Is the lecithinase test selective or differential?

For the identification of Clostridium perfringens and differentiating it from other Clostridia species, Egg Yolk Agar is used. It is an enriched, non-selective, and differential medium, and is also used in the Nagler Test for the presumptive identification of Clostridium perfringens.

What is lecithinase activity?

Lecithinase is a type of phospholipase that acts upon lecithin. It can be produced by Clostridium perfringens, Staphylococcus aureus, Pseudomonas aeruginosa or Listeria monocytogenes. aureus is used in detection of coagulase-positive strains, because of high link between lecithinase activity and coagulase activity.

What does Nagler reaction detect?

The Nagler test is a biochemical test that is used to identify organisms which liberate phospholipases (lecithinases) e.g. Clostridium perfringens. The alpha toxin of C.

What enzyme are you testing for egg yolk hydrolysis?

The Lipase enzyme hydrolyzes the fats within the egg yolk, which results in an iridescent sheen on the colony surface. Another common reaction observed is proteolysis of the egg yolk as indicated by a clearing of the medium around the colonies.

How do you test for lecithinase?

Procedure

1. Take a loopful of test organism and streak it as a straight line on the plate.
2. Incubate anaerobically in a gas pak jar immediately after streaking and transfer into the incubator maintained at 35-37oC for 24-48 hours for anaerobes and for aerobes incubate the plate at 35-37oC for 24-48 hours.

Is lecithinase a lipase?

Lecithinase and lipase are useful as part of identification of Clostridium to the species level. C. perfringens is lipase negative and lecithinase positive, which can be neutralized by adding anti-α toxin prior to inoculation of the agar (the Nagler reaction).

Where is lecithinase found?

Phosphatidylcholine or simply, lecithin is a substance widely distributed in animal tissues, egg yolk, and some higher plants, consisting of phospholipids linked to choline. Some microorganisms possess lecithinase, also called phospholipase C, which is an enzyme that splits the phospholipid lecithin.

What is lecithinase positive?

Positive test:Appearance of a white, opaque, diffuse zone that extends into the medium surrounding the colonies. Negative test:Absence of a white, opaque zone extending from the edge of the colony.

Does Bacillus subtilis produce lecithinase?

Bacillus subtilis is a gram-positive, rod-shaped, mannitol-fermenting bacterium that lacks the ability to produce enzyme lecithinase. It is also catalase positive. This bacterium is commonly found in the soil and gastrointestinal tract of ruminants and humans.