[Transfer of multi-drug resistance in vivo by salmonellae and shigella in white mice].

The oral infection accomplished by 0.3 cm3 X 10(10) microbial bodies of Salmonella heidelberg and Shigella sonnei in albino mice the pathogens were found to localize in the intestines. The Salmonellae were detected up to the 10th day, and the Shigellae--up to the 14th day. Both Shigella and Salmonella transferred multi-drug resistance to some enterobacteria--E. coli and Proteus as well as to Salmonella typhimurium when the latter was also present in the intestinal tract; of these some 10--40 per cent acquire the multi-drug resistance of Salmonella heidelberg and Shigella sonnei. This type of resistance was most often transferred en bloc for the six, resp., eight markers. On some occasions segregation was observed with the transference of particular markers only.