This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Systemic Bacteriology (Gram Positive Bacilli, Gram Negative Bacilli), Subject name: Microbiology
Naegler's reaction is used for: 
Select and explain. 
A. Cl. Tetani, B. Cl. Botulinum, C. Cl. Perfringens, D. Cl. Septicum
C: Cl. Perfringens
Answer: C: Cl. Perfringens 
Explanation: Nagler's reaction Nagler's reaction is an example of Neutralization test done for detection of a toxin (lecithinase) produced by C. perfringens. The alpha toxin of C. perfringens has phospholipase activity , when grown on a medium containing egg yolk phospholipid, the organism can break this insoluble triglyceride. Phosphoryl choline release is seen as an area of opacity around the bacterial colonies. Antitoxin can inhibit a positive Nagler's response.