Of the 92 AD associated genes evaluated in the P. gingivalis 24-weeks post infection the key genes with statistically significant changes of their expression were cholinergic receptor nicotinic alpha 7 subunit or Chrna7 (0.10 log fold change, p = 0.02), mitogen-activated protein kinase 1 or Mapk1 (0.10 log fold change, p = 0.05) and visinin like 1 or Vnsl1 (0.01 log fold change, p = 0.04). This evidence concerns the gene CHRNA7 and Alzheimer disease.