Native Microalgae-Bacteria Consortia: A Sustainable Approach for Effective Urban Wastewater Bioremediation and Disinfection.

Urban wastewater is a significant by-product of human activities. Conventional urban wastewater treatment plants have limitations in their treatment, mainly concerning the low removal efficiency of conventional and emerging contaminants. Discharged wastewater also contains harmful microorganisms, posing risks to public health, especially by spreading antibiotic-resistant bacteria and genes. Therefore, this study assesses the potential of a native microalgae-bacteria system (MBS) for urban wastewater bioremediation and disinfection, targeting NH4+-N and PO43--P removal, coliform reduction, and antibiotic resistance gene mitigation. The MBS showed promising results, including a high specific growth rate (0.651 ± 0.155 d-1) and a significant average removal rate of NH4+-N and PO43--P (9.05 ± 1.24 mg L-1 d-1 and 0.79 ± 0.06 mg L-1 d-1, respectively). Microalgae-induced pH increase rapidly reduces coliforms (r > 0.9), including Escherichia coli, within 3 to 6 days. Notably, the prevalence of intI1 and the antibiotic resistance genes sul1 and blaTEM are significantly diminished, presenting the MBS as a sustainable approach for tertiary wastewater treatment to combat eutrophication and reduce waterborne disease risks and antibiotic resistance spread.

A concept for international societally relevant microbiology education and microbiology knowledge promulgation in society.

