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.
On the other hand, regarding reducing acidity of the stomach, an acid environment is needed to kill the organisms that colonize the gastrointestinal tract; agents, such as proton pump inhibitors, that decrease the acidity of the stomach, may favor the growth of bacteria and increase the risk of pneumonia. Treatment
Adjusting the patients posture should come first, then the oropharyngeal contents should be suctioned with the nasogastric tube in place. Humidified oxygen is given to patients who are not intubated, and the head end of the bed should be elevated by 45 degrees. Its crucial to keep a close eye on the patients oxygen saturation, and if hypoxia is detected, urgent intubation with mechanical breathing should be given. Flexible bronchoscopy is often used to gather samples of bronchoalveolar lavage for quantitative bacteriological tests as well as high volume aspiration to clear the secretion. In general practice The main treatment of aspiration pneumonia revolves around the use of antibiotics to remove the bacteria causing the infection. Broad antibiotic coverage is required to account for the diverse types of bacteria possibly causing the infection. Even though they are not necessary in cases with aspiration pneumonitis, antibiotics are typically started right away to stop the diseases development.Recommended antibiotics include clindamycin, meropenem, ertapenem, ampicillin/sulbactam, and moxifloxacin. Treatment with piperacillin/tazobactam, cefepime, levofloxacin, imipenem, or meropenem is recommended in cases of potential antibiotic resistance. The typical duration of antibiotic therapy is about 5 to 7 days.