In January 2018, CDC and public health laboratory partners transitioned from pulsed-field gel electrophoresis (PFGE) – used for the past 20 years – to whole genome sequencing (WGS) for outbreak surveillance of Listeria. Since 2013, a nationwide Listeria pilot using WGS resulted in more outbreaks detected with fewer cases compared to older methods like PFGE. Disease detectives identified foods like ice cream, frozen vegetables, and caramel apples as outbreak sources and made these foods safer for the public.
The pilot led to nationwide implementation of WGS. Fifty-one public health labs in 46 states are transitioning to WGS. By the end of 2018, all 50 states will use WGS to look for outbreaks of other common foodborne bacteria, such as Campylobacter, Salmonella, Shiga toxin-producing Escherichia coli (STEC), and Shigella.