Pneumonia is the infection and inflammation of the small alveolus inside the lungs and of the surrounding tissues. Pneumonia can be a cause of death for persons with additional chronic conditions and to pneumonia sufferers in developing countries. Pneumonia cases occurred inside the community are usually caused by the germ Streptococcus Pneumoniae, while pneumonias appeared in hospitals or institutions are mostly caused by Staphylococcus aureus, Klebsiella or Pseudomonas aeruginosa. The severity of the symptoms and the required treatment depend a great deal on the type of the causing agent.

A series of factors can expose and predispose certain persons to developing pneumonia. Some medications, the age of the subject or some diseases can lead to the deprimation of the immune system and increase the susceptibility to pneumonia caused by abnormal microorganisms. Other conditions like alcoholism, smoking, diabetes, heart failure also predispose to pneumonia as well as extreme ages, debilitation, paralyzes or unconscious estates.

Pneumonia can appear after direct inhalation of infectious agents like bacteria, viruses or fungi or after the migration of the infection with the bloodstream from the initial localization. Pneumonia can occur after surgical interventions, after injuries especially chest injuries when the patient is unable to cough and mucus retention is possible. The aspiration pneumonia appears when different food, liquid or dust particles are inhaled from the mouth or when a bacterium is stuck inside the respiratory tract due to an obstruction.

The primer symptom of pneumonia is productive cough resulting in different amounts of mucus. Additional symptoms might be fever, chills, chest pains and breathing shortness. Auditory, pneumonia can be detected by the doctor listening to the patient's lungs with a stethoscope. Pneumonia produces particular sounds caused by the presence of inflammatory cells inside the air tubes usually filled with air. A certain diagnose can be established with a chest X-ray that shows usually a dense white patch in place of the involved tissue. Pneumonia diagnose can also be established by help of sputum and blood specimen culture.

Some types of pneumonia can be prevented by vaccination against the Influenza virus and against the bacterium Haemophillus Influenzae. Persons at high risk of developing pneumonia can prevent it by making physical exercises and breathing exercises to fasten the clearance of the secretions.

Bacterial pneumonia is treated with antibiotics and the medication is started even before the exact agent is identified in order to prevent possible complications. Some patients with breathing difficulties require additional oxygen and assisted breathing. Low severity cases can be treated at home by oral medication but more severe symptoms make hospitalization necessary and the intravenous administration of antibiotics.

Antibiotics have no benefic effect on pneumonias caused by viruses or fungi.