title: Nosocomial infection caused by vancomycin-susceptible multidrug-resistant Enterococcus faecalis over a long period in a university hospital in Japan.
abstract: Compared with other developed countries, vancomycin-resistant enterococci (VRE) are not widespread in clinical environments in Japan. There have been no VRE outbreaks and only a few VRE strains have sporadically been isolated in our university hospital in Gunma, Japan. To examine the drug susceptibility of Enterococcus faecalis and nosocomial infection caused by non-VRE strains, a retrospective surveillance was conducted in our university hospital. Molecular epidemiological analyses were performed on 1711 E. faecalis clinical isolates collected in our hospital over a 6-year period [1998-2003]. Of these isolates, 1241 (72.5%) were antibiotic resistant and 881 (51.5%) were resistant to two or more drugs. The incidence of multidrug resistant E. faecalis (MDR-Ef) isolates in the intensive care unit increased after enlargement and restructuring of the hospital. The major group of MDR-Ef strains consisted of 209 isolates (12.2%) resistant to the five drug combination tetracycline/erythromycin/kanamycin/streptomycin/gentamicin. Pulsed-field gel electrophoresis analysis of the major MDR-Ef isolates showed that nosocomial infections have been caused by MDR-Ef over a long period (more than 3 years). Multilocus sequence typing showed that these strains were mainly grouped into ST16 (CC58) or ST64 (CC8). Mating experiments suggested that the drug resistances were encoded on two conjugative transposons (integrative conjugative elements), one encoded tetracycline-resistance and the other erythromycin/kanamycin/streptomycin/gentamicin-resistance. To our knowledge, this is the first report of nosocomial infection caused by vancomycin-susceptible MDR-Ef strains over a long period in Japan.
authors.affiliation: Department of General Surgical Science (Surgery I); Department of Bacteriology.
authors.forename: Michiaki
authors.initials: M
authors.lastname: Kudo
authors.forename: Takahiro
authors.initials: T
authors.lastname: Nomura
authors.forename: Sachie
authors.initials: S
authors.lastname: Yomoda
authors.forename: Koichi
authors.initials: K
authors.lastname: Tanimoto
authors.forename: Haruyoshi
authors.initials: H
authors.lastname: Tomita
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D003227:Conjugation, Genetic; D003428:Cross Infection / Q000453:epidemiology* / Q000382:microbiology; D024901:Drug Resistance, Multiple, Bacterial; D016521:Electrophoresis, Gel, Pulsed-Field; D013293:Enterococcus faecalis / Q000145:classification / Q000187:drug effects* / Q000235:genetics / Q000302:isolation & purification*; D005838:Genotype; D016908:Gram-Positive Bacterial Infections / Q000453:epidemiology* / Q000382:microbiology; D006785:Hospitals, University; D006801:Humans; D007564:Japan / Q000453:epidemiology; D008826:Microbial Sensitivity Tests; D017720:Molecular Epidemiology; D058885:Multilocus Sequence Typing; D010957:Plasmids / Q000032:analysis; D012189:Retrospective Studies; D014640:Vancomycin / Q000494:pharmacology*
chemical_list: D000900:Anti-Bacterial Agents; D014640:Vancomycin
keywords: Enterococcus faecalis; multidrug resistance; non-vancomycin-resistant enterococci; nosocomial infection