CDH1 and listeriosis: Only serotypes 4b, 1/2a, and 1/2b are known to cause over 98% of the human listeriosis case reported.9 Serotype 4b is notorious for causing invasive listeriosis.10 Gastric acidity is protective against Listeria and people taking H2 antagonists have increased prevalence of asymptomatic Listeria monocytogenes in stool.11 Although Listeria does not produce any enterotoxin and the mechanism of pathogenesis is unknown, direct invasion of bacterial protein with E-cadherin on the host cell, leading to diarrhea, fever, and bacteremia, is proposed.12,13