title: Clinical and molecular characterization of vancomycin-resistant Enterococcus faecium strains during establishment of endemicity.
abstract: To characterize the molecular epidemiology of vancomycin-resistant Enterococcus faecium (VREF) in Tennessee, VREF isolates that were recovered from patients during a 3-year period at a tertiary care center and throughout the state were typed by means of pulsed-field gel electrophoresis. Clinical characteristics and outcomes of patients colonized or infected with different strain types were also examined. A total of 34 different strain types were identified. A single VREF strain (type O) predominated (63 [61%] of 103 single-patient isolates (i.e., 1 isolate per patient) obtained from 7 different health care institutions). There were no significant differences between patients harboring type O strains and those harboring non-type O strains (P> or =.05). The rate of recovery of type O subtypes and strains other than type O increased over the 3-year study period. Establishment of VREF endemicity was initially characterized by clonal spread of type O strains. Subsequently, polyclonal dissemination may have been due to microevolutionary changes among type O strains.
authors.affiliation: Department of Medicine, Division of Infectious Diseases, Vanderbilt University School of Medicine, Medical Center North A-3310, 21st Ave. and Garland St., Nashville, TN 37232, USA. erika.d'agata@mcmail.vanderbilt.edu
authors.forename: E M
authors.initials: EM
authors.lastname: D'Agata
authors.forename: H
authors.initials: H
authors.lastname: Li
authors.forename: C
authors.initials: C
authors.lastname: Gouldin
authors.forename: Y W
authors.initials: YW
authors.lastname: Tang
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology; D015373:Bacterial Typing Techniques; D016000:Cluster Analysis; D016521:Electrophoresis, Gel, Pulsed-Field; D019353:Endemic Diseases; D016984:Enterococcus faecium / Q000145:classification* / Q000187:drug effects* / Q000235:genetics / Q000302:isolation & purification; D005260:Female; D016908:Gram-Positive Bacterial Infections / Q000453:epidemiology* / Q000382:microbiology / Q000503:physiopathology; D006801:Humans; D008297:Male; D008875:Middle Aged; D016133:Polymerase Chain Reaction; D013714:Tennessee / Q000453:epidemiology; D014640:Vancomycin / Q000494:pharmacology; D020713:Vancomycin Resistance / Q000235:genetics*
chemical_list: D000900:Anti-Bacterial Agents; D014640:Vancomycin