Published online on 10 February 2023. Tabah, A., Buetti, N., Staiquly, Q. et al. Epidemiology and outcomes of hospital-acquired bloodstream infections in intensive care unit patients: the EUROBACT-2 international cohort study. Intensive Care Med (2023). https://doi.org/10.1007/s00134-022-06944-2

What and Why?

The Eurobact 2 study aimed to provide new insights on the management of critically ill patients with severe infections and difficult to treat pathogens. Eight years after the first Eurobact study the epidemiology of antibiotic resistance has changed. Meanwhile there have been advances in the management of patients with sepsis and microbiology laboratory techniques. Recently new antibiotic combinations have been made available for difficult to treat pathogens and an update on the management of patients with severe infections acquired in the hospital is required.

The Eurobact 1 study collected multinational data on HA-BSI in 2010-11 as part of a large multicentric collaboration coordinated by the Infection Section of the ESICM. By including 1156 patients with HA-BSI from 162 ICUs in 24 countries, this was the largest and most cited study of HA-BSI treated in the ICU. It has been topical in describing the relationship between antimicrobial resistance (AMR) and increased delays in effective drug therapy and how resistance is independently associated with mortality  (See publication).

Following research recommendations of the recently published ESICM/SCMID roundtable on AMR (De Waele, Intensive Care Med, 2018) we have developed Eurobact 2 to provide granular data that will guide the understanding of the respective impact of the disease (source, microorganism), the host and the treatment (source control, antibiotics) in determining the outcomes of ICU patients with severe infections.

Eurobact 2 was developed by the infection section of the ESICM to specifically answer  three questions: 1. to make AMR a priority in research activities, 2. to document Gram Negative AMR infection from a global perspective and 3. to collect data on treatment and outcome of XDR/PDR infections. Furthermore recent changes in the overall management of patients with sepsis and shock and a reported change in prognosis makes it urgent to obtain current data on HA-BSI in the critically ill.

By targeting HA-BSI in a large multinational study, it is expected to obtain granular data and the researchers will investigate how management and outcomes may have changed while there has been a worldwide increase in AMR.


  • To describe the organisation of microbiology processing
  • To describe the determinants of outcomes of HA-BSI, specifically the effects
    • Source
    • Microorganisms, species, resistance and “difficult to treat” status
    • Antimicrobial therapy, timing, spectrum and adequacy
    • Source control, including timing and adequacy.
    • Patient specific factors
    • Severity of shock, organ failures and lactate levels.
    • Organisational factors
  • To assess the respective impact of the source the microorganism and the components of therapy on outcomes.
  • To describe the determinants of management of HA-BSI, including
    • Diagnostic methods and how they influences starting and modifying therapy (MALDI-TOF and molecular vs traditional methods for identification, speciation and susceptibility reporting. )
    • Type, dosing and duration of antimicrobial therapy
    • Source control
    • Other treatments for sepsis (steroids)
  • To describe epidemiological changes since the Eurobact study.


Trial Design

The study is designed as a prospective observational multicenter cohort study.
No intervention. No additional tests. All data to be collected from the patient’s file.

Inclusion Criteria

All adult patients with a Hospital Acquired Bloodstream Infection (HA-BSI) treated in the ICU.

HA-BSI is defined as a positive blood culture (BC)sampled after 48 hours following hospital admission.

For CNS and common contaminants (coagulase-negative staphylococci, Corynebacterium species, Bacillus species, Propionibacterium species, Aerococcus species, Micrococcus species), 2 blood cultures with the same antimicrobial susceptibility profile are mandatory or strong clinical grounds that it is not a contaminant. One example is infected material proven as a source for the HA-BSI.

Exclusion Criteria

Community acquired BSI = Blood culture sampled before 48 following hospital admissions.

Patient not treated in the ICU.

Patients that had a positive blood culture in the hospital and transferred to ICU for a different reason than specific treatment of the causes or consequences of HA-BSI.

Patients less than 18 years of age.

ICU mortality rate, defined as the number of deaths for any cause occurred during the ICU stay (censored at 90 days)

Secondary outcome: see protocol

Financial support

The project received a  €25,000 grant from ESICM after inclusion in the ESICM Trial Group portfolio.

Primary Investigators

Dr.Alexis Tabah, MD, FCICM. Caboolture and Redcliffe Intensive Care Units, Metro North Hospitals and Health Services.  Faculty of Medicine, The University of Queensland Brisbane, Australia

Prof. Jean-Francois Timsit, MD, PhD. IAME, Inserm U1137, Paris Diderot University. Director of the Medical and Infectious Diseases Intensive Care Unit, AP-HP, Bichat University Hospital, Paris, France