Listeria Meningitis in a Patient With Plaque Psoriasis on Ustekinumab Therapy.

Listeria monocytogenes is a foodborne infection and is a leading cause of meningitis. The at-risk population includes patients over age 65, neonates, pregnant females, and patients with impaired cell immunity. Ustekinumab is a human monoclonal antibody that binds to and interferes with the proinflammatory cytokines, interleukin-12 (IL-12) and interleukin-23(IL-23). The drug is used for the treatment of Crohn's disease, ulcerative colitis, psoriatic arthritis, and plaque psoriasis. We present a case of listeria meningitis in a patient on ustekinumab therapy for plaque psoriasis.