title: Molecular characterization of vancomycin-resistant Enterococcus spp. clinical isolates recovered from hospitalized patients among several medical institutions in China.
abstract: The epidemiology and molecular characteristics of vancomycin-resistant enterococci (VRE) from China deserve further investigation. This study reports on the molecular characterization of 101 unique VRE (96 E. faecium and 5 E. faecalis strains) recovered from diverse samples of 12 hospitals in China. MIC results were obtained by reference broth microdilution methods, and vancomycin resistance and virulence genes were screened by polymerase chain reaction. All strains were subjected to pulsed-field gel electrophoresis (PFGE) and multilocus sequence typing. E. faecalis exhibited vancomycin and teicoplanin MIC results at ≥256 μg/mL and harbored vanA, except for 1 vanB-carrying strain (MIC, 32 and 1 μg/mL, respectively). This strain had a unique PFGE pattern and was associated with ST410 (clonal complex [CC]4). E. faecium displayed vancomycin MIC values of ≥256 μg/mL with variable results for teicoplanin (1-256 μg/mL). One E. faecium had a teicoplanin MIC value of 1 μg/mL and carried a vanB, while the other 2 strains had teicoplanin MIC values of 4 and 8 μg/mL and harbored vanA. E. faecalis strains were susceptible to ampicillin, and all VRE displayed a susceptible phenotype to daptomycin, linezolid, and tigecycline. Four E. faecalis from a particular hospital were grouped within a single PFGE type and were associated with ST470 and ST471 (CC4), which are double- and triple-locus variants of ST410 and ST4, respectively. Overall, E. faecium displayed genetic variability, but clonal dissemination was noted within and among hospitals. All E. faecium belonged to STs associated with CC17, except for 1 strain (ST362; CC362). A total of 77.2% and 29.7% of all strains carried esp and hyl, respectively. In conclusion, these results show that vanA-carrying isolates predominated in strains from China, and E. faecium strains are usually associated with a common and human-adapted lineage (CC17). Unlike the majority of clinical E. faecalis (CC2 and CC9), strains included in this study showed ST profiles similar to ST4 (CC4), which has been associated with human infections in other Asia-Pacific countries.
authors.affiliation: Peking Union Medical College Hospital, Chinese Academy of Medical Sciences, Beijing, China.
authors.forename: Hongli
authors.initials: H
authors.lastname: Sun
authors.forename: Hui
authors.initials: H
authors.lastname: Wang
authors.forename: Yingchun
authors.initials: Y
authors.lastname: Xu
authors.forename: Ronald N
authors.initials: RN
authors.lastname: Jones
authors.forename: Andrew J
authors.initials: AJ
authors.lastname: Costello
authors.forename: Yali
authors.initials: Y
authors.lastname: Liu
authors.forename: Gang
authors.initials: G
authors.lastname: Li
authors.forename: Minjun
authors.initials: M
authors.lastname: Chen
authors.forename: Rodrigo E
authors.initials: RE
authors.lastname: Mendes
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology; D002681:China / Q000453:epidemiology; D016000:Cluster Analysis; D004269:DNA, Bacterial / Q000235:genetics; D016521:Electrophoresis, Gel, Pulsed-Field; D013293:Enterococcus faecalis / Q000145:classification / Q000187:drug effects* / Q000235:genetics / Q000302:isolation & purification*; D016984:Enterococcus faecium / Q000145:classification / Q000187:drug effects* / Q000235:genetics / Q000302:isolation & purification*; D005798:Genes, Bacterial; D014644:Genetic Variation; D005838:Genotype; D016908:Gram-Positive Bacterial Infections / Q000453:epidemiology / Q000382:microbiology*; D006760:Hospitalization; D006801:Humans; D008826:Microbial Sensitivity Tests; D017720:Molecular Epidemiology; D058889:Molecular Typing; D016133:Polymerase Chain Reaction; D017334:Teicoplanin / Q000494:pharmacology; D014640:Vancomycin / Q000494:pharmacology; D020713:Vancomycin Resistance
chemical_list: D000900:Anti-Bacterial Agents; D004269:DNA, Bacterial; D017334:Teicoplanin; D014640:Vancomycin