An inoculum size of 10-100 bacteria or cysts can produce infection in all except :

For Shigella, enterohemorrhagic Escherichia coli, Giardia lamblia, or Entamoeba, 10-100 bacteria or cysts can produce infection, while 1,00,000-10,00,00,000 Vibrio cholerae organisms must be ingested to cause disease. Reference: Harrisons Principles of Internal Medicine, 18th Edition, Page 1084