THE EFFECT OF ANTIBACTERIAL DRUGS ON THE FECAL FLORA OF MICE

Area of Science:

• Microbiology
• Pharmacology
• Animal Nutrition

Background:

• The gut microbiome plays a crucial role in host health.
• Antibiotics can significantly disrupt the composition of the gut microbiota.
• Dietary factors are known to influence gut microbial populations.

Purpose of the Study:

• To investigate the impact of oral antibiotics on the fecal flora of mice.
• To determine the influence of different antibiotic types and dosages on gut microbiota.
• To assess the role of nutritional regimens in the recovery of fecal flora after antibiotic treatment.

Main Methods:

• Oral administration of various antibiotics (penicillin, terramycin, chloramphenicol, isoniazid) to mice.
• Analysis of fecal samples to quantify changes in bacterial populations (lactobacilli, enterococci, Gram-negative bacilli).
• Comparison of fecal flora recovery under different dietary conditions (commercial pellets, semisynthetic diets).

Main Results:

• Penicillin, terramycin, and chloramphenicol caused a decrease in lactobacilli and an increase in enterococci and Gram-negative bacilli.
• Isoniazid had no discernible effect on fecal flora.
• Diet significantly influenced the duration of antibiotic-induced fecal flora alterations; recovery was faster with complex diets.
• Penicillin treatment led to a persistent increase in lactose-fermenting Gram-negative bacilli, especially in mice fed semisynthetic diets.

Conclusions:

• Oral antibiotics profoundly alter mouse fecal flora, with effects varying by drug type, dosage, and duration.
• Nutritional regimen is a critical factor in the recovery of gut microbiota following antibiotic exposure.
• Semisynthetic diets may prolong the persistence of antibiotic-induced microbial shifts, including the proliferation of specific Gram-negative bacteria.