Resistance of bacteria to antibacterial agents: report of Task Force 2.

The use of a growing number of antibacterial agents over the past half century has elicited a widespread deployment of genes for resistance to these agents in populations of bacteria throughout the world. Task Force 2 of the NIH Study on Antibiotic Use and Antibiotic Resistance Worldwide found that data on prevalence of resistance was fragmentary and underanalyzed but indicative of several trends. Resistance to older antibacterial agents appears to have stabilized overall, but shifts of resistance genes into new strains and species have continued to cause new clinical problems. Resistance to newer antibacterial agents has increased. Resistance is more prevalent in developing countries. Systematic surveillance of resistance integrated with understanding of its molecular basis is needed for control of resistance.