Breeding an Epidemic Antibiotics and Meat

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After 25 years of effort, the mechanisms that had long been suspected were established: Antibiotics fed to animals had created a resistant strain of bacteria for which the fatality rate in humans was 21 times higher than for non resistant strains . . . and antibiotics taken directly by the people had cleared the way for the disease-causing microorganisms.

THE OVERRIDING CONCERN

As alarming as it is that diseases made resistant by antibiotics can be transferred from animals to people, that threat to human health may be small compared with the possibility—indeed, the likelihood—that antibiotics are gradually becoming ineffective treatments for many diseases as resistance is transferred from one type of bacteria to another.

When England banned subtherapeutic use of antibiotics, the decision was based in part on a study showing that while 30% of Salmonella typhimurium were resistant in 1963, fully 73% had become resistant by 1979. A more alarming fact is that even if animals are fed only one antibiotic, their bacterial cultures may develop resistance to a variety of other antibiotics at the same time. Today in the U.S. approximately 25% of the salmonella infections in humans are resistant to drugs.

It may be that the overprescribing of antibiotics for people bears a similar responsibility for the development of resistant strains of bacteria, but the fact remains that the use of antibiotics in animals certainly adds to the problem. Though most of the bacteria that inhabit a cow's intestinal tract are different from those that live in humans, there's no distinguishable difference between the carriers of resistance: the R plasmids. Even though E. coli from cattle may be expelled by humans within a day, these able carriers of resistance can work numerous transfers during their stay. The routes of travel are mind-boggling, and the bacteria's persistence is remarkable. Some of us may bear a bigger burden of R plasmids than others, but it's safe to say that nearly all of us have some . . . and that the number is increasing.

REGULATORY STONEWALL

North American countries stand practically alone among developed nations in allowing the indiscriminate use of antibiotics in animals. Czechoslovakia, Denmark, England, the Netherlands, Norway, Sweden, and West Germany all require veterinary prescriptions for animal antibiotics. In the U.S., however, the director of the FDA's Center for Veterinary Medicine, Lester M. Crawford, has been unsuccessfully pursuing a ban on subtherapeutic use of antibiotics since 1977. It seems that each year since 1979 the House of Representatives Appropriations Committee has written a clause into the FDA budget which specifically prohibited the agency from restricting antibiotic use in animals until further research was completed!

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