Tests for Identification of Nonhemolytic
Streptococci/Enterococci
Clinical Microbiology Review 168
TEST PRINCIPLE KEY REACTIONS OTHER
Pyrrolidonase (PYR) test
Bile-esculin agar
Esculin test
6.5% NaCl broth
Bile inhibits GPs other than group D
strep & enterococci.
Doesn’t test for bile tolerance.
Requires overnight incubation.
See “Tests for Identification of
Beta-Hemolytic Streptococci”
Organisms that can grow in
40% bile & produce esculinase
hydrolyse esculin, producing
black precipitate
Organisms that produce esculi-
nase hydrolyze esculin on disk,
producing dark spot
Organisms that can grow in
6.5% NaCl produce turbidity
Enterococci pos (also GAS)
Group D strep & enterococci pos
Group D strep & enterococci pos
Enterococci pos (also GBS).
Group D strep neg
