For veterinarians, antibiotics are a crucial tool for treating bacterial infections in animals. However, these antibiotics aren’t selective when eliminating bacteria in your dog’s gut microbiome. As the drugs wipe out “bad” bacterial pathogens, your dog’s gut could also lose “good” bacteria that help the digestive system function properly.

Some of those beneficial bacteria:

• absorb crucial nutrients
• aid in fighting inflammation
• help maintain a strong immune system

Loss of key beneficial bacteria may cause an ongoing bacterial imbalance in your dog’s gut that can contribute to or worsen health conditions like chronic digestive disorders.

A new study published in the Journal of Veterinary Internal Medicine investigated the effects of metronidazole on the microbiome in healthy dogs. The authors found that a 14 day course of treatment with metronidazole given to healthy dogs, resulted in significant changes in microbiome composition, including severely decreased amounts of a key group of beneficial bacteria, Fusobacteria.

• Metronidazole, also known as Flagyl, is the most commonly prescribed antimicrobial agent for acute diarrhea in dogs.
• Antibiotics are known to cause both short and long-term changes to the bacterial community in the gut microbiome of cats and dogs.
• A recent study suggests that metronidazole disrupts the gut microbiome of dogs.
• Dr. Becker recommends dog parents do a gut microbiome analysis after antibiotic treatment.
• A new study suggests metronidazole is not as effective as microbiome restoration therapy (fecal microbiota transplant--FMT) for addressing acute diarrhea.