title: Endocarditis caused by extended-spectrum-beta-lactamase-producing Klebsiella pneumoniae: emergence of resistance to ciprofloxacin and piperacillin-tazobactam during treatment despite initial susceptibility.
abstract: Three episodes of bacteremia occurred in the course of prosthetic valve endocarditis caused by an extended-spectrum-beta-lactamase (ESBL)-producing Klebsiella pneumoniae strain. The second isolate developed resistance to ciprofloxacin and the third isolate to piperacillin-tazobactam (PIP-TZ) following sequential therapy with each agent. The first isolate was resistant to PIP-TZ only at high inocula, the second isolate acquired increased transcription of the acrA gene, and the third isolate became resistant to PIP-TZ due to loss of beta-lactamase inhibition by TZ. We question if and how PIP-TZ susceptibility should be reported for ESBL-producing Enterobacteriaceae.
authors.affiliation: Division of Infectious Diseases, Kaplan Medical Center Rehovot, Hebrew University and Hadassah, Jerusalem, Israel. oren_z@clalit.org.il
authors.forename: Oren
authors.initials: O
authors.lastname: Zimhony
authors.forename: Inna
authors.initials: I
authors.lastname: Chmelnitsky
authors.forename: Rita
authors.initials: R
authors.lastname: Bardenstein
authors.forename: Sorel
authors.initials: S
authors.lastname: Goland
authors.forename: Orly
authors.initials: O
authors.lastname: Hammer Muntz
authors.forename: Shiri
authors.initials: S
authors.lastname: Navon Venezia
authors.forename: Yehuda
authors.initials: Y
authors.lastname: Carmeli
mesh_terms: D002939:Ciprofloxacin / Q000494:pharmacology / Q000627:therapeutic use*; D024901:Drug Resistance, Multiple, Bacterial; D004697:Endocarditis, Bacterial / Q000188:drug therapy* / Q000382:microbiology; D005260:Female; D006350:Heart Valve Prosthesis / Q000382:microbiology; D006801:Humans; D007710:Klebsiella Infections / Q000188:drug therapy* / Q000382:microbiology; D007711:Klebsiella pneumoniae / Q000187:drug effects* / Q000201:enzymology / Q000235:genetics / Q000302:isolation & purification; D000077731:Meropenem; D008875:Middle Aged; D010397:Penicillanic Acid / Q000031:analogs & derivatives / Q000494:pharmacology / Q000627:therapeutic use; D010878:Piperacillin / Q000494:pharmacology / Q000627:therapeutic use; D000077725:Piperacillin, Tazobactam Drug Combination; D016459:Prosthesis-Related Infections / Q000188:drug therapy / Q000382:microbiology; D013845:Thienamycins / Q000627:therapeutic use; D001618:beta-Lactamases / Q000096:biosynthesis* / Q000378:metabolism
chemical_list: D013845:Thienamycins; D000077725:Piperacillin, Tazobactam Drug Combination; D002939:Ciprofloxacin; D010397:Penicillanic Acid; D001618:beta-Lactamases; D000077731:Meropenem; D010878:Piperacillin