self-medication are magnified because significant amounts of the available antimicrobials are poorly manufactured, counterfeit, or have exceeded their effective lifetimes.

Various practices common in hospitals contribute to the resistance problem as well. Indeed, hospitals are especially fertile grounds for breeding resistant microbes. They deal regularly with large numbers of patients (many with suppressed immune systems) in relatively close proximity to each other, and they frequently treat their patients with intensive and prolonged antimicrobial therapy. Large hospitals and teaching hospitals generally experience more problems with drug-resistant microbes, probably because they treat greater numbers of the sickest patients and those at highest risk of becoming infected. Transmission of drug-resistant organisms among patients may be airborne, from a point source (such as contaminated equipment), or by direct or indirect contact with a contaminated environment or the contaminated hands of staff. Failure of health care workers to practice simple control measures (e.g., hand washing and changing gloves after examining a patient) is a leading contributor to the spread of infection in hospitals.

Hospitals typically rely on two major forms of intervention to minimize resistance problems. One approach involves limiting antimicrobial use as much as possible; the other involves implementing intensive infection-control programs. Important components of these programs include surveillance; outbreak investigation and control; sterilization and disinfection of equipment; and implementation of such patient-care practices as handwashing, isolation, and barriers between infected patients.

Although much is known about how hospitals can minimize the spread of infection, research is still needed to fill some important gaps in knowledge. One need is for development of rapid, reliable diagnostic methods for identifying the presence of infection, the specific infecting organism, and the susceptibility of the microbe to various therapeutic agents. Diagnostic precision is the key to effectively modifying the current approach of widespread empiric antimicrobial use in ill patients with suspected infections. A further need is to develop materials for use in medical devices, such as catheters, that are resistant to colonization by microorganisms. In addition, continuing development of new antimicrobial agents remains a priority.

Another factor that is widely believed to contribute to resistance problems is the use of various antimicrobial agents in animals raised commercially for food, such as poultry, pigs, and cows. Participants debated just what contribution such agricultural use makes to the spread of antimicrobial resistance among human pathogens. While some participants maintained that the problem is minimal and being effectively managed by various public and private programs, others described a greater level of risk. They expressed concern that use of antimicrobials in animals, either for



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