Abstract

Among 309 cultures of Salmonella typhimurium , phage-type 27, fifteen, isolated from eight patients, were found to be resistant to the three drugs, streptomycin, tetracycline and sulphathiazole. This triple resistance could be transferred by growth in mixed broth culture to a strain of Skigella sonnei and back again to sensitive cultures of S. typhimurium . In whole cultures the resistance was stable, but spontaneous loss could be demonstrated in a small proportion of the organisms in such cultures. No elimination of resistance was demonstrated after treatment with acriflavine. Resemblances to the multiple drug resistance in enteric bacteria reported from Japan are noted. The author is most grateful to Dr E. S. Anderson, Director of the Enteric Reference Laboratory, Colindale, N.W. 9, for phage-typing the cultures of Salmonella typhimurium , and to Dr K. Patricia Carpenter, Director of the Dysentery Reference Laboratory, for supplying cultures of Sh. sonnei which were essential for the experimental work.