Epidemiological factors influencing the emergence of antimicrobial resistance.

Antimicrobial resistance is becoming an important public health problem for both hospital- and community-acquired infections. In the hospital, infections caused by drug-resistant Staphylococcus aureus, Mycobacterium tuberculosis, enterococci, and a variety of Gram-negative rods are resulting in increased morbidity, mortality and costs, in part because of prolonged hospitalization and the use of more expensive antimicrobial agents. Drug-resistant, community-acquired infections are also causing important problems in both the developed and the developing world. Although the relative importance of specific pathogens varies with the geographical area, community-acquired pathogens including Salmonella, Shigella, Neisseria gonorrhoeae, Haemophilus influenzae and Streptococcus pneumoniae are causing both sporadic cases and outbreaks of drug-resistant illness. The emergence of antimicrobial resistance is being attributed to a series of societal, technological, environmental and microbial changes. These include increasing populations of susceptible hosts, international travel and commerce, changes in technology and industry, microbial adaptation and change, and the breakdown of public health measures. Addressing emerging problems and antimicrobial resistance will require enhanced surveillance, prudent use of existing antimicrobial drugs, development of new antimicrobial agents, increased emphasis on infection control and hygienic practices, effective disease control programs, better use of existing vaccines, and development of more and better vaccines.