title: vanA Gene Harboring Enterococcal and Non-enterococcal Isolates Expressing High Level Vancomycin and Teicoplanin Resistance Reservoired in Surface Waters.
abstract: Untreated wastewaters and treated effluents even after final disinfection contain antibiotic resistant bacteria and resistance genes before they are released into surface waters. A correlation between resistant bacteria and antibiotics in surface waters has been found, as have antibiotic resistance genes. Of particular interest are vancomycin-resistant enterococci harboring vanA gene that confers high level of resistance to glycopeptide antibiotics including teicoplanin. Therefore, in this study, river water samples were analysed to investigate vancomycin- and teicoplanin-resistant bacterial isolates harboring vanA gene. Out of 290, 15 surface water isolates displayed resistance to both antibiotics. These glycopeptide resistant enterococcal and non-enterococcal isolates, identified by 16S rRNA sequencing, were found to harbor vanA gene with sequence similarities of 50 % to 100 %. The presence of D-alanine-D-lactate ligase encoded by vanA gene was also shown for all vancomycin- and teicoplanin-resistant isolates through western blot analysis. Due to reuse of treated wastewater and release of untreated wastewaters to water bodies, antibiotic resistant bacteria and resistance genes are being introduced into surface waters and present human health risks. Therefore, surface waters are not only hot spots for vanA harboring enterococcal isolates but also non-enterococcal isolates due to gene dissemination and require special scientific consideration.
authors: Department of Biotechnology, Middle East Technical University, 06800, Ankara, Turkey.
authors: Mustafa
authors: M
authors: Nakipoğlu
authors: Department of Environmental Engineering, Middle East Technical University, 06800, Ankara, Turkey.
authors: Fadime
authors: F
authors: Yilmaz
authors: Department of Biotechnology, Middle East Technical University, 06800, Ankara, Turkey. bicgen@metu.edu.tr.|Department of Environmental Engineering, Middle East Technical University, 06800, Ankara, Turkey. bicgen@metu.edu.tr.
authors: Bulent
authors: B
authors: Icgen
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics*; D019729:Carbon-Oxygen Ligases / Q000235:genetics*; D024901:Drug Resistance, Multiple, Bacterial; D016983:Enterococcus / Q000187:drug effects / Q000235:genetics*; D006801:Humans; D008826:Microbial Sensitivity Tests; D012336:RNA, Ribosomal, 16S / Q000302:isolation & purification; D017422:Sequence Analysis, DNA; D017334:Teicoplanin / Q000494:pharmacology*; D014640:Vancomycin / Q000494:pharmacology*; D014867:Water / Q000737:chemistry; D014871:Water Microbiology
chemical_list: D001426:Bacterial Proteins; D012336:RNA, Ribosomal, 16S; C071437:VanA ligase, Bacteria; D014867:Water; D017334:Teicoplanin; D014640:Vancomycin; D019729:Carbon-Oxygen Ligases
keywords: D-Alanine-D-lactate ligase; Glycopeptide resistance; Surface waters; Teicoplanin; VanA; Vancomycin