Heavy Metal Resistance Determinants of the Foodborne Pathogen Listeria monocytogenes

Listeria monocytogenes is ubiquitous in the environment and causes the disease listeriosis. Metal homeostasis is one of the key processes utilized by L. monocytogenes in its role as either a saprophyte or pathogen. In the environment, as well as within an animal host, L. monocytogenes needs to both acquire essential metals and mitigate toxic levels of metals. While the mechanisms associated with acquisition and detoxification of essential metals such as copper, iron, and zinc have been extensively studied and recently reviewed, a review of the mechanisms associated with non-essential heavy metals such as arsenic and cadmium is lacking. Resistance to both cadmium and arsenic is frequently encountered in L. monocytogenes, including isolates from human listeriosis. In addition, a growing body of work indicates the association of these determinants with other cellular functions such as virulence, suggesting the importance of further study in this area.