The effects of emerging environmental contaminants on Stenotrophomonas maltophilia isolated from drinking water in planktonic and sessile states

Coaggregation dynamics in drinking water biofilms and implications for chlorine disinfection

Biofilms in drinking water (DW) systems persistently challenge traditional disinfection methods due to intricate microbial interactions, with coaggregation playing a crucial role in forming multispecies biofilms. This study examined the implications of coaggregation on tolerance towards sodium hypochlorite (NaOCl) disinfection. Dual-species biofilms were formed for seven days on polyvinyl chloride coupons, comprising a strain of the emerging pathogen Stenotrophomonas maltophilia and the coaggregating strain Delftia acidovorans 005 P. For comparison, dual-species biofilms were also formed with a non-coaggregation strain (D. acidovorans 009 P). The minimum bactericidal concentration (MBC) for each planktonic strain varied (D. acidovorans: 1 mg/L, S. maltophilia: 1.5 mg/L) below the safe DW treatment limits. However, high NaOCl doses (10 ×MBC and 100 ×MBC,) showed low efficacy against dual-species biofilms, indicating significant biofilm tolerance to disinfection. Membrane damage occurred at sub-MBC without culturability loss, underscoring biofilm resilience. The biofilm analysis revealed a complex interplay between the composition of extracellular polymeric substances and the architecture, which was influenced by the presence of the coaggregating strain. Overall, coaggregation significantly influenced biofilm formation and resilience, impacting NaOCl disinfection. These findings underscore the challenges of microbial interactions in biofilms, emphasizing the need for improved disinfection strategies to control biofilms in drinking water systems.

Which organic contaminants should be paid more attention: Based on an improved health risk assessment framework

The increasing chemical pollution of the drinking water is widely concerned. Large number of organic contaminants cannot be removed by conventional water treatment technology due to their low concentration, and long-term exposure may pose significant risks to human health. Which organic contaminants in drinking water should be given more attention has been a topic of great concern in recent years. To identify the organic contaminants that need attention, this research proposes an improved health risk screening method to quantitatively analyze the risks of accumulation, persistence, toxicity, and antibiotic resistance. Compared with conventional method, 26 compounds were added to the improved screening list, including 9 DBPs (e.g., NDMA), 3 antibiotics (e.g., oxytetracycline), PFNA and other compounds. Overall, antibiotics and plasticizers rose in the risk rankings. From the perspective of the proportion of total risk value, a single risk plays a decisive role (more than 99%) in the ranking. This change suggests that antibiotic resistance and the accumulation of organic matter are as important as their toxic risks to humans. 58 compounds were recommended for the priority control organic contaminants list in drinking water. This list provides the necessary information for authoritative regulations to monitor, control, assess, and manage the risks of environmentally relevant compounds in drinking water in China.

The effects of methylparaben exposure on biofilm tolerance to chlorine disinfection

Parabens are emerging contaminants that have been detected in drinking water. Their presence in DW distribution systems (DWDS) can alter bacterial behaviour, characteristics, and structure, which may compromise DW disinfection. This work provides insights into the impact of methylparaben (MP) on the tolerance to chlorine disinfection and antibiotics from dual-species biofilms formed by Acinetobacter calcoaceticus and Stenotrophomonas maltophilia isolated from DW and grown on high-density polyethylene (HDPE) and polypropylene (PPL). Results showed that dual-species biofilms grown on PPL were more tolerant to chlorine disinfection, expressing a decrease of over 50 % in logarithmic reduction values of culturable cells in relation to non-exposed biofilms. However, bacterial tolerance to antibiotics was not affected by MP presence. Although MP-exposed dual-species biofilms grown on HDPE and PPL were metabolically more active than non-exposed counterparts, HDPE seems to be the material with lower impact on DW risk management and disinfection, if MP is present. Overall, results suggest that MP presence in DW may compromise chlorine disinfection, and consequently affect DW quality and stability, raising potential public health issues.

Co-regulation of Thermosensor Pathogenic Factors by C-di-GMP-Related Two-Component Systems and a cAMP Receptor-like Protein (Clp) in Stenotrophomonas maltophilia

Stenotrophomonas maltophilia is a major threat to the food industry and human health owing to its strong protease production and biofilm formation abilities. However, information regarding regulatory factors or potential mechanisms is limited. Herein, we observed that temperature differentially regulates biofilm formation and protease production, and a cAMP receptor-like protein (Clp) negatively regulates thermosensor biofilm formation, in contrast to protease synthesis. Among four c-di-GMP-related two-component systems (TCSs), promoter fusion analysis revealed that clp transcription levels were predominantly controlled by LotS/LotR, partially controlled by both RpfC/RpfG and a novel TCS Sm0738/Sm0737, with no obvious effect caused by Sm1912/Sm1911. Biofilm formation in Δclp and ΔTCSs strains suggested that LotS/LotR controlled biofilm formation in a Clp-mediated manner, whereas both RpfC/RpfG and Sm0738/Sm0737 may occur in a distinct pathway. Furthermore, enzymatic activity analysis combined with c-di-GMP level indicated that the enzymatic activity of c-di-GMP-related metabolism proteins may not be a vital contributor to changes in c-di-GMP level, thus influencing physiological functions. Our findings elucidate that the regulatory pathway of c-di-GMP-related TCSs and Clp in controlling spoilage or the formation of potentially pathogenic factors in Stenotrophomonas expand the understanding of c-di-GMP metabolism and provide clues to control risk factors of S. maltophilia in food safety.

