Enterococcus spp.

Enterococcus spp. are bile esculin positive and grow in 6.5% NaCl. If they grow on the 6 µg/mL vancomycin screen agar as this isolate does, it is vancomycin resistant. If there is no growth on the 6 µg/mL vancomycin screen agar, the isolate is susceptible to vancomycin. Streptococcus Group D, not Enterococcus will not grow in the 6.5% NaCl and should not be tested for vancomycin resistance. Staphylococcus epidermidis is catalase positive.

The images below represent a gram-positive, catalase-negative, non-motile coccus inoculated to bile esculin agar, 6.5% NaCl broth and to 6 µg/mL of vancomycin in Mueller Hinton agar. It should be reported as: