title: Epidemiology of nalidixic acid resistance and TEM-1- and TEM-52-mediated ampicillin resistance of Shigella sonnei isolates obtained in Korea between 1980 and 2000.
abstract: The resistance to ampicillin and nalidixic acid in Shigella sonnei isolates obtained in Korea during the period 1998 to 2000 was characterized. Recently (J. Y. Oh, H. S. Yu, S. K. Kim, S. Y. Seol, D. T. Cho, and J. C. Lee, J. Clin. Microbiol. 41:421-423, 2003) ampicillin and nalidixic acid resistance was found in 49 and 70%, respectively, of the 67 S. sonnei isolates obtained during this period. We analyzed 138 S. sonnei isolates collected during the same period. Ampicillin and nalidixic acid resistance was found in 30 and 86% of the isolates, respectively. The ampicillin resistance was mediated by a TEM-1 beta-lactamase, and TEM-52 extended-spectrum beta-lactamase was identified in one sporadic S. sonnei isolate from 1999. bla(TEM-1) and bla(TEM-52) were located in conjugative R-plasmids. Tn3 was detected in 41% of the ampicillin-resistant isolates. The R-plasmids from the transconjugants that transferred resistance to ampicillin exhibited different restriction fragment length polymorphism patterns, and a bla(TEM-1) probe was hybridized with the different fragments. The nalidixic acid resistance was exclusively associated with an amino acid substitution, Ser83-->Leu (TCG-->TTG), in gyrA. These findings indicate that the genetically related S. sonnei strains readily acquire resistance to ampicillin, streptomycin, trimethoprim, and sulfamethoxazole but not nalidixic acid through conjugative R-plasmids from difference sources when confronted by antibiotic selective pressures.
authors.affiliation: Department of Microbiology, Kyungpook National University School of Medicine, Taegu 700-422, Korea.
authors.forename: Young Sook
authors.initials: YS
authors.lastname: Jeong
authors.forename: Je Chul
authors.initials: JC
authors.lastname: Lee
authors.forename: Hee Young
authors.initials: HY
authors.lastname: Kang
authors.forename: Hak Sun
authors.initials: HS
authors.lastname: Yu
authors.forename: Eun Young
authors.initials: EY
authors.lastname: Lee
authors.forename: Chul Hee
authors.initials: CH
authors.lastname: Choi
authors.forename: Seong Ho
authors.initials: SH
authors.lastname: Tae
authors.forename: Yoo Chul
authors.initials: YC
authors.lastname: Lee
authors.forename: Dong Taek
authors.initials: DT
authors.lastname: Cho
authors.forename: Sung Yong
authors.initials: SY
authors.lastname: Seol
mesh_terms: D000668:Ampicillin Resistance / Q000235:genetics*; D000890:Anti-Infective Agents / Q000494:pharmacology*; D015139:Blotting, Southern; D027081:DNA Gyrase / Q000235:genetics / Q000378:metabolism; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics; D024881:Drug Resistance, Bacterial; D004405:Dysentery, Bacillary / Q000453:epidemiology* / Q000382:microbiology*; D006801:Humans; D007723:Korea / Q000453:epidemiology; D008826:Microbial Sensitivity Tests; D009268:Nalidixic Acid / Q000494:pharmacology*; D010957:Plasmids / Q000235:genetics; D012150:Polymorphism, Restriction Fragment Length; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012764:Shigella sonnei / Q000187:drug effects* / Q000235:genetics; D001618:beta-Lactamases / Q000235:genetics / Q000378:metabolism*
chemical_list: D000890:Anti-Infective Agents; D004269:DNA, Bacterial; D009268:Nalidixic Acid; C445691:TEM-52 beta-lactamase; D001618:beta-Lactamases; C034413:beta-lactamase TEM-1; D027081:DNA Gyrase