EXECUTIVE SUMMARY: Microbes are all pervasive in their distribution and influence on the functioning and well-being of humans, life in general and the planet. Microbially-based technologies contribute hugely to the supply of important goods and services we depend upon, such as the provision of food, medicines and clean water. They also offer mechanisms and strategies to mitigate and solve a wide range of problems and crises facing humanity at all levels, including those encapsulated in the sustainable development goals (SDGs) formulated by the United Nations. For example, microbial technologies can contribute in multiple ways to decarbonisation and hence confronting global warming, provide sanitation and clean water to the billions of people lacking them, improve soil fertility and hence food production and develop vaccines and other medicines to reduce and in some cases eliminate deadly infections. They are the foundation of biotechnology, an increasingly important and growing business sector and source of employment, and the centre of the bioeconomy, Green Deal, etc. But, because microbes are largely invisible, they are not familiar to most people, so opportunities they offer to effectively prevent and solve problems are often missed by decision-makers, with the negative consequences this entrains. To correct this lack of vital knowledge, the International Microbiology Literacy Initiative-the IMiLI-is recruiting from the global microbiology community and making freely available, teaching resources for a curriculum in societally relevant microbiology that can be used at all levels of learning. Its goal is the development of a society that is literate in relevant microbiology and, as a consequence, able to take full advantage of the potential of microbes and minimise the consequences of their negative activities. In addition to teaching about microbes, almost every lesson discusses the influence they have on sustainability and the SDGs and their ability to solve pressing problems of societal inequalities. The curriculum thus teaches about sustainability, societal needs and global citizenship. The lessons also reveal the impacts microbes and their activities have on our daily lives at the personal, family, community, national and global levels and their relevance for decisions at all levels. And, because effective, evidence-based decisions require not only relevant information but also critical and systems thinking, the resources also teach about these key generic aspects of deliberation. The IMiLI teaching resources are learner-centric, not academic microbiology-centric and deal with the microbiology of everyday issues. These span topics as diverse as owning and caring for a companion animal, the vast range of everyday foods that are produced via microbial processes, impressive geological formations created by microbes, childhood illnesses and how they are managed and how to reduce waste and pollution. They also leverage the exceptional excitement of exploration and discovery that typifies much progress in microbiology to capture the interest, inspire and motivate educators and learners alike. The IMiLI is establishing Regional Centres to translate the teaching resources into regional languages and adapt them to regional cultures, and to promote their use and assist educators employing them. Two of these are now operational. The Regional Centres constitute the interface between resource creators and educators-learners. As such, they will collect and analyse feedback from the end-users and transmit this to the resource creators so that teaching materials can be improved and refined, and new resources added in response to demand: educators and learners will thereby be directly involved in evolution of the teaching resources. The interactions between educators-learners and resource creators mediated by the Regional Centres will establish dynamic and synergistic relationships-a global societally relevant microbiology education ecosystem-in which creators also become learners, teaching resources are optimised and all players/stakeholders are empowered and their motivation increased. The IMiLI concept thus embraces the principle of teaching societally relevant microbiology embedded in the wider context of societal, biosphere and planetary needs, inequalities, the range of crises that confront us and the need for improved decisioning, which should ultimately lead to better citizenship and a humanity that is more sustainable and resilient. ABSTRACT: The biosphere of planet Earth is a microbial world: a vast reactor of countless microbially driven chemical transformations and energy transfers that push and pull many planetary geochemical processes, including the cycling of the elements of life, mitigate or amplify climate change (e.g., Nature Reviews Microbiology, 2019, 17, 569) and impact the well-being and activities of all organisms, including humans. Microbes are both our ancestors and creators of the planetary chemistry that allowed us to evolve (e.g., Life's engines: How microbes made earth habitable, 2023). To understand how the biosphere functions, how humans can influence its development and live more sustainably with the other organisms sharing it, we need to understand the microbes. In a recent editorial (Environmental Microbiology, 2019, 21, 1513), we advocated for improved microbiology literacy in society. Our concept of microbiology literacy is not based on knowledge of the academic subject of microbiology, with its multitude of component topics, plus the growing number of additional topics from other disciplines that become vitally important elements of current microbiology. Rather it is focused on microbial activities that impact us-individuals/communities/nations/the human world-and the biosphere and that are key to reaching informed decisions on a multitude of issues that regularly confront us, ranging from personal issues to crises of global importance. In other words, it is knowledge and understanding essential for adulthood and the transition to it, knowledge and understanding that must be acquired early in life in school. The 2019 Editorial marked the launch of the International Microbiology Literacy Initiative, the IMiLI. HERE, WE PRESENT: our concept of how microbiology literacy may be achieved and the rationale underpinning it; the type of teaching resources being created to realise the concept and the framing of microbial activities treated in these resources in the context of sustainability, societal needs and responsibilities and decision-making; and the key role of Regional Centres that will translate the teaching resources into local languages, adapt them according to local cultural needs, interface with regional educators and develop and serve as hubs of microbiology literacy education networks. The topics featuring in teaching resources are learner-centric and have been selected for their inherent relevance, interest and ability to excite and engage. Importantly, the resources coherently integrate and emphasise the overarching issues of sustainability, stewardship and critical thinking and the pervasive interdependencies of processes. More broadly, the concept emphasises how the multifarious applications of microbial activities can be leveraged to promote human/animal, plant, environmental and planetary health, improve social equity, alleviate humanitarian deficits and causes of conflicts among peoples and increase understanding between peoples (Microbial Biotechnology, 2023, 16(6), 1091-1111). Importantly, although the primary target of the freely available (CC BY-NC 4.0) IMiLI teaching resources is schoolchildren and their educators, they and the teaching philosophy are intended for all ages, abilities and cultural spectra of learners worldwide: in university education, lifelong learning, curiosity-driven, web-based knowledge acquisition and public outreach. The IMiLI teaching resources aim to promote development of a global microbiology education ecosystem that democratises microbiology knowledge.

Continuous UV-C/H2O2 and UV-C/Chlorine applied to municipal secondary effluent and nanofiltration retentate: Removal of contaminants of emerging concern, ecotoxicity, and reuse potential.