Reviewing the interdecadal dynamics of micropollutants in the Tanzanian coastal zone from 2002 to 2022

The Tanzanian coast is a vastly diversified ecosystem offering ecological, cultural, and economic services. However, anthropogenic and environmental stressors threaten its productivity and sustainability, prompting extensive research to understand the contamination extent, sources, and impacts. This review covers 77 original field research studies published between 2002 and 2022, focusing on the Tanzanian coastal area. A summary of information on the occurrences, levels, distributions, sources, and impacts of organic and inorganic micropollutants in environmental and biological compartments is provided. The studies were further discussed based on their research focus, where seven key areas were identified, which included the types of micropollutants analyzed, the parameters sampled, the locations investigated, and the crucial conclusions reached. The aim was to evaluate the research trends and identify gaps for future investigations. The studies reveal varying contamination levels, from low to severe, encompassing metals, persistent organic pollutants, pesticide residues, nutrients, and microbial contaminants. However, data gaps exist for micropollutant concentrations in ambient air, microplastics, pharmaceuticals, and emerging contaminants of concern. With increasing urbanization and socio-economic activities, the review emphasizes the necessity for solution-based research to remove and control micropollutants in the area. Addressing these challenges is crucial for sustaining the diverse ecological nature of this vital coastal system.

Parabens as environmental contaminants of aquatic systems affecting water quality and microbial dynamics

Among different pollutants of emerging concern, parabens have gained rising interest due to their widespread detection in water sources worldwide. This occurs because parabens are used in personal care products, pharmaceuticals, and food, in which residues are generated and released into aquatic environments. The regulation of the use of parabens varies across different geographic regions, resulting in diverse concentrations observed globally. Concentrations of parabens exceeding 100 μg/L have been found in wastewater treatment plants and surface waters while drinking water (DW) sources typically exhibit concentrations below 6 μg/L. Despite their low levels, the presence of parabens in DW is a potential exposure route for humans, raising concerns for both human health and environmental microbiota. Although a few studies have reported alterations in the functions and characteristics of microbial communities following exposure to emerging contaminants, the impact of the exposure to parabens by microbial communities, particularly biofilm colonizers, remains largely understudied. This review gathers the most recent information on the occurrence of parabens in water sources, as well as their effects on human health and aquatic organisms. The interactions of parabens with microbial communities are reviewed for the first time, filling the knowledge gaps on the effects of paraben exposure on microbial ecosystems and their impact on disinfection tolerance and antimicrobial resistance, with potential implications for public health.

Source, transport, and toxicity of emerging contaminants in aquatic environments: A review on recent studies

Emerging contaminants (ECs) are gaining global attention owing to their widespread presence and adverse effects on human health. ECs comprise numerous composite types and pose a potential threat to the growth and functional traits of species and ecosystems. Although the occurrence and fate of ECs has been extensively studied, little is known about their long-term biological effects. This review attempts to gain insights into the unhindered connections and overlaps in aquatic ecosystems. Microplastics (MPs), one of the most representative ECs, are carriers of other pollutants because of their strong adsorption capacity. They form a complex of pollutants that can be transmitted to aquatic organisms and humans through the extended food chain, increasing the concentration of pollutants by tens of thousands of times. Adsorption, interaction and transport effects of emerging contaminants in the aquatic environment are also discussed. Furthermore, the current state of knowledge on the ecotoxicity of single- and two-pollutant models is presented. Herein, we discuss how aquatic organisms within complex food networks may be particularly vulnerable to harm from ECs in the presence of perturbations. This review provides an advanced understanding of the interactions and potential toxic effects of ECs on aquatic organisms.

Prevalence of antimicrobial resistance in a full-scale drinking water treatment plant

Antibiotic resistance in drinking water has received increasing attention in recent years. In this study, the occurrence and abundance of antibiotic resistance genes (ARGs) in a drinking water treatment plant (DWTP) was comprehensively investigated using metagenomics. Bioinformatics analysis showed that 381 ARG subtypes belonging to 15 ARG types were detected, and bacitracin had the highest abundance (from 0.26 × 10-2 to 0.86 copies/cell), followed by multidrug (from 0.57 × 10-1 to 0.47 copies/cell) and sulfonamide (from 0.83 × 10-2 to 0.35 copies/cell). Additionally, 933 ARG-carrying contigs (ACCs) were obtained from the metagenomic data, among which 153 contigs were annotated as pathogens. The most abundant putative ARG host was Staphylococcus (7.9%), which most frequently carried multidrug ARGs (43.2%). Additionally, 38 high-quality metagenome-assembled genomes (MAGs) were recovered, one of which was identified as Staphylococcus aureus (Bin.624) and harboured the largest number of ARGs (n = 16). Using the cultivation technique, 60 isolates were obtained from DWTP samples, and Staphylococcus spp. (n = 11) were found to be dominant in all isolates, followed by Bacillus spp. (n = 17). Antimicrobial susceptibility testing showed that most Staphylococcus spp. were multidrug resistant (MDR). These results deepen our understanding of the distribution profiles of ARGs and antibiotic resistant bacteria (ARB) in DWTPs for potential health risk evaluation. Our study also highlights the need for new and efficient water purification technologies that can be introduced and applied in DWTPs.

