title: National surveillance on vancomycin-resistant Enterococcus faecium in Taiwan: emergence and widespread of ST414 and a Tn1546-like element with simultaneous insertion of IS1251-like and IS1678.
abstract: Cases of bacteremia caused by vancomycin-resistant E. faecium (VRE-fm) increased significantly in Taiwan. The present multicenter surveillance study was performed to reveal the associated epidemiological characteristics. In 2012, 134 non-repetitive VRE-fm isolates were prospectively collected from 12 hospitals in Taiwan. Antimicrobial susceptibility, pulsed-field gel electrophoresis (PFGE), multilocus sequence typing (MLST), and analysis of van genes and Tn1546 structures were investigated. Two isolates carried vanB genes, while all the remaining isolates carried vanA genes. Three isolates demonstrated a specific vanA genotype - vanB phenotype. Nine (6.7%) isolates demonstrated tigecycline resistance, and all were susceptible to daptomycin and linezolid. Molecular typing revealed 58 pulsotypes and 13 sequence types (STs), all belonged to three major lineages 17, 18, and 78. The most frequent STs were ST17 (n = 48, 35.8%), ST414 (n = 22, 16.4%), and ST78 (n = 16, 11.9%). Among the vanA harboring isolates, eight structure types of the Tn1546-like element were demonstrated. Type I (a partial deletion in the orf1 and insertion of IS1251-like between the vanS - vanH genes) and Type II (Type I with an additional insertion of IS1678 between orf2 - vanS genes) were the most predominant, consisted of 60 (45.5%) and 62 (47.0%) isolates, respectively. The increase of VRE-fm bacteremia in Taiwan may be associated with the inter- and intra-hospital spread of some major STs and horizontal transfer of vanA genes mostly carried on two efficient Tn1546-like elements. The prevailing ST414 and widespread of the Type II Tn1546-like elements are an emerging problem that requires continuous monitoring.
authors.affiliation: Department of Laboratory Medicine, Chang Gung Memorial Hospital, Linkou, Taoyuan, Taiwan, ROC; Department of Medical Biotechnology and Laboratory Science, College of Medicine, Chang Gung University, Taoyuan, Taiwan, ROC.
authors.forename: An-Jing
authors.initials: AJ
authors.lastname: Kuo
authors.affiliation: Department of Laboratory Medicine, Chang Gung Memorial Hospital, Linkou, Taoyuan, Taiwan, ROC; Department of Medical Biotechnology and Laboratory Science, College of Medicine, Chang Gung University, Taoyuan, Taiwan, ROC.
authors.forename: Lin-Hui
authors.initials: LH
authors.lastname: Su
authors.affiliation: Department of Medical Biotechnology and Laboratory Science, College of Medicine, Chang Gung University, Taoyuan, Taiwan, ROC; Research Center for Pathogenic Bacteria, Chang Gung University, Taoyuan, Taiwan, ROC.
authors.forename: Jwu-Ching
authors.initials: JC
authors.lastname: Shu
authors.affiliation: Division of Infectious Diseases, Department of Medicine, National Taiwan University Hospital, Taipei, Taiwan, ROC.
authors.forename: Jann-Tay
authors.initials: JT
authors.lastname: Wang
authors.affiliation: Division of Infectious Diseases, Department of Internal Medicine, China Medical University Hospital, Taichung, Taiwan, ROC.
authors.forename: Jen-Hsien
authors.initials: JH
authors.lastname: Wang
authors.affiliation: Section of Infectious Diseases, Department of Medicine, Taipei Veterans General Hospital, National Yan-Ming University, Taipei, Taiwan, ROC.
authors.forename: Chang-Phone
authors.initials: CP
authors.lastname: Fung
authors.affiliation: Department of Laboratory Medicine, Chang Gung Memorial Hospital, Linkou, Taoyuan, Taiwan, ROC; Department of Medical Biotechnology and Laboratory Science, College of Medicine, Chang Gung University, Taoyuan, Taiwan, ROC.
authors.forename: Ju-Hsin
authors.initials: JH
authors.lastname: Chia
authors.affiliation: Department of Laboratory Medicine, Chang Gung Memorial Hospital, Linkou, Taoyuan, Taiwan, ROC; Department of Medical Biotechnology and Laboratory Science, College of Medicine, Chang Gung University, Taoyuan, Taiwan, ROC.
authors.forename: Jang-Jih
authors.initials: JJ
authors.lastname: Lu
authors.affiliation: Department of Laboratory Medicine, Chang Gung Memorial Hospital, Linkou, Taoyuan, Taiwan, ROC; Department of Medical Biotechnology and Laboratory Science, College of Medicine, Chang Gung University, Taoyuan, Taiwan, ROC.
authors.forename: Tsu-Lan
authors.initials: TL
authors.lastname: Wu
mesh_terms: D016470:Bacteremia / Q000453:epidemiology / Q000235:genetics / Q000378:metabolism; D001426:Bacterial Proteins / Q000235:genetics; D019729:Carbon-Oxygen Ligases / Q000235:genetics; D004251:DNA Transposable Elements; D016984:Enterococcus faecium / Q000235:genetics / Q000302:isolation & purification / Q000472:pathogenicity; D005260:Female; D016908:Gram-Positive Bacterial Infections / Q000453:epidemiology / Q000235:genetics / Q000382:microbiology; D006801:Humans; D008297:Male; D013624:Taiwan / Q000453:epidemiology; D065507:Vancomycin-Resistant Enterococci / Q000235:genetics / Q000302:isolation & purification / Q000472:pathogenicity
chemical_list: D001426:Bacterial Proteins; D004251:DNA Transposable Elements; C071437:VanA ligase, Bacteria; C079913:VanB protein, Enterococcus; D019729:Carbon-Oxygen Ligases