1. Intranasal immunization with outer membrane vesicles (OMV) protects against airway colonization and systemic infection with Acinetobacter baumannii.
- Author
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Higham, Sophie L., Baker, Stephen, Flight, Katie E., Krishna, Aishwarya, Kellam, Paul, Reece, Stephen T., and Tregoning, John S.
- Abstract
The multidrug-resistant bacteria Acinetobacter baumannii is a major cause of hospital-associated infection; a vaccine could significantly reduce this burden. The aim was to develop a clinically relevant model of A. baumannii respiratory tract infection and to test the impact of different immunization routes on protective immunity provided by an outer membrane vesicle (OMV) vaccine. BALB/c mice were intranasally challenged with isolates of oxa23 -positive global clone GC2 A. baumannii from the lungs of patients with ventilator-associated pneumonia. Mice were immunized with OMVs by the intramuscular, subcutaneous or intranasal routes; protection was determined by measuring local and systemic bacterial load. Infection with A. baumannii clinical isolates led to a more disseminated infection than the prototype A. baumannii strain ATCC17978; with bacteria detectable in upper and lower airways and the spleen. Intramuscular immunization induced an antibody response but did not protect against bacterial infection. However, intranasal immunization significantly reduced airway colonization and prevented systemic bacterial dissemination. Use of clinically relevant isolates of A. baumannii provides stringent model for vaccine development. Intranasal immunization with OMVs was an effective route for providing protection, demonstrating that local immunity is important in preventing A. baumannii infection. [Display omitted] • Clinical A. baumannii isolates cause more severe respiratory infection in mice. • Outer membrane vesicles induce strong antibody responses and reduce bacterial load. • Intramuscular and subcutaneous OMV vaccination induce systemic IgG and IgM response. • Intranasal immunization with OMVs induce systemic IgG, IgM, and mucosal IgA response. • Intranasal vaccination with OMVs protects against respiratory tract infection. [ABSTRACT FROM AUTHOR]
- Published
- 2023
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