Page Banner

United States Department of Agriculture

Agricultural Research Service

Title: Colicins Inhibit Growth of Escherichia Coli O157:h7 But Not Salmonella in Vitro

Authors
item Callaway, Todd
item Stahi, C - IOWA STATE UNIV
item Edrington, Thomas
item Genovese, Kenneth
item Lincoln, L - IOWA STATE UNIV
item Anderson, Robin
item Lonergan, S - IOWA STATE UNIV
item Poole, Toni
item Harvey, Roger
item Nisbet, David

Submitted to: Journal of Food Protection
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: May 30, 2004
Publication Date: November 1, 2004
Citation: Callaway, T.R., Stahi, C.H., Edrington, T.S., Genovese, K.J., Lincoln, L.M., Anderson, R.C., Lonergan, S.M., Poole, T.L., Harvey, R.B., Nisbet, D.J. 2004. Colicin concentrations inhibit growth of Escherichia coli O157:H7 in vitro. Journal of Food Protection. 67:2603-2607.

Interpretive Summary: Escherichia coli O157:H7 and Salmonella Typhimurium are food-borne pathogens that cause severe human illnesses and inhabit the intestinal tract of food animals. Colicins are antimicrobial proteins produced by certain E. coli strains that inhibit or kill other E. coli. Colicin activity against strains of E. coli O157:H7 and Salmonella were quantified in vitro. Colicin E1 was most effective against E. coli O157:H7 strains, followed by colicin N; colicin A did not affect E. coli O157:H7. Colicin E1 inhibited the growth of E. coli O157:H7 at very low concentrations. In swine, colicin E1 treatment reduced E. coli O157:H7 populations. Because colicins are proteins, in order for them to be an effective strategy to reduce food borne pathogens in live animals, colicins must be protected from host animal digestion. These potent antimicrobial proteins may potentially provide an effective and environmentally sound pre-harvest strategy to reduce E. coli O157:H7 in food animals.

Technical Abstract: Escherichia coli O157:H7 and Salmonella Typhimurium are food-borne pathogens that cause severe human illnesses and inhabit the intestinal tract of food animals. Colicins are antimicrobial proteins produced by E. coli strains that inhibit or kill other E. coli. In the present study, the efficacy of three pore-forming colicins (E1, N and A) were quantified in vitro against E. coli O157:H7 strains 86-24 and 933 and Salmonella Typhimurium. Colicin E1 and N reduced the growth of E. coli O157:H7 strains, but the efficacy of each colicin varied among strains. Colicin E1 was more effective against both strains of E. coli O157:H7 than colicins A and N, and reduced (P < 0.05) populations of E. coli O157:H7 at concentrations less than 0.1 ug/ml. Growth rates, final optical densities, and cell numbers of Salmonella Typhimurium were not affected by colicin treatment. These potent antimicrobial proteins may potentially provide an effective and environmentally sound pre-harvest strategy to reduce E. coli O157:H7 in food animals.

Last Modified: 10/1/2014
Footer Content Back to Top of Page