title: Influence of tetracycline on the microbial community composition and activity of nitrifying biofilms.
abstract: The present work aims to evaluate the bacterial composition and activity (carbon and nitrogen removal) of nitrifying biofilms exposed to 50 μg L(-1) of tetracycline. The tetracycline removal efficiency and the occurrence of tetracycline resistance (tet) genes were also studied. Two sequencing batch biofilm reactors (SBBRs) fed with synthetic wastewater were operated without (SBBR1) and with (SBBR2) the antibiotic. Both SBBRs showed similar organic matter biodegradation and nitrification activity. Tetracycline removal was about 28% and biodegradation was probably the principal removal mechanism of the antibiotic. Polymerase chain reaction-denaturing gradient gel electrophoresis analysis of the bacterial community showed shifts leading to not only the fading of some ribotypes, but also the emergence of new ones in the biofilm with tetracycline. The study of the tet genes showed that tet(S) was only detected in the biofilm with tetracycline, suggesting a relationship between its occurrence and the presence of the antibiotic.
authors.affiliation: CEB - Centre of Biological Engineering, University of Minho, Campus de Gualtar, 4710-057 Braga, Portugal. Electronic address: mariaines.matos@deb.uminho.pt.
authors.forename: Maria
authors.initials: M
authors.lastname: Matos
authors.affiliation: CEB - Centre of Biological Engineering, University of Minho, Campus de Gualtar, 4710-057 Braga, Portugal.
authors.forename: Maria A
authors.initials: MA
authors.lastname: Pereira
authors.affiliation: Centre of Chemistry, University of Minho, Campus de Gualtar, 4710-057 Braga, Portugal.
authors.forename: Pier
authors.initials: P
authors.lastname: Parpot
authors.affiliation: CEB - Centre of Biological Engineering, University of Minho, Campus de Gualtar, 4710-057 Braga, Portugal; Institute of Agronomy, Department of Biosystems Sciences and Engineering, University of Lisbon, Tapada da ajuda, 1349-017 Lisboa, Portugal.
authors.forename: António G
authors.initials: AG
authors.lastname: Brito
authors.affiliation: ISAH - Institute of Sanitary Engineering and Waste Management, University of Hannover, Welfengarten 1, D-30167 Hannover, Germany.
authors.forename: Regina
authors.initials: R
authors.lastname: Nogueira
mesh_terms: D000327:Adsorption; D000900:Anti-Bacterial Agents / Q000378:metabolism / Q000494:pharmacology*; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D018441:Biofilms / Q000187:drug effects*; D064307:Microbiota / Q000187:drug effects* / Q000502:physiology*; D008969:Molecular Sequence Data; D058465:Nitrification / Q000187:drug effects; D011108:Polymers / Q000378:metabolism; D017422:Sequence Analysis, DNA; D013752:Tetracycline / Q000378:metabolism / Q000494:pharmacology*; D013753:Tetracycline Resistance
chemical_list: D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins; D011108:Polymers; D013752:Tetracycline
keywords: Antibiotics; Bacterial community; Nitrifying biofilms; Resistance genes; Tetracycline removal