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Salmonella-macrophage interactions upon manganese supplementation
Praveen Rishi1, Natasha Jindal, Sushma Bharrhan
1Department of Microbiology, Basic Medical Sciences Block, Panjab University, Chandigarh 160014, India. rishipraveen@yahoo.com
Biological Trace Element Research
|May 23, 2009
Summary
Manganese (Mn) supplementation boosts Salmonella typhimurium virulence by increasing its superoxide dismutase (SOD) levels. This impairs macrophage functions like phagocytosis, enhancing bacterial survival and infection severity.
Area of Science:
- Microbiology
- Immunology
- Pathogen-Host Interactions
Background:
- Manganese (Mn) is implicated in pathogen virulence.
- Salmonella typhimurium is an intracellular pathogen that replicates within macrophages.
Purpose of the Study:
- To investigate the impact of manganese supplementation on Salmonella-macrophage interactions.
- To assess effects on Salmonella virulence and macrophage functions.
Main Methods:
- Salmonella typhimurium grown with and without manganese.
- Infection of mice with supplemented and non-supplemented bacteria.
- Assessment of lethal dose 50 (LD50).
- Evaluation of macrophage phagocytic activity, superoxide dismutase (SOD), catalase, nitrite levels, and lipid peroxidation.
Main Results:
- Manganese supplementation decreased Salmonella LD50 by 50-fold, indicating increased virulence.
- Salmonella grown in manganese showed elevated SOD levels.
- Macrophages interacting with manganese-exposed Salmonella exhibited reduced phagocytosis.
- Manganese supplementation led to increased lipid peroxidation and decreased SOD and catalase activity in macrophages.
Conclusions:
- Manganese supplementation enhances Salmonella virulence, potentially by increasing bacterial SOD expression.
- Altered Salmonella function inhibits macrophage phagocytosis and antioxidant defenses.
- This leads to impaired macrophage function and increased pathogen virulence.
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