Which phenotypic assay could be used to determine whether a new Streptococcus spp. is of the pyogenes or viridans group?
A) catalase assay with H₂O₂
B) hemolytic type after growth on a blood agar plate
C) occurrence of cells being in clusters or as individual cells under a microscope
D) product(s) formed during lactose fermentation

Question

Quizplus · Accepted Answer

Hemolytic type after growth on a blood agar plate is a reliable phenotypic assay for differentiating between pyogenes and viridans group Streptococcus spp. Pyogenes generally exhibit beta-hemolysis whereas viridans group Streptococcus spp. typically display alpha- or gamma-hemolysis. The other options listed are not specific to the differentiation between these two groups of Streptococcus spp.

Which Phenotypic Assay Could Be Used to Determine Whether a New