High-pressure transient sensitization of Escherichia coli to lysozyme and nisin by disruption of outer-membrane permeability

Escherichia coli MG1655 suspensions in 10 mM phosphate buffer (pH 7.0) were subjected to high pressures in the range of 180 to 320 MPa for 15 min. Cell death was evident at 220 MPa and increased exponentially with pressure. Surviving populations were sublethally injured, as demonstrated by their red...

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Bibliographic Details
Published in:Journal of food protection 1996-04, Vol.59 (4), p.350-355
Main Authors: Hauben, K.J.A. (Katholieke Universiteit Leuven, Heverlee, Belgium.), Wuytack, E.Y, Soontjens, C.C.F, Michiels, C.W
Format: Article
Language:English
Subjects:
Action of physical and chemical agents on bacteria
AGENTES NOCIVOS
ALIMENTOS
Bacteriology
Biological and medical sciences
Cereal and baking product industries
CHELATEUR
ESCHERICHIA COLI
FACTEUR NUISIBLE
Food industries
Fundamental and applied biological sciences. Psychology
LISOZIMA
LYSOZYME
MEMBRANAS CELULARES
MEMBRANE CELLULAIRE
Microbiology
MORTALIDAD
MORTALITE
NISINA
NYSINE
PERMEABILIDAD
PERMEABILITE
PRESERVACION
PRESERVATION
PRESION
PRESSION
PRODUIT ALIMENTAIRE
QUELATOS
TECHNOLOGIE ALIMENTAIRE
TECNOLOGIA DE LOS ALIMENTOS
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Summary:Escherichia coli MG1655 suspensions in 10 mM phosphate buffer (pH 7.0) were subjected to high pressures in the range of 180 to 320 MPa for 15 min. Cell death was evident at 220 MPa and increased exponentially with pressure. Surviving populations were sublethally injured, as demonstrated by their reduced ability to form colonies on violet red bile glucose agar, a selective growth medium containing crystal violet and bile salts. During exposure to high pressure ( 180 MPa), cells were sensitive to lysozyme, nisin, and ethylenediaminetetraacetic acid (EDTA), as was apparent from an increased lethality of pressure in the presence of these agents. Sublethal injury in the surviving population was lower in the presence of nisin and lysozyme, but higher in the presence of EDTA. Combinations of EDTA with nisin or lysozyme present during pressure treatment increased lethality in an additive manner. However, the addition of lysozyme, nisin and/or EDTA to pressurized cell suspensions immediately after pressure treatment did not cause any viable count reduction. Finally, we observed leakage of the periplasmic enzyme beta-lactamase from an ampicillin-resistant recombinant E. coli MG1655 under high pressure. These results suggest that high pressure transiently disrupts the permeability of the E. coli outer membrane for water-soluble proteins
ISSN:0362-028X
1944-9097
DOI:10.4315/0362-028x-59.4.350