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Hospital-acquired pneumonia, also called nosocomial pneumonia, is pneumonia acquired during or after hospitalization for another illness or procedure. The causes, microbiology, treatment and prognosis are different than those of community-acquired pneumonia. Up to 5% of patients admitted to a hospital for other causes subsequently develop pneumonia. Hospitalized patients may have many risk factors for pneumonia, including mechanical ventilation, prolonged malnutrition, underlying heart and lung diseases, decreased amounts of stomach acid, and immune disturbances. Additionally, the microorganisms a person is exposed to in a hospital are often different from those at home. Hospital-acquired microorganisms may include resistant bacteria such as MRSA, Pseudomonas, Enterobacter, and Serratia. Because individuals with hospital-acquired pneumonia usually have underlying illnesses and are exposed to more dangerous bacteria, it tends to be more deadly than community-acquired pneumonia. Ventilator-associated pneumonia (VAP) is a subset of hospital-acquired pneumonia. VAP is pneumonia which occurs after at least 48 hours of intubation and mechanical ventilation.
Hospital-acquired infections encompass almost all clinically evident infections that do not originate from patient's original admitting diagnosis. Within hours after admission, a patient's flora begins to acquire characteristics of the surrounding bacterial pool. Most infections that become clinically evident after 48 hours of hospitalization are considered hospital-acquired. Infections that occur after the patient's discharge from the hospital can be considered to have a nosocomial origin if the organisms were acquired during the hospital stay.
Hospital acquired pneumonia occurs mostly in patients who are severely debilitated or who are immune suppressed.
The different organisms responsible for causing hospital acquired pneumonia are listed below:
- gram negative bacilli (particularly Klebsiella spp. and pseudomonas spp.) 50% cases
- staphylococcal aureus 15% cases
- anaerobic infection 9% cases
- streptococcus pneumoniae 6% cases
- other causes, e.g. fungi, legionella 20% cases
The organism may be very antibiotic resistant and an intravenous, broad spectrum agent is indicated, such as cefotaxmime or ceftazidine (1). Metronidazole should be used in addition if there is a likelihood of anaerobic infection.
Hospital-acquired pneumonia (HAP) is associated with high morbidity and mortality. Early, appropriate, and adequate empiric therapy can increase the chance of survival. In 1995, the American Thoracic Society provided guidelines for the initial treatment of immunocompetent HAP patients, which is one of the principal HAP management approaches available to physicians today. However, these guidelines have several important limitations, including a lack of recommendations for duration of therapy and no recognition of newer drugs such as cefepime, trovafloxacin, and meropenem. Furthermore, they fail to distinguish among similar compounds (ie, ß-lactam/ß-lactamase inhibitor combinations) or to recommend specific antibiotics. The clinician using these guidelines needs to address local patterns of antimicrobial resistance, especially in ICUs. Effective computerized antibiotic management programs that incorporate information on local patterns of antimicrobial resistance can assist physicians in empiric therapy decision making, improve patient quality of care, and reduce medical costs.
Nosocomial Pneumonia Causes
Nosocomial Pneumonia Symptoms
Nosocomial Pneumonia Diagnosis
Nosocomial Pneumonia Treatment
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