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

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. To compare the mortality of patients with nosocomial infections according to bacterial resistance profiles. 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. 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. Patients with bacterial resistance had higher ICU mortality and increased length of stay, regardless of the bacterial species or origin of the patient.