Pneumonia Types Hospital Acquired

Hospital-acquired pneumonia refers to types of pneumonia that develop in a hospital at least 48 hours after the patient is admitted. Also called “hospital-associated pneumonia” or “nosocomial pneumonia,” this condition can be extremely serious, especially when combined with the conditions that lead to hospitalization.

Hospital-Acquired Pneumonia Types

The phrase “hospital-acquired pneumonia” can refer to one of several subtypes of pneumonia, including:

  • Hospital associated pneumonia in patients not on ventilators
  • Postoperative pneumonia
  • Ventilator-associated pneumonia.

In addition, “hospital-acquired pneumonia” can also refer to healthcare-associated pneumonia, which includes pneumonia caused by infection in extended care, dialysis and infusion centers.

Why is Hospital-Associated Pneumonia Dangerous?

Hospital-acquired pneumonia is one of the most serious types of pneumonia due to a convergence of risk factors. People who catch hospital-acquired pneumonia are often already weakened by illness, surgery or trauma, which impairs their ability to fight infection. The elderly are especially vulnerable to hospital-associated pneumonia.

In addition, hospital-acquired infections are often difficult to treat. So-called “super bugs” are bacteria that develop resistance to antibiotics. Super bugs are often seen in healthcare and hospital environments. An example is methicilllin-resistant Staphylococcus aureus bacteria.

Mechanical ventilation drastically increases the risk of developing pneumonia. During ventilation, a tube is inserted down the trachea, or windpipe, to deliver oxygen to the lungs. This tracheal tube increases the risk of aspiration, which allows mouth, throat or nasal secretions into the lungs. Organisms in these secretions then multiply in the lungs and on the tracheal tube, causing pneumonia. According to the Cleveland Clinic, between 17 and 23 percent of ventilator patients develop pneumonia.

Other risk factors for hospital-acquired pneumonia include:

  • Age of patient (the very young and the elderly have high pneumonia risks)
  • Co-morbid heart, lung, liver or kidney conditions
  • High levels of stomach pH (less acidic)
  • Immune system diseases
  • Organ transplants
  • Previous antibiotic treatment
  • Recent abdominal or thoracic surgery
  • Use of immune-suppressing medications.

Types of Pneumonia-Causing Organisms

Bacterial organisms are the most common cause of hospital-associated pneumonia. Hospital-acquired pneumonia can be caused by viruses or fungi, but these cases are much rarer than their bacterial counterparts.

Bacterial hospital acquired infections include:

  • Escherichia coli
  • Haemophilus influenza
  • Klebsiella pneumoniae
  • Pseudomonas aeruginosa
  • Serratia marcescens
  • Staphylococcus aureaus
  • Streptococcus pneumoniae.

Symptoms of Hospital-Acquired Pneumonia

Symptoms of hospital-acquired pneumonia are similar to those of other types of pneumonia, including:

  • Cough
  • Fatigue
  • Fever
  • Nausea and vomiting.

Patients who develop ventilator-acquired pneumonia have a high risk of developing breathing difficulties and respiratory distress.

Treating Hospital-Associated Pneumonia

Hospital-acquired pneumonia has a poorer treatment outcome than community-acquired pneumonia. In some cases, it is fatal, either as a result of respiratory distress caused by the pneumonia itself, or the negative effect of pneumonia on existing medical conditions.

Treatment of hospital-acquired pneumonia usually involves antibiotics selected after identifying the infectious agent and its antibiotic susceptibilities. Broad-based antibiotics may be administered while awaiting diagnostic results, after which targeted antibiotics are used.

With successful treatment, a case of hospital-acquired pneumonia lengthens a hospital stay by a week to nine days, on average. The gravity of hospital-acquired infections cannot be overstated: 300,000 cases of hospital-associated pneumonia are reported annually in the United States. Depending on the nature of the infectious agent and existing medical conditions, mortality rates range from 30 to 70 percent of cases.


Merck Manuals Online Medical Library Staff. (2008). Hospital-acquired pneumonia. Retrieved March 8, 2010, from the Merck Web site:

Arroliga, A., et al. (n.d.). Hospital-acquired, health care-associated, and ventilator-associated pneumonia. Retrieved March 8, 2010, from the Cleveland Clinic Web site:

U.S. National Library of Medicine Staff. (2009). Hospital-acquired pneumonia. Retrieved March 8, 2010, from the MedlinePlus Web site: