Contribution of bacterial outer membrane vesicles to innate bacterial defense.

Manning, Andrew J

Kuehn, Meta J

England

2015-10-05T18:41:37Z

2011-12-01

BACKGROUND: Outer membrane vesicles (OMVs) are constitutively produced by Gram-negative bacteria throughout growth and have proposed roles in virulence, inflammation, and the response to envelope stress. Here we investigate outer membrane vesiculation as a bacterial mechanism for immediate short-term protection against outer membrane acting stressors. Antimicrobial peptides as well as bacteriophage were used to examine the effectiveness of OMV protection. RESULTS: We found that a hyper-vesiculating mutant of Escherichia coli survived treatment by antimicrobial peptides (AMPs) polymyxin B and colistin better than the wild-type. Supplementation of E. coli cultures with purified outer membrane vesicles provided substantial protection against AMPs, and AMPs significantly induced vesiculation. Vesicle-mediated protection and induction of vesiculation were also observed for a human pathogen, enterotoxigenic E. coli (ETEC), challenged with polymyxin B. When ETEC with was incubated with low concentrations of vesicles concomitant with polymyxin B treatment, bacterial survival increased immediately, and the culture gained resistance to polymyxin B. By contrast, high levels of vesicles also provided immediate protection but prevented acquisition of resistance. Co-incubation of T4 bacteriophage and OMVs showed fast, irreversible binding. The efficiency of T4 infection was significantly reduced by the formation of complexes with the OMVs. CONCLUSIONS: These data reveal a role for OMVs in contributing to innate bacterial defense by adsorption of antimicrobial peptides and bacteriophage. Given the increase in vesiculation in response to the antimicrobial peptides, and loss in efficiency of infection with the T4-OMV complex, we conclude that OMV production may be an important factor in neutralizing environmental agents that target the outer membrane of Gram-negative bacteria.

http://www.ncbi.nlm.nih.gov/pubmed/22133164

1471-2180-11-258

1471-2180

https://hdl.handle.net/10161/10657

eng

Springer Science and Business Media LLC

BMC Microbiol

10.1186/1471-2180-11-258

Bacteriophage T4

Cell Membrane Structures

Colistin

Enterotoxigenic Escherichia coli

Microbial Viability

Polymyxin B

Virulence

Contribution of bacterial outer membrane vesicles to innate bacterial defense.

Journal article

http://www.ncbi.nlm.nih.gov/pubmed/22133164

258

Basic Science Departments

Biochemistry

Duke

Duke Cancer Institute

Institutes and Centers

Molecular Genetics and Microbiology

School of Medicine

Published online

11