title: Microbiological contamination and resistance genes in biofilms occurring during the drinking water treatment process.
abstract: Biofilms are the predominant mode of microbial growth in drinking water systems. A dynamic exchange of individuals occurs between the attached and planktonic populations, while lateral gene transfer mediates genetic exchange in these bacterial communities. Integrons are important vectors for the spread of antimicrobial resistance. The presence of class 1 integrons (intI1, qac and sul genes) was assessed in biofilms occurring throughout the drinking water treatment process. Isolates from general and specific culture media, covering a wide range of environmental bacteria, fecal indicators and opportunistic pathogens were tested. From 96 isolates tested, 9.37% were found to possess genetic determinants of putative antimicrobial resistance, and these occurred in both Gram-positive and Gram-negative bacteria. Class 1 integron integrase gene was present in 8.33% of bacteria, all positive for the qacEΔ1 gene. The sul1 gene was present in 3.12% of total isolates, representing 37.5% of the class 1 integron positive cells. The present study shows that biofilm communities in a drinking water treatment plant are a reservoir of class 1 integrons, mainly in bacteria that may be associated with microbiological contamination. Eight out of nine integron bearing strains (88.8%) were identified based on 16S rRNA gene sequencing as either enteric bacteria or species that may be connected to animal and anthropogenic disturbance.
authors.affiliation: Someş Water Company, 79 21 December 1989 Boulevard, 400604 Cluj-Napoca, Romania. farkasanca@yahoo.com
authors.forename: Anca
authors.initials: A
authors.lastname: Farkas
authors.forename: Anca
authors.initials: A
authors.lastname: Butiuc-Keul
authors.forename: Dorin
authors.initials: D
authors.lastname: Ciatarâş
authors.forename: Călin
authors.initials: C
authors.lastname: Neamţu
authors.forename: Cornelia
authors.initials: C
authors.lastname: Crăciunaş
authors.forename: Dorina
authors.initials: D
authors.lastname: Podar
authors.forename: Mihail
authors.initials: M
authors.lastname: Drăgan-Bularda
mesh_terms: D001419:Bacteria / Q000235:genetics; D018441:Biofilms; D060766:Drinking Water / Q000382:microbiology*; D004352:Drug Resistance, Microbial / Q000235:genetics*; D022761:Gene Transfer, Horizontal; D032023:Integrons; D016133:Polymerase Chain Reaction; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D014871:Water Microbiology
chemical_list: D060766:Drinking Water; D012336:RNA, Ribosomal, 16S