title: Impairment of polymorphonuclear neutrophil functions precedes nosocomial infections in critically ill patients.
abstract: OBJECTIVE
  A postinjury immunodepression involving neutrophil functions has been described in critically ill patients. The aim of this prospective study was to search for a relationship between an impairment of neutrophil functions and the subsequent development of nosocomial infection.
  
  
  METHODS
  Twenty-one severely ill (simplified acute physiology score II >20 on admission), nonimmunosuppressed patients who were receiving no antibiotics active against methicillin-resistant Staphylococcus aureus and highly resistant Pseudomonas aeruginosa were included. Twelve healthy subjects constituted a control group.
  
  
  METHODS
  Neutrophil functions (phagocytosis and bactericidal activity toward S. aureus and P. aeruginosa in homologous plasma, reactive oxygen species secretion) were studied at day 4 +/- 1 after admission, and occurrence of nosocomial infection was prospectively recorded over the following 5 days. Interleukin-10 concentration was assessed by enzyme-linked immunosorbent assay. Results are expressed as median (25th-75th percentiles).
  
  
  RESULTS
  Six out of the 21 patients acquired a nosocomial infection during the 5 days after blood sampling (infected group). Compared with the patients who did not acquire nosocomial infection (noninfected group, n = 15), the neutrophils of the infected group demonstrated a higher percentage of intracellular bacterial survival (17% [2% to 67%] vs. infected: 62% [22% to 100%], p <.05), leading to an impairment of S. aureus killing in homologous plasma (killed bacteria: 4.93 log(10) colony forming units/mL [4.24-5.29] vs. infected: 3.62 log(10) colony forming units/mL [0.00-4.58], p <.05). Interleukin-10 plasma concentration was higher in infected patients (78 pg/mL [60-83]) compared with noninfected patients (22 pg/mL [14-58], p <.05). By contrast, P. aeruginosa killing was similar in patients whether or not they acquired a nosocomial infection.
  
  
  CONCLUSIONS
  A decrease in S. aureus killing capabilities of neutrophils can be evidenced within the days before occurrence of a nosocomial infection.
authors.affiliation: Surgical Intensive Care Unit, Hôpital Henri Mondor, Assistance Publique-Hôpitaux de Paris, Paris, France.
authors.forename: François
authors.initials: F
authors.lastname: Stephan
authors.forename: Kun
authors.initials: K
authors.lastname: Yang
authors.forename: Jacques
authors.initials: J
authors.lastname: Tankovic
authors.forename: Claude-James
authors.initials: CJ
authors.lastname: Soussy
authors.forename: Gilles
authors.initials: G
authors.lastname: Dhonneur
authors.forename: Philippe
authors.initials: P
authors.lastname: Duvaldestin
authors.forename: Laurent
authors.initials: L
authors.lastname: Brochard
authors.forename: Christian
authors.initials: C
authors.lastname: Brun-Buisson
authors.forename: Alain
authors.initials: A
authors.lastname: Harf
authors.forename: Christophe
authors.initials: C
authors.lastname: Delclaux
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001770:Blood Bactericidal Activity; D003428:Cross Infection / Q000453:epidemiology / Q000276:immunology*; D005260:Female; D005602:France / Q000453:epidemiology; D006801:Humans; D066298:In Vitro Techniques; D016753:Interleukin-10 / Q000097:blood; D015850:Interleukin-6 / Q000097:blood; D008297:Male; D008875:Middle Aged; D009504:Neutrophils / Q000276:immunology / Q000382:microbiology*; D010587:Phagocytosis / Q000276:immunology*; D011552:Pseudomonas Infections / Q000453:epidemiology / Q000276:immunology*; D017382:Reactive Oxygen Species / Q000097:blood; D013203:Staphylococcal Infections / Q000453:epidemiology / Q000276:immunology*; D018709:Statistics, Nonparametric
chemical_list: D015850:Interleukin-6; D017382:Reactive Oxygen Species; D016753:Interleukin-10