Safety and Prophylactic Efficacy of Liposome-Based Vaccine against the Drug-Resistant Acinetobacter baumannii in Mice

Abstract

In recent years, the emergence of multidrug-resistant Acientobacter baumannii has greatly threatened public health and depleted our currently available antibacterial armory. Due to limited therapeutic options, the development of an effective vaccine formulation becomes critical in order to fight this drug-resistant pathogen. The objective of the present study was to develop a safe vaccine formulation that can be effective against A. baumannii infection and its associated complications. Here, we prepared liposomes-encapsulated whole cell antigens (Lip-WCAgs) as a vaccine formulation and investigated its prophylactic efficacy against the systemic infection of A. baumannii. The immunization with Lip-WCAgs induced the higher production of antigen-specific antibody titers, greater lymphocyte proliferation, and increased secretion of Th1 cytokines, particularly IFN-γ and IL-12. Antisera from Lip-WCAgs-immunized mice showed the utmost bactericidal activity and potently inhibited the biofilm formation by A. baumannii. Interestingly, Lip-WCAgs-induced immune response was translated in in vivo protection studies as the immunized mice exhibited the highest resistance to A. baumannii infection. Mice in the group immunized with Lip-WCAgs had an 80% survival rate and a bacterial burden of 5464 ± 1193 CFUs per gram of the lung tissue, whereas the mice immunized with IFA-WCAgs had a 50% survival rate and 51,521 ± 8066 CFUs. In addition, Lip-WCAgs vaccinated mice had lower levels of the inflammatory markers, including CRP, IL-6, IL-1β, and TNF-α. The findings of this study suggest that Lip-WCAgs may be considered a potential vaccine formulation to protect individuals against A. baumannii infection.

Novel Coumarins Derivatives for A. baumannii Lung Infection Developed by High-Throughput Screening and Reinforcement Learning

“…To evaluate the inhibitory activity of the S1032 compound on bacterial biofilm formation, the crystal violet staining assay was performed in this research. All the conduction was finished strictly under the guidance with only a little modification (Khan et al 2022). In short, A. baumannii strain were seeded in 96 well plates and cultured in the incubator at the condition of 37℃ for 24 h. After the bacterial biofilm formation, 0.1% crystal violet (CV) (Sigma) solution was added into wells for staining at 37 °C for 10 min.…”

Non-antibiotic prevention and treatment against Acinetobacter baumannii infection: Are vaccines and adjuvants effective strategies?

“…It may be because antibiotic pretreatment can enhance the protein expression of A. baumannii and produce a stronger immune response (Shu et al, 2016 ). Recently, the first study showed the protection of liposomes-encapsulated whole cell antigens (Lip-WCAgs) in infection model, Liposomes owned strong immunoadjuvant potential, Lip-WCAgs induced the higher production of antibody titers, stimulate immunocyte proliferation, the antisera from immunized mice can inhibited the biofilm formation, and 80% mice survived from challenge (Khan et al, 2022 ). The latest research shows that in addition to formalin inactivation, the relatively innovative radiation inactivation method also shows 80–100% protection ability (Dollery et al, 2021 ).…”