Can listeria be passed through breastmilk (if a mother is infected) to her infant?

There’s no evidence of Listeria passing to the breast milk in an infected mother. The treatment of Listeria with Penicillin, Ampicillin, or Trimethoprim Sulfa (Bactrim) is not a contraindication for breastfeeding either. A full good article about infections and breastfeeding is found in: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7152307/.gov/pmc/articles/PMC7152307/

Listeria cannot be passed via breast milk. Direct contact could cause infection if the mother inadvertently contaminated her baby with infected secretions (hand/mouth) , however this transmission is very unlikely when good hand washing practices are in effect