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Pseudomonas aeruginosa Nosocomial Pneumonia: Impact of Pneumonia Classification

  • Scott T. Micek (a1), Marin H. Kollef (a2), Antoni Torres (a3), Catherine Chen (a2), Jordi Rello (a4), Jean Chastre (a5), Massimo Antonelli (a6), Tobias Welte (a7), Bernard Clair (a8), Helmut Ostermann (a9), Esther Calbo (a10), Richard Wunderink (a11), Francesco Menichetti (a12), Garrett Schramm (a13) and Vandana Menon (a14)...



To describe and compare the mortality associated with nosocomial pneumonia due to Pseudomonas aeruginosa (Pa-NP) according to pneumonia classification (community-onset pneumonia [COP], hospital-acquired pneumonia [(HAP], and ventilator-associated pneumonia [VAP]).


We conducted a retrospective cohort study of adults with Pa-NP. We compared mortality for Pa-NP among patients with COP, HAP, and VAP and used logistic regression to identify risk factors for hospital mortality and inappropriate initial antibiotic therapy (IIAT).


Twelve acute care hospitals in 5 countries (United States, 3; France, 2; Germany, 2; Italy, 2; and Spain, 3).


A total of 742 patients with Pa-NP.


Hospital mortality was greater for those with VAP (41.9%) and HAP (40.1%) compared with COP (24.5%) (P<.001). In multivariate analyses, independent predictors of hospital mortality differed by pneumonia classification (COP: need for mechanical ventilation and intensive care; HAP: multidrug-resistant isolate; VAP: IIAT, increasing age, increasing Charlson comorbidity score, bacteremia, and use of vasopressors). Presence of multidrug resistance was identified as an independent predictor of IIAT for patients with COP and HAP, whereas recent antibiotic administration was protective in patients with VAP.


Among patients with Pa-NP, pneumonia classification identified patients with different risks for hospital mortality. Specific risk factors for hospital mortality also differed by pneumonia classification and multidrug resistance appeared to be an important risk factor for IIAT. These findings suggest that pneumonia classification for P. aeruginosa identifies patients with different mortality risks and specific risk factors for outcome and IIAT.

Infect Control Hosp Epidemiol 2015;36(10):1190–1197


Corresponding author

Address correspondence to Scott T. Micek, PharmD, St. Louis College of Pharmacy, 4588 Parkview Pl, St. Louis, Missouri 63110-1088 (


