It can, but due to the high agar content of MacConkey agar the swarming is slow and restricted. So it is usually quite easy to select non-Proteus colonies for sub-culture if done within 24 hours of incubation.
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Proteus vulgaris is a bacterium that shows beta hemolysis on blood agar plates. In the Blood Hemolysis Test, this means that Proteus vulgaris will cause complete lysis of red blood cells, resulting in a clear zone around the bacterial growth on the agar plate.
Yes, Proteus vulgaris is known to cause complete hemolysis on blood agar, resulting in a greenish discoloration around the colonies due to its ability to break down red blood cells. This process is also known as beta-hemolysis.
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.
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)
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.