Pneumonia exposure to cigarettes or air pollution, malnutrition, and poverty. The use of acid-suppressing medications — such as proton-pump inhibitors or H2 blockers — is associated with an increased risk of pneumonia. Approximately 10% of people who require mechanical ventilation develop ventilator associated pneumonia, and people with gastric feeding tube have an increased risk of developing of aspiration pneumonia. For people with specific variants of FER gene, the risk of death is reduced in sepsis caused by pneumonia. However, for those with TLR6 variants, the risk of getting Legionnaires' disease is increased. Bacteria are the most-common cause of community-acquired pneumonia (CAP),
Legionella The side chains of the cell wall carry the bases responsible for the somatic antigen specificity of these organisms. The chemical composition of these side chains both with respect to components and arrangement of the different sugars determines the nature of the somatic or O antigen determinants, which are essential means of serologically classifying many Gram-negative bacteria. "Legionella" acquired its name after an outbreak of a then-unknown "mystery disease" sickened 221 persons, causing 34 deaths. The outbreak was first noticed among people attending a convention of the American Legion—an association of U.S. military veterans. The convention occurred in Philadelphia during