consists of agar, lactose, peptone, neutral red dye, crystal violet dye & bile salts. Bile salts inhibit growth of Gram positive bacteria & allow growth of Gram negative bacteria only. It differentiates lactose fermentating Gram negative bacteria from non lactose fermentating Gram negative bacteria.
E. coli that grow on MacConkey agar typically exhibit lactose fermentation, causing them to produce pink or red colonies. These colonies may also appear mucoid due to the production of a polysaccharide capsule. Additionally, E. coli on MacConkey agar will typically not grow well under acidic conditions, as the agar contains crystal violet which inhibits the growth of Gram-positive bacteria.
MacConkey agar is a selective and differential medium used in microbiology for the isolation and identification of Gram-negative bacteria, particularly Enterobacteriaceae. It selects for growth of these bacteria by inhibiting the growth of Gram-positive organisms through the use of crystal violet and bile salts. It also differentiates between lactose-fermenting and non-lactose-fermenting bacteria based on the color change of colonies.
Staphylococcus epidermidis is a gram-positive bacterium and does not ferment lactose. Therefore, on a MacConkey agar plate, S. epidermidis would appear as colorless, indicating a negative result for lactose fermentation. Additionally, there would not be any pink or red colonies representing acid production.
Most gram positive bacteria cannot grow on MacConkey Agar because the agar contains crystal violet and bile salts that inhibit the growth of gram positive organisms. Additionally, the agar is designed to selectively isolate and differentiate gram negative bacteria based on their ability to ferment lactose, producing pink colonies.
MacConkey agar contains bile salts, lactose, peptone. crystal violet dye, and neutral red dye. The agar appears a medium pink with a copper undertone.
Scanning about the microbiologic community, a few references to Gram pos bacteria growing on MacConkey's showed up. One reports a Gram positive rod of unspecified species (see links). Another article says some forms of Enterococcus and Staphylococcus can grow in spite of the bile salts that make this medium so antagonistic to Gram positives. But just as many articles opine that, if this happens, the medium may not have been properly prepared.