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Volume 18 Supplement 2

Sepsis 2014

  • Poster presentation
  • Open Access

Aetiology of community-acquired pneumonia in the ICU setting and its effect on mortality, length of mechanical ventilation and length of ICU stay: a 1-year retrospective review

  • D Ryan1,
  • R Connolly1,
  • J Fennell1 and
  • G Fitzpatrick1
Critical Care201418(Suppl 2):P64

Published: 3 December 2014


InfluenzaMechanical VentilationStreptococcus PneumoniaeInternal AuditInpatient Mortality


Community-acquired pneumonia (CAP) is the most common infectious reason for admission to ICUs and has mortality of up to 37% [1]. Highest mortality rates are in Gram-negative infections with lower rates in Streptococcus pneumoniae and viral infections [2]. Microbiology is difficult to establish with most prospective studies identifying agents in only 50% of cases [3]. We analysed microbial aetiology of CAP in ICU over 1 year and assessed its effects on inpatient mortality, length of mechanical ventilation and length of ICU stay.


We retrospectively reviewed admissions to AMNCH ICU between February 2013 and February 2014 catalogued as having pneumonia from chest radiograph and clinical findings on the internal audit system (n = 91). After chart review, 28 were excluded as hospital-acquired pneumonias, 12 due to insufficient information and 21 due to primary diagnosis other than pneumonia. Thirty patients were selected on the basis that CAP was the likely reason for ICU admission.


Pathogens were detected in 73% of patients by culture, antigen detection or molecular methods: S. pneumoniae (n = 6; 20%), influenza (n = 4; 13%), viral with superimposed bacterial infection (n = 4; 13%), viruses other than influenza (n = 3; 10%), Gram-negative bacilli (n = 2; 7%), Legionella spp. (n = 2; 7%) and Haemophilus spp. (n = 1; 3%). No organism was identified in 27%. Gram-negative infection had highest mortality (100%), average length of mechanical ventilation (57 days) and average ICU stay (64 days). The mean age of affected patients was 68.2. Mortality was lower in influenza/other viral infections (75/50%), patients spent less time mechanically ventilated (mean 6.6/13.3 days) and less time in ICU (mean 4/16.3 days), reflecting the younger mean age of patients (53.2/51.4). Of patients infected with S. pneumonia e, Legionella spp. or Haemophilus spp. alone, all survived to discharge. However, of note, when superimposed on viral infection, these pathogens carried a higher mortality (50%). Infection with pneumococcus alone occurred in younger patients (mean age 50.6) and was associated with a shorter ventilation period (mean 2.66 days) and ICU stay (mean 6 days).


Microbial aetiology was identified in a high proportion of patients (72%) admitted to ICU with CAP, reflecting timely collection of appropriate specimens. Infection with Gram-negative organisms had the highest mortality, length of mechanical ventilation and length of ICU stay, while the pathogens usually seen in CAP were associated with more favourable outcomes.

Authors’ Affiliations

The Adelaide and Meath Hospital, incorporating the National Children's Hospital (AMNCH), Dublin, Ireland


  1. Fine MJ, Smith MA, Carson CA, Mutha SS, Sankey SS, Weissfeld LA, Kapoor WN: Prognosis and outcomes of patients with community-acquired pneumonia. A meta-analysis. JAMA 1996, 275: 134. 10.1001/jama.1996.03530260048030View ArticlePubMedGoogle Scholar
  2. Kothe H, Bauer T, Marre R, Suttorp N, Welte T, Dalhoff K, Competence Network for Community-Acquired Pneumonia study group: Outcome of community-acquired pneumonia: influence of age, residence status and antimicrobial treatment. Eur Respir J 2008, 32: 139. 10.1183/09031936.00092507View ArticlePubMedGoogle Scholar
  3. Miyashita N, Shimizu H, Ouchi K, et al.: Assessment of the usefulness of sputum Gram stain and culture for diagnosis of community-acquired pneumonia requiring hospitalization. Med Sci Monit 2008, 14: CR171-CR176.PubMedGoogle Scholar


© Ryan et al.; licensee BioMed Central Ltd. 2014

This article is published under license to BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. The Creative Commons Public Domain Dedication waiver ( applies to the data made available in this article, unless otherwise stated.