Listeria monocytogenes silent lactose utilization

We evaluated a collection of L. monocytogenes isolates of different origins for their ability to utilize lactose , a disaccharide composed of galactose and glucose and the main carbon source in milk and dairy products. Notably, the dairy-associated outbreak strain F2365 could not utilize lactose efficiently, conceivably due to a frameshift mutation (lacR887del) resulting in a truncated LacR