scholarly journals Induction of Shiga Toxin-Converting Prophage in Escherichia coli by High Hydrostatic Pressure

2005 ◽  
Vol 71 (3) ◽  
pp. 1155-1162 ◽  
Author(s):  
Abram Aertsen ◽  
David Faster ◽  
Chris W. Michiels
Keyword(s):  
Escherichia Coli ◽  
Hydrostatic Pressure ◽  
Shiga Toxin ◽  
High Hydrostatic Pressure ◽  
Sos Response ◽  
Resistant Mutant ◽  
Food Preservation ◽  
Bacterial Survival ◽  
E Coli ◽  
Pressure Resistance

ABSTRACT Since high hydrostatic pressure is becoming increasingly important in modern food preservation, its potential effects on microorganisms need to be thoroughly investigated. In this context, mild pressures (<200 MPa) have recently been shown to induce an SOS response in Escherichia coli MG1655. Due to this response, we observed a RecA- and LexA-dependent induction of lambda prophage upon treating E. coli lysogens with sublethal pressures. In this report, we extend this observation to lambdoid Shiga toxin (Stx)-converting bacteriophages in MG1655, which constitute an important virulence trait in Stx-producing E. coli strains (STEC). The window of pressures capable of inducing Stx phages correlated well with the window of bacterial survival. When pressure treatments were conducted in whole milk, which is known to promote bacterial survival, Stx phage induction could be observed at up to 250 MPa in E. coli MG1655 and at up to 300 MPa in a pressure-resistant mutant of this strain. In addition, we found that the intrinsic pressure resistance of two types of Stx phages was very different, with one type surviving relatively well treatments of up to 400 MPa for 15 min at 20°C. Interestingly, and in contrast to UV irradiation or mitomycin C treatment, pressure was not able to induce Stx prophage or an SOS response in several natural Stx-producing STEC isolates.

scholarly journals Inactivation of Escherichia coli andListeria innocua in Milk by Combined Treatment with High Hydrostatic Pressure and the Lactoperoxidase System

2000 ◽  
Vol 66 (10) ◽  
pp. 4173-4179 ◽  
Author(s):  
Cristina García-Graells ◽  
Caroline Valckx ◽  
Chris W. Michiels
Keyword(s):  
Escherichia Coli ◽  
High Pressure ◽  
Hydrostatic Pressure ◽  
High Hydrostatic Pressure ◽  
Combined Treatment ◽  
Food Preservation ◽  
Pressure Treatment ◽  
E Coli ◽  
Preservation Method ◽  
Lactoperoxidase System

ABSTRACT We have studied inactivation of four strains each ofEscherichia coli and Listeria innocua in milk by the combined use of high hydrostatic pressure and the lactoperoxidase-thiocyanate-hydrogen peroxide system as a potential mild food preservation method. The lactoperoxidase system alone exerted a bacteriostatic effect on both species for at least 24 h at room temperature, but none of the strains was inactivated. Upon high-pressure treatment in the presence of the lactoperoxidase system, different results were obtained for E. coli and L. innocua. For none of the E. coli strains did the lactoperoxidase system increase the inactivation compared to a treatment with high pressure alone. However, a strong synergistic interaction of both treatments was observed for L. innocua. Inactivation exceeding 7 decades was achieved for all strains with a mild treatment (400 MPa, 15 min, 20°C), which in the absence of the lactoperoxidase system caused only 2 to 5 decades of inactivation depending on the strain. Milk as a substrate was found to have a considerable effect protecting E. coli and L. innocua against pressure inactivation and reducing the effectiveness of the lactoperoxidase system under pressure on L. innocua. Time course experiments showed that L. innocua counts continued to decrease in the first hours after pressure treatment in the presence of the lactoperoxidase system.E. coli counts remained constant for at least 24 h, except after treatment at the highest pressure level (600 MPa, 15 min, 20°C), in which case, in the presence of the lactoperoxidase system, a transient decrease was observed, indicating sublethal injury rather than true inactivation.

scholarly journals Variation in Resistance to High Hydrostatic Pressure andrpoS Heterogeneity in Natural Isolates ofEscherichia coli O157:H7

