Structural and functional changes in the gut microbiota associated to Clostridium difficile infection

Area of Science:

• Microbiology
• Gastroenterology
• Immunology

Background:

• Antibiotic therapy can severely disrupt the gut microbiota, diminishing its protective functions.
• This disruption can lead to opportunistic infections like Clostridium difficile infection (CDI), a major cause of antibiotic-associated diarrhea.
• Understanding the microbial differences between infected and non-infected patients is crucial for developing preventative strategies.

Purpose of the Study:

• To analyze gut microbiota composition and function in patients with and without Clostridium difficile infection (CDI) following antibiotic treatment.
• To identify bacterial taxa and metabolic functions that may confer protection against C. difficile colonization.
• To compare microbial diversity and functional profiles between CDI-positive and CDI-negative patients.

Main Methods:

• Utilized 16S rRNA gene and metagenomic 454-based pyrosequencing.
• Collected samples before, during, and after antibiotic treatment.
• Performed comparative analyses between C. difficile infected (CD+) and non-infected (CD-) patient groups.

Main Results:

• CDI patients generally exhibited lower microbial diversity and richness compared to non-infected patients.
• Potentially protective taxa against C. difficile were primarily identified within the Firmicutes phylum (e.g., Clostridiales).
• Candidate protective functions included aromatic amino acid biosynthesis and stress response mechanisms; CDI patients showed altered carbohydrate and ion transport gene abundance.

Conclusions:

• Gut microbiota composition and function significantly differ between patients with and without C. difficile infection post-antibiotic therapy.
• Specific bacterial groups within Firmicutes may play a protective role against C. difficile colonization.
• Restoring microbial diversity and specific metabolic functions could be key strategies to prevent CDI.