Question

station 25
49 which of the following media can be used to distinguish staphylococcus aureus from staphylococcus epidermidis?
a. dnase
b. bea
c. macconkey
d. mrvp
50 based on the results from an msa plate and bap plate shown here,
what is the most likely organism? (genus and species)
a. staphylococcus aureus
b. staphylococcus epidermidis
c. micrococcus luteus
d. streptococcus pyogenes

Explanation:

For question 49: DNase test differentiates S. aureus (DNase-positive) from S. epidermidis (DNase-negative). BEA is for enterococci, MacConkey for gram-negatives, MRVP for enterobacteriaceae.
For question 50: MSA plate (red, no yellowing) shows non-mannitol fermenting Staphylococcus; BAP plate with golden colonies (characteristic of S. aureus) is absent, but S. epidermidis is a common non-mannitol fermenting Staph.

Answer:

1. A. DNAse
2. B. Staphylococcus epidermidis