What is whole genome sequencing (WGS) and why is it pivotal in foodborne illness investigations

Whole genome sequencing (WGS) is a laboratory process that determines the complete DNA sequence of an organism’s genome at a single time. This includes identifying the order of bases in the DNA molecules (adenine (A), cytosine (C), guanine (G), and thymine (T)) and assembling them to map out all of an organism’s genetic material.

WGS examines the entire genome, covering all the genetic material in the organism, rather than focusing on specific genes or regions. This offers a detailed and complete view of the genome.

Because WGS investigates the entire genome, it provides high-resolution data that can distinguish even slight genetic variations between different strains of an organism.

The process begins with extracting DNA from an organism’s cells. This DNA is then broken into smaller fragments that are sequenced using advanced technologies. The sequences from these fragments are computationally assembled to reconstruct the complete genome sequence.

In public health, it is instrumental in identifying and tracking pathogens in outbreaks of infectious diseases, like foodborne illnesses.

In summary, whole genome sequencing is a powerful tool that provides a complete picture of an organism’s genetic makeup, allowing for in-depth analysis and understanding of its biological functions, evolutionary history, and role in causing diseases.

Whole genome sequencing (WGS) has become a pivotal technology in the investigation of foodborne illnesses due to its capability to provide comprehensive insights into the genetic makeup of pathogens.

WGS allows for precise identification of pathogens at the strain or sub-strain level. This level of detail surpasses traditional methods, enabling investigators to differentiate between closely related strains, which is crucial during outbreak investigations.

By comparing the whole genome sequences of pathogens isolated from different sources, WGS helps trace the source of an outbreak. It can identify the point of contamination along the food supply chain, whether it’s on the farm, processing plant, or point of sale.

WGS can detect and link seemingly sporadic cases by identifying common genetic markers, revealing unrecognized outbreaks. It allows public health officials to compare current strains with those from past outbreaks globally, aiding in pinpointing sources and connections.

WGS can identify genes linked to antibiotic resistance, providing insights into resistance patterns and helping guide treatment options for affected individuals. This data is crucial for managing public health responses and developing regulatory policies.

The detailed genetic information obtained through WGS helps scientists understand the evolution and adaptation mechanisms of pathogens, including mutations and horizontal gene transfer, leading to better risk assessments and prevention strategies.

Integrated WGS-based surveillance systems, like those utilized by public health agencies (e.g., PulseNet in the U.S.), enhance the ability to monitor and respond to foodborne illnesses in real time. The technology supports a shift towards proactive rather than reactive public health responses.

While initially more expensive, advances in WGS technology have made it more cost-effective and faster than many traditional typing methods, allowing for more rapid public health interventions.

Overall, the implementation of whole genome sequencing in foodborne illness investigations represents a transformative step in public health, providing comprehensive and actionable data that enhances the ability to prevent and control outbreaks effectively.

Republished with permission from Bill Marler and Marler Clark. Copyright (c) Marler Clark LLP, PS. All rights reserved.

Source: https://www.marlerblog.com/case-news/what-is-whole-genome-sequencing-wgs-and-why-is-it-pivotal-in-foodborne-illness-investigations/