Antibiotic resistance genes show enhanced mobilization through suspended growth and biofilm-based wastewater treatment processes

Morgan Petrovich, Binh Chu, Dorothy Wright, Jim Griffin, Maryam Elfeki, Brian T. Murphy, Rachel Poretsky, George Wells*

*Corresponding author for this work

Research output: Contribution to journalArticle

13 Scopus citations

Abstract

Wastewater treatment plants (WWTPs) are known to harbor antibiotic resistance genes (ARGs) that are disseminated into the environment via effluent. However, few studies have compared abundance, mobilization and selective pressures for ARGs in WWTPs as a function of variations in secondary treatment bioprocesses. We used shotgun metagenomics to provide a comprehensive analysis of ARG composition, relationship to mobile genetic elements and co-occurrences with antibiotic production genes (APGs) throughout two full-scale municipal WWTPs, one of which employs biofilm-based secondary treatment and another that uses a suspended growth system. Results showed that abundances of ARGs declined by over 90% per genome equivalent in both types of wastewater treatment processes. However, the fractions of ARGs associated with mobile genetic elements increased substantially between influent and effluent in each plant, indicating significant mobilization of ARGs throughout both treatment processes. Strong positive correlations between ARGs and APGs were found for the aminoglycoside antibiotic class in the suspended growth system and for the streptogramin antibiotic class in the biofilm system. The biofilm and suspended growth WWTPs exhibited similarities in ARG abundances, composition and mobilization trends. However, clear differences were observed for within-plant ARG persistence. These findings suggest that both biofilm and suspended growth-based WWTPs may promote genetic mobilization of persistent ARGs that are then disseminated in effluent to receiving water bodies.

Original languageEnglish (US)
Article numberfiy041
JournalFEMS microbiology ecology
Volume94
Issue number5
DOIs
StatePublished - May 1 2018

Keywords

  • Activated sludge
  • Antibiotic production
  • Antibiotic resistance
  • Biofilm
  • Mobile genetic elements
  • Wastewater

ASJC Scopus subject areas

  • Microbiology
  • Ecology
  • Applied Microbiology and Biotechnology

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