2001 ◽  
Vol 67 (10) ◽  
pp. 4901-4907 ◽  
Author(s):  
Marianne Robey ◽  
Amparo Benito ◽  
Roger H. Hutson ◽  
Cristina Pascual ◽  
Simon F. Park ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Hydrostatic Pressure ◽  
Stationary Phase ◽  
Sigma Factor ◽  
High Hydrostatic Pressure ◽  
E Coli ◽  
Commensal Strain ◽  
Natural Isolates ◽  
Pressure Resistance ◽  
Sigma Factor Rpos

ABSTRACT Several natural isolates of Escherichia coliO157:H7 have previously been shown to exhibit stationary-phase-dependent variation in their resistance to inactivation by high hydrostatic pressure. In this report we demonstrate that loss of the stationary-phase-inducible sigma factor RpoS resulted in decreased resistance to pressure inE. coli O157:H7 and in a commensal strain. Furthermore, variation in the RpoS activity of the natural isolates of O157:H7 correlated with the pressure resistance of those strains. Heterogeneity was noted in the rpoS alleles of the natural isolates that may explain the differences in RpoS activity. These results are consistent with a role for rpoS in mediating resistance to high hydrostatic pressure in E. coliO157:H7.

High Pressure Inactivation of Escherichia coli, Campylobacter jejuni, and Spoilage Microbiota on Poultry Meat

2012 ◽  
Vol 75 (3) ◽  
pp. 497-503 ◽  
Author(s):  
YANG LIU ◽  
MIRKO BETTI ◽  
MICHAEL G. GÄNZLE
Keyword(s):  
Escherichia Coli ◽  
High Pressure ◽  
Campylobacter Jejuni ◽  
Resistant Mutant ◽  
Poultry Meat ◽  
E Coli ◽  
Cell Counts ◽  
Meat Spoilage ◽  
Brochothrix Thermosphacta ◽  
Pressure Resistance

This study evaluated the high pressure inactivation of Campylobacter jejuni, Escherichia coli, and poultry meat spoilage organisms. All treatments were performed in aseptically prepared minced poultry meat. Treatment of 19 strains of C. jejuni at 300 MPa and 30°C revealed a large variation of pressure resistance. The recovery of pressure-induced sublethally injured C. jejuni depended on the availability of iron. The addition of iron content to enumeration media was required for resuscitation of sublethally injured cells. Survival of C. jejuni during storage of refrigerated poultry meat was analyzed in fresh and pressure-treated poultry meat, and in the presence or absence of spoilage microbiota. The presence of spoilage microbiota did not significantly influence the survival of C. jejuni. Pressure treatment at 400 MPa and 40°C reduced cell counts of Brochothrix thermosphacta, Carnobacterium divergens, C. jejuni, and Pseudomonas fluorescens to levels below the detection limit. Cell counts of E. coli AW1.7, however, were reduced by only 3.5 log (CFU/g) and remained stable during subsequent refrigerated storage. The resistance to treatment at 600 MPa and 40°Cof E. coli AW1.7 was compared with Salmonella enterica, Shiga toxin–producing E. coli and nonpathogenic E. coli strains, and Staphylococcus spp. Cell counts of all organisms except E. coli AW 1.7 were reduced by more than 6 log CFU/g. Cell counts of E. coli AW1.7 were reduced by 4.5 log CFU/g only. Moreover, the ability of E. coli AW1.7 to resist pressure was comparable to the pressure-resistant mutant E. coli LMM1030. Our results indicate that preservation of fresh meat requires a combination of high pressure with high temperature (40 to 60°C) or other antimicrobial hurdles.

scholarly journals Identification of novel genes involved in high hydrostatic pressure resistance of Escherichia coli

2019 ◽  
Vol 78 ◽  
pp. 171-178 ◽  
Author(s):  
Elisa Gayán ◽  
Nele Rutten ◽  
Jan Van Impe ◽  
Chris W. Michiels ◽  
Abram Aertsen
Keyword(s):  
Escherichia Coli ◽  
Hydrostatic Pressure ◽  
High Hydrostatic Pressure ◽  
Novel Genes ◽  
Pressure Resistance

