To study the role of macrophage in the protection against post‐stroke pneumonia by BM‐MSC, lung sections of tMCAO models were subjected to immunol staining of Iba1 (macrophage marker, green) and colabeling with fluorescence in situ hybridization (FISH) of total bacteria (FISH probe EUB338, red). The gene discussed is AIF1; the disease is stroke disorder.