Intestinal bacteria antagonistic to Clostridium difficile in mice

Area of Science:

• Microbiology
• Gastroenterology
• Animal Models

Background:

• Clostridium difficile overgrowth is a known issue in mice treated with ampicillin.
• Understanding the specific indigenous bacteria affected by ampicillin is crucial for preventing C. difficile proliferation.

Purpose of the Study:

• To identify intestinal bacteria eliminated by ampicillin that permit C. difficile overgrowth.
• To determine which indigenous gut bacteria antagonize C. difficile growth.

Main Methods:

• Conventional mice were injected with ampicillin, and their gut microbiota composition was analyzed.
• Gnotobiotic mice were inoculated with specific bacterial groups or fecal samples to assess C. difficile colonization resistance.

Main Results:

• Ampicillin treatment led to decreased lactobacilli and increased bacteroidaceae, correlating with C. difficile overgrowth.
• Lactobacilli, bacteroides, and some clostridia strains did not prevent C. difficile colonization.
• Colonization resistance was established by inoculating with whole feces from conventional or limited-flora mice, indicating the importance of a diverse microbiota.

Conclusions:

• The elimination of specific indigenous gut bacteria by ampicillin facilitates Clostridium difficile overgrowth.
• A diverse intestinal microbiota, particularly certain clostridia, is essential for preventing C. difficile colonization.