Title: A Targeted Multilocus Genotyping Assay for Lineage, Serogroup, and Epidemic Clone Typing of Listeria monocytogenes Authors
Submitted to: Applied and Environmental Microbiology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: August 5, 2010
Publication Date: October 1, 2010
Citation: Ward, T.J., Usgaard, T.R., Evans, P. 2010. A targeted multilocus genotyping assay for lineage, serogroup, and epidemic clone typing of Listeria monocytogenes. Applied and Environmental Microbiology. 76(19):6680-6684. Interpretive Summary: Listeria monocytogenes is a food-borne bacterium responsible for serious invasive illness in humans and other animals. L. monocytogenes is responsible for over 25% of foodborne disease-related deaths attributable to known pathogens and is a leading cause of food recalls. In 2005, the Food Safety and Inspection Service (FSIS) implemented a risk-based approach to determine inspection frequencies for food processing facilities that takes into account production volume, the ability of L. monocytogenes to grow in the product, steps taken to prevent contamination, and previous sampling history. However, a variety of recent studies demonstrate that not all L. monocytogenes strains pose the same risk to human health, indicating that strain typing data could be used to improve risk-based inspection programs. Therefore, we developed and validated a simple DNA test to classify L. monocytogenes isolates into major subgroups and identify isolates that pose the greatest risk to human health. The results of this research will assist food processors and regulatory agencies to allocate inspection and sanitation resources, identify sources of contamination, and develop science-based intervention strategies and regulations that reduce the public health and economic burdens imposed by this pathogen.
Technical Abstract: A 30 probe assay was developed for simultaneous classification of Listeria monocytogenes isolates by lineage (I-IV), major serogroup (4b, 1/2b, 1/2a, and 1/2c), and epidemic clone (ECI, ECIa, ECII, and ECIII). The assay was designed to facilitate rapid strain characterization and the integration of subtype data into risk based-inspection programs.