title: Evaluation of endotoxin release and cytokine production induced by antibiotics in patients with Gram-negative nosocomial pneumonia.
abstract: OBJECTIVE
  To determine the plasma concentrations of lipopolysaccharide, tumor necrosis factor-alpha, interleukin-1 beta, and interleukin-6 in a homogeneous group of septic patients and to evaluate the effect of antibiotic treatment, imipenem or ceftazidime, on the release of lipopolysaccharide and cytokines.
  
  
  METHODS
  Prospective, randomized study.
  
  
  METHODS
  Sixteen-bed multidisciplinary intensive care unit.
  
  
  METHODS
  Twenty-four septic patients with documented Gram-negative nosocomial pneumonia. Controls were 20 patients admitted without sepsis and 20 healthy volunteers.
  
  
  METHODS
  Septic patients were randomized between imipenem and ceftazidime. Blood samples were collected before (0 hrs) and after (4 and 12 hrs) antibiotic treatment. Concentrations of lipopolysaccharide were measured by using the limulus assay, and cytokine concentrations were measured by enzyme-linked immunosorbent assay. Statistical analyses were performed by Kruskal-Wallis test, Mann-Whitney U test, and Student's t-test.
  
  
  RESULTS
  The mean age was 48.5 +/- 19.5. The mean Acute Physiology and Chronic Health Evaluation II score was 18.4 +/- 4.5. Overall mortality rate was 45.4%. All septic patients showed significant higher concentrations of lipopolysaccharide (p <.001), tumor necrosis factor-alpha (p <.04), and interleukin-6 (p <.001) than the controls, but interleukin-1 beta was never detected. We did not find statistically significant changes in lipopolysaccharide or cytokine plasma concentrations over time within any of the two arms of the study (ceftazidime vs. imipenem). There were no statistically significant differences in lipopolysaccharide and interleukin-6 plasma concentrations between the two antibiotic treatments. Although tumor necrosis factor-alpha plasma concentrations were significantly higher in the group treated with ceftazidime compared with the group treated with imipenem at the baseline and 4 hrs later, these differences were not statistically significant after 12 hrs of initiation of both treatments.
  
  
  CONCLUSIONS
  Patients with Gram-negative nosocomial pneumonia have high plasma concentrations of lipopolysaccharide, interleukin-6, and tumor necrosis factor-alpha, but the antibiotic therapy evaluated did not significantly modify these concentrations.
authors.affiliation: Intensive Care Unit, Hospital Alejandro Posadas, Buenos Aires, Argentina. Bermask@datamarkets.com.ar
authors.forename: Bernardo
authors.initials: B
authors.lastname: Maskin
authors.forename: Patricia A
authors.initials: PA
authors.lastname: Fontán
authors.forename: Emma G
authors.initials: EG
authors.lastname: Spinedi
authors.forename: Daniel
authors.initials: D
authors.lastname: Gammella
authors.forename: Adelina
authors.initials: A
authors.lastname: Badolati
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D002442:Ceftazidime / Q000494:pharmacology; D002511:Cephalosporins / Q000494:pharmacology; D003428:Cross Infection / Q000188:drug therapy* / Q000276:immunology; D016207:Cytokines / Q000097:blood / Q000187:drug effects*; D005260:Female; D016905:Gram-Negative Bacterial Infections / Q000188:drug therapy* / Q000276:immunology; D006801:Humans; D015378:Imipenem / Q000494:pharmacology; D007375:Interleukin-1 / Q000378:metabolism; D015850:Interleukin-6 / Q000378:metabolism; D008070:Lipopolysaccharides / Q000097:blood*; D008297:Male; D008875:Middle Aged; D018410:Pneumonia, Bacterial / Q000188:drug therapy* / Q000276:immunology; D011446:Prospective Studies; D018805:Sepsis / Q000188:drug therapy / Q000276:immunology; D018709:Statistics, Nonparametric; D013845:Thienamycins / Q000494:pharmacology; D014409:Tumor Necrosis Factor-alpha / Q000187:drug effects / Q000378:metabolism
chemical_list: D000900:Anti-Bacterial Agents; D002511:Cephalosporins; D016207:Cytokines; D007375:Interleukin-1; D015850:Interleukin-6; D008070:Lipopolysaccharides; D013845:Thienamycins; D014409:Tumor Necrosis Factor-alpha; D015378:Imipenem; D002442:Ceftazidime