The tide of antimicrobial resistance and selection.

The cumulative ecological damage, both to the individual patient and to patient populations, secondary to antibiotic prescribing is increasingly recognised. The impact of antibiotics on pathogens and normal flora should be a criterion for antimicrobial selection. Measures to reduce the use of third-generation cephalosporins and fluoroquinolones should be considered. Increased reliance on carbapenems may accelerate the emergence of extremely resistant isolates, and these antimicrobials should be restricted to key scenarios. There is a clear need for new agents with novel modes of action and low ecological damage potential to treat nosocomial infections. Tigecycline has a spectrum of activity that theoretically may reduce the selection pressure for key nosocomial pathogens, and represents an alternative to carbapenems. Further studies are needed to confirm this potentially low selection pressure.