As global effects of water scarcity raise concerns and environmental regulations evolve, contemporary wastewater treatment plants (WWTPs) face the challenge of effectively removing a diverse range of contaminants of emerging concern (CECs) from municipal effluents. This study focuses on the assessment of advanced oxidation processes (AOPs), specifically UV-C/H2O2 and UV-C/Chlorine, for the removal of 14 target CECs in municipal secondary effluent (MSE, spiked with 10 µg L-1 of each CEC) or in the subsequent MSE nanofiltration retentate (NFR, no spiking). Phototreatments were carried out in continuous mode operation, with a hydraulic retention time of 3.4 min, using a tube-in-tube membrane photoreactor. For both wastewater matrices, UV-C photolysis (3.3 kJ L-1) exhibited high efficacy in removing CECs susceptible to photolysis, although lower treatment performance was observed for NFR. In MSE, adding 10 mg L-1 of H2O2 or Cl2 enhanced treatment efficiency, with UV-C/H2O2 outperforming UV-C/Chlorine. Both UV-C/AOPs eliminated the chronic toxicity of MSE toward Chlorella vulgaris. In the NFR, not only was the degradation of target CECs diminished, but chronic toxicity to C. vulgaris persisted after both UV-C/AOPs, with UV-C/Chlorine increasing toxicity due to potential toxic by-products. Nanofiltration permeate (NFP) exhibited low CECs and microbial content. A single chlorine addition effectively controlled Escherichia coli regrowth for 3 days, proving NFP potential for safe reuse in crop irrigation (<1 CFU/100 mL for E. coli; <1 mg L-1 for free chlorine). These findings provide valuable insights into the applications and limitations of UV-C/H2O2 and UV-C/Chlorine for distinct wastewater treatment scenarios.

Catalyst-free persulfate activation by UV/visible radiation for secondary urban wastewater disinfection.

This study focuses on the treatment of secondary urban wastewater (W) to improve the effluent quality aiming at the reduction of pathogenic microorganisms for the safe reuse of the treated wastewater (TW). Catalyst-free persulfate activation by radiation-based oxidation was applied as a treatment technology. A parametric study was carried out to select the best operating conditions. Total enterobacteria inactivation (quantified by the log reduction (CFU/100 mL)) was achieved when using [S2O82-] = 1 mM, pH = 8.5 (natural pH of W), T = 25 °C, and I = 500 W/m2. However, storing TW for 3 days promoted the regrowth of bacteria, risking its reutilization. Therefore, in this study, and for the first time, the potential beneficial role of inoculation of wastewater treated by the radiation-activated persulfate process with a diverse bacterial community was evaluated in order to control the regrowth of potentially harmful microorganisms through bacterial competition. For this, TW was diluted with river water (R) in the volume percentages of 5, 25, and 50 (percentages refer to R content), and enterobacteria and total heterotrophs were enumerated before and after storage for 72 h. The results showed total heterotrophs and enterobacteria regrowth for TW and R + TW diluted 5 and 25% after storage. However, for R + TW diluted 50%, only the total heterotrophs regrew. Hence, the treated wastewater generated by the oxidative process diluted with 50% river water complies with the legislated limits for reuse in urban uses or irrigation.

Survival of clinical and environmental carbapenem-resistant Klebsiella pneumoniae ST147 in surface water.

Carbapenem-resistant Klebsiella pneumoniae represents a healthcare threat, already disseminated in the environment. This study aimed to compare the behaviour of a clinical and an environmental K. pneumoniae strain (multilocus sequence type ST147) harbouring the gene blaKPC-3 in water. The abundance of the genes phoE (specific for K. pneumoniae) and blaKPC-3 was monitored by quantitative PCR in urban runoff water and sterile ultra-pure water microcosms, aiming to assess survival, blaKPC-3 persistence, and the effect of the native water microbiota. In sterile ultra-pure water, the abundance of cultivable K. pneumoniae and blaKPC-3 gene did not change over the incubation period (8 days). In contrast, in urban runoff, the K. pneumoniae and the genes phoE and blaKPC genes decreased by up to 3 log-units. These results suggest that K. pneumoniae were outcompeted by the native microbiota of the urban runoff water and that the decay of blaKPC-3 gene was due to host death, rather than to gene loss. The study highlights that although native microbiota is essential to hamper the persistence of non-native bacteria, carbapenemase producing K. pneumoniae can survive in urban runoff water for at least one week.

Novel photoelectrochemical 3D-system for water disinfection by deposition of modified carbon nitride on vitreous carbon foam.

