title: Conjugative resistance to tazobactam plus piperacillin among extended-spectrum beta-lactamase-producing nosocomial Klebsiella pneumoniae.
abstract: We studied the genetic origins of piperacillin-tazobactam resistance among nosocomial Klebsiella pneumoniae strains. A total of 30 nosocomial isolates resistant to piperacillin-tazobactam were obtained from various regions of Turkey. Isoelectric focusing demonstrated at least 2 enzymes common to all strains: I at a pI of 8.0 and the other at 5.4. Piperacillin-tazobactam resistance was successfully transferred from all of the strains to Escherichia coli. Of the piperacillin-tazobactam-resistant transconjugates, 23 were also resistant to ceftazidime. However, 7 transconjugates were susceptible to ceftazidime but resistant to piperacillin-tazobactam, producing a single enzyme focusing at pI 5.4. Piperacillin resistance caused by this enzyme was reversed by clavulanate and by increased amounts of tazobactam, which indicates that this enzyme confers resistance due to its high amount. Sequence analysis revealed this enzyme to be TEM-1. This study demonstrates that transferable hyper-produced TEM-1 causes piperacillin-tazobactam resistance in Klebsiella strains in Turkish hospitals.
authors.affiliation: Kocaeli Universitesi Tip Fakültesi, Klinik Bakteriyoloji & Enfeksiyon Hastaliklari AD, Turkey.
authors.forename: S
authors.initials: S
authors.lastname: Akhan
authors.forename: F
authors.initials: F
authors.lastname: Coskunkan
authors.forename: O
authors.initials: O
authors.lastname: Tansel
authors.forename: H
authors.initials: H
authors.lastname: Vahaboglu
mesh_terms: D001483:Base Sequence; D003428:Cross Infection / Q000188:drug therapy; D004359:Drug Therapy, Combination / Q000494:pharmacology* / Q000627:therapeutic use; D004791:Enzyme Inhibitors / Q000494:pharmacology* / Q000627:therapeutic use; D006801:Humans; D007710:Klebsiella Infections / Q000188:drug therapy* / Q000201:enzymology; D007711:Klebsiella pneumoniae / Q000187:drug effects* / Q000201:enzymology / Q000235:genetics / Q000302:isolation & purification; D008969:Molecular Sequence Data; D010397:Penicillanic Acid / Q000031:analogs & derivatives* / Q000494:pharmacology* / Q000627:therapeutic use; D010406:Penicillins / Q000494:pharmacology* / Q000627:therapeutic use; D010878:Piperacillin / Q000494:pharmacology* / Q000627:therapeutic use; D016133:Polymerase Chain Reaction; D000078142:Tazobactam; D014421:Turkey; D018440:beta-Lactam Resistance; D001618:beta-Lactamases / Q000378:metabolism*
chemical_list: D004791:Enzyme Inhibitors; D010406:Penicillins; D010397:Penicillanic Acid; D001618:beta-Lactamases; D000078142:Tazobactam; D010878:Piperacillin