Shiga toxin-producing E. coli (STEC) is a major foodborne pathogen. Its detection requires the preliminary testing, culture isolation and confirmation testing on single colonies. The whole process of obtaining a result normally takes a week or longer. Digital PCR aliquots a tube of reaction into thousands of tiny chambers and the majority of occupied chambers contain a single copy of the target. Experiments indicate that we can mobilize intact E. coli cells into the chamber, lyse the cells and PCR amplify the O-antigens and virulence genes from the same chamber. Thus, we can confirm if the virulence genes are carried by the given O-group E. coli without culture isolation of the bacterial strain. We have generated data using pure culture, culture-spiked bovine feces and ground beef and successfully differentiated STEC and non-STEC E. coli strains. Instead of a week-long process, this procedure is able to provide next-day results.

About the speaker
Jianfa Bai, PhD, Professor
Kansas State University
Dr. Jianfa Bai is a professor and Section Head of Molecular Research and Development at Kansas State Veterinary Diagnostic Laboratory (KSVDL), Kansas State University, where he’s in charge of molecular assay development and validations. His team has built more than 60 molecular diagnostic assays including several syndromic panel assays for different animal species. His team has also developed several assays for E. coli and STEC including a culture-independent digital PCR method for STEC detections. Dr. Bai has published more than 130 peer-reviewed journal articles and delivered numerous conference presentations.
Date of recording:Thursday, May 22, 2025
Duration:60 minutes
Categories
Webinar
Microbiology
Veterinary Testing
dPCR
Digital PCR