Emerging healthcare-associated problem pathogens in the United States.

Healthcare-associated infections are a major cause of morbidity and mortality. Dramatic changes in the delivery of healthcare during the past decade have changed the definition of healthcare-associated infections. Healthcare delivery changes include a reduction in the number of general hospital beds, an increase in the proportion of patients who are in intensive care units, a larger proportion of surgical procedures performed as outpatient procedures, a marked increase in patients cared for in outpatient settings, and an increase in the delivery of healthcare in the home setting. These changes have blurred the border between hospital- and community-acquired infections, increased the challenge of controlling transmission of antimicrobial-resistant pathogens, and complicated clinicians' treatment decisions. Data from the National Nosocomial Infections Surveillance system show that between the periods of 1993-1997 and 1998, infections caused by vancomycin-resistant enterococci, methicillin-resistant Staphylococcus aureus (MRSA), methicillin-resistant coagulase-negative staphylococci, and imipenem- or quinolone-resistant Pseudomonas aeruginosa have significantly increased. In addition, we have witnessed the emergence of vancomycin-intermediate resistant S aureus and the community transmission of MRSA. If we are to turn the tide on the continued emergence of antimicrobial-resistant pathogens, we will need to enhance and expand our infection control programs in all settings in which healthcare is provided and improve the appropriateness of antimicrobial use.