Which organism shows lecithinase activity on egg yolk agar?

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Multiple Choice

Which organism shows lecithinase activity on egg yolk agar?

Lecithinase activity on egg yolk agar comes from an enzyme that breaks down lecithin, a phospholipid in the egg yolk. When this phospholipase C enzyme is present, it hydrolyzes lecithin and you see a visible zone of hydrolysis around the colony—an opalescent halo or clearing in the medium. Clostridium perfringens is famous for producing this lecithinase (alpha-toxin), so it reliably shows a lecithinase-positive reaction on egg yolk agar. The other organisms listed don’t typically produce this enzyme in this test, so they won’t create that characteristic halo.

Lecithinase activity on egg yolk agar comes from an enzyme that breaks down lecithin, a phospholipid in the egg yolk. When this phospholipase C enzyme is present, it hydrolyzes lecithin and you see a visible zone of hydrolysis around the colony—an opalescent halo or clearing in the medium. Clostridium perfringens is famous for producing this lecithinase (alpha-toxin), so it reliably shows a lecithinase-positive reaction on egg yolk agar. The other organisms listed don’t typically produce this enzyme in this test, so they won’t create that characteristic halo.

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