The occurrence of specific markers of Bacteroides fragilis group, B. dorei and antibiotic-resistance genes in the wastewater treatment plants

Sebastian Niestępski,Monika Harnisz,Adriana Osińska,Ewa Korzeniewska

doi:10.1051/e3sconf/20184400124

Sebastian Niestępski, Monika Harnisz + Show 2 more

Open Access

https://doi.org/10.1051/e3sconf/20184400124

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Abstract

Wastewater treatment plants (WWTPs) are one of the main transmission sources of pathogenic bacteria and antibiotic-resistance genes in the natural environment. In this study, the presence of specific markers of Bacteroides fragilis group (BFG), B. dorei and genes encoding resistance to beta-lactams (cepA, cfxA), tetracyclines (tet(Q)), macrolides, lincosamides and streptogramins (MLS) mechanism (ermF, linA) was analyzed by standard PCR in the inflows and outflows from three wastewater treatment plants with the activated sludge process. Genetic material was isolated from wastewater samples with the use of two commercial kits for genomic DNA extraction, the Fast DNA SPIN Kit for Soil and the Genomic Micro AX Bacteria Gravity Kit. The quality of the isolated genetic material differed between the tested isolation kits. The Fast DNA SPIN Kit for Soil was more effective in detecting cfxA, ermF and linA genes. However, both extraction kits effectively identified tet(Q), bfr and HF183/BacR287 genes in all wastewater samples. The results of the study indicate that genes specific to BFG and B. dorei, and genes encoding resistance to MLS and tetracyclines are not completely eliminated during the wastewater treatment process.

Highlights

The anaerobic bacteria of the genus Bacteroides naturally colonize the human and animal digestive tracts [1]
All of the analyzed antibiotic-resistance genes are specific to Bacteroides fragilis group (BFG), including B. dorei
The presence of the 16S rRNA gene specific to BFG and B. dorei (HF183/BacR287) was determined in all wastewater samples analyzed with both DNA extraction kits

Summary

Introduction

The anaerobic bacteria of the genus Bacteroides naturally colonize the human and animal digestive tracts [1]. The genus Bacteroides comprises 38 potentially pathogenic species of bacteria, including B. dorei, a member of the Bacteroides fragilis group (BFG) [2]. This bacterial group is characterized by high levels of drug resistance. Bacteroides spp., including BFG, are excreted in feces and evacuated via sewers to wastewater treatment plants (WWTPs). These microorganisms contain catalase, an enzyme which enables bacteria to survive wastewater treatment processes, including aeration. The presence of BFG in the natural environment testifies to fecal contamination.

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