Graphitic carbon nitride (GCN) is an optical semiconductor with excellent photoactivity under visible light irradiation. It has been widely applied for organic micropollutant removal from contaminated water, and less investigated for microorganisms' inactivation. The photocatalytic degradation mechanism using GCN is attributed to a series of reactions with reactive oxygen species and photogenerated holes that can be boosted by modifying its physical-chemical structure. This work reports a successful improvement of the overall photocatalytic and electrocatalytic activities of the pristine material by thermal and chemical modification by a copolymerisation synthesis method. The copolymerisation of dicyandiamide as a precursor with barbituric acid strongly reduced photoluminescence due to the enhanced charge separation thus improving the catalyst efficiency under visible light irradiation. The material with 1.6 wt% of barbituric acid showed the best photocatalytic performance and electrochemical properties. This photocatalyst was selected for immobilisation on a conductive carbon foam, which promotes a higher electrochemical active surface area and enhanced mass transfer. This three-dimensional metal-free electrode was employed for the photoelectrochemical inactivation of two different microorganisms, Escherichia coli, and Enterococcus faecalis, obtaining removals below the detection limit after 30 min in simulated faecal-contaminated waters. This photoelectrochemical reactor was also applied to treat polluted river and urban waste waters, and the faecal contamination indicators were vastly reduced to values below the detection limit in 60 min in both cases, showing the wide applicability of this innovative photoelectrode for different types of polluted aqueous matrices.

Ozone membrane contactor for tertiary treatment of urban wastewater: Chemical, microbial and toxicological assessment.

A membrane ozone contactor, operated under continuous mode, was applied to promote the tertiary treatment of urban wastewater (UWW), targeting the removal of contaminants of emerging concern (CECs), bacterial disinfection, and toxicity reduction. This system relies on the homogeneous radial distribution of ozone (O3) in the reaction zone by "titration" through a microfiltration borosilicate tubular membrane, while the UWW swirls around the membrane and drags the O3 microbubbles generated in the membrane shell-side. The membrane is coated with titanium dioxide (TiO2-P25) and radiation can be externally supplied via four UV lamps. The ozonation tests were carried out with secondary-treated UWW collected in different seasons (winter and summer) and spiked with a mix of 19 CECs (10 µg L-1 each). For an O3 dose of 18 g m-3, the best performance was obtained by increasing the O3 concentration (maximum [O3]G,inlet of 200 g Nm-3) and decreasing the gas flow rate (minimum QG of 0.15 Ndm3 min-1), providing the highest ozone transfer yield (88 %) and, thus higher specific ozone dose (g O3 per g dissolved organic carbon). Under these conditions, removals >80 % or concentrations below the limit of quantification were obtained for up to 13 of the 19 CECs and reductions up to 5 log units for total heterotrophs and below the limit of detection for enterobacteria and enterococci. Tests including a UVC dose of 0.10 kJ L-1 enhanced disinfection ability but had no impact on CECs oxidation. After ozonation, the abundance of antibiotic resistant bacteria was reduced but not eliminated, and microbial regrowth after 3-day storage was observed. No toxic effect was detected on zebrafish embryos using a dilution factor of 4 for the ozonized UWW and when granular activated carbon adsorption was subsequently applied the dilution factor decreased to 2.

Microalgae systems - environmental agents for wastewater treatment and further potential biomass valorisation.

