Which bacterium shows a characteristic green sheen when grown on eosin-methylene blue (EMB)agar?
A) Escherichia coli
B) Salmonella enterica
C) Staphylococcus aureus
D) Streptococcus pyogenes

Question

Quizplus · Accepted Answer

E. coli is known to produce a characteristic green metallic sheen on EMB agar due to its ability to ferment lactose, causing the release of acid byproducts that react with the eosin and methylene blue dyes in the agar. Salmonella enterica may also grow on EMB agar but will usually produce pink to purple colonies rather than green. Staphylococcus aureus and Streptococcus pyogenes are both gram-positive bacteria and are unlikely to grow on EMB agar.

Which Bacterium Shows a Characteristic Green Sheen When Grown on Eosin-Methylene