Bacterial colonization: Poor oral hygiene can result in colonization of the mouth with excessive amounts of bacteria, which is linked to increased incidence of aspiration pneumonia. Ethnicity: Asians diagnosed with aspiration pneumonia have a lower risk of death compared to other ethnic groups while African Americans and whites share a relatively similar risk of death. Hispanics have a lower risk of death than non-Hispanics. Others: Age, male gender, diabetes mellitus, malnutrition, use of antipsychotic drugs, proton pump inhibitors, and angiotensin-converting enzyme inhibitors. Residence in an institutional setting, prolonged hospitalization or surgical procedures, gastric tube feeding, mechanical airway interventions, immunocompromised, history of smoking, antibiotic therapy, advanced age, reduced pulmonary clearance, diminished cough reflex, disrupted normal mucosal barrier, impaired mucociliary clearance, alter cellular and humoral immunity, obstruction of the airways, and damaged lung tissue. Bacteria
Bacteria involved in aspiration pneumonia may be either aerobic or anaerobic. Common aerobic bacteria involved include:

Streptococcus pneumoniae
Staphylococcus aureus
Haemophilus influenzae
Pseudomonas aeruginosa
Klebsiella: often seen in aspiration lobar pneumonia in alcoholicsAnaerobic bacteria also play a key role in the pathogenesis of aspiration pneumonia. They make up the majority of normal oral flora and the presence of putrid fluid in the lungs is highly suggestive of aspiration pneumonia secondary to an anaerobic organism. While it is difficult to confirm the presence of anaerobes through cultures, the treatment of aspiration pneumonia typically includes anaerobic coverage regardless. Potential anaerobic bacteria are as follows:

Bacteroides
Prevotella
Fusobacterium
Peptostreptococcus

Pathophysiology
Aspiration is defined as inhalation of oropharyngeal or gastric contents into the pulmonary tree.
Defects in nuclear-encoded mitochondrial genes are associated with hundreds of clinical disease phenotypes including anemia, dementia, hypertension, lymphoma, retinopathy, seizures, and neurodevelopmental disorders.A study by Yale University researchers (published in the February 12, 2004, issue of the New England Journal of Medicine) explored the role of mitochondria in insulin resistance among the offspring of patients with type 2 diabetes. Other studies have shown that the mechanism may involve the interruption of the mitochondrial signaling process in body cells (intramyocellular lipids). A study conducted at the Pennington Biomedical Research Center in Baton Rouge, Louisiana showed that this, in turn, partially disables the genes that produce mitochondria. Mechanisms
The effective overall energy unit for the available body energy is referred to as the daily glycogen generation capacity, and is used to compare the mitochondrial output of affected or chronically glycogen-depleted individuals to healthy individuals. This value is slow to change in a given individual, as it takes between 18 and 24 months to complete a full cycle.The glycogen generation capacity is entirely dependent on, and determined by, the operating levels of the mitochondria in all of the cells of the human body; however, the relation between the energy generated by the mitochondria and the glycogen capacity is very loose and is mediated by many biochemical pathways. The energy output of full healthy mitochondrial function can be predicted exactly by a complicated theoretical argument, but this argument is not straightforward, as most energy is consumed by the brain and is not easily measurable.