Epidemiology, pathogenesis, microbiology, and diagnosis of hospital-acquired and ventilator-associated pneumonia in adults
- Thomas M File, Jr, MD
Thomas M File, Jr, MD
- Section Editor — Pulmonary Infections
- Professor of Medicine
- Northeast Ohio Medical University
Hospital-acquired (or nosocomial) pneumonia (HAP) and ventilator-associated pneumonia (VAP) are important causes of morbidity and mortality despite improved antimicrobial therapy, supportive care, and prevention.
The epidemiology, pathogenesis, and microbiology of HAP and VAP will be reviewed here. The diagnosis, risk factors, prevention, and treatment of HAP and VAP are discussed separately. (See "Clinical presentation and diagnostic evaluation of ventilator-associated pneumonia" and "Risk factors and prevention of hospital-acquired and ventilator-associated pneumonia in adults" and "Treatment of hospital-acquired and ventilator-associated pneumonia in adults".)
Pneumonia types — The 2016 Infectious Diseases Society of America/American Thoracic Society (IDSA/ATS) guidelines on the management of adults with hospital-acquired pneumonia (HAP) and ventilator-associated pneumonia (VAP) used the following definitions  (see 'Society guideline links' below):
●HAP (or nosocomial pneumonia) is pneumonia that occurs 48 hours or more after admission and did not appear to be incubating at the time of admission.
●VAP is a type of pneumonia that develops more than 48 to 72 hours after endotracheal intubation.To continue reading this article, you must log in with your personal, hospital, or group practice subscription. For more information on subscription options, click below on the option that best describes you:
- Kalil AC, Metersky ML, Klompas M, et al. Management of Adults With Hospital-acquired and Ventilator-associated Pneumonia: 2016 Clinical Practice Guidelines by the Infectious Diseases Society of America and the American Thoracic Society. Clin Infect Dis 2016; 63:e61.
- American Thoracic Society, Infectious Diseases Society of America. Guidelines for the management of adults with hospital-acquired, ventilator-associated, and healthcare-associated pneumonia. Am J Respir Crit Care Med 2005; 171:388.
- Kollef MH. Health care-associated pneumonia: perception versus reality. Clin Infect Dis 2009; 49:1875.
- Murri R, De Pascale G. The challenge of identifying resistant-organism pneumonia in the emergency department: still navigating on the erie canal? Clin Infect Dis 2012; 54:199.
- Ewig S, Welte T, Torres A. Is healthcare-associated pneumonia a distinct entity needing specific therapy? Curr Opin Infect Dis 2012; 25:166.
- Chalmers JD, Taylor JK, Singanayagam A, et al. Epidemiology, antibiotic therapy, and clinical outcomes in health care-associated pneumonia: a UK cohort study. Clin Infect Dis 2011; 53:107.
- Yap V, Datta D, Metersky ML. Is the present definition of health care-associated pneumonia the best way to define risk of infection with antibiotic-resistant pathogens? Infect Dis Clin North Am 2013; 27:1.
- Ma HM, Wah JL, Woo J. Should nursing home-acquired pneumonia be treated as nosocomial pneumonia? J Am Med Dir Assoc 2012; 13:727.
- Chalmers JD, Rother C, Salih W, Ewig S. Healthcare-associated pneumonia does not accurately identify potentially resistant pathogens: a systematic review and meta-analysis. Clin Infect Dis 2014; 58:330.
- Lopez A, Amaro R, Polverino E. Does health care associated pneumonia really exist? Eur J Intern Med 2012; 23:407.
- Paterson DL. The epidemiological profile of infections with multidrug-resistant Pseudomonas aeruginosa and Acinetobacter species. Clin Infect Dis 2006; 43 Suppl 2:S43.
- Edwards JR, Peterson KD, Andrus ML, et al. National Healthcare Safety Network (NHSN) Report, data summary for 2006, issued June 2007. Am J Infect Control 2007; 35:290.
- Dudeck MA, Weiner LM, Allen-Bridson K, et al. National Healthcare Safety Network (NHSN) report, data summary for 2012, Device-associated module. Am J Infect Control 2013; 41:1148.
- Metersky ML, Wang Y, Klompas M, et al. Trend in Ventilator-Associated Pneumonia Rates Between 2005 and 2013. JAMA 2016; 316:2427.
- Muscedere JG, Day A, Heyland DK. Mortality, attributable mortality, and clinical events as end points for clinical trials of ventilator-associated pneumonia and hospital-acquired pneumonia. Clin Infect Dis 2010; 51 Suppl 1:S120.
- Kollef MH, Hamilton CW, Ernst FR. Economic impact of ventilator-associated pneumonia in a large matched cohort. Infect Control Hosp Epidemiol 2012; 33:250.
- Scheld WM. Developments in the pathogenesis, diagnosis and treatment of nosocomial pneumonia. Surg Gynecol Obstet 1991; 172 Suppl:42.
- Safdar N, Crnich CJ, Maki DG. The pathogenesis of ventilator-associated pneumonia: its relevance to developing effective strategies for prevention. Respir Care 2005; 50:725.
- Garrouste-Orgeas M, Chevret S, Arlet G, et al. Oropharyngeal or gastric colonization and nosocomial pneumonia in adult intensive care unit patients. A prospective study based on genomic DNA analysis. Am J Respir Crit Care Med 1997; 156:1647.
- Nseir S, Di Pompeo C, Pronnier P, et al. Nosocomial tracheobronchitis in mechanically ventilated patients: incidence, aetiology and outcome. Eur Respir J 2002; 20:1483.
- Rello J, Quintana E, Ausina V, et al. Incidence, etiology, and outcome of nosocomial pneumonia in mechanically ventilated patients. Chest 1991; 100:439.
- Jones RN. Microbial etiologies of hospital-acquired bacterial pneumonia and ventilator-associated bacterial pneumonia. Clin Infect Dis 2010; 51 Suppl 1:S81.
- Sievert DM, Ricks P, Edwards JR, et al. Antimicrobial-resistant pathogens associated with healthcare-associated infections: summary of data reported to the National Healthcare Safety Network at the Centers for Disease Control and Prevention, 2009-2010. Infect Control Hosp Epidemiol 2013; 34:1.
- Weber DJ, Rutala WA, Sickbert-Bennett EE, et al. Microbiology of ventilator-associated pneumonia compared with that of hospital-acquired pneumonia. Infect Control Hosp Epidemiol 2007; 28:825.
- Kollef MH, Morrow LE, Niederman MS, et al. Clinical characteristics and treatment patterns among patients with ventilator-associated pneumonia. Chest 2006; 129:1210.
- Marik PE, Careau P. The role of anaerobes in patients with ventilator-associated pneumonia and aspiration pneumonia: a prospective study. Chest 1999; 115:178.
- Fàbregas N, Ewig S, Torres A, et al. Clinical diagnosis of ventilator associated pneumonia revisited: comparative validation using immediate post-mortem lung biopsies. Thorax 1999; 54:867.
- Caliendo AM, Gilbert DN, Ginocchio CC, et al. Better tests, better care: improved diagnostics for infectious diseases. Clin Infect Dis 2013; 57 Suppl 3:S139.
- Lung M, Codina G. Molecular diagnosis in HAP/VAP. Curr Opin Crit Care 2012; 18:487.
- Hayashi Y, Morisawa K, Klompas M, et al. Toward improved surveillance: the impact of ventilator-associated complications on length of stay and antibiotic use in patients in intensive care units. Clin Infect Dis 2013; 56:471.