Loss of cAMP/CRP regulation confers extreme high hydrostatic pressure resistance in Escherichia coli O157:H7

2013 ◽  
Vol 166 (1) ◽  
pp. 65-71 ◽  
Author(s):  
Dietrich Vanlint ◽  
Brecht J.Y. Pype ◽  
Nele Rutten ◽  
Kristof G.A. Vanoirbeek ◽  
Chris W. Michiels ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Hydrostatic Pressure ◽  
High Hydrostatic Pressure ◽  
Escherichia Coli O157 ◽  
Pressure Resistance

scholarly journals Heat Shock Protein-Mediated Resistance to High Hydrostatic Pressure in Escherichia coli

2004 ◽  
Vol 70 (5) ◽  
pp. 2660-2666 ◽  
Author(s):  
Abram Aertsen ◽  
Kristof Vanoirbeek ◽  
Philipp De Spiegeleer ◽  
Jan Sermon ◽  
Kristel Hauben ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
High Pressure ◽  
Hydrostatic Pressure ◽  
Heat Shock ◽  
Heat Shock Proteins ◽  
High Hydrostatic Pressure ◽  
Polyacrylamide Gel Electrophoresis ◽  
Sodium Dodecyl ◽  
E Coli ◽  
Shock Proteins

ABSTRACT A random library of Escherichia coli MG1655 genomic fragments fused to a promoterless green fluorescent protein (GFP) gene was constructed and screened by differential fluorescence induction for promoters that are induced after exposure to a sublethal high hydrostatic pressure stress. This screening yielded three promoters of genes belonging to the heat shock regulon (dnaK, lon, clpPX), suggesting a role for heat shock proteins in protection against, and/or repair of, damage caused by high pressure. Several further observations provide additional support for this hypothesis: (i) the expression of rpoH, encoding the heat shock-specific sigma factor σ32, was also induced by high pressure; (ii) heat shock rendered E. coli significantly more resistant to subsequent high-pressure inactivation, and this heat shock-induced pressure resistance followed the same time course as the induction of heat shock genes; (iii) basal expression levels of GFP from heat shock promoters, and expression of several heat shock proteins as determined by two-dimensional sodium dodecyl sulfate-polyacrylamide gel electrophoresis of proteins extracted from pulse-labeled cells, was increased in three previously isolated pressure-resistant mutants of E. coli compared to wild-type levels.

Combined Effect of High Hydrostatic Pressure and Nisin on Loss of Viability, Membrane Damage and Release of Intracellular Contents of Bacillus subtilis and Escherichia coli

2010 ◽  
Vol 6 (5) ◽  
Author(s):  
Wei-Min Qi ◽  
Ping Qian ◽  
Jian-Yong Yu ◽  
Chi-Yu Zhang ◽  
Xiao Chen ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Bacillus Subtilis ◽  
Hydrostatic Pressure ◽  
Synergistic Effect ◽  
High Hydrostatic Pressure ◽  
Cell Envelope ◽  
Membrane Damage ◽  
Combined Effect ◽  
Gram Negative Bacteria ◽  
E Coli

Bacillus subtilis and Escherichia coli were chosen to investigate the combined effect of high hydrostatic pressure (HHP) and Nisin on loss of viability, membrane damage and release of intracellular contents of microorganisms. The results showed that the combination of 200 IU/mL Nisin and HHP exhibited a synergistic effect over 2 log on the inactivation of B. subtilis at pressure 300 MPa. The similar synergistic effect was observed on the membrane damage and release of intracellular contents of B. subtilis. The Nisin alone had no effect against E. coli, which belongs to gram negative bacteria. However, at pressure 300 MPa, Nisin caused the membrane damage from 55% to 80%. The synergistic effect of Nisin and HHP on loss of viability, membrane damage and release of intracellular contents of E. coli were also illustrated when the HHP pressure exceeded 300 MPa as the consequence of the serious changes produced by HHP at higher pressure in the cell envelope. It allows the entry of Nisin molecules to cell membrane.

