Stability of Clostridioides difficile toxins in stool samples

Area of Science:

• Microbiology
• Clinical Diagnostics

Background:

• Clostridioides difficile infection (CDI) is a significant healthcare-associated infection.
• CDI pathogenesis involves cytotoxins TcdA and TcdB.
• Accurate toxin detection is crucial for diagnosing CDI.

Purpose of the Study:

• To evaluate the stability of Clostridioides difficile toxins (TcdA and TcdB) in stool samples.
• To assess the impact of transport conditions on toxin stability and subsequent diagnostic accuracy.

Main Methods:

• Stool samples were spiked with purified TcdA or TcdB and stored under simulated transport conditions.
• Stool samples from CDI patients were analyzed for toxin levels and viable C. difficile counts.
• Toxin concentrations were measured over time using enzyme immunoassays (EIA).

Main Results:

• In spiked samples, TcdB concentration decreased more rapidly than TcdA within 72 hours.
• In patient samples, toxin levels remained stable within 24 hours of transport.
• Viable C. difficile counts showed a slight increase in patient samples during transport.

Conclusions:

• Toxin instability, particularly for TcdB in spiked samples, was observed under certain conditions.
• However, toxin levels in actual patient stool samples were stable during standard transport durations (24 hours).
• This stability suggests that current EIA methods are reliable for detecting C. difficile toxins in clinical settings.