title: Epidemiological analysis of Salmonella enterica serotype typhimurium from Hong Kong by ribotyping and pulsed-field gel electrophoresis.
abstract: We investigated the antimicrobial susceptibilities and molecular epidemiology of 200 strains of Salmonella enterica serotype typhimurium isolated from 1989 to 1996 in Hong Kong. Only 22% of strains were susceptible to all 19 antibiotics tested but all were susceptible to second- and third-generation cephalosporins. Up to 9% of strains were resistant to 0.12 mg/l concentrations of ciprofloxacin or ofloxacin but none were resistant to 1 or 2 mg/l concentrations of these 2 drugs, respectively. The isolates were grouped into 15 types by ribotyping with restriction endonuclease EcoRI and into 53 types by pulsed-field gel electrophoresis of XbaI-restricted DNA fragments. When DNA fragments of the ribotypes and pulsotypes were pooled and analyzed 87 types resulted, 76 (87%) of which were of > 90% similarity and were grouped into 15 clusters. About 60% of the isolates belonged to 3 clusters, which probably represented 3 clones endemic in the community. The rest of the isolates were of a large variety of types or clusters. For epidemiological purposes analysis of pooled results from different molecular techniques would be more discriminative than results from individual techniques alone.
authors.affiliation: Department of Microbiology, The Chinese University of Hong Kong, The Prince of Wales Hospital, Shatin, New Territories, People's Republic of China.
authors.forename: J M
authors.initials: JM
authors.lastname: Ling
authors.forename: I C
authors.initials: IC
authors.lastname: Koo
authors.forename: A F
authors.initials: AF
authors.lastname: Cheng
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology; D002511:Cephalosporins / Q000494:pharmacology; D004269:DNA, Bacterial / Q000235:genetics; D016521:Electrophoresis, Gel, Pulsed-Field; D006723:Hong Kong / Q000453:epidemiology; D006801:Humans; D008826:Microbial Sensitivity Tests; D017720:Molecular Epidemiology; D021521:Ribotyping; D012480:Salmonella Infections / Q000453:epidemiology / Q000382:microbiology*; D012486:Salmonella typhimurium / Q000187:drug effects / Q000235:genetics / Q000302:isolation & purification*
chemical_list: D000900:Anti-Bacterial Agents; D002511:Cephalosporins; D004269:DNA, Bacterial