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In-vitro activity of azithromycin in against intracellular Helicobacter pylori
1Department of Infectious Diseases and Clinical Microbiology, University Hospital, Uppsala, Sweden.
Abstract:
We studied the effect in vitro of azithromycin on the clinical strain Helicobacter pylori H:72 growing intracellularly in monolayers of HEp-2 epithelial cells. After using gentamicin to eradicate extracellular bacteria, different concentrations of azithromycin were added to the infected cells and samples were taken after 0, 4, 8 and 24 h. Infected cells not exposed to antibiotic were included as controls. The MIC of azithromycin to the H. pylori was 0.25 mg/L and the MBC 0.5 mg/L in a broth dilution plate count method. A bactericidal effect was observed on intracellular H. pylori, with inhibition increasing with increasing azithromycin concentrations. However, extracellular concentrations of 200 x MBC were necessary to achieve intracellular killing. Our results show that azithromycin is active against intracellular H. pylori suggesting that it might be possible to exploit this activity when treating infections due to the organism.
Insights
Azithromycin demonstrates bactericidal activity against intracellular Helicobacter pylori (H. pylori) in epithelial cells. High concentrations are needed, suggesting potential for treating persistent H. pylori infections.
Area of Science:
- Microbiology
- Pharmacology
- Cell Biology
Background:
- Helicobacter pylori (H. pylori) is a significant human pathogen.
- Intracellular H. pylori infections pose treatment challenges.
- Azithromycin is a macrolide antibiotic with known antibacterial properties.
Purpose of the Study:
- To investigate the in vitro efficacy of azithromycin against intracellular H. pylori.
- To determine the concentrations of azithromycin required for killing intracellular H. pylori.
- To assess the potential of azithromycin in treating intracellular H. pylori infections.
Main Methods:
- In vitro study using HEp-2 epithelial cell monolayers infected with H. pylori H:72.
- Gentamicin used to eliminate extracellular bacteria.
- Exposure of infected cells to varying azithromycin concentrations over 24 hours.
- Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC) determination via broth dilution and plate count.
Main Results:
- Azithromycin exhibited a Minimum Inhibitory Concentration (MIC) of 0.25 mg/L and a Minimum Bactericidal Concentration (MBC) of 0.5 mg/L against H. pylori.
- A dose-dependent bactericidal effect on intracellular H. pylori was observed.
- Extracellular azithromycin concentrations 200 times the MBC were required to achieve intracellular bacterial killing.
Conclusions:
- Azithromycin possesses activity against intracellular H. pylori.
- Achieving intracellular bacterial eradication requires significantly higher azithromycin concentrations.
- Azithromycin's activity against intracellular H. pylori suggests a potential therapeutic role in persistent infections.