title: The occurrence and impact of bacterial organisms complicating critical care illness associated with 2009 influenza A(H1N1) infection.
abstract: BACKGROUND
  Although secondary infections are recognized as a cause of morbidity and mortality in seasonal influenza, their frequency, characteristics, and associated clinical outcomes in 2009 influenza A(H1N1) (A[H1N1])-related critical illness are unknown.
  
  
  METHODS
  In a prospective cohort of adult patients admitted to Canadian ICUs with influenza A(H1N1) infection, the frequency and associated clinical outcomes of prevalent (culture taken within 72 h of ICU admission) and ICU-acquired (culture taken after 72 h from ICU admission) positive bacterial cultures were determined.
  
  
  RESULTS
  Among 681 patients, the mean age was 47.9 years (SD, 15.1), APACHE (Acute Physiology and Chronic Health Examination) II score was 21.0 (9.9), and 573 patients (84.0%) were invasively mechanically ventilated. Positive cultures were obtained in 259 patients (38.0%): 77 (29.7%) had prevalent, 115 (44.4%) had ICU-acquired, and 40 (15.4%) had both; culture date was unavailable in 27 (10.4%). The most common bacterial organisms isolated were coagulase-negative staphylococci, Staphylococcus aureus, Pseudomonas species, and Streptococcus pneumoniae. Antibiotics were prescribed in 661 (97.1%), with 3.8 (1.9) prescriptions per patient. Patients with any positive culture had longer days of mechanical ventilation (mean [SD], 15.2 [10.7] vs 10.7 [9.0]; P<.0001), ICU stay (median [interquartile range (IQR)], 18.2 [12.5] days vs 10.8 [9.0] days, P<.0001), and hospitalization (median [IQR], 30.7 [20.7] days vs 19.2 [17.4] days, P<.0001) and a trend toward increased hospital mortality (25.1% vs 19.9%, P=.15). Patients with ICU-acquired positive cultures had worse outcomes compared with those with positive prevalent cultures or who were culture-negative.
  
  
  CONCLUSIONS
  Culture-based evidence of secondary infections commonly complicates A(H1N1)-related critical illness and is associated with worse clinical outcomes despite nearly ubiquitous antibiotic administration.
authors: Department of Medicine, Queen's University, Kingston, ON. Electronic address: muscedej@kgh.kari.net.
authors: John
authors: J
authors: Muscedere
authors: Public Health Agency of Canada, Ottawa, ON and Winnipeg, MB.
authors: Marianna
authors: M
authors: Ofner
authors: Winnipeg Health Sciences Centre and St. Boniface Hospital, University of Manitoba, Winnipeg, MB.
authors: Anand
authors: A
authors: Kumar
authors: Sunnybrook Health Sciences Center, University of Toronto, Toronto, ON.
authors: Jennifer
authors: J
authors: Long
authors: Clinical Research Centre Étienne Le Bel and Department of Medicine, Université de Sherbrooke, Sherbrooke, QC.
authors: Francois
authors: F
authors: Lamontagne
authors: Faculty of Health Sciences, McMaster University, Hamilton, ON.
authors: Deborah
authors: D
authors: Cook
authors: Mt. Sinai Hospital, University of Toronto, Toronto, ON.
authors: Allison
authors: A
authors: McGeer
authors: St. Michael's Hospital, Toronto, ON.
authors: Clarence
authors: C
authors: Chant
authors: St. Michael's Hospital, Toronto, ON.
authors: John
authors: J
authors: Marshall
authors: Sainte-Justine Research Center, Université de Montréal, QC, Canada.
authors: Philippe
authors: P
authors: Jouvet
authors: Sunnybrook Health Sciences Center, University of Toronto, Toronto, ON.
authors: Robert
authors: R
authors: Fowler
mesh_terms: D000328:Adult; D002170:Canada; D015331:Cohort Studies; D016638:Critical Illness / Q000453:epidemiology*; D005260:Female; D006801:Humans; D015994:Incidence; D053118:Influenza A Virus, H1N1 Subtype; D007251:Influenza, Human / Q000150:complications*; D007362:Intensive Care Units; D007902:Length of Stay; D008297:Male; D008875:Middle Aged; D011379:Prognosis; D011446:Prospective Studies; D011552:Pseudomonas Infections / Q000175:diagnosis / Q000453:epidemiology*; D012121:Respiration, Artificial; D013203:Staphylococcal Infections / Q000175:diagnosis / Q000453:epidemiology*; D013290:Streptococcal Infections / Q000175:diagnosis / Q000453:epidemiology*