Why is a blood agar, rather than a nutrient agar, plate used for the culture from the mouth?

i am new on here but was needing the same answer. how can i see replys?

First of all blood agar is a form of nutrient agar. However, every nutrient agar, be it complex ones like LB, BHIS, BAP, chocolate, etc. or minimal media will only allow a certain range of bacteria to grow on it. The complex media obviously tend to have a broader range, though. In any case, bacteria growing on or in hosts are often cultivated with nutrients that the host have to offer, hence often blood agar or BHIS is used. Howeever for oral bacteria one could also use THB, MM10SB, to name a few.

I think if you are looking for oral pathogens then Blood agar is used to show B haemolysis a trait commont to some Streptococci causing infection.