Binding and Inactivating Pathogenic E. Coli Using Antimicrobial Peptide Cecropin P1-Cys Fragments

Escherichia coli O157:H7 is a pathogenic strain of bacteria that commonly contaminates foods such as ground beef and spinach. One potential way to prevent E. coli contamination is to attach antimicrobial peptides (AMPs) to food preparation surfaces. Previous studies have shown that the AMP cecropin P1-cys (CP1-cys) can effectively bind and kill E. coli when attached to a gold substrate. The purpose of this study was to determine if fragments of CP1-cys attached to gold could kill E. coli as effectively as the whole peptide. Quartz Crystal Microbalance with Dissipation monitoring (QCM-D) was used to attach the peptide fragments and bacteria to the gold substrate, and a LIVE/DEAD^® BacLight^TM Kit quantified the live versus dead cells on the substrate. The performances of fragments H2N-LSKTAKKLENSAKKC-OH and H2N-EGIAIAIC-OH were compared to the performance of the whole peptide, H2N-SWLSKTAKKLENSAKKRISEGIAIAIQGGPRC-OH. Initial studies indicate that although the fragments can bind to the gold substrate and kill E. coli, the thickness of peptide on the gold as well as the amount of cells killed were relatively less than when the entire peptide was used. This could lead to further understanding of AMP behavior with respect to substrate binding and the binding and inactivation of E. coli.