Proceedings: Antibiotic resistance in coliforms from animal feeding stuffs.

D. H. M. JOYNSON AND C. H. L. HOWELLS (Public Health Laboratory, University Hospital of Wales, Cardiff) Samples of animal feeding stuffs were examined for the presence of Gram-negative, lactosefermenting organisms (hereafter called coliforms) and the antibiotic resistance of any strain isolated was determined. Coliforms were found in 13% of all the feeds examined and of these organisms 64-4% were found to be resistant to one or more antibiotic. A high proportion (45 5 %) were resistant to ampicillin, but resistance to other antibiotics was lower: colistin (16-6 %), streptomycin (10-6 %), tetracycline (5 8 %), and neomycin (0-1 %). Resistance to three or more antibiotics was demonstrated by 6-5 % of the coliforms isolated. Transfer of R-factors to a sensitive E. coli recipient was demonstrated in 86-4% of the multiresistant strains examined. Antibiotic-resistant strains of coliforms have been regarded as a danger to human health for many years. It is believed that these bacteria arise from animals which have been given antibiotics as growth supplements, the organisms eventually finding their way to man via untreated meats, etcetera. It has also been demonstrated that some of these microorganisms may find their way into the hospital kitchen and thus, via washing-up water and utensils, to the patients. As far as known, however, no one has yet suggested that animal feeding stuffs already containing antibiotic-resistant strains of coliforms may be the source of animal infection with such organisms.