Attributable mortality of ICU-acquired bloodstream infections: Impact of the source, causative micro-organism, resistance profile and antimicrobial therapy
Introduction
Intensive Care Unit (ICU)-acquired bloodstream infection (ICUBSI) is defined by bloodstream infection occurring in patients 72 h after their ICU admission. It occurs within approximately 5% of all ICU patients,1, 2 and remains a frequent cause of severe sepsis associated with increased cost and burden.3 In large cohorts, ICU–BSI was an independent factor for higher mortality when adjusted to severity of illness.4 Conflicting results have been reported regarding the potential influence on the mortality related to ICU–BSI of factors such as the source of infection, the illness severity, the existence of superinfection risk factors, and finally on the pathogen and its susceptibility profile. These discrepancies were likely related to the case-mix: limited cohorts, studies focusing on specific pathogens,5, 6, 7, 8 or on catheter-related ICU–BSI,9 to the definition used for catheter-related ICU–BSI, and to the adjustment for confounding factors. For instance, after the third day in ICU, the capability of many severity scores at admission in predicting the mortality hazard became poor.10, 11 In addition, although its impact on mortality is still debated,4 the increase of antimicrobial resistance, particularly amongst Gram-negative pathogens, may lead to inappropriate initial therapy.12 Not only assessing ICU–BSI impact on mortality is clinically important, but ICU–BSI rate is also an indicator for quality care when benchmarking ICUs. Therefore, determining its exact impact on outcome is critical for an accurate evaluation of ICU care by critical car team.
In the present study, we analyzed the epidemiology, characteristics, risk factors, and microorganism resistance pattern associated with the 30-day mortality of ICU–BSI in a large cohort of patients admitted in the ICUs of the Outcomerea Network. We also evaluated the importance of the antimicrobial treatment according to the drug resistance pattern of the causative pathogen.
Section snippets
Data collection
In participating ICUs, data were collected daily by study monitors helped by senior physicians. For each patient, the data were entered into an electronic case-report form using VIGIREA® and RHEA® data-capture softwares, and then loaded into the OutcomeRea® data warehouse. All codes and definitions were established prior to study initiation. For each patient, age, sex, McCabe score, severity of illness on the first ICU day using the Simplified Acute Physiology Score (SAPS II), Sequential Organ
Results
Out of the 17,014 adult patients included in the database, we restricted the analysis to 10,734 patients who stayed more than 72 h in the ICU as they were susceptible to develop nosocomial infection according to the usual definition. Then we excluded 337 patients who were re-admitted in ICU, and 356 patients with therapeutic limitation. Overall, 4819 (48%) patients were followed up to 30 days or died before; the event-free survival at Day 30 was hypothesized for 1696 (17%) patients who were
Discussion
In this large cohort patients, ICU–BSI was independently associated with a higher risk of mortality, particularly for those not receiving an early initial adequate therapy, regardless of the antimicrobial susceptibility profile of the causative pathogen. This was particularly true in Gram-negative bacilli (non-fermenting ones excluded). An initial combination with fluoroquinolone appeared to be associated with an improved outcome. We worked on a large and high quality database, and used a Cox
Conflict of interest
None.
Financial/nonfinancial disclosures
The study was entirely funded by the Outcomerea Research Network and was supported in part by a research grant on ICU-acquired bloodstream infections from 3M company.
Acknowledgment
The authors thank Celine Feger, MD (EMIBiotech), for her editorial support.
References (39)
- et al.
Epidemiology and economic evaluation of severe sepsis in France: age, severity, infection site, and place of acquisition (community, hospital, or intensive care unit) as determinants of workload and cost
J Crit Care
(2005) - et al.
Reappraisal of attributable mortality in critically ill patients with nosocomial bacteraemia involving Pseudomonas aeruginosa
J Hosp Infect
(2003) - et al.
Evaluation of outcome in critically ill patients with nosocomial enterobacter bacteremia: results of a matched cohort study
Chest
(2003) - et al.
Multidrug-resistant, extensively drug-resistant and pandrug-resistant bacteria: an international expert proposal for interim standard definitions for acquired resistance
Clin Microbiol Infect
(2012) - et al.
Clinical outcomes of health-care-associated infections and antimicrobial resistance in patients admitted to European intensive-care units: a cohort study
Lancet Infect Dis
(2011) - et al.
Does combination antimicrobial therapy reduce mortality in gram-negative bacteraemia? A meta-analysis
Lancet Infect Dis
(2004) - et al.
Clinical implications of beta-lactam-aminoglycoside synergism: systematic review of randomised trials
Int J Antimicrob Agents
(2011) - et al.
Acquired bloodstream infection in the intensive care unit: incidence and attributable mortality
Crit Care
(2011) - et al.
International study of the prevalence and outcomes of infection in intensive care units
JAMA
(2009) - et al.
Update on bloodstream infections in ICUs
Curr Opin Crit Care
(2013)
Nosocomial bacteremia involving Acinetobacter baumannii in critically ill patients: a matched cohort study
Intensive Care Med
Absence of excess mortality in critically ill patients with nosocomial Escherichia coli bacteremia
Infect Control Hosp Epidemiol
Attributable morbidity and mortality of catheter-related septicemia in critically ill patients: a matched, risk-adjusted, cohort study
Infect Control Hosp Epidemiol
Calibration and discrimination by daily logistic organ dysfunction scoring comparatively with daily sequential organ failure assessment scoring for predicting hospital mortality in critically ill patients
Crit Care Med
Excess risk of death from intensive care unit-acquired nosocomial bloodstream infections: a reappraisal
Clin Infect Dis
Characteristics and determinants of outcome of hospital-acquired bloodstream infections in intensive care units: the EUROBACT International Cohort Study
Intensive Care Med
Reliability of diagnostic coding in intensive care patients
Crit Care
The international sepsis forum consensus conference on definitions of infection in the intensive care unit
Crit Care Med
Coagulase-negative staphylococcal bacteremia. Mortality and hospital stay
Ann Intern Med
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