Antimicrobial resistance: factors and outcomes.

Antimicrobial resistance in the ICU is characterized by increasing overall resistance rates among gram-negative and gram-positive pathogens and increased frequency of multidrug-resistant organisms. In addition to basic principles of appropriate drug selection for empiric and definitive therapy, other specific strategies that may decrease problems of resistance through improved use of antimicrobials include appropriate application of pharmacokinetic and pharmacodynamic principles to antimicrobial use, aggressive dosing of antimicrobials, use of broad-spectrum and combination antimicrobial therapy for initial treatment, decreased duration of antimicrobial therapy, hospital formulary-based antimicrobial restrictions, use of antimicrobial protocols and guidelines, programs for restriction of target antimicrobials, scheduled antimicrobial rotation, and use of antimicrobial management programs. Combinations of various approaches may offer the best potential for effectively intervening in and reducing the spread of resistant pathogens in critically ill patients.