Water is the most valuable resource on the planet. However, massive anthropogenic activities generate threatening levels of biological, organic, and inorganic pollutants that are not efficiently removed in conventional wastewater treatment systems. High levels of conventional pollutants (carbon, nitrogen, and phosphorus), emerging chemical contaminants such as antibiotics, and pathogens (namely antibiotic-resistant ones and related genes) jeopardize ecosystems and human health. Conventional wastewater treatment systems entail several environmental issues: (i) high energy consumption; (ii) high CO2 emissions; and (iii) the use of chemicals or the generation of harmful by-products. Hence, the use of microalgal systems (entailing one or several microalgae species, and in consortium with bacteria) as environmental agents towards wastewater treatment has been seen as an environmentally friendly solution to remove conventional pollutants, antibiotics, coliforms and antibiotic resistance genes. In recent years, several authors have evaluated the use of microalgal systems for the treatment of different types of wastewater, such as agricultural, municipal, and industrial. Generally, microalgal systems can provide high removal efficiencies of: (i) conventional pollutants, up to 99%, 99%, and 90% of total nitrogen, total phosphorus, and/or organic carbon, respectively, through uptake mechanisms, and (ii) antibiotics frequently found in wastewaters, such as sulfamethoxazole, ciprofloxacin, trimethoprim and azithromycin at 86%, 65%, 42% and 93%, respectively, through the most desirable microalgal mechanism, biodegradation. Although pathogens removal by microalgal species is complex and very strain-specific, it is also possible to attain total coliform and Escherichia coli removal of 99.4% and 98.6%, respectively. However, microalgal systems' effectiveness strongly relies on biotic and abiotic conditions, thus the selection of operational conditions is critical. While the combination of selected species (microalgae and bacteria), ratios and inoculum concentration allow the efficient removal of conventional pollutants and generation of high amounts of biomass (that can be further converted into valuable products such as biofuels and biofertilisers), abiotic factors such as pH, hydraulic retention time, light intensity and CO2/O2 supply also have a crucial role in conventional pollutants and antibiotics removal, and wastewater disinfection. However, some rationale must be considered according to the purpose. While alkaline pH induces the hydrolysis of some antibiotics and the removal of faecal coliforms, it also decreases phosphates solubility and induces the formation of ammonium from ammonia. Also, while CO2 supply increases the removal of E. coli and Pseudomonas aeruginosa, as well as the microalgal growth (and thus the conventional pollutants uptake), it decreases Enterococcus faecalis removal. Therefore, this review aims to provide a critical review of recent studies towards the application of microalgal systems for the efficient removal of conventional pollutants, antibiotics, and pathogens; discussing the feasibility, highlighting the advantages and challenges of the implementation of such process, and presenting current case-studies of different applications of microalgal systems.

Disinfection of treated urban effluents for reuse by combination of coagulation/flocculation and Fenton processes.

In this study, a combination of coagulation/flocculation and Fenton processes was studied as tertiary treatment in order to generate treated water susceptible to reuse. The combination of both processes has never been applied in disinfection of real urban wastewater. The best removals of turbidity and enterobacteria were achieved when applying a coagulant (FeCl3) dosage of 120 mg/L and the natural pH of the effluent (7.14). The following Fenton reaction presented the maximal enterobacteria inactivation after 120 min at 25 °C, when using hydrogen peroxide and added iron concentrations of 100 mg/L and 7 mg/L, respectively. The abundance of antibiotic resistant (amoxicillin and sulfamethoxazole) enterobacteria and total enterobacteria, enterococci, and heterotrophs, and antibiotic resistance genes - ARG - (sul1, blaTEM and qnrS) was evaluated before and after each step of the treatment. Values below 10 CFU/100 mL were achieved for total and resistant cultivable enterobacteria immediately after treatment and after storage for 72 h, therefore meeting the strictest limit imposed for E. coli. Physico-chemical parameters also met the established limits for water reuse. Despite harbouring a rich and diverse bacterial community, the final stored disinfected wastewater contained high relative abundance of potentially hazardous bacteria. Such results point out the need of a deep microbiological characterization of treated wastewater to evaluate the risk of its reuse in irrigation.

Carbon-based materials for water disinfection and heavy metals removal.

The presence of heavy metals and/or harmful bacteria in drinking water represents significant risks to human health. This study aimed to develop a low-cost water treatment technology using synthesized nanocomposites with metal nanoparticles supported on activated carbon (AC) for bacteria and heavy metal removal. In addition, the performance of the developed nanomaterials was compared with that of commercial materials - carbon fibers of three different typologies. The chemical and textural properties of all tested materials were characterized. To simulate a technology to be applied in a water outlet point, removal tests were carried out in a continuous system using suspensions of Escherichia coli and/or Staphylococcus aureus, wherein the contact time with the two phases was minimal (1 min). The obtained results revealed that iron and copper oxides supported on AC with a calcination treatment (CuFeO/AC-C) was the nanocomposite with the best performance, achieving a 6 log reduction for both bacteria in the same suspension up to 9 h operation. A mix of bacteria and heavy metals, simulating a real water, was treated with CuFeO/AC-C obtaining a 6 log reduction of bacteria, a Pb2+ removal >99.9% and Cd2+ removal between 97 and 98% over 180 passage times.

The Complex Interplay Between Antibiotic Resistance and Pharmaceutical and Personal Care Products in the Environment.

