Burden of highly resistant microorganisms in a Dutch intensive care unit

The occurrence of highly resistant microorganisms (HRMOs) is a major threat to critical care patients, leading to worse outcomes, need for isolation measures, and demand for second-line or rescue antibiotics. The aim of this study was to quantify the burden of HRMOs in an intensive care unit (ICU) for adult patients in a university hospital in the Netherlands. We evaluated local distribution of different HRMO categories and proportion of ICU-imported versus ICU- acquired HRMOs. Outcome of HRMO-positive patients versuscontrols was compared.

In this prospective single-centre study, culture results of all ICU patients during a four-month period were recorded, as well as APACHE scores, ICU mortality and length of stay (LOS) in the ICU.

58 of 962 (6.0%) patients were HRMO positive during ICU stay. The majority (60%) of those patients were HRMO positive on ICU admission. HRMO-positive patients had significantly higher APACHE scores, longer LOS and higher mortality compared with controls.

Our study suggests that a large part of antibiotic resistance in the ICU is imported. This underscores the importance of a robust surveillance and infection control program throughout the hospital, and implies that better recognition of those at risk for HRMO carriage before ICU admission may be worthwhile. Only a small minority of patients with HRMO at admission did not have any known risk factors for HRMO.