Community-acquired respiratory coinfection in critically ill patients with pandemic 2009 influenza A(H1N1) virus

Chest. 2011 Mar;139(3):555-562. doi: 10.1378/chest.10-1396. Epub 2010 Oct 7.


Background: Little is known about the impact of community-acquired respiratory coinfection in patients with pandemic 2009 influenza A(H1N1) virus infection.

Methods: This was a prospective, observational, multicenter study conducted in 148 Spanish ICUs.

Results: Severe respiratory syndrome was present in 645 ICU patients. Coinfection occurred in 113 (17.5%) of patients. Streptococcus pneumoniae (in 62 patients [54.8%]) was identified as the most prevalent bacteria. Patients with coinfection at ICU admission were older (47.5±15.7 vs 43.8±14.2 years, P<.05) and presented a higher APACHE (Acute Physiology and Chronic Health Evaluation) II score (16.1±7.3 vs 13.3±7.1, P<.05) and Sequential Organ Failure Assessment (SOFA) score (7.0±3.8 vs 5.2±3.5, P<.05). No differences in comorbidities were observed. Patients who had coinfection required vasopressors (63.7% vs 39.3%, P<.05) and invasive mechanical ventilation (69% vs 58.5%, P<.05) more frequently. ICU length of stay was 3 days longer in patients who had coinfection than in patients who did not (11 [interquartile range, 5-23] vs 8 [interquartile range 4-17], P=.01). Coinfection was associated with increased ICU mortality (26.2% vs 15.5%; OR, 1.94; 95% CI, 1.21-3.09), but Cox regression analysis adjusted by potential confounders did not confirm a significant association between coinfection and ICU mortality.

Conclusions: During the 2009 pandemics, the role played by bacterial coinfection in bringing patients to the ICU was not clear, S pneumoniae being the most common pathogen. This work provides clear evidence that bacterial coinfection is a contributor to increased consumption of health resources by critical patients infected with the virus and is the virus that causes critical illness in the vast majority of cases.

Publication types

  • Multicenter Study

MeSH terms

  • Adult
  • Community-Acquired Infections / epidemiology*
  • Community-Acquired Infections / therapy
  • Community-Acquired Infections / virology
  • Comorbidity
  • Critical Illness*
  • Female
  • Humans
  • Influenza A Virus, H1N1 Subtype*
  • Influenza, Human / epidemiology*
  • Intensive Care Units / statistics & numerical data
  • Male
  • Middle Aged
  • Prevalence
  • Prospective Studies
  • Regression Analysis
  • Respiration, Artificial
  • Respiratory Tract Infections / epidemiology*
  • Respiratory Tract Infections / therapy
  • Respiratory Tract Infections / virology
  • Retrospective Studies
  • Spain / epidemiology