7 OCTOBER 1972, Page 33


Drug resistance

Bernard Dixon

The American investor's weekly Baron's has just launched an extraordinarily vicious attack on the US Food and Drug Administration for its recent report proposing restrictions on the use of antibiotics in agriculture. Similar to, though more far-reaching than, the Swann committee's recommendations in Britain two years ago (since enacted in part by the Government), the FDA proposals stem from the public health risks inherent in the wholesale inclusion of antibiotics in animal feedstuffs to promote growth and prevent disease. Regular feeding of small doses of antibiotics makes pigs, poultry, and other livestock grow more quickly (how it does so is unclear), but at the same time encourages the proliferation of strains of intestinal bacteria resistant to the effects of the drugs used. The same thing happens when antibiotics are given as prophylactics. Mass medication is a convenient way of curbing disease in intensive farming, whereas the most sensible way of Preventing infection is to improve the physical conditions of husbandry and treat disease if and when it occurs.

The end result of both indiscriminate uses of antibiotics is that drug-resistant strains of bacteria begin to flourish. In classical Darwinian fashion, they replace the sensitive ones. This is dangerous in two ways. Some bacteria — such as Salmonella typhimurium, a common agent of food poisoning — can cause disease in both farm animals and man. Particularly in old people and the very young, antibiotics may be needed to treat the infection. If the bacteria responsible are resistant organisms, acquired from animals either directly or via meat, the disease will not respond to treatment. A more insidious danger is transferable resistance, which even harmless bacteria can pass on to those that cause disease. Often, the resistance conferred renders a previously sensitive organism invulnerable not just to a single antibiotic, but to several drugs at the same time. The long-term hazards here are incalculable.

Baron's does not see it this way. Instead they dismiss the dangers on the basis of "two decades of experience to the contrary" (which they do not enlarge upon) and the FDA's "striking official disregard for the principles of scientific enquiry" (which they criticise without a single supporting fact or statistic). No matter that medical journals over the past ten years have been replete with incriminating evidence. No matter that two expert government committees — both notable for their independence and for not including the more extreme advocates of restrictive legislation — have called for severe restrictions. No matter that alternative drugs do exist which are not used in human medicine but which are effective in growth-promotion. The reaction of Baron's is based solely on the supposed cash losses to the farming community and what it calls the "nation's pocketbook."

In just one sense, Baron's and other critics are on safe ground. It is extremely difficult to establish precisely the origin of the resistance in a particular microbe, causing a particular infection at a particular time. What we do know with absolute certainty is that indiscriminate use of antibiotics, whether by farmers or by doctors who over-prescribe and give antibiotics for trivial conditions, creates the very conditions under which resistance thrives. It is probable, for example, that sloppy antibiotic usage has been responsible for the drug-resistant typhoid bacilli now causing considerable trouble in Mexico and Kerala — just as seemed likely with the organism that killed twelve children with gastroenteritis on Tees-side in December 1967. The one clear lesson from these incidents, and from countless others that never make the headlines, is that we should do everything possible to curb any increase in drug resistance. At a stroke, ending the reckless use of antibiotics in farming is one important means of doing so.