title: Bacterial co-infection with H1N1 infection in patients admitted with community acquired pneumonia.
abstract: BACKGROUND
  Bacterial co-infection is an important contributor to morbidity and mortality during influenza pandemics .We investigated the incidence, risk factors and outcome of patients with influenza A H1N1 pneumonia and bacterial co-infection.
  
  
  METHODS
  Prospective observational study of consecutive hospitalized patients with influenza A H1N1 virus and community-acquired pneumonia (CAP). We compared cases with and without bacterial co-infection.
  
  
  RESULTS
  The incidence of influenza A H1N1 infection in CAP during the pandemic period was 19% (n, 667). We studied 128 patients; 42(33%) had bacterial co-infection. The most frequently isolated bacterial pathogens were Streptococcus pneumoniae (26, 62%) and Pseudomonas aeruginosa (6, 14%). Predictors for bacterial co-infection were chronic obstructive pulmonary disease (COPD) and increase of platelets count. The hospital mortality was 9%. Factors associated with mortality were age ≥ 65 years, presence of septic shock and the need for mechanical ventilation. Although patients with bacterial co-infection presented with higher Pneumonia Severity Index risk class, hospital mortality was similar to patients without bacterial co-infection (7% vs. 11%, respectively, p = 0.54).
  
  
  CONCLUSIONS
  Bacterial co-infection was frequent in influenza A H1N1 pneumonia, with COPD and increased platelet count as the main predictors. Although associated with higher severe scales at admission, bacterial co-infection did not influence mortality of these patients.
authors.affiliation: Department of Pneumology, Institut del Tórax, Hospital Clinic, IDIBAPS, University of Barcelona, Villarroel 170, Barcelona 08036, Spain.
authors.forename: Catia
authors.initials: C
authors.lastname: Cillóniz
authors.forename: Santiago
authors.initials: S
authors.lastname: Ewig
authors.forename: Rosario
authors.initials: R
authors.lastname: Menéndez
authors.forename: Miquel
authors.initials: M
authors.lastname: Ferrer
authors.forename: Eva
authors.initials: E
authors.lastname: Polverino
authors.forename: Soledad
authors.initials: S
authors.lastname: Reyes
authors.forename: Albert
authors.initials: A
authors.lastname: Gabarrús
authors.forename: Maria Angeles
authors.initials: MA
authors.lastname: Marcos
authors.forename: Juan
authors.initials: J
authors.lastname: Cordoba
authors.forename: Josep
authors.initials: J
authors.lastname: Mensa
authors.forename: Antoni
authors.initials: A
authors.lastname: Torres
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000900:Anti-Bacterial Agents / Q000627:therapeutic use; D001424:Bacterial Infections / Q000188:drug therapy / Q000382:microbiology* / Q000821:virology; D060085:Coinfection / Q000382:microbiology* / Q000821:virology; D017714:Community-Acquired Infections / Q000382:microbiology* / Q000821:virology; D005260:Female; D006801:Humans; D015994:Incidence; D053118:Influenza A Virus, H1N1 Subtype / Q000302:isolation & purification*; D007251:Influenza, Human / Q000382:microbiology* / Q000821:virology; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D018410:Pneumonia, Bacterial / Q000382:microbiology* / Q000821:virology; D011446:Prospective Studies; D012307:Risk Factors
chemical_list: D000900:Anti-Bacterial Agents