Nonpathogenic Listeria Strains Developing Concerning Characteristics, Study Finds
Using whole genome sequencing (WGS), researchers from the University of Johannesburg have identified a trend of nonpathogenic Listeria strains developing concerning characteristics, such as virulence and stress tolerance. Like the pathogenic L. monocytogenes, the “harmless” strains L. innocua and L. welshimeri are common to food processing facilities.
For the study, the researchers acquired L. innocua and L. welshimeri strains from raw, dried, and processed meats at commercial food processing plants across South Africa. Although the present study was conducted in one country, the authors state that their findings confirm other research demonstrating growing resistance traits in Listeria species around the world.