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Effect of influenza virus infection on susceptibility to bacteria in mice
Abstract:
A model of combined infection was established with intranasal influenza virus and systemic Listeria monocytogenes infections of mice. Prior infection of mice with influenza virus markedly influenced resistance to subsequent challenge with L. monocytogenes. If mice were infected with influenza virus within the 24-hr period before challenge, a substantial increase in mortality was reflected by enhanced growth of Listeria in the spleen. If mice were infected with influenza virus three or five days before challenge, mortality was decreased, with an accompanying reduction in the growth of Listeria in the spleen. Thus, pulmonary infection with influenza virus has a major effect on susceptibility to systemic infection, exerting a depressive effect on host resistance in the first 48 hr and then causing a longer period of enhanced resistance.
Insights
Influenza virus infection alters host resistance to Listeria monocytogenes. Early influenza infection increases mortality, while later infection enhances resistance, impacting Listeria growth.
Area of Science:
- Immunology
- Infectious Diseases
- Microbiology
Background:
- Combined infections can complicate disease progression and outcomes.
- Influenza virus and Listeria monocytogenes are significant human pathogens.
Purpose of the Study:
- To investigate the impact of prior influenza virus infection on susceptibility to systemic Listeria monocytogenes infection in a mouse model.
- To determine the temporal effects of influenza on host defense mechanisms against secondary bacterial infections.
Main Methods:
- Establishment of a combined infection model using intranasal influenza virus and systemic Listeria monocytogenes in mice.
- Assessment of host mortality and bacterial load in the spleen following sequential infections.
Main Results:
- Influenza infection within 24 hours before Listeria challenge significantly increased mortality and Listeria growth.
- Influenza infection 3-5 days before Listeria challenge decreased mortality and Listeria growth.
- Pulmonary influenza infection initially depressed host resistance for 48 hours, followed by a period of enhanced resistance.
Conclusions:
- Prior influenza virus infection profoundly modulates host susceptibility to systemic Listeria monocytogenes.
- The timing of influenza infection relative to Listeria challenge dictates the outcome, shifting from increased susceptibility to enhanced resistance.
- Understanding these temporal dynamics is crucial for managing coinfections and developing effective therapeutic strategies.