Purification and characterization of Clostridium difficile toxin.

Area of Science:

• Microbiology
• Toxicology
• Biochemistry

Background:

• Toxigenic Clostridium difficile strains are linked to ileocecitis in animals and colitis in humans.
• Understanding the toxin's properties is crucial for disease management.

Purpose of the Study:

• To purify and characterize the toxin produced by Clostridium difficile ATCC 9689.
• To elucidate the toxin's role in antimicrobial-associated gastrointestinal diseases.

Main Methods:

• Cultivation of C. difficile and toxin purification via ultrafiltration, precipitation, and chromatography.
• Characterization using polyacrylamide gel electrophoresis, isoelectric focusing, and molecular weight determination.
• Assessing biological activity through cell culture assays and animal models (rabbits, hamsters).

Main Results:

• A single-banded toxin was purified, showing cytopathic effects on human cells.
• The toxin is heat-labile, inactivated at pH 4 and 9, and has an isoelectric point of 5.0.
• Molecular weight was estimated at 530,000, dissociating into 185,000 and 50,000 components upon reduction.

Conclusions:

• The purified C. difficile toxin is protoplasmic and released upon cell autolysis.
• Enzymatic activity was not directly correlated with the toxin's effects.
• These findings contribute to understanding the toxin's pathogenic mechanisms in colitis and diarrhea.