Chloramphenicol-resistant Salmonella typhi from a patient in Addis Abeba

The clinical history and treatment outcome of a twenty-year old female patient (EN) with typhoid fever is presented. Laboratory examination showed that the etiological agent was a strain of Salmonella typhi which was simultaneously resistant to chloramphenicol (C), streptomycin (S), sulphonamides (Su) and tetracycline (T). Genetic and molecular analysis of this strain demonstrated that resistance to CSSuT was encoded in a plasmid which showed a thermosensitive (28 degrees C) transfer to an Escherichia coli K12 recipient, at a frequency of 4.0 x 10(-2). The R-plasmid had a molecular weight of 110 megadaltons and belonged to incompatibility group H1 plasmids. The present finding should warn medical personnel of the possible dissemination of this epidemic strain in Addis Abeba area.