title: Characterisation of fosfomycin resistance mechanisms and molecular epidemiology in extended-spectrum β-lactamase-producing Klebsiella pneumoniae isolates.
abstract: Although fosfomycin is a treatment option for infections caused by extended-spectrum β-lactamase (ESBL)-producing Enterobacteriaceae, fosfomycin resistance has been documented. To our knowledge, fosfomycin resistance mechanisms in Klebsiella pneumoniae have not been systematically investigated. A total of 108 ESBL-producing K. pneumoniae isolates collected from Kaohsiung Medical University Hospital, Taiwan, from August 2012 to May 2013 were analysed in this study. Pulsed-field gel electrophoresis (PFGE) revealed 64 pulsotypes and six non-typeable isolates, indicating high genetic diversity. Moreover, pulsotypes V (n = 6), VII (n = 11) and LI (n = 4) belonging to ST11 were major types. Among 30 (27.8%) fosfomycin-non-susceptible isolates, 21 (70%) had a MurA amino acid substitution, and seven new variations increased the fosfomycin minimum inhibitory concentration (MIC) by 8- to 16-fold compared with wild-type MurA in Escherichia coli DH5α.strain. Functionless transporters (GlpT and UhpT) with various mutations were found in 29 isolates (97%). No known fosfomycin-modifying enzymes were detected in this study. The major resistance mechanisms to fosfomycin in K. pneumoniae were amino acid variations in the drug target and transporters.
authors.affiliation: Department of Laboratory Medicine, Kaohsiung Medical University Chung-Ho Memorial Hospital, Kaohsiung, Taiwan; College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan; Department of Internal Medicine, Kaohsiung Medical University Hospital, Kaohsiung, Taiwan.
authors.forename: Po-Liang
authors.initials: PL
authors.lastname: Lu
authors.affiliation: Department of Medical Imaging and Radiological Sciences, Kaohsiung Medical University, Kaohsiung, Taiwan.
authors.forename: Ya-Ju
authors.initials: YJ
authors.lastname: Hsieh
authors.affiliation: Department of Medical Laboratory Science and Biotechnology, College of Health Sciences, Kaohsiung Medical University, Kaohsiung, Taiwan.
authors.forename: Jun-En
authors.initials: JE
authors.lastname: Lin
authors.affiliation: Department of Medical Laboratory Science and Biotechnology, College of Health Sciences, Kaohsiung Medical University, Kaohsiung, Taiwan.
authors.forename: Jun-Wei
authors.initials: JW
authors.lastname: Huang
authors.affiliation: Department of Medical Laboratory Science and Biotechnology, College of Health Sciences, Kaohsiung Medical University, Kaohsiung, Taiwan.
authors.forename: Tsung-Ying
authors.initials: TY
authors.lastname: Yang
authors.affiliation: Department of Culinary Art, I-Shou University, Kaohsiung, Taiwan.
authors.forename: Lin
authors.initials: L
authors.lastname: Lin
authors.affiliation: Department of Medical Laboratory Science and Biotechnology, College of Health Sciences, Kaohsiung Medical University, Kaohsiung, Taiwan; Department of Marine Biotechnology and Resources, National Sun Yat-sen University, Kaohsiung, Taiwan. Electronic address: tsengsp@kmu.edu.tw.
authors.forename: Sung-Pin
authors.initials: SP
authors.lastname: Tseng
mesh_terms: D019883:Alkyl and Aryl Transferases / Q000235:genetics; D019943:Amino Acid Substitution; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D016521:Electrophoresis, Gel, Pulsed-Field; D004926:Escherichia coli / Q000187:drug effects / Q000235:genetics; D005578:Fosfomycin / Q000494:pharmacology*; D015870:Gene Expression; D014644:Genetic Variation; D006801:Humans; D007710:Klebsiella Infections / Q000382:microbiology*; D007711:Klebsiella pneumoniae / Q000145:classification* / Q000187:drug effects* / Q000235:genetics / Q000302:isolation & purification; D026901:Membrane Transport Proteins / Q000235:genetics; D008826:Microbial Sensitivity Tests; D017720:Molecular Epidemiology; D058889:Molecular Typing; D013624:Taiwan; D001618:beta-Lactamases / Q000378:metabolism*
chemical_list: D000900:Anti-Bacterial Agents; D026901:Membrane Transport Proteins; D005578:Fosfomycin; D019883:Alkyl and Aryl Transferases; C022566:UDP-N-acetylglucosamine 1-carboxyvinyltransferase; D001618:beta-Lactamases
keywords: Fosfomycin resistance mechanism; Transporters; glpT; murA; uhpT