title: Development of trimethoprim-resistance in Salmonella typhi during therapy.
abstract: A typhoid patient was infected with a fully-sensitive, plasmidless strain of Salmonella typhi which acquired resistance to kanamycin, sulfamethoxazole and trimethoprim during cotrimoxazole therapy. The resistant post-treatment strain harboured 4 plasmids of 62, 4.1, 3.8 and 3.0 Md in size. Kanamycin-, sulfamethoxazole- and trimethoprim-resistance were borne on a transferable 62 Md plasmid which was compatible with groups FI, FIme, FII, FIV, H1, H2, B, I1, I2, J, K, M, N, T, X, W and P. Sulfamethoxazole-resistance was also borne on the 4.1 Md plasmid. The 3.8 Md plasmid was not transferable; the 3.0 Md plasmid was transferable but did not confer antibiotic resistance. Excluding the strain described here, only 5 out of 35 other S typhi isolates contained plasmids. This is the first report of trimethoprim-resistant S typhi in Hong Kong.
authors.affiliation: Department of Microbiology, Chinese University of Hong Kong.
authors.forename: J M
authors.initials: JM
authors.lastname: Ling
authors.forename: Y W
authors.initials: YW
authors.lastname: Hui
authors.forename: A F
authors.initials: AF
authors.lastname: Cheng
authors.forename: G L
authors.initials: GL
authors.lastname: French
mesh_terms: D000328:Adult; D004352:Drug Resistance, Microbial; D006801:Humans; D007613:Kanamycin Resistance; D008297:Male; D012485:Salmonella typhi / Q000187:drug effects*; D014296:Trimethoprim Resistance; D015662:Trimethoprim, Sulfamethoxazole Drug Combination / Q000627:therapeutic use; D014435:Typhoid Fever / Q000188:drug therapy*
chemical_list: D015662:Trimethoprim, Sulfamethoxazole Drug Combination