title: tet genes as indicators of changes in the water environment: relationships between culture-dependent and culture-independent approaches.
abstract: The aim of this study was to identify tetracycline resistance determinants that could be used as molecular indicators of anthropogenic changes in aquatic environments. Two parallel approaches were used to examine the prevalence of tet genes: a culture-based method involving standard PCR and a method relying on quantitative PCR. The studied site was the Łyna River in Olsztyn (Poland). The culture-dependent method revealed that the concentrations of doxycycline-resistant bacteria harboring the tet(B) gene were higher in wastewater and downstream river samples than in upstream water samples. The tet(B) gene was transferred from environmental bacteria to Escherichia coli. The results generated by the culture-independent method validated statistically significant differences in tet(B) concentrations between upstream and downstream river sections, and revealed that tet(B) levels were correlated with the presence of other tetracycline resistance genes, dissolved oxygen concentrations, temperature and doxycycline concentrations in water. Our findings indicate that doxycycline-resistant bacteria, in particular E. coli harboring tet(B) or increased concentrations of tet(B), are potentially robust indicators of changes in water environments.
authors.affiliation: Department of Environmental Microbiology, University of Warmia and Mazury in Olsztyn, Prawocheńskiego 1, 10-957 Olsztyn, Poland. Electronic address: monika.harnisz@uwm.edu.pl.
authors.forename: Monika
authors.initials: M
authors.lastname: Harnisz
authors.affiliation: Department of Environmental Microbiology, University of Warmia and Mazury in Olsztyn, Prawocheńskiego 1, 10-957 Olsztyn, Poland.
authors.forename: Ewa
authors.initials: E
authors.lastname: Korzeniewska
authors.affiliation: Department of Environmental Biotechnology, University of Warmia and Mazury in Olsztyn, Słoneczna 45G, 10-957 Olsztyn, Poland.
authors.forename: Sławomir
authors.initials: S
authors.lastname: Ciesielski
authors.affiliation: Department of Environmental Microbiology, University of Warmia and Mazury in Olsztyn, Prawocheńskiego 1, 10-957 Olsztyn, Poland.
authors.forename: Iwona
authors.initials: I
authors.lastname: Gołaś
mesh_terms: D001419:Bacteria / Q000235:genetics* / Q000254:growth & development; D004784:Environmental Monitoring / Q000379:methods*; D005798:Genes, Bacterial; D008826:Microbial Sensitivity Tests; D011044:Poland; D013753:Tetracycline Resistance / Q000235:genetics*; D062065:Wastewater; D014871:Water Microbiology; D014876:Water Pollution / Q000032:analysis*
chemical_list: D062065:Wastewater
keywords: Antibiotics; Bacteria; Genes; Resistance; River; Tetracyclines; Wastewater