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L-Ascorbic Acid Shapes Bovine Pasteurella multocida Serogroup A Infection
Guangfu Zhao1,2, Pan Li1, Hao Mu3
1Chongqing Key Laboratory of Forage and Herbivorce, College of Veterinary Medicine, Southwest University, Chongqing, China.
Abstract:
Bovine Pasteurella multocida serogroup A (bovine PmA) is one of the most important pathogens causing fatal pneumonia in cattle. However, it is largely unknown how nutrition shapes bovine PmA infection. Here, we discovered that the infected lung held the highest bacterial density than other tissues during infection. By screening the different metabolites between high (lung)- and low (liver)-bacterial density tissues, the present work revealed that L-ascorbic acid and L-aspartic acid directly influenced bovine P. multocida growth. Interestingly, L-ascorbic acid, which is expressed at higher levels in the infected livers, inhibited bovine PmA growth as well as virulence factor expression and promoted macrophage bactericidal activity in vitro. In addition, ascorbic acid synthesis was repressed upon bovine PmA infection, and supplementation with exogenous L-ascorbic acid significantly reduced the bacterial burden of the infected lungs and mouse mortality. Collectively, our study has profiled the metabolite difference of the murine lung and liver during bovine PmA infection. The screened L-ascorbic acid showed repression of bovine PmA growth and virulence expression in vitro and supplementation could significantly increase the survival rate of mice and reduce the bacterial load in vivo, which implied that L-ascorbic acid could serve as a potential protective agent for bovine PmA infection in clinic.
Insights
L-ascorbic acid inhibits bovine Pasteurella multocida growth and virulence. Supplementing with L-ascorbic acid reduces bacterial load and mortality in mice, suggesting its potential as a protective agent.
Area of Science:
- Veterinary Microbiology
- Animal Nutrition
- Immunology
Background:
- Bovine Pasteurella multocida serogroup A (bovine PmA) causes fatal pneumonia in cattle.
- The role of nutrition in bovine PmA infection is poorly understood.
- Bacterial density varies significantly between infected lung and liver tissues.
Purpose of the Study:
- To investigate the influence of host metabolites on bovine PmA infection.
- To identify specific metabolites affecting bovine PmA growth and virulence.
- To evaluate the therapeutic potential of identified metabolites against bovine PmA.
Main Methods:
- Metabolomic screening of infected lung and liver tissues to identify key metabolites.
- In vitro assays to assess the effect of L-ascorbic acid and L-aspartic acid on bovine PmA growth and virulence factors.
- In vivo studies using a mouse model to evaluate the efficacy of L-ascorbic acid supplementation in reducing bacterial burden and mortality.
Main Results:
- L-ascorbic acid and L-aspartic acid were identified as key metabolites influencing bovine PmA growth.
- L-ascorbic acid inhibited bovine PmA growth, virulence factor expression, and enhanced macrophage bactericidal activity in vitro.
- Ascorbic acid synthesis was repressed during infection, and exogenous L-ascorbic acid supplementation reduced bacterial load and mortality in vivo.
Conclusions:
- L-ascorbic acid demonstrates significant inhibitory effects on bovine PmA growth and virulence.
- Supplementation with L-ascorbic acid offers a promising therapeutic strategy for bovine PmA infection.
- L-ascorbic acid may serve as a potential protective agent in clinical settings for cattle pneumonia.
