Broad and efficient control of major foodborne pathogenic strains of Escherichia coli by mixtures of plant-produced colicins.
Enterohemorrhagic Escherichia coli (EHEC) is one of the leading causes of bacterial enteric infections worldwide, causing ∼100,000 illnesses, 3,000 hospitalizations, and 90 deaths annually in the United States alone. These illnesses have been linked to consumption of contaminated animal products and vegetables. Currently, other than thermal inactivation, there are no effective methods to eliminate pathogenic bacteria in food. Colicins are nonantibiotic antimicrobial proteins, produced by E. coli strains that kill or inhibit the growth of other E. coli strains. Several colicins are highly effective against key EHEC strains. Here we demonstrate very high levels of colicin expression (up to 3 g/kg of fresh biomass) in tobacco and edible plants (spinach and leafy beets) at costs that will allow commercialization. Among the colicins examined, plant-expressed colicin M had the broadest antimicrobial activity against EHEC and complemented the potency of other colicins. A mixture of colicin M and colicin E7 showed very high activity against all major EHEC strains, as defined by the US Department of Agriculture/Food and Drug Administration. Treatments with low (less than 10 mg colicins per L) concentrations reduced the pathogenic bacterial load in broth culture by 2 to over 6 logs depending on the strain. In experiments using meats spiked with E. coli O157:H7, colicins efficiently reduced the population of the pathogen by at least 2 logs. Plant-produced colicins could be effectively used for the broad control of pathogenic E. coli in both plant- and animal-based food products and, in the United States, colicins could be approved using the generally recognized as safe (GRAS) regulatory approval pathway.
Nomad Bioscience GmbH, Biozentrum Halle, D-06120 Halle (Saale), Germany;
Steve
S
Schulz
Nomad Bioscience GmbH, Biozentrum Halle, D-06120 Halle (Saale), Germany;
Anett
A
Stephan
Nomad Bioscience GmbH, Biozentrum Halle, D-06120 Halle (Saale), Germany;
Simone
S
Hahn
Nomad Bioscience GmbH, Biozentrum Halle, D-06120 Halle (Saale), Germany;
Luisa
L
Bortesi
Icon Genetics GmbH, Biozentrum Halle, D-06120 Halle (Saale), Germany;
Franziska
F
Jarczowski
Icon Genetics GmbH, Biozentrum Halle, D-06120 Halle (Saale), Germany;
Ulrike
U
Bettmann
Icon Genetics GmbH, Biozentrum Halle, D-06120 Halle (Saale), Germany;
Anne-Katrin
AK
Paschke
DT/Consulting Group, Sacramento, CA 95818;
Daniel
D
Tusé
Department of Animal and Avian Sciences, University of Maryland, College Park, MD 20742.
Chad H
CH
Stahl
Nomad Bioscience GmbH, Biozentrum Halle, D-06120 Halle (Saale), Germany; giritch@nomadbioscience.com.
Anatoli
A
Giritch
Nomad Bioscience GmbH, Biozentrum Halle, D-06120 Halle (Saale), Germany;
Yuri
Y
Gleba
D000595:Amino Acid Sequence; D000818:Animals; D027461:Beta vulgaris / Q000235:genetics / Q000378:metabolism; D003087:Colicins / Q000235:genetics / Q000378:metabolism* / Q000494:pharmacology*; D004591:Electrophoresis, Polyacrylamide Gel; D004927:Escherichia coli Infections / Q000382:microbiology; D019453:Escherichia coli O157 / Q000187:drug effects* / Q000254:growth & development; D005399:Fishes; D005516:Food Microbiology; D008460:Meat / Q000382:microbiology; D008969:Molecular Sequence Data; D010945:Plants, Edible / Q000235:genetics / Q000378:metabolism*; D030821:Plants, Genetically Modified; D011994:Recombinant Proteins / Q000302:isolation & purification / Q000378:metabolism / Q000494:pharmacology; D018724:Spinacia oleracea / Q000235:genetics / Q000378:metabolism; D013552:Swine; D014026:Nicotiana / Q000235:genetics / Q000378:metabolism
D003087:Colicins; D011994:Recombinant Proteins
EHEC; antimicrobials; colicin; food safety; plant-made recombinant proteins