Levy SB. The challenge of antibiotic resistance. Scientific American 283(3):46-53, 1998.

A glycopeptide chemically related to vancomycin, avoparcin has been used as a growth promoter in animal feeds in Europe since the mid-1970s. There are now indications that avoparcin use is selecting for vancomycin resistance in enterococci so that in Europe, VRE are found in community populations, waste water, farm animals, and some food products, unlike the United States where VRE are found largely in hospitals (U.S. Congress, op. cit., note 4).

Dowell S and B Schwartz, unpublished data. Atlanta: Centers for Disease Control and Prevention, 1997.

There is a considerable literature on the extent to which guidelines provide protection from liability, for example: National Health Lawyers Association. Legal Issues Related to Clinical Practice Guidelines: Colloquium Report. Washington, D.C.: National Health Lawyers Association, 1995.

The Alliance for the Prudent Use of Antibiotics, P.O. Box 1372, Boston, MA 02117.

Report of a study sponsored by the Fogarty International Center of the National Institutes of Health, 1983-1986. Antibiotic use and antibiotic resistance worldwide. Review of Infectious Diseases 9(Suppl. 3):S23 1-316, 1987.

The subject of off-label use of antibiotics, including its implications for the development of drug resistance and its regulatory aspects, is very large and very complex but was not addressed at the workshop.

Furthermore, two major activities are engaged in different processes for obtaining a more systematic understanding of this large problem. The Committee for Veterinary Medicinal Projects (the body responsible for evaluating documentation related to applications for licensing drugs for veterinary use in the European Community) established an ad hoc group charged with carrying out an epidemiological analysis of the status of antimicrobial resistance in animals and humans, as a basis for subsequent risk assessment. In addition, a major WHO workshop on "The Medical Impact of Use of Antimicrobial Drugs in Food Animals" recently reviewed this subject and will make recommendations regarding different aspects of the rational use of anti-infective drugs in food animals.

Feinman SE. Antibiotics in animal feed—drug resistance revisited. ASM News 64(4):24, 1998.

Milk is removed from each quarter of the cow's udder through the "streak canal" in the end of each teat. The canal is kept closed by a circular muscle (sphincter) that prevents milk from escaping and bacteria from entering. The cells lining the canal make keratin, which traps organisms that attempt to invade through the teat end, keeping them from gaining access to immune cells in the teat epithelium lining. If the sphincter muscles are weak, the teat will leak milk and is more likely to become infected.