RecurrentListeria monocytogenesInfection: Relapse or Reinfection with a Unique Strain Confirmed by Molecular Subtyping

We report a case of recurrent listeriosis for which molecular subtyping by automated ribotyping and pulsed-field gel electrophoresis confirmed either relapse of infection or reinfection due to a common source almost 9 months after initial infection due to a unique Listeria monocytogenes strain in a patient with colorectal cancer. This case report illustrates the potential use of molecular subtyping to further understand the pathogenesis and epidemiology of listeriosis and the potential for relapse of Listeria infections in humans.