by Bernard Dixon
New Scientist, 27 June 1979
This year marks a decade since a committee under Professor (now Sir) Michael Swann advised the British government to curb the then wholesale, indiscriminate use of antibiotics in agriculture.
This committee was established because of amply evidenced claims that the inclusion of potent antimicrobial drugs in feedstuffs for pigs, poultry and other livestock (to promote growth and prevent disease) had encouraged the emergence of bacteria resistant to those agents and capable of causing human gastrointestinal disease.
Salmonella typhimurium, a food poisoner of man and farm animals, caused particular concern because of its increasing invulnerability to antibiotics, The government took the Swann committee’s advice and brought in restrictions. In particular, feedstuff manufacturers could no longer put penicillins and tetracyclines in their products; these antibiotics would be given to livestock in future only by veterinary prescription, for the treatment of disease rather than to prevent outbreaks – something which can be achieved far more satisfactorily by the wider use of improved methods of husbandry.
A decade later, we have witnessed a massive increase in drug resistance among salmonellae in the UK (with a particularly disquieting spread of multiply resistant strains in the past two years, New Scientist, vol 80 p 90). There has been continued squabbling between bacteriologists, the drug industry, and the medical profession as to how much of this burden of resistance is attributable to the use of such drugs in animal husbandry. And, in the United States, an aggressive and interminable debate on the subject has so far allowed the industry lobby to neutralise the Food and Drug Administration’s efforts to take positive steps to deal with what has in recent years become a serious public health hazard.
Against this background, two items in the current issue of the Veterinary Record (vol 104, p 513 and 511) make salutary reading. The first is a report of a recent case in which an animal feedstuff company was fined £5,850 for illegally incorporating penicillin, chlortetracycline and sulphadimidine into their products. The second is a leading article warning veterinarians of the considerable difficulties posed by drug resistance and urging them to “think more critically” before prescribing any drugs of this sort.
“Events of the last couple of years indicate that it may not be purely alarmist science fiction to suggest that we could be considerably nearer to a return to the therapeutic days status of the pre-M&B 693 days of the early 1930s than we realise” the article says. It was in just such terms that Professor E.S. Anderson and others directed public attention to the problem well over a decade ago, and called for vigorous measures to turn the tide. What has gone wrong?
The agricultural antibiotics market in Britain is worth £20 million a year, so it is unsurprising that the industry has not been enthusiastic, at any stage, about measures likely to threaten its sales. Even self-interest has not induced the drug companies to take more interest in the fate of their products – products which, should the present growth of resistance continue, may well prove to be useless and therefore unused in another decade. Further down the line, the two Veterinary Record items show, illicitly use of antibiotics does go on (an idea always fiercely resented when this subject is raised publicly) and veterinarians unfortunately need reminding of their responsibilities in the matter. Antimicrobial drugs should be administered only to treat an identified outbreak of disease; they should not be procured in large quantities on prescription, from an absentee vet, who then leaves their use to the farmer.
But hard information is hard to come by. The data we do have – and lots of them – relate to the epidemic spread of drug resistance, particularly the transmissible type. It is important that we continue to monitor this dismal picture. Just as necessary now, however, are measures instigated by the Ministry of Agriculture, Fisheries and Food to monitor the spread of antibiotics themselves, to show how they are being deployed on the farm and in what quantities. The very existence of such machinery might make a considerable impact on the pattern of drug use, and could hardly fail to be beneficial.