β-lactam allergy and risk of multidrug resistant bacteria in intensive care unit: A cohort study

ABSTRACT Patients labelled β-lactam allergic are frequently exposed to treatments by broad spectrum antibiotics. However, the risk of extended spectrum β-lactamase (ESBL) carriage in this population has been poorly investigated. Aim of this study was to evaluate characteristics and clinical outcomes of patients admitted in intensive care unit (ICU) with and without declared β-lactam allergy at admission. A retrospective monocentric study was performed including adult patients admitted in ICU between 2007 and 2012. The presence of multidrug resistant bacteria was documented in rectal and nasal swab at admission and discharge. Patients labelled allergic to β-lactams and unlabelled patients were compared. Patients labelled allergic had significantly higher rates of ESBL at admission (13.3 % vs 4.3%, p=0.0220) and at discharge (20% vs 8.9%, p=0.0460) than unlabelled patients but no significant difference in rates of ESBL acquisition was detected. No differences in mortality, duration of hospitalisation and typical risk factors of ESBL acquisition (intubation, CVC and duration of hospitalization) were reported. No differences in carriage of methicillin resistant Staphylococcus aureus were detected. This study showed that patients with declared β-lactam allergy had a higher risk of ESBL carriage in ICU at admission and discharge.