The role of the innate immune response in hospital- versus community-acquired infection in febrile medical patients.
OBJECTIVE
To study the role of the innate immune response in the higher mortality of hospital- than of community-acquired infections, in febrile medical patients.


METHODS
We studied presumably immunocompetent patients with new-onset fever and a clinically presumed focus of infection (N=212) at a university department of internal medicine. Clinical and microbiological data were collected for 2 days from inclusion, and circulating complement activation product C3a, secretory phospholipase A(2), interleukin (IL)-6, procalcitonin, and elastase-alpha(1)-antitrypsin were measured. Patients were followed for septic shock and outcome, up to a maximum of 7 and 28 days after inclusion, respectively. Infection was considered hospital-acquired if it developed at least 72h after admission.


RESULTS
Fifty-four patients had hospital-acquired infections and 158 had community-acquired infections, with septic shock and mortality rates of 15% and 24%, and 4% and 6% (p=0.001), respectively. Bloodstream infection predisposed to septic shock and the latter predisposed to death. Bloodstream infection was relatively more common in septic shock originating from community-acquired infection and was associated with an innate immune response in both hospital- and community-acquired infection, as judged from circulating immune variables. In contrast, circulating C3a, IL-6, and procalcitonin were more elevated when septic shock developed following hospital- than community-acquired infection, independent of infectious focus. The levels of C3a, secretory phospholipase A(2), IL-6, and elastase-alpha(1)-antitrypsin were more elevated in ultimate non-survivors than in survivors in both infection groups.


CONCLUSIONS
The data suggest that rates of septic shock and mortality from hospital- vs. community-acquired infections in febrile medical patients are not increased by impaired innate immunity. In contrast, proinflammatory factors may be particularly useful to predict a downhill course in hospital-acquired infections.
Department of Intensive Care, Institute for Cardiovascular Research, Vrije Universiteit Medical Centre, De Boelelaan 1117, 1081 HV Amsterdam, the Netherlands. johan.groeneveld@vumc.nl
A B Johan
AB
Groeneveld
C Erik
CE
Hack
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D016470:Bacteremia / Q000453:epidemiology / Q000276:immunology / Q000382:microbiology; D017714:Community-Acquired Infections / Q000453:epidemiology / Q000276:immunology* / Q000401:mortality; D003428:Cross Infection / Q000453:epidemiology / Q000276:immunology* / Q000401:mortality; D005260:Female; D005334:Fever / Q000453:epidemiology / Q000276:immunology*; D017052:Hospital Mortality; D006801:Humans; D007113:Immunity, Innate; D007249:Inflammation; D008297:Male; D008875:Middle Aged; D012772:Shock, Septic / Q000453:epidemiology / Q000276:immunology / Q000401:mortality; D055815:Young Adult