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Updated: Dec 25, 2025
A Non-invasive and Technically Non-intensive Method for Induction and Phenotyping of Experimental Bacterial Pneumonia in Mice
Published on: September 28, 2016
Biological sex influences susceptibility to Acinetobacter baumannii pneumonia in mice
Sílvia Pires1, Adeline Peignier1, Jeremy Seto2
1Department of Pathology, Immunology and Laboratory Medicine, Center for Immunity and Inflammation, Rutgers New Jersey Medical School, Newark, New Jersey, USA.
Abstract:
Acinetobacter baumannii (A. baumannii) is an extremely versatile multidrug-resistant pathogen with a very high mortality rate; therefore, it has become crucial to understand the host response during its infection. Given the importance of mice for modeling infection and their role in preclinical drug development, equal emphasis should be placed on the use of both sexes. Through our studies using a murine model of acute pneumonia with A. baumannii, we observed that female mice were more susceptible to infection. Likewise, treatment of male mice with estradiol increased their susceptibility to infection. Analysis of the airway compartment revealed enhanced inflammation and reduced neutrophil and alveolar macrophage numbers compared with male mice. Depletion of either neutrophils or alveolar macrophages was important for bacterial clearance; however, depletion of alveolar macrophages further exacerbated female susceptibility because of severe alterations in metabolic homeostasis. Our data highlight the importance of using both sexes when assessing host immune pathways.
Insights
Female mice show higher susceptibility to Acinetobacter baumannii pneumonia. This study reveals sex-based differences in immune response and highlights the need for including both sexes in infection research and drug development.
Area of Science:
- Immunology
- Infectious Diseases
- Microbiology
Background:
- Acinetobacter baumannii is a multidrug-resistant pathogen causing severe infections.
- Understanding host immune responses is critical for developing effective treatments.
- Sex-based differences in host response are increasingly recognized in infectious diseases.
Purpose of the Study:
- To investigate sex-based differences in the host response to Acinetobacter baumannii pneumonia in a murine model.
- To elucidate the role of neutrophils and alveolar macrophages in sex-specific susceptibility.
- To emphasize the importance of using both male and female mice in preclinical studies.
Main Methods:
- Establishment of a murine model of acute Acinetobacter baumannii pneumonia.
- Comparative analysis of immune cell populations (neutrophils, alveolar macrophages) in the airway compartment.
- Assessment of bacterial clearance and inflammatory markers.
- Experimental manipulation of immune cell populations (depletion studies).
Main Results:
- Female mice exhibited increased susceptibility to Acinetobacter baumannii infection compared to male mice.
- Estradiol treatment enhanced susceptibility in male mice.
- Airway inflammation was heightened in females, with reduced neutrophil and alveolar macrophage numbers.
- Depletion of alveolar macrophages exacerbated female susceptibility due to metabolic dysregulation.
Conclusions:
- Sex is a significant factor influencing the host immune response to Acinetobacter baumannii infection.
- Alveolar macrophages play a critical role in controlling bacterial burden and maintaining metabolic homeostasis.
- Future research and drug development should incorporate both sexes to accurately model infection and assess therapeutic efficacy.