Antibiotic-resistant bacteria (ARB) and antibiotic resistance genes (ARGs) are important environmental contaminants. Nonetheless, what drives the evolution, spread, and transmission of antibiotic resistance dissemination is still poorly understood. The abundance of ARB and ARGs is often elevated in human-impacted areas, especially in environments receiving fecal wastes, or in the presence of complex mixtures of chemical contaminants, such as pharmaceuticals and personal care products. Self-replication, mutation, horizontal gene transfer, and adaptation to different environmental conditions contribute to the persistence and proliferation of ARB in habitats under strong anthropogenic influence. Our review discusses the interplay between chemical contaminants and ARB and their respective genes, specifically in reference to co-occurrence, potential biostimulation, and selective pressure effects, and gives an overview of mitigation by existing man-made and natural barriers. Evidence and strategies to improve the assessment of human health risks due to environmental antibiotic resistance are also discussed. Environ Toxicol Chem 2023;00:1-16. © 2022 SETAC.

Application of iron-activated persulfate for municipal wastewater disinfection.

To address the increasing contamination of aquatic environments and incidence of waterborne diseases, advanced oxidation processes with activated persulfate have emerged as tools to inactivate wastewater microorganisms and contaminants. In this work, the disinfection of a secondary effluent from a wastewater treatment plant by iron-based persulfate activation was studied. Experiments in a batch stirred tank reactor were carried out to evaluate the performance along reaction time and the effect of operational parameters in the oxidative process efficiency (oxidant and iron concentration, pH and temperature). After 60 min of reaction, persulfate and iron concentrations of 3 mM and 0.75 mM, respectively, combined with a neutral initial pH (7.5) and a temperature of 40 °C, allowed to reach values below the detection limit (<10 CFU/100 mL) of enterococci and enterobacteria with and without ciprofloxacin resistance, as well as a 91% inactivation of total heterotrophic organisms and a 70% removal of total organic carbon. Regrowth of microorganisms was evaluated 72 h after treatment and it was only noticed a slight increase in total heterotrophs. Evaluation of physico-chemical characteristics of the treated water showed that it meets the requirements imposed by European and Portuguese legislation for its reuse in irrigation and most urban utilities.

Overgrowth control of potentially hazardous bacteria during storage of ozone treated wastewater through natural competition.

Improving the chemical and biological quality of treated wastewater is particularly important in world regions under water stress. In these regions, reutilization of wastewater is seen as an alternative to reduce water demand, particularly for agriculture irrigation. In a reuse scenario, the treated wastewater must have enough quality to avoid chemical and biological contamination of the receiving environment. Ozonation is among the technologies available to efficiently remove organic micropollutants and disinfect secondary effluents, being implemented in full-scale urban wastewater treatment plants worldwide. However, previous studies demonstrated that storage of ozone treated wastewater promoted the overgrowth of potentially harmful bacteria, putting at risk its reutilization, given for instance the possibility of contaminating the food-chain. Therefore, this study was designed to assess the potential beneficial role of inoculation of ozone treated wastewater with a diverse bacterial community during storage, for the control of the overgrowth of potentially hazardous bacteria, through bacterial competition. To achieve this goal, ozone treated wastewater (TWW) was diluted with river water (RW) in the same proportion, and the resulting bacterial community (RW+TWW) was compared to that of undiluted TWW over 7 days storage. As hypothesized, in contrast to TWW, where dominance of Beta- and Gammaproteobacteria, namely Pseudomonas spp. and Acinetobacter spp., was observed upon storage for 7 days, the bacterial communities of the diluted samples (RW+TWW) were diverse, resembling those of RW. Moreover, given the high abundance of antibiotic resistance genes in RW, the concentration of these genes in RW+TWW did not differ from that of the non-ozonated controls (WW, RW and RW+WW) over the storage period. These results highlight the necessity of finding a suitable pristine diverse bacterial community to be used in the future to compete with bacteria surviving ozonation, to prevent reactivation of undesirable bacteria during storage of treated wastewater.

Rethinking water treatment targets: Bacteria regrowth under unprovable conditions.

