Trends in antimicrobial resistance in intensive care units in the United States

Antimicrobial resistance and a paucity of new antimicrobial agents are ongoing challenges. This review focuses on the major epidemiologic trends and novel treatments, when available, for methicillin-resistant Staphylococcus aureus (MRSA), vancomycin-resistant enterococcus, Clostridium difficile, and multidrug-resistant Gram-negative bacilli in the United States during 2010-2011.

MRSA bloodstream infection rates have declined, primarily due to interventions aimed at decreasing vascular catheter infections. The proportion of MRSA due to the community-associated strain USA300 continues to increase. Recent studies of active surveillance and contact isolation for MRSA prevention provide conflicting views of efficacy. Two novel treatments for recurrent C. difficile infection, monoclonal antibodies and fidaxomicin, show promising results. Antimicrobial resistance among Gram-negative bacilli has become widespread; extended-spectrum beta-lactamases are now commonly found among Escherichia coli causing community-acquired infections in the United States. Klebsiella pneumoniae carbapenemases have spread beyond the northeast, and the New Delhi metallo-beta-lactamase has been reported in multiple countries within a few years of its discovery.

Antimicrobial resistance, particularly among Gram-negative bacilli, continues to increase at a rapid rate. Given the frequent transfer of patients between outpatient and acute care settings, as well as between different geographic regions, coordinated infection control interventions are warranted.