Browsing by Author "Teixeira, Ana Margarida Ribeiro"
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- Biomarkers for monitoring antibiotic resistance in aquatic environmentsPublication . Teixeira, Ana Margarida Ribeiro; Vaz-Moreira, Ivone; Calderón-Franco, David; Weissbrodt, David Gregory; Purkrtova, Sabina; Gajdos, S.; Dottorini, G.; Nielsen, Per Halkjær; Khalifa, Leron; Cytryn, Eddie; Bartacek, Jan; Manaia, CéliaThe occurrence of antimicrobial resistance raises concerns as a human health threat that can be propagated through the environment. Wastewater discharge into the environment is an important source for antibiotic resistant bacteria (ARB) and antibiotic resistance genes (ARGs). Sewage collection and urban wastewater treatment plants (UWTPs) are major barriers that reduce environmental contamination by sewage-derived pathogens and nutrients. However, the continuous discharge of ARB and ARGs through wastewater, including when well-functioning UWTPs are available, is unavoidable. Regular and integrated antibiotic resistance monitoring in both wastewater and receiving water bodies would contribute to improve control measures. However, monitoring processes are not harmonized being the choice of suitable biomarkers a first limitation. In this study, we tested 10 selected potential antibiotic resistance biomarkers, which have been described has being associated to humans, and rare in clean environments - intI1, sul1, ermB, ermF, aph(3’’)-Ib, qacEΔ1, uidA, mefC, tetX and crAssphage. The public database MGnify (https://www.ebi.ac.uk/metagenomics/; hosted by EMBL-EBI), was screened using the filters corresponding to origin - human gut, wastewater, sewage, and fresh water. These biomarkers and the 16S rRNA gene were monitored by quantitative PCR (qPCR) tested in raw wastewater, activated sludge, treated wastewater and surface water (upstream and downstream the UWTP) samples, collected from different countries (Portugal, Czech Republic, Denmark, The Netherlands, and Israel). The abundance of the 10 potential biomarkers decreased on average by up to 2.5 log-units gene copies/mL of sample from raw wastewater to surface water, due to treatment and/or dilution in surface water. A clustering analysis of samples based on biomarkers abundance, grouped the samples according to the (waste)water type. This classification was confirmed when 12 anonymous (waste)water samples were analysed in a blind test. The tested biomarkers were observed to differentiate different types of sample, permitting the assessment of wastewater treatment efficiency or of impacts of UWTPs discharge or others in aquatic environments. The selection of suitable biomarkers that can typify different water sources and levels of ARG contamination, along with harmonized qPCR procedures, can facilitate regular and integrated legal requirements to antibiotic resistance monitoring in wastewater and related aquatic environments.
- Fecal contamination, antibiotic resistance and organic micropollutants in full-scale constructed wetlands in northern Portugal rural areasPublication . Teixeira, Ana Margarida Ribeiro; Matos, Diana; Coelho, Norberta; Halwatura, Lahiruni M.; Abaya, Liezel Mari; Vaz-Moreira, Ivone; Castro, Paula M. L.; Aga, Diana S.; Manaia, Célia M.Background and Aims Constructed wetlands (CWs) are recognized as a promising alternative or complement to traditional wastewater treatments. Their cost-effectiveness and seamless integration into natural landscapes, fostering wildlife habitats, are notable advantages. This study aimed to assess the efficacy of three horizontal subsurface flow CWs with Phragmites australis for reducing fecal contamination, antibiotic resistance, and organic micropollutants (OMPs). Methods Influent, effluent, and sediments samples (n=36) collected throughout 2023 were examined for cultivable Escherichia coli and total coliforms, 10 biomarkers for anthropogenic contamination and 16S rRNA gene by qPCR, 119 OMPs by LC-HRMS, and 16S rRNA-based bacterial community analysis. Results The reduction in fecal contamination (log-units) was of <4.8 for E. coli, <4.0 for total coliforms, and <3.6 for genetic biomarkers. Target OMPs showed variable removal rates, with different substances persisting after treatment (e.g. acetaminophen, fenofibric acid, irbesartan, oxazepam). The bacterial community was dominated by Pseudomonadota (>40%), and treatment led to the reduction of Bacillota and Actinomycetota and increase of the “Halobacterota” and Verrumicrobiota relative abundance. Conclusions The results reveal that the growth of macrophytes and climatic conditions, particularly temperature, influenced the treatment effectiveness, improved during summer. However, the capacity of the plants to uptake bacteria/genes from wastewater has been suggested and its meaning in pathogens ecology is being investigated.