What are the causes for Bacterial Pneumonia?

  • Most pneumonia is caused by bacteria or a virus. Pneumonia from any cause can occur at any age, but people in certain age groups are at higher risk for certain types of pneumonia.
  • The most common cause of bacterial pneumonia is a type of bacteria known as Streptococcus pneumoniae. Haemophilus influenzae, Chlamydia pneumoniae, Mycoplasma pneumoniae, and Legionella pneumophila are some other major bacteria that cause pneumonia.
  • People who inhale toxic materials can injure the lungs and cause chemical pneumonia. This is more accurately referred to as chemical pneumonitis, since the process is mainly due to inflammation not from an infectious source.
  • Fungi can also cause pneumonia. In certain areas of the United States, specific fungi are well known. Coccidioidomycosis, usually seen in the Southwest, is a type of fungal infection that causes a pneumonia called "San Joaquin fever" or "Valley fever." Histoplasmosis (seen primarily in the Midwest) and blastomycosis (seen primarily in the Southeast) are other fungal diseases that cause pneumonias.
  • The most common way you catch pneumonia is to aspirate bacteria from the upper airway, usually the oral cavity. Other ways to catch pneumonia can be by breathing in infected air droplets from someone who has pneumonia. In some cases, the bacteria can be generated by an improperly cleaned air conditioner or Jacuzzi. Yet another source of infection in the lungs is spread of an infection from somewhere else in the body, such as the kidney. Bacteria can enter the bloodstream from any source and be deposited in the lungs, resulting in pneumonia.
  • The risk of catching pneumonia is determined by the specific bacteria, virus, or fungus, the number of organisms the person inhales, and the body's ability to fight infections.
  • A person cannot "catch pneumonia" by not dressing properly for cold weather or by being caught in the rain.

    Source: http://www.emedicinehealth.com