In the food processing industry, the Listeria monocytogenes can be deadly to humans and is monitored closely. Not only can the pathogen make people extremely ill, it is now known to be developing resistance to various food safety measures across the world.
A study conducted in South Africa and recently published in the journal Microbiology Spectrum used whole-genome sequencing to provide insights into two species of presumed nonpathogenic Listeria—L. innocua and L. welshimeri—and found that they are developing a surprising number of characteristics that are potentially harmful to humans.
The researchers conclude that Listeria innocua strains are developing resistance to temperature, pH, dehydration, and other stresses, and the species is developing hypervirulence genetically identical to that of Listeria monocytogenes.
In fact, some strains of L. innocua and L. welshimeri examined in the study show three genes for resistance to a widely-used disinfectant, from the quaternary ammonium