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Evaluation of various oral antimicrobial formulations for eradication of Helicobacter hepaticus
1Division of Comparative Medicine, Massachusetts Institute of Technology, Cambridge 02139, USA.
Abstract:
Helicobacter hepaticus colonizes the cecum and colon of several strains of mice from a variety of commercial suppliers, persistently infects mice, causes chronic hepatitis, is linked to hepatic tumors in A/JCr mice, and has been associated with inflammatory bowel disease of athymic and scid mice. For this reason, eradication of the organism from infected mouse colonies is desirable. We recently reported that amoxicillin or tetracycline-based triple therapy (amoxicillin or tetracycline in combination with metronidazole and bismuth) given by oral gavage 3 times daily for 2 weeks eradicated H. hepaticus in 8- to 10-week-old A/JCr mice. To establish a more convenient therapy regimen for eradicating H. hepaticus, we evaluated water and dietary administration of various antibiotic combinations in A/JCr and DBA/2 mice naturally infected with H. hepaticus. The A/JCr male mice received amoxicillin-based triple therapy in drinking water or by oral gavage, or received tetracycline-based triple therapy in the drinking water. The DBA/2J female mice received amoxicillin-based triple therapy in a specially formulated dietary wafer or by oral gavage, or received enrofloxacin in drinking water. All treatments were given for a 2-week period. Control animals received no treatment. One month after treatment, H. hepaticus was recovered from the liver, cecum, or colon of A/JCr control mice and mice receiving amoxicillin- or tetracycline-based triple therapy in drinking water but not in mice receiving amoxicillin-based triple therapy by oral gavage. Helicobacter hepaticus was not recovered from DBA/2J mice receiving amoxicillin-based triple therapy in dietary wafer or by oral gavage but was recovered from control mice and 7 of 10 mice receiving enrofloxacin in drinking water. Results indicate that amoxicillin-based triple therapy administered in the diet or by oral gavage is effective in eradicating H. hepaticus. Antibiotics administered in the water, however, were not effective in eradicating the organism.
Insights
Eradicating Helicobacter hepaticus in mice is crucial for research. Amoxicillin-based triple therapy delivered via diet or oral gavage effectively eliminated this persistent infection.
Area of Science:
- Veterinary Microbiology
- Infectious Diseases
- Animal Models
Background:
- Helicobacter hepaticus is a persistent pathogen in mouse colonies, causing chronic hepatitis and linked to hepatic tumors and inflammatory bowel disease.
- Eradication of H. hepaticus is essential for maintaining the integrity of research mouse models.
- Previous studies demonstrated successful eradication using oral gavage triple therapy.
Purpose of the Study:
- To evaluate more convenient therapeutic regimens for H. hepaticus eradication.
- To assess the efficacy of water and dietary administration of antibiotic combinations.
- To compare different antibiotic therapies in A/JCr and DBA/2 mouse models.
Main Methods:
- Antibiotic efficacy was tested via oral gavage, drinking water, and dietary wafers in naturally infected mice.
- Amoxicillin-based and tetracycline-based triple therapies were administered for two weeks.
- H. hepaticus recovery was assessed from liver, cecum, and colon one month post-treatment.
Main Results:
- Amoxicillin-based triple therapy administered by oral gavage or in dietary wafers effectively eradicated H. hepaticus.
- Antibiotic administration via drinking water was ineffective in clearing the infection.
- Enrofloxacin in drinking water showed limited efficacy in DBA/2 mice.
Conclusions:
- Amoxicillin-based triple therapy is an effective strategy for eradicating H. hepaticus in mice when administered orally or through diet.
- Water-based antibiotic delivery is not a viable method for H. hepaticus eradication.
- Optimized delivery methods are key to successful pathogen elimination in research animal populations.