Question

Which among the following is not a probiotic mechanism of action

• A. Enhancement of epithelial barrier function
• B. Enhancement of pathogen adhesion
• C. Modulation of immune system
• D. Production of antimicrobial substances

Hint:

Probiotics act through competitive exclusion, meaning they occupy binding sites to prevent pathogen colonization. This directly blocks the adhesion of pathogenic bacteria to the host intestinal mucosa.

Answer 1

The Correct Option is B

Step 1: Understanding the Concept:
Probiotics are live microorganisms that, when administered in adequate amounts, confer a health benefit on the host.
They protect the host gut using several distinct biochemical, physical, and immunological pathways.
Detailed Explanation:
Let us analyze each of the given options to evaluate standard probiotic mechanisms:
- Enhancement of epithelial barrier function: Probiotics help reinforce the gut barrier by upregulating tight junction proteins, stimulating mucin secretion, and preventing epithelial cell apoptosis. This prevents the translocation of harmful antigens. Thus, (A) is a valid mechanism.
- Enhancement of pathogen adhesion: Probiotics prevent pathogens from colonizing the gut. They do this by competitively binding to mucosal receptors, which blocks pathogen adhesion and displacement. Therefore, probiotics inhibit rather than enhance pathogen adhesion. Thus, (B) is not a probiotic mechanism.
- Modulation of the immune system: Probiotics interact with gut-associated lymphoid tissue (GALT), dendritic cells, and macrophages to stimulate immunoglobulin A (IgA) secretion and balance pro-inflammatory and anti-inflammatory cytokine production. Thus, (C) is a valid mechanism.
- Production of antimicrobial substances: Probiotics produce bacteriocins, hydrogen peroxide, and short-chain fatty acids (SCFAs like lactic and acetic acid). These substances lower the local pH and inhibit the growth of competing pathogens. Thus, (D) is a valid mechanism.
Therefore, the enhancement of pathogen adhesion is not a probiotic mechanism of action.
Final Answer:
The enhancement of pathogen adhesion is not a probiotic mechanism of action. Hence, the correct option is (B).