Influence of bacterial resistance on mortality in intensive care units: a registry study from 2000 to 2013 (IICU Study)

Abstract

Background: Bacterial resistance to antibiotics is a daily concern in intensive care units. However, few data are available concerning the clinical consequences of in-vitro-defined resistance.

Aim: To compare the mortality of patients with nosocomial infections according to bacterial resistance profiles.

Methods: The prospective surveillance registry in 29 French intensive care units (ICUs) participating during the years 2000-2013 was retrospectively analysed. All patients presenting with a nosocomial infection in ICU were included.

Findings: The registry contained 88,000 eligible patients, including 10,001 patients with a nosocomial infection. Among them, 3092 (36.7%) were related to resistant micro-organisms. Gram-negative bacilli exhibited the highest rate of resistance compared to Gram-positive cocci (52.8% vs 48.1%; P < 0.001). In-hospital mortality was higher in cases of patients with antibiotic-resistant infectious agents (51.9% vs 45.5%; P < 0.001), and critical care length of stay was longer (33 ± 26 vs 29 ± 22 days; P < 0.001). These results remained significant after SAPS II matching (P < 0.001) and in the Gram-negative bacilli and Gram-positive cocci subgroups. No difference in mortality was found with respect to origin prior to admission.

Conclusion: Patients with bacterial resistance had higher ICU mortality and increased length of stay, regardless of the bacterial species or origin of the patient.

Keywords: Antibiotic resistance; Cross-infection; Epidemiology; Microbiology; Mortality; Registry.