Ozonation is among the currently used technologies to remove chemical and biological contaminants from secondary treated urban wastewater (UWW). Despite its effectiveness on the abatement of organic micropollutants (OMPs) and disinfection, previous studies have shown that regrow of bacteria may occur upon storage of the ozonated UWW. This reactivation has been attributed to the high content of assimilable organic carbon after treatment. In order to investigate if ozonation by-products are the main biological regrowth drivers in stored ozonated UWW, the ozonation surviving cells were resuspended in sterile bottled mineral water (MW), simulating a pristine oligotrophic environment. After 7 days storage, organisms such as Acinetobacter, Methylobacterium, Cupriavidus, Massilia, Acidovorax and Pseudomonas were dominant in both ozonated UWW and pristine MW, demonstrating that bacterial regrowth is not strictly related to the eventual presence of ozonation by-products, but instead with the ability of the surviving cells to cope with nutrient-poor environments. The resistome of UWW before and after ozonation was analysed by metagenomic techniques. Draft metagenome assembled genomes (dMAGs), recovered from both ozonated UWW and after cell resuspension in MW, harboured genes conferring resistance to diverse antibiotics classes. Some of these antibiotic resistance genes (ARGs) were located in the vicinity of mobile genetic elements, suggesting their potential to be mobilized. Among these, dMAGs affiliated to taxa with high relative abundance in stored water, such as P. aeruginosa and Acinetobacter spp., harboured ARGs conferring resistance to 12 and 4 families of antibiotics, respectively, including those encoding carbapenem hydrolysing oxacillinases. The results herein obtained point out that the design and development of new wastewater treatment technologies should include measures to attenuate the imbalance of the bacterial communities promoted by storage of the final treated wastewater, even when applying processes with high mineralization rates.

Feasibility of using magnetic nanoparticles in water disinfection.

Disinfection is a crucial step during the water treatment process due to the significant risks of water contamination with human and animal excreta. The development of innovative disinfection technologies that can be applied at water point of use, avoiding contamination problems in water distribution systems and reservoirs, are needed. Thus, the present work aimed at assessing the disinfection efficiency of iron oxide magnetic nanoparticles (MNPs) modified with different compounds, such as carbon nanotubes, copper and silver, in water solutions contaminated with bacteria. Kinetic and influence of nanoparticles concentration experiments, performed with Escherichia coli, allowed to define the optimal reaction conditions to apply in batch experiments (1 min of contact time and 50 mg/mL of MNPs). During these experiments, CuFeO/CNT, C-FeO@CVD750 and 5% Ag/FeO were selected as the most efficient presenting log reduction values of 2.99, 1.50 and 2.11, respectively; however, experiments performed with Staphylococcus aureus suspension and a mixed bacterial suspension (E. coli + S. aureus) allowed to observe a slight decrease in nanomaterials efficiency, which was more evident for C-FeO@CVD750 and 5% Ag/FeO materials achieving efficiencies of 94 and 83% (corresponding log reductions of 1.26 and 0.77, respectively). CuFeO/CNT nanoparticles proved to be the most efficient material for both bacteria removal presenting an efficiency of 99% (corresponding log reduction of 1.99) for the mixed bacterial suspension. These nanoparticles proved to have great stability over successive experiments, and the low leaching values of the metals present in their composition after reaction proved the resistance and efficiency of these magnetic nanoparticles.

Effect of copper and zinc as sulfate or nitrate salts on soil microbiome dynamics and blaVIM-positive Pseudomonas aeruginosa survival.

The exposure of soil to metals and to antibiotic resistant bacteria may lead to the progressive deterioration of soil quality. The persistence of antibiotic resistant bacteria or antibiotic resistance genes in soil can be influenced by the microbial community or by soil amendments with metal salts. This work assessed the effect of soil amendment with copper and zinc, as sulfate or nitrate salts, on the fate of a carbapenem-resistant (blaVIM+) hospital effluent isolate of Pseudomonas aeruginosa (strain H1FC49) and on the variations of the microbial community composition. Microcosms with soil aged or not with copper and zinc salts (20 mM), and inoculated with P. aeruginosa H1FC49 were monitored at 0, 7, 14 and/or 30 days, for community composition (16S rRNA gene amplicon) and strain H1FC49 persistence. Data on culturable P. aeruginosa, quantitative PCR of the housekeeping gene ecf, and the presumably acquired genes blaVIM+ and integrase (intI1), and community composition were interpreted based on descriptive statistics and multivariate analysis. P. aeruginosa and the presumably acquired genes, were quantifiable in soil for up to one month, in both metal-amended and non-amended soil. Metal amendments were associated with a significant decrease of bacterial community diversity and richness. The persistence of P. aeruginosa and acquired genes in soils, combined with the adverse effect of metals on the bacterial community, highlight the vulnerability of soil to both types of exogenous contamination.