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1. 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;171:388416.
2. Kollef, MH, Shorr, A, Tabak, YP, Gupta, V, Liu, LZ, Johannes, RS. Epidemiology and outcomes of health-care-associated pneumonia: results from a large US database of culture-positive pneumonia. Chest 2005;128:38543862.
3. Sopena, N, Sabria, M. Multicenter study of hospital-acquired pneumonia in non-ICU patients. Chest 2005;127:213219.
4. Weber, DJ, Rutala, WA, Sickbert-Bennett, EE, Samsa, GP, Brown, V, Niederman, MS. Microbiology of ventilator-associated pneumonia compared with that of hospital-acquired pneumonia. Infect Control Hosp Epidemiol 2007;28:825831.
5. Esperatti, M, Ferrer, M, Theessen, A, et al. Nosocomial pneumonia in the intensive care unit acquired by mechanically ventilated versus nonventilated patients. Am J Respir Crit Care Med 2010;182:15331539.
6. Wang, CY, Jerng, JS, Chen, KY, et al. Pandrug-resistant Pseudomonas aeruginosa among hospitalised patients: clinical features, risk-factors and outcomes. Clin Microbiol Infect 2006;12:6368.
7. Tumbarello, M, De Pascale, G, Trecarichi, EM, et al. Clinical outcomes of Pseudomonas aeruginosa pneumonia in intensive care unit patients. Intensive Care Med 2013;39:682692.
8. Chung, DR, Song, JH, Kim, SH, et al. High prevalence of multidrug-resistant nonfermenters in hospital-acquired pneumonia in Asia. Am J Respir Crit Care Med 2011;184:14091417.
9. Parker, CM, Kutsogiannis, J, Muscedere, J, et al. Ventilator-associated pneumonia caused by multidrug-resistant organisms or Pseudomonas aeruginosa: prevalence, incidence, risk factors, and outcomes. J Crit Care 2008;23:1826.
10. Zilberberg, MD, Shorr, AF. Prevalence of multidrug-resistant Pseudomonas aeruginosa and carbapenem-resistant Enterobacteriaceae among specimens from hospitalized patients with pneumonia and bloodstream infections in the United States from 2000 to 2009. J Hosp Med 2013;8:559563.
11. Driscoll, JA, Brody, SL, Kollef, MH. The epidemiology, pathogenesis and treatment of Pseudomonas aeruginosa infections. Drugs 2007;67:351368.
12. Crouch Brewer, S, Wunderink, RG, Jones, CB, Leeper, KV Jr. Ventilator-associated pneumonia due to Pseudomonas aeruginosa . Chest 1996;109:10191029.
13. Kollef, MH, Chastre, J, Clavel, M, et al. A randomized trial of 7-day doripenem versus 10-day imipenem-cilastatin for ventilator-associated pneumonia. Crit Care 2012;16:R218.
14. Garnacho-Montero, J, Sa-Borges, M, Sole-Violan, J, et al. Optimal management therapy for Pseudomonas aeruginosa ventilator-associated pneumonia: an observational, multicenter study comparing monotherapy with combination antibiotic therapy. Crit Care Med 2007;35:18881895.
15. Micek, ST, Reichley, RM, Kollef, MH. Health care-associated pneumonia (HCAP): empiric antibiotics targeting methicillin-resistant Staphylococcus aureus (MRSA) and Pseudomonas aeruginosa predict optimal outcome. Medicine (Baltimore) 2011;90:390395.
16. Magiorakos, AP, Srinivasan, A, Carey, RB, et al. Multidrug-resistant, extensively drug-resistant and pandrug-resistant bacteria: an international expert proposal for interim standard definitions for acquired resistance. Clin Microbiol Infect 2012;18:268281.
17. Kollef, MH. Broad-spectrum antimicrobials and the treatment of serious bacterial infections: getting it right up front. Clin Infect Dis 2008;47:S313.
18. Clinical and Laboratory Standards Institute. Performance standards for antimicrobial susceptibility testing: 19th informational supplement. Wayne, PA: CLSI, 2009:M100S19.
19. European Committee on Antimicrobial Susceptibility Testing. Breakpoint tables for interpretation of MICs and zone diameters, versions 1.3 and 2.0. Accessed August 25, 2014.
20. Micek, ST, Kollef, KE, Reichley, RM, Roubinian, N, Kollef, MH. Health care-associated pneumonia and community-acquired pneumonia: a single-center experience. Antimicrob Agents Chemother 2007;51:35683573.
21. Ewig, S, Welte, T, Chastre, J, Torres, A. Rethinking the concepts of community-acquired and health-care-associated pneumonia. Lancet Infect Dis 2010;10:279287.
22. Vallés, J, Martin-Loeches, I, Torres, A, et al. Epidemiology, antibiotic therapy and clinical outcomes of healthcare-associated pneumonia in critically ill patients: a Spanish cohort study. Intensive Care Med 2014;40:572581.
23. Maruyama, T, Fujisawa, T, Okuno, M, et al. A new strategy for healthcare-associated pneumonia: a 2-year prospective multicenter cohort study using risk factors for multidrug-resistant pathogens to select initial empiric therapy. Clin Infect Dis 2013;57:13731383.
24. Quartin, AA, Scerpella, EG, Puttagunta, S, Kett, DH. A comparison of microbiology and demographics among patients with healthcare-associated, hospital-acquired, and ventilator-associated pneumonia: a retrospective analysis of 1184 patients from a large, international study. BMC Infect Dis 2013;13:561.
25. Piskin, N, Aydemir, H, Oztoprak, N, et al. Inadequate treatment of ventilator-associated and hospital-acquired pneumonia: risk factors and impact on outcomes. BMC Infect Dis 2012;12:268.
26. Iregui, M, Ward, S, Sherman, G, Fraser, VJ, Kollef, MH. Clinical importance of delays in the initiation of appropriate antibiotic treatment for ventilator-associated pneumonia. Chest 2002;122:262268.
27. Garnacho-Montero, J, Garcia-Garmendia, JL, Barrero-Almodovar, A, Jimenez-Jimenez, FJ, Perez-Paredes, C, Ortiz-Leyba, C. Impact of adequate empirical antibiotic therapy on the outcome of patients admitted to the intensive care unit with sepsis. Crit Care Med 2003;31:27422751.
28. Kumar, A, Roberts, D, Wood, KE, et al. Duration of hypotension before initiation of effective antimicrobial therapy is the critical determinant of survival in human septic shock. Crit Care Med 2006;34:15891596.
29. Ferrer, R, Martin-Loeches, I, Phillips, G, et al. Empiric antibiotic treatment reduces mortality in severe sepsis and septic shock from the first hour: results from a guideline-based performance improvement program. Crit Care Med 2014;42:17491755.
30. Ferrer, R, Artigas, A, Suarez, D, et al. Effectiveness of treatments for severe sepsis: a prospective, multicenter, observational study. Am J Respir Crit Care Med 2009;180:861866.
31. Zilberberg, MD, Shorr, AF, Micek, MT, Mody, SH, Kollef, MH. Antimicrobial therapy escalation and hospital mortality among patients with HCAP: a single center experience. Chest 2008;134:963968.
32. Kollef, MH, Morrow, LE, Niederman, MS, et al. Clinical characteristics and treatment patterns among patients with ventilator-associated pneumonia. Chest 2006;129:12101218.
33. Zilberberg, MD, Shorr, AF. Prevalence of multidrug-resistant Pseudomonas aeruginosa and carbapenem-resistant Enterobacteriaceae among specimens from hospitalized patients with pneumonia and bloodstream infections in the United States from 2000 to 2009. J Hosp Med 2013;8:559563.
34. Vardakas, KZ, Rafailidis, PI, Konstantelias, AA, Falagas, ME. Predictors of mortality in patients with infections due to multi-drug resistant gram negative bacteria: the study, the patient, the bug or the drug? J Infect 2013;66:401414.
35. Arancibia, F, Bauer, TT, Ewig, S, et al. Community-acquired pneumonia due to gram-negative bacteria and Pseudomonas aeruginosa: incidence, risk, and prognosis. Arch Intern Med 2002;162:18491858.
36. Shindo, Y, Ito, R, Kobayashi, D, et al. Risk factors for drug-resistant pathogens in community-acquired and healthcare-associated pneumonia. Am J Respir Crit Care Med 2013;188:985995.
37. Shorr, AF, Zilberberg, MD, Reichley, R, et al. Validation of a clinical score for assessing the risk of resistant pathogens in patients with pneumonia presenting to the emergency department. Clin Infect Dis 2012;54:193198.
38. Burnham, CA, Frobel, RA, Herrera, ML, Wickes, BL. Rapid ertapenem susceptibility testing and Klebsiella pneumoniae carbapenemase phenotype detection in Klebsiella pneumoniae isolates by use of automated microscopy of immobilized live bacterial cells. J Clin Microbiol 2014;52:982986.


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