title: Identification of a novel cephalosporinase (DHA-3) in Klebsiella pneumoniae isolated in Taiwan.
abstract: A strain of Klebsiella pneumoniae resistant to cefoxitin and oxyimino-cephalosporins, but susceptible to cefepime, was isolated from an adult patient hospitalised in Taichung, Taiwan. Isoelectric focusing revealed three beta-lactamases with isoelectric points of 5.4, 8.2 and 7.9, respectively. Following PCR with plasmid DNA templates and gene sequencing, these enzymes were shown to correspond to TEM-1, SHV-5 and a novel DHA-1-like enzyme (designated DHA-3). The bla genes for TEM-1 and SHV-5 were transferable, but the bla(DHA-3) gene was non-self-transferable in conjugation experiments. All three bla genes were successfully introduced by electrotransformation into an Escherichia coli recipient (DH5alpha), resulting in a similar resistance profile to that observed in the original donor strain. Other K. pneumoniae strains producing DHA-1-like enzymes have been identified previously in Taiwan, and this report suggests that DHA-type beta-lactamases are continuing to emerge in this country.
authors.affiliation: Institute of Medical Science and Department of Microbiology, China Medical University, Taiwan.
authors.forename: L-T
authors.initials: LT
authors.lastname: Wu
authors.forename: S-W
authors.initials: SW
authors.lastname: Hung
authors.forename: Y-C
authors.initials: YC
authors.lastname: Chuang
authors.forename: H-E
authors.initials: HE
authors.lastname: Chen
authors.forename: R N
authors.initials: RN
authors.lastname: Jones
authors.forename: W-L
authors.initials: WL
authors.lastname: Yu
mesh_terms: D000328:Adult; D000595:Amino Acid Sequence; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D001426:Bacterial Proteins / Q000032:analysis / Q000302:isolation & purification; D002440:Cefoxitin / Q000494:pharmacology; D002510:Cephalosporinase / Q000032:analysis* / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification; D003227:Conjugation, Genetic; D024881:Drug Resistance, Bacterial; D004926:Escherichia coli / Q000187:drug effects / Q000235:genetics; D022761:Gene Transfer, Horizontal; D005798:Genes, Bacterial; D006801:Humans; D007526:Isoelectric Point; D007710:Klebsiella Infections / Q000382:microbiology*; D007711:Klebsiella pneumoniae / Q000201:enzymology* / Q000302:isolation & purification; D008969:Molecular Sequence Data; D010957:Plasmids; D016133:Polymerase Chain Reaction; D017422:Sequence Analysis, DNA; D013624:Taiwan
chemical_list: D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins; D002440:Cefoxitin; D002510:Cephalosporinase