Impairment of polymorphonuclear neutrophil functions precedes nosocomial infections in critically ill patients

Crit Care Med. 2002 Feb;30(2):315-22. doi: 10.1097/00003246-200202000-00009.


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.

Design: 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.

Measurements: 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).

Main 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.

Conclusion: A decrease in S. aureus killing capabilities of neutrophils can be evidenced within the days before occurrence of a nosocomial infection.

MeSH terms

  • Adult
  • Aged
  • Aged, 80 and over
  • Blood Bactericidal Activity*
  • Cross Infection / epidemiology
  • Cross Infection / immunology*
  • Female
  • France / epidemiology
  • Humans
  • In Vitro Techniques
  • Interleukin-10 / blood
  • Interleukin-6 / blood
  • Male
  • Middle Aged
  • Neutrophils / immunology
  • Neutrophils / microbiology*
  • Phagocytosis / immunology*
  • Pseudomonas Infections / epidemiology
  • Pseudomonas Infections / immunology*
  • Reactive Oxygen Species / blood
  • Staphylococcal Infections / epidemiology
  • Staphylococcal Infections / immunology*
  • Statistics, Nonparametric


  • Interleukin-6
  • Reactive Oxygen Species
  • Interleukin-10