Journal Article

Clinical outcomes of health-care-associated infections and antimicrobial resistance in patients admitted to European intensive-care units: a cohort study

Savey, Anne, Mertens, Karl, Schumacher, Martin, Wolkewitz, Martin, Suetens, Carl, Lambert, Marie-Laurence, Morales, Ingrid, Palomar, Mercedes, Hiesmayr, Michael, Frank, Uwe, Agodi, Antonella

2011

Overview

Patients admitted to intensive-care units are at high risk of health-care-associated infections, and many are caused by antimicrobial-resistant pathogens. We aimed to assess excess mortality and length of stay in intensive-care units from bloodstream infections and pneumonia. We analysed data collected prospectively from intensive-care units that reported according to the European standard protocol for surveillance of health-care-associated infections. We focused on the most frequent causative microorganisms. Resistance was defined as resistance to ceftazidime ( Acinetobacter baumannii or Pseudomonas aeruginosa), third-generation cephalosporins ( Escherichia coli), and oxacillin ( Staphylococcus aureus). We defined 20 different exposures according to infection site, microorganism, and resistance status. For every exposure, we compared outcomes between patients exposed and unexposed by use of time-dependent regression modelling. We adjusted results for patients' characteristics and time-dependency of the exposure. We obtained data for 119 699 patients who were admitted for more than 2 days to 537 intensive-care units in ten countries between Jan 1, 2005, and Dec 31, 2008. Excess risk of death (hazard ratio) for pneumonia in the fully adjusted model ranged from 1·7 (95% CI 1·4–1·9) for drug-sensitive S aureus to 3·5 (2·9–4·2) for drug-resistant P aeruginosa. For bloodstream infections, the excess risk ranged from 2·1 (1·6–2·6) for drug-sensitive S aureus to 4·0 (2·7–5·8) for drug-resistant P aeruginosa. Risk of death associated with antimicrobial resistance (ie, additional risk of death to that of the infection) was 1·2 (1·1–1·4) for pneumonia and 1·2 (0·9–1·5) for bloodstream infections for a combination of all four microorganisms, and was highest for S aureus (pneumonia 1·3 [1·0–1·6], bloodstream infections 1·6 [1·1–2·3]). Antimicrobial resistance did not significantly increase length of stay; the hazard ratio for discharge, dead or alive, for sensitive microorganisms compared with resistant microorganisms (all four combined) was 1·05 (0·97–1·13) for pneumonia and 1·02 (0·98–1·17) for bloodstream infections. P aeruginosa had the highest burden of health-care-acquired infections because of its high prevalence and pathogenicity of both its drug-sensitive and drug-resistant strains. Health-care-associated bloodstream infections and pneumonia greatly increase mortality and pneumonia increase length of stay in intensive-care units; the additional effect of the most common antimicrobial resistance patterns is comparatively low. European Commission (DG Sanco).

• Publisher: Elsevier Ltd,Lancet Publishing Group,Elsevier Limited,New York, NY : Elsevier Science ; The Lancet Pub. Group, 2001
• Subject: Acinetobacter baumannii / Adult / Aged / Anti-Bacterial Agents - pharmacology / Anti-Bacterial Agents - therapeutic use / Bacteremia - drug therapy / Bacteremia - microbiology / Bacteremia - mortality / Bacteria - classification / Bacteria - drug effects / Bacteria - isolation & purification / Biological and medical sciences / Ceftazidime / Cephalosporins / Cohort Studies / Cross Infection - drug therapy / Cross Infection - microbiology / Cross Infection - mortality / Data processing / Drug resistance / Drug Resistance, Bacterial / E coli / Escherichia coli / Europe / Female / General aspects / Health care / Health risks / Human infectious diseases. Experimental studies and models / Humans / Infection / Infectious Disease / Infectious diseases / Intensive Care Units / Length of Stay - statistics & numerical data / Life Sciences / Male / Medical sciences / Microorganisms / Middle Aged / Mortality / Other / Oxacillin / Pathogenicity / Pathogens / Pneumonia / Pneumonia, Bacterial - drug therapy / Pneumonia, Bacterial - microbiology / Pneumonia, Bacterial - mortality / Pseudomonas aeruginosa / Public health / Risk factors / Staphylococcus aureus / Treatment Outcome