Dichotomus key gram postive bacteria coccus Lab Report

Dichotomus key gram postive bacteria coccus - Lab Report Example However, so is the gram-(+) Streptococcus and Enterococcus. In fact, they are collectively known as the gram-(+) cocci. Thus, to differentiate them, we use the catalase test, which determines whether an organism is able to convert the toxic hydrogen peroxide into water and oxygen. Of the four main gram-(+) cocci genera, only Staphylococcus and Micrococcus are catalase-(+). We then try to grow it on Mannitol Salt Agar. The genus of Micrococcus is unable to use mannitol for food, and thus will not grow on MSA medium. On the other hand, Staphylococcus is able to grow on MSA because they can oxidize mannitol. Finally, we try to determine whether the unknown is S. aureus or S. epidermidis by growing it on blood agar. Since it did not cause hemolysis, then the organism is S. epidermidis, because S. aureus is a known alpha-hemolytic organism. http://www.mesacc.edu/~aleid84161/personalhomepage/Flow%20Charts.pdf, n.