DNA metabarcoding of benthic diatoms has been successfully applied for biomonitoring at the national scale and can now be considered technically ready for routine application. However, protocols and methods still vary between and within countries, limiting their transferability and the comparability of results. In order to overcome this, routine use of DNA metabarcoding for diatom biomonitoring requires knowledge of the sources of variability introduced by the different steps of the procedure. Here, we examine how elements of routine procedures contribute to variability between European laboratories. A set of four experiments were performed focusing on DNA extraction and PCR amplification steps to evaluate their reproducibility between different laboratories and the variability introduced by different protocols currently applied by the scientific community. Under the guidance of a reference laboratory, 17 participants from 14 countries performed DNA extraction and PCR amplification in parallel, using the same fixed protocol and their own choice of protocol. Experiments were performed by each participant on a set of standardised DNA and biofilm samples (river, lake and mock community) to investigate potential systematic and random errors. Our results revealed the successful transferability of a protocol amongst labs and a highly similar and consistent ecological assessment outcome obtained regardless of the protocols used by each participant. We propose an “all for one but prove them all” strategy, suggesting that distinct protocols can be used within the scientific community, as long as their consistency is be proven by following minimum standard requirements.

Syntrophy and interspecies electron transfer among different microbial groups occurs in anaerobic digestion, and many papers recently reported their positive effect on biogas and methane production. In this paper, we present the results on the effect of conductive material, i.e., graphene, PAC and biochar addition in 3.5 L batch experiments, analyzing the biogas production curve. A peculiar curve pattern occurred in the presence of conductive materials. Compared to the respective controls, the addition of graphene produced a biogas surplus of 33%, PAC 20% and biochar 8%. Microbial community molecular analysis showed that syntrophic microorganisms present in the inoculum were stimulated by the conductive material addition. Graphene also appears to promote an interspecies electron transfer between Geobacter sp. and ca. Methanofastidiosum. This paper contributes to the understanding of the DIET-related microbial community dynamic in the presence of graphene and PAC, which could be exploited to optimize biogas and methane production in real-scale applications.

Antibiotic resistance genes (ARGs) are causing increasing problems, especially in clinical settings. Nowadays, they are considered important environmental contaminants, but little is known about their fate in the environment or how they affect natural microbial populations. In the environment, especially in water affected by anthropic activities such as discharge of hospital, urban, and industrial wastewater treatment plant (WWTP) and agricultural runoff, antibiotic determinants may become part of the environmental gene pool, spread horizontally, and be ingested by humans and animals via contaminated food and drinking water. The aim of this work was to monitor long-term the presence of antibiotic resistance determinants in water samples collected from a subalpine lake and some tributary rivers located in the southern part of Switzerland, and to assess if anthropic activities could influence the distribution of antibiotic resistance genes present in water environments. We analysed water samples by qPCR to quantify five antibiotic resistance genes that confer resistance to the major classes of antibiotics used in clinical and veterinary settings (β-lactams, macrolides, tetracycline, quinolones, and sulphonamides). Water samples were collected from January 2016 to December 2021, from three rivers located in south Switzerland and from five different sites of Lugano Lake. The most abundant genes were sulII, followed by ermB, qnrS, and tetA; they were found especially in the river influenced by wastewater treatment plants and in the lake near the potable water uptake plant. We observed an overall decrease in the number of resistance genes during the three years. Our results indicate that the aquatic ecosystems monitored in this study are a reservoir of ARGs and could potentially be a setting for the transmission of resistance from the environment to humans.

The quagga mussel Dreissena rostriformis bugensis is an invasive species that has recently spread to Western Europe, causing major impacts on aquatic ecosystems and human activities. We considered lakes Lugano and Maggiore (Ticino River basin, Italy and Switzerland) to be at high risk of colonization due to leisure boat traffic from already-colonized lakes. We performed an environmental DNA based survey to detect any quagga mussel invasions in these lakes as early as possible. The results of the survey confirmed the presence of this species in the lakes and support the use of molecular approaches for the early detection of invasive mussels.

Wastewater-based epidemiology (WBE) is a promising approach that has been used to monitoring the exposure to pathogens and understanding the status of disease outbreaks in defined population groups. Viral RNAs of SARS-Cov-2 and influenza A and B were detected and quantified by two commercial kits in three wastewater treatment plants (WWTP) selected in different regions of Canton Ticino (Switzerland). We have monitored the presence of SARS-CoV-2 during two big waves of pandemic, from March 2021 until June 2023, when number of confirmed cases and tests decreased. The presence of influenza A and B viruses was investigated from October 2022 to June 2023. We confirmed the presence of SARS-CoV-2 and influenza A and B in all the WWTP monitored; RNA concentration in wastewater could be correlated with clinical cases confirming that WBE is a powerful tool to monitor diseases dissemination supporting the management of an epidemic.