Harmful strains of Escherichia coli bacteria, primarily found in cattle cause severe, sometimes life-threatening human illness. According to the US Centers for Disease Control and Prevention, an estimated 110,000 cases (due to specifically enterohaemorrhagic E. coli (EHEC)) occur annually in the United States, and is now plaguing more than 30 countries around the globe. The other E. coli virotype, enterotoxigenic E. coli (ETEC), according to the World Health Organization, causes more than 200 million cases of diarrhea and 380,000 deaths, mostly in children in developing countries.
A team of WSU researchers have identified a proximity-dependent inhibition phenotype of E.coli, expressed when E. coli strains are co-cultured in defined minimal media. The inhibitory activity was specifically found effective against all E. coli O157:H7 strains tested, all STEC strains tested, Shigella sp, ETEC strains, multi-drug resistant, and commensal E. coli. The strains expressing the inhibitory phenotype are likewise immune to inhibition by other inhibitor strains.  In addition, genetic manipulations of the system have been demonstrated by cause-and-effect (gene knockouts and complementation), confirmation of the putative immunity protein, and confirmation that inhibition is caused by a bactericidal event.

The researchers have expressed and purified the Microcin and demonstrate the same inhibitory function in Vitro.


Applications and Advantages

¦ The effectiveness of our inhibitory mechanism offers great potential for dipstick type application to cattle prior to their entry into slaughterhouse.
¦ Discovery is novel and unique from all recognized contact-based inhibition mechanisms.
¦ Inhibition mechanism has broad spectrum activity that includes E. coli strains pathogenic to both humans and animals and shows reduction by at least five logs.   

IP Status & Publication

US patent application allowed

Ashish Sawant,  N. C. Casavant, Douglas Call, & Thomas Besser. (2011). Identification and Characterization of Proximity-Dependent Inhibition in Eschirichia coli Isolated from Cattle.  Applied and Environmental Microbiology, 2345-2351.

Learn More

Karin Biggs
Technology Licensing Associate
Washington State University
(509) 335-3553
Reference No: 1264-OIPA-OC


Douglas Call
Lauren Eberhart
Kelly Brayton
Thomas Besser
Ashish Sawant
Lisa Orfe

Key Words