Augmentation of killing of Escherichia coli O157 by combinations of lactate, ethanol, and low-pH conditions.
The acid tolerance of Escherichia coli O157:H7 strains can be overcome by addition of lactate, ethanol, or a combination of the two agents. Killing can be increased by as much as 4 log units in the first 5 min of incubation at pH 3 even for the most acid-tolerant isolates. Exponential-phase, habituated, and stationary-phase cells are all sensitive to incubation with lactate and ethanol. Killing correlates with disruption of the capacity for pH homeostasis. Habituated and stationary-phase cells can partially offset the effects of the lowering of cytoplasmic pH.
Institute of Food Research, Reading Laboratory, Reading, RG6 6BZ, Foresterhill, Aberdeen, AB25 2ZD, United Kingdom. sarah.jordan@bbsrc.ac.uk
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Jordan
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Glover
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Malcolm
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Thomson-Carter
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Booth
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Park
D000818:Animals; D002645:Chickens; D015169:Colony Count, Microbial; D003470:Culture Media; D004926:Escherichia coli / Q000187:drug effects / Q000254:growth & development / Q000302:isolation & purification; D004927:Escherichia coli Infections / Q000382:microbiology*; D019453:Escherichia coli O157 / Q000254:growth & development* / Q000302:isolation & purification; D000431:Ethanol / Q000494:pharmacology*; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007773:Lactates / Q000494:pharmacology*; D008460:Meat / Q000382:microbiology; D008461:Meat Products / Q000382:microbiology*; D013552:Swine
D003470:Culture Media; D007773:Lactates; D000431:Ethanol