scholarly journals An SOS Response Induced by High Pressure in Escherichia coli

2004 ◽  
Vol 186 (18) ◽  
pp. 6133-6141 ◽  
Author(s):  
Abram Aertsen ◽  
Rob Van Houdt ◽  
Kristof Vanoirbeek ◽  
Chris W. Michiels
Keyword(s):  
Escherichia Coli ◽  
Dna Damage ◽  
Current Knowledge ◽  
Sos Response ◽  
Fluorescence Induction ◽  
Food Preservation ◽  
E Coli ◽  
Mediated Effects ◽  
Bona Fide ◽  
First Time

ABSTRACT Although pressure is an important environmental parameter in microbial niches such as the deep sea and is furthermore used in food preservation to inactivate microorganisms, the fundamental understanding of its effects on bacteria remains fragmentary. Our group recently initiated differential fluorescence induction screening to search for pressure-induced Escherichia coli promoters and has already reported induction of the heat shock regulon. Here the screening was continued, and we report for the first time that pressure induces a bona fide SOS response in E. coli, characterized by the RecA and LexA-dependent expression of uvrA, recA, and sulA. Moreover, it was shown that pressure is capable of triggering lambda prophage induction in E. coli lysogens. The remnant lambdoid e14 element, however, could not be induced by pressure, as opposed to UV irradiation, indicating subtle differences between the pressure-induced and the classical SOS response. Furthermore, the pressure-induced SOS response seems not to be initiated by DNA damage, since ΔrecA and lexA1 (Ind−) mutants, which are intrinsically hypersensitive to DNA damage, were not sensitized or were only very slightly sensitized for pressure-mediated killing and since pressure treatment was not found to be mutagenic. In light of these findings, the current knowledge of pressure-mediated effects on bacteria is discussed.

Pasteurization of Fruit Juices of Different pH Values by Combined High Hydrostatic Pressure and Carbon Dioxide

2012 ◽  
Vol 75 (10) ◽  
pp. 1873-1877 ◽  
Author(s):  
LI WANG ◽  
JIAN PAN ◽  
HUIMING XIE ◽  
YI YANG ◽  
DIANFEI ZHOU ◽  
...  
Keyword(s):  
Hydrostatic Pressure ◽  
Orange Juice ◽  
High Hydrostatic Pressure ◽  
Combined Treatment ◽  
Physiological Saline ◽  
Fruit Juices ◽  
E Coli ◽  
Sublethal Injury ◽  
Pressure Resistance ◽  
Low Pressures

The inactivation of the selected vegetative bacteria Escherichia coli, Listeria innocua, and Lactobacillus plantarum by high hydrostatic pressure (HHP) in physiological saline (PS) and in four fruit juices with pHs ranging from 3.4 to 6.3, with or without dissolved CO2, was investigated. The inactivation effect of HHP on the bacteria was greatly enhanced by dissolved CO2. Effective inactivation (&gt;7 log) was achieved at 250 MPa for E. coli and 350 MPa for L. innocua and L. plantarum in the presence of 0.2 M CO2 at room temperature for 15 min in PS, with additional inactivation of more than 4 log for all three bacteria species compared with the results with HHP treatment alone. The combined inactivation by HHP and CO2 in tomato juice of pH 4.2 and carrot juice of pH 6.3 showed minor differences compared with that in PS. By comparison, the combined effect in orange juice of pH 3.8 was considerably promoted, while the HHP inactivation was enhanced only to a limited extent. In another orange juice with a pH of 3.4, all three strains lost their pressure resistance. HHP alone completely inactivated E. coli at relatively mild pressures of 200 MPa and L. innocua and L. plantarum at 300 MPa. Observations of the survival of the bacteria in treated juices also showed that the combined treatment caused more sublethal injury, which increased further inactivation at a relatively mild pH of 4.2 during storage. The results indicated that the combined treatment of HHP with dissolved CO2 may provide an effective method for the preservation of low- or medium-acid fruit and vegetable juices at relatively low pressures. HHP alone inactivated bacteria effectively in high-acid fruit juice.

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