[Characterization of antibiotic resistance plasmids in 2 strains of Salmonella typhi isolated in Belgium].

Two strains of Salmonella typhi resistant to streptomycin, tetracycline, chloramphenicol and sulfonamides were studied. Conjugation and analysis of plasmid DNA suggested that in the two strains, these resistance characters were mediated by a single R plasmid. The plasmids of both strains belonged to the FI-incompatibility group, whereas that isolated from the resistant Mexican S. typhi belonged to incomtibility group H. Therefore, the two resistant S. typhi isolated in Belgium do not represent an extension of the H plasmid which was responsible for chloramphenicol resistance in S. typhi during the 1972 Mexican epidemic.