Unit of Infectious Disease, Microbiology, and Preventive Medicine, Institute of Biomedicine of Sevilla (IBiS), University Hospital Virgen del Rocío/CSIC/University of Sevilla, 41013 Sevilla, Spain.
Vaccine. 2011 Aug 5;29(34):5705-10. doi: 10.1016/j.vaccine.2011.06.001. Epub 2011 Jun 14.
Acinetobacter baumannii produces different types of infections including pneumonia, meningitis, and bloodstream infections. The optimal treatment of these infections has been complicated by the global emergence of multidrug resistant strains, requiring the development of novel approaches for treatment and prevention. Outer membrane vesicles are outpouchings of the bacterial outer membrane that are secreted from numerous pathogenic Gram-negative bacteria. In the present study, we describe the isolation of outer membrane vesicles from A. baumannii and their use as a vaccine in a mouse model of disseminated sepsis. Immunization produced a robust antibody response against multiple bacterial antigens which consisted of antigen-specific IgG and IgM. In addition, both IgG1 and IgG2c subtypes were produced by immunization. Immunized mice had lower tissue bacterial loads and lower serum levels of the pro-inflammatory cytokines IL-6 and IL-1β post-infection compared to control mice. Importantly, vaccination protected mice from challenge with the ATCC 19606 strain and provided protection against two clinical isolates, including a pan-resistant strain. These results indicate that vaccination with outer membrane vesicles may be a viable strategy for preventing A. baumannii infection.
鲍曼不动杆菌可引起多种类型的感染，包括肺炎、脑膜炎和血流感染。由于全球出现了多种耐药菌株，这些感染的最佳治疗方法变得复杂，需要开发新的治疗和预防方法。外膜囊泡是许多革兰氏阴性致病菌从细菌外膜向外突出的囊泡。在本研究中，我们描述了从鲍曼不动杆菌中分离出外膜囊泡，并将其用作播散性败血症小鼠模型中的疫苗。免疫接种产生了针对多种细菌抗原的强烈抗体反应，其中包括抗原特异性 IgG 和 IgM。此外，免疫接种还产生了 IgG1 和 IgG2c 两种亚型。与对照组小鼠相比，感染后免疫小鼠的组织细菌载量较低，促炎细胞因子 IL-6 和 IL-1β 的血清水平也较低。重要的是，疫苗接种可保护小鼠免受 ATCC 19606 株的挑战，并可预防两种临床分离株的感染，包括一株泛耐药株。这些结果表明，用外膜囊泡进行疫苗接种可能是预防鲍曼不动杆菌感染的一种可行策略。
