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United States Department of Agriculture

Agricultural Research Service


item Callaway, Todd
item Anderson, Robin
item Edrington, Thomas
item Bischoff, Kenneth
item Genovese, Kenneth
item Poole, Toni
item Harvey, Roger
item Byrd, James
item Nisbet, David

Submitted to: Current Issues in Intestinal Microbiology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: February 17, 2004
Publication Date: March 8, 2004
Citation: Callaway, T.R., Anderson, R.C., Edrington, T.S., Bischoff, K.M., Genovese, K.J., Poole, T.L., Harvey, R.B., Byrd II, J.A., Nisbet, D.J. 2004. Effects of sodium chlorate on toxin production by Escherichia coli O157:H7. Current Issues in Intestinal Microbiology. 5:19-22.

Interpretive Summary: Escherichia coli O157:H7 is a food borne pathogenic bacterium that is killed by the addition of sodium chlorate. Toxin production by E. coli O157:H7 is dramatically increased when this bacterium is treated with traditional, medically-important antibiotics; thus causing a negative impact on human health. Because of this increase in toxin production, antibiotics are not recommended for use in human infections by E. coli O157:H7. This study demonstrates that chlorate does not increase toxin production by strains of E. coli O157:H7. This result indicates that chlorate could be used to treat a broad range of E. coli O157:H7 infections without fear of stimulating toxin production.

Technical Abstract: Chlorate kills E. coli O157:H7 and has been proposed as a feed additive to be included in cattle rations immediately prior to slaughter to reduce E. coli O157:H7 populations in the gut. Antibiotic usage is not recommended in cases of E. coli O157:H7-induced hemorrhagic colitis because some antibiotics stimulate toxin production. This study was undertaken to determine if chlorate treatment affected toxin production. Pure cultures of E. coli O157:H7 were treated with ¼ MIC of antibiotics (ampicillin, tetracycline, ceftiofur, gentamicin, monensin, tylosin, penicillin, ciprofloxacin, and novobiocin); toxin production was significantly increased by some antibiotics, but not by chlorate. Studies with mixed fecal bacteria demonstrated that chlorate killed E. coli O157:H7, but again did not stimulate toxin production. Chlorate appears to be an effective method to reduce shiga toxin-producing E. coli (STEC) populations in food animals, but additional studies are warranted before it is used to control infections.

Last Modified: 11/27/2015
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