Polyphasic characterization of carbapenem-resistant Klebsiella pneumoniae clinical isolates suggests vertical transmission of the blaKPC-3 gene.

Carbapenem-resistant Klebsiella pneumoniae are a major global threat in healthcare facilities. The propagation of carbapenem resistance determinants can occur through vertical transmission, with genetic elements being transmitted by the host bacterium, or by horizontal transmission, with the same genetic elements being transferred among distinct bacterial hosts. This work aimed to track carbapenem resistance transmission by K. pneumoniae in a healthcare facility. The study involved a polyphasic approach based on conjugation assays, resistance phenotype and genotype analyses, whole genome sequencing, and plasmid characterization by pulsed field gel electrophoresis and optical DNA mapping. Out of 40 K. pneumoniae clinical isolates recovered over two years, five were carbapenem- and multidrug-resistant and belonged to multilocus sequence type ST147. These isolates harboured the carbapenemase encoding blaKPC-3 gene, integrated in conjugative plasmids of 140 kbp or 55 kbp, belonging to replicon types incFIA/incFIIK or incN/incFIIK, respectively. The two distinct plasmids encoding the blaKPC-3 gene were associated with distinct genetic lineages, as confirmed by optical DNA mapping and whole genome sequence analyses. These results suggested vertical (bacterial strain-based) transmission of the carbapenem-resistance genetic elements. Determination of the mode of transmission of antibiotic resistance in healthcare facilities, only possible based on polyphasic approaches as described here, is essential to control resistance propagation.

The challenge of removing waste from wastewater: let technology use nature!

Tertiary treatments capable of removing chemical and biological contaminants of emerging concern have been successfully developed and implemented at full scale, opening the possibility of using wastewater treatment plants as recycling units, capable of producing wastewater that can be reused in various activities, such as agriculture irrigation; However, tertiary treatments remove only part of the wastewater microbiota, leaving the opportunity for regrowth and/or reactivation of potentially hazardous microorganisms, facilitated by the poor competition among the surviving microorganisms; Under the motto 'added by technology, lead by nature', the treatment and storage of treated wastewater must find the balance to develop a protection shield against the impoverishment the microbial quality and the development of potentially hazardous bacteria.

Living with sulfonamides: a diverse range of mechanisms observed in bacteria.

Sulfonamides are the oldest class of synthetic antibiotics still in use in clinical and veterinary settings. The intensive utilization of sulfonamides has been leading to the widespread contamination of the environment with these xenobiotic compounds. Consequently, in addition to pathogens and commensals, also bacteria inhabiting a wide diversity of environmental compartments have been in contact with sulfonamides for almost 90 years. This review aims at giving an overview of the effect of sulfonamides on bacterial cells, including the strategies used by bacteria to cope with these bacteriostatic agents. These include mechanisms of antibiotic resistance, co-metabolic transformation, and partial or total mineralization of sulfonamides. Possible implications of these mechanisms on the ecosystems and dissemination of antibiotic resistance are also discussed. KEY POINTS: • Sulfonamides are widespread xenobiotic pollutants; • Target alteration is the main sulfonamide resistance mechanism observed in bacteria; • Sulfonamides can be modified, degraded, or used as nutrients by some bacteria.

Re-thinking the main goals of biological sciences: is it possible to build new knowledge without fundamental research?

Relationships between collective scientific knowledge and country's economic prosperity and competitiveness have been described. Hence, interaction between industry and academic institutions is seen as a way to valorize this knowledge at social and economic levels. The ability to translate scientific knowledge in social and economic benefits is now receiving most of the funding for public research. However, and despite the evident long-term benefits of funding applied science, drastic reduction of budget for fundamental research may eventually lead to the opposite outcome.