title: Identification of Enterococcus faecium and Enterococcus faecalis as vanC-type Vancomycin-Resistant Enterococci (VRE) from sewage and river water in the provincial city of Miyazaki, Japan.
abstract: As a first step for assessing the risk to human health posed by vancomycin-resistant enterococci (VRE) in the aquatic environment, we screened sewage and urban river water samples from Miyazaki, Japan for VRE. Because vancomycin-resistant organisms are not as prevalent in sewage and river water as vancomycin-susceptible organisms, the samples were screened by minimum inhibitory concentration test using the vancomycin-supplemented membrane-Enterococcus indoxyl-β-d-glucoside (mEI) agar. The isolates, presumed to be enterococci, were identified using 16S rRNA sequencing analysis. The percentages of VRE isolates screened using 4 μg mL(-1) vancomycin-supplemented mEI agar from sewage and urban river water samples were 12% and 24%, respectively. The vancomycin-resistant genes vanC1 and vanC2/3 were detected in the isolates from both samples by PCR analysis. All enterococci isolates containing vanC1, which is a specific gene for vanC-type of VRE, were identified as Enterococcus casseliflavus/gallinarum. Further, 92% enterococci isolates containing vanC2/3 were identified as E. casseliflavus/gallinarum, the remaining isolates containing vanC2/3 were E. faecium (4%) and E. faecalis (4%). Thereafter, the distribution of E. faecium and E. faecalis, which are the major types of enterococci in humans containing vanC2/3, was observed in the water samples collected.
authors.affiliation: a Department of Civil and Environmental Engineering, Faculty of Engineering , University of Miyazaki , Miyazaki , Japan.
authors.forename: Masateru
authors.initials: M
authors.lastname: Nishiyama
authors.forename: Atsushi
authors.initials: A
authors.lastname: Iguchi
authors.forename: Yoshihiro
authors.initials: Y
authors.lastname: Suzuki
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics*; D013293:Enterococcus faecalis / Q000187:drug effects / Q000235:genetics / Q000302:isolation & purification*; D016984:Enterococcus faecium / Q000187:drug effects / Q000235:genetics / Q000302:isolation & purification*; D004784:Environmental Monitoring; D006801:Humans; D007564:Japan; D008826:Microbial Sensitivity Tests; D012336:RNA, Ribosomal, 16S / Q000032:analysis; D045483:Rivers / Q000382:microbiology*; D012722:Sewage / Q000382:microbiology*; D014640:Vancomycin / Q000494:pharmacology; D065507:Vancomycin-Resistant Enterococci / Q000187:drug effects / Q000235:genetics / Q000302:isolation & purification*
chemical_list: D001426:Bacterial Proteins; D012336:RNA, Ribosomal, 16S; D012722:Sewage; C079914:VanC protein, Bacteria; D014640:Vancomycin
keywords: Antibiotic-resistance; Vancomycin-resistant enterococci; minimum inhibitory concentration; vancomycin-resistant genes; water environment