Antimicrobial resistance in the intensive care unit: impact of new patterns.

The effects of resistance are being observed on an increasing scale in the intensive care unit (ICU). Multi-resistant organisms are diminishing our ability to treat and control the spread of infection. Strategies for the control of resistant organisms in the ICU must be based on the underlying pathophysiology of resistance mechanisms. Resistance is also influenced by the setting in which health care is provided. In the United States (US), changes in the health care delivery system have had a dramatic impact on the number and type of ICU patients. Project ICARE (Intensive Care Antimicrobial Resistance Epidemiology) is a co-operative project to measure antibiotic resistance and antibiotic use. Results show a relative increase in the number of ICU beds in US hospitals. They also indicate a significant stepwise decrease in the percentage of resistant organisms isolated from ICU patients, non-ICU inpatients, and outpatients. These results suggest that resources allocated to control of antimicrobial resistance should continue to be focused on the hospital and particularly the ICU. Study findings also indicate that antimicrobial use and resistance are usually, but not always, linked. This means that strategies for dealing with resistance must address several additional factors including infection control practices, community burden of resistance, and possibly others. Thus national or regional guidelines for preventing resistance will have to be modified to take into account local care patterns, problems and resources. When dealing with resistance in the ICU, 'one size will not fit all'.