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Medical AI Inquiry: You was designed to assist in medical decision-making based on the provided user questions. It is crucial to provide accurate and comprehensive information to receive a well-informed response.  Labels: OBJECTIVE, METHODS, RESULTS. Meshes: Acinetobacter Infections, Acinetobacter baumannii, Animals, Bronchoalveolar Lavage Fluid, Cell Line, Cell Membrane, Cytokines, Disease Models, Animal, Drug Resistance, Multiple, Bacterial, Immune Sera, Immunization, Immunoglobulin A, Immunoglobulin G, Inflammation, Lung, Mice, Opsonin Proteins, Phagocytosis, Pneumonia, Sepsis, Survival Analysis.
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Does immunization against multidrug-resistant Acinetobacter baumannii effectively protect mice in both pneumonia and sepsis models? Context: Acinetobacter baumannii is considered the prototypical example of a multi- or pan- drug-resistant bacterium. It has been increasingly implicated as a major cause of nosocomial and community-associated infections. This study proposed to evaluate the efficacy of immunological approaches to prevent and treat A. baumannii infections. Mice were immunized with outer membrane vesicles (OMVs) prepared from a clinically isolated multidrug-resistant strain of A. baumannii. Pneumonia and sepsis models were used to evaluate the efficacy of active and passive immunization with OMVs. The probable effective mechanisms and the protective potential of clonally distinct clinical isolates were investigated in vitro using an opsonophagocytic assay. Intramuscular immunization with OMVs rapidly produced high levels of OMV-specific IgG antibodies, and subsequent intranasal challenge with A. baumannii elicited mucosal IgA and IgG responses. Both active and passive immunization protected the mice from challenges with homologue bacteria in a sepsis model. Bacterial burden in bronchoalveolar lavage fluids (BALF), lung, and spleen, inflammatory cell infiltration in BALF and lung, and inflammatory cytokine accumulation in BALF was significantly suppressed in the pneumonia model by both active and passive immunization strategies. The antisera from immunized mice presented with significant opsonophagocytic activities in a dose-dependent manner against not only homologous strains but also five of the other six clonally distinct clinical isolates.
assistant
Utilizing immunological characteristics of outer membrane proteins to elevate protective immunity and circumvent complex multidrug-resistance mechanisms might be a viable approach to effectively control A. baumannii infections. Final Decision: yes