Cryo-electron tomography analysis of membrane vesicles from Acinetobacter baumannii ATCC19606T

Koning, Roman I.; Breij, Anna de; Oostergetel, Gert T.; Nibbering, Peter H.; Koster, Abraham J.; Dijkshoorn, Lenie

doi:10.1016/j.resmic.2013.02.007

Cited by 43 publications

(33 citation statements)

References 39 publications

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“…However, inner-outer membrane vesicles are produced by A. baumannii in the stationary phase, and they also contain cytoplasmic proteins [25]. To establish the dominant antigen components in the OMV preparation in the current study and determine their possible cellular distribution, OMVs, OMCs, and WC proteins were used for western blot analyses with the antisera collected from vaccinated mice or adjuvant only-treated mice on day 52 (Figure 1C).…”

Section: Resultsmentioning

confidence: 99%

Immunization against Multidrug-Resistant Acinetobacter baumannii Effectively Protects Mice in both Pneumonia and Sepsis Models

et al. 2014

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Objective 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.MethodsMice 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.ResultsIntramuscular 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.ConclusionsUtilizing 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.

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Section: Resultsmentioning

confidence: 99%

Immunization against Multidrug-Resistant Acinetobacter baumannii Effectively Protects Mice in both Pneumonia and Sepsis Models

et al. 2014

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“…Several previous studies have shown that MV production is increased by exposure to antibiotics, including gentamicin, polymyxin B, colistin, ceftazidime, and imipenem (Kadurugamuwa and Beveridge, 1995; Manning and Kuehn, 2011; Koning et al, 2013; Devos et al, 2015). In particular, gentamicin and antimicrobial peptides (polymyxin B and colistin) bound to LPS on bacterial cell surfaces resulted in increased MV formation (Kadurugamuwa and Beveridge, 1995; Manning and Kuehn, 2011).…”

Section: Discussionmentioning

confidence: 99%

Interaction of Bacterial Membrane Vesicles with Specific Species and Their Potential for Delivery to Target Cells

et al. 2017

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Membrane vesicles (MVs) are secreted from a wide range of microbial species and transfer their content to other cells. Although MVs play critical roles in bacterial communication, whether MVs selectively interact with bacterial cells in microbial communities is unclear. In this study, we investigated the specificity of the MV-cell interactions and evaluated the potential of MVs to target bacterial cells for delivery. MV association with bacterial cells was examined using a fluorescent membrane dye to label MVs. MVs derived from the enterobacterium Buttiauxella agrestis specifically interacted with cells of the parent strain but interacted less specifically with those of other genera tested in this study. Electron microscopic analyses showed that MVs were not only attached on B. agrestis cells but also fused to them. The interaction energy, which was characterized by hydrodynamic diameter and zeta potential based on the Derjaguin–Landau–Verwey–Overbeek (DLVO) theory, was significant low between MVs and cells in B. agrestis, compared to those between B. agrestis MVs and cells of other genera. Similar specific interaction was also occurred between B. agrestis MVs and cells of six other species belonging to Buttiauxella spp. B. agrestis harboring plasmid pBBR1MCS-1 secreted plasmid-containing MVs (p-MVs), and plasmid DNA in p-MVs was transferred to the same species. Moreover, antibiotic-associated MVs enabled effective killing of target species; the survival rate of B. agrestis was lower than those of Escherichia coli and Pseudomonas aeruginosa in the presence of gentamicin-associated MVs derived from B. agrestis. Altogether, we provide the evidence that MVs selectively interact with target bacterial cells and offer a new avenue for controlling specific bacterial species using bacterial MVs in microbial communities.

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“…Initial molecular and proteomic characterizations of A. baumannii OMVs defined their size range as 20-160nm [85]; however, a diverse array of OMV sizes, shapes, and compositions can be readily purified depending on what phase of growth the A. baumannii OMVs are captured. Cryo-electron tomographic analysis of A. baumannii ATCC 19606T at different stages of growth defined multiple sub-types of membrane vesicles, all of which may contribute to the phenotypes observed in OMV focused studies [86]. The first membrane vesicles observed were small prototypical outer membrane vesicles (less than 100 nm) budding from the outer-membrane of log phase A. baumannii cells.…”

Section: Outer Membrane Vesicles and Other Secreted Proteinsmentioning

confidence: 99%

The Secrets of Acinetobacter Secretion

Weber

Kinsella

Harding

et al. 2017

Trends in Microbiology

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Infections caused by the bacterial pathogen Acinetobacter baumannii are a mounting concern for healthcare practitioners as widespread antibiotic resistance continues to limit therapeutic treatment options. The biological processes used by A. baumannii to cause disease are not well-defined, but recent research has indicated that secreted proteins may play a major role. A variety of mechanisms have now been shown to contribute to protein secretion by A. baumannii and other pathogenic species of Acinetobacter, including a type II and type VI secretion system, autotransporter, and outer membrane vesicles. In this review, we summarize the current knowledge of secretion systems in Acinetobacter species, and highlight their unique aspects that contribute to the pathogenicity and persistence of these emerging pathogens.

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Cryo-electron tomography analysis of membrane vesicles from Acinetobacter baumannii ATCC19606T

Cited by 43 publications

References 39 publications

Immunization against Multidrug-Resistant Acinetobacter baumannii Effectively Protects Mice in both Pneumonia and Sepsis Models

Immunization against Multidrug-Resistant Acinetobacter baumannii Effectively Protects Mice in both Pneumonia and Sepsis Models

Interaction of Bacterial Membrane Vesicles with Specific Species and Their Potential for Delivery to Target Cells

The Secrets of Acinetobacter Secretion

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