Realism-based assessment of the efficacy of potassium peroxymonosulphate on Stenotrophomonas maltophilia biofilm control

The potential of pentapotassium bis(peroxymonosulphate) bis(sulphate) (OXONE) to control biofilms in drinking water distribution systems (DWDS) was evaluated and compared to chlorine disinfection. Mature biofilms of drinking water (DW)-isolated Stenotrophomonas maltophilia were formed using a simulated DWDS with a rotating cylinder reactor (RCR). After 30 min of exposure, OXONE at 10 × minimum bactericidal concentration (MBC) caused a significant 4 log reduction of biofilm culturability in comparison to the unexposed biofilms and a decrease in the number of non-damaged cells below the detection limit (4.8 log cells/cm2). The effects of free chlorine were restricted to approximately 1 log reduction in both biofilm culturability and non-damaged cells. OXONE in synthetic tap water (STW) at 25 ºC was more stable over 40 days than free chlorine in the same conditions. OXONE solution exhibited a disinfectant decrease of about 10% of the initial concentration during the first 9 days, and after this time the values remained stable. Whereas possible reaction of chlorine with inorganic and organic substances in STW contributed to free chlorine depletion of approximately 48% of the initial concentration. Electron paramagnetic resonance (EPR) spectroscopy studies confirmed the presence of singlet oxygen and other free radicals during S. maltophilia disinfection with OXONE. Overall, OXONE constitutes a relevant alternative to conventional DW disinfection for effective biofilm control in DWDS.

Nanoscale designing of metal organic framework moieties as efficient tools for environmental decontamination

Environmental pollutants, being a major and detrimental component of the ecological imbalance, need to be controlled. Serious health issues can get intensified due to contaminants present in the air, water, and soil. Accurate and rapid monitoring of environmental pollutants is imperative for the detoxification of the environment and hence living beings. Metal-organic frameworks (MOFs) are a class of porous and highly diverse adsorbent materials with tunable surface area and diverse functionality. Similarly, the conversion of MOFs into nanoscale regime leads to the formation of nanometal-organic frameworks (NMOFs) with increased selectivity, sensitivity, detection ability, and portability. The present review majorly focuses on a variety of synthetic methods including the ex situ and in situ synthesis of MOF nanocomposites and direct synthesis of NMOFs. Furthermore, a variety of applications such as nanoabsorbent, nanocatalysts, and nanosensors for different dyes, antibiotics, toxic ions, gases, pesticides, etc., are described along with illustrations. An initiative is depicted hereby using nanostructures of MOFs to decontaminate hazardous environmental toxicants.

Drinking-water isolated Delftia acidovorans selectively coaggregates with partner bacteria and facilitates multispecies biofilm development

Coaggregation plays an important role in the development of multispecies biofilms in different environments, often serving as an active bridge between biofilm members and other organisms that, in their absence, would not integrate the sessile structure. The ability of bacteria to coaggregate has been reported for a limited number of species and strains. In this study, 38 bacterial strains isolated from drinking water (DW) were investigated for their ability to coaggregate, in a total of 115 pairs of combinations. Among these isolates, only Delftia acidovorans (strain 005P) showed coaggregating ability. Coaggregation inhibition studies have shown that the interactions mediating D. acidovorans 005P coaggregation were both polysaccharide-protein and protein-protein, depending on the interacting partner bacteria. Dual-species biofilms of D. acidovorans 005P and other DW bacteria were developed to understand the role of coaggregation on biofilm formation. Biofilm formation by Citrobacter freundii and Pseudomonas putida strains highly benefited from the presence of D. acidovorans 005P, apparently due to the production of extracellular molecules/public goods favouring microbial cooperation. This was the first time that the coaggregation capacity of D. acidovorans was demonstrated, highlighting its role in providing a metabolic opportunity for partner bacteria.

Sonochemical advanced oxidation process for the degradation of furosemide in water: Effects of sonication's conditions and scavengers

The intensive consumption of pharmaceuticals and drugs in the last decades has led to their increased concentrations in wastewaters from industrial sources. The present paper deals, for the first time, with the sonochemical degradation and mineralization of furosemide (FSM) in water. FSM is a potent loop diuretic used to treat fluid build-up due to heart failure, liver scarring, or kidney disease. The influence of several operating parameters such as acoustic intensity, ultrasonic frequency, initial FSM concentration, solution's pH, nature of the dissolved gas (Ar, air and N2) and radical scavengers (2-propanol and tert-butanol) on the oxidation of FSM was assessed. The obtained results showed that the degradation rate of the drug increased significantly with the increase of the acoustic intensity in the range of 0.83 to 4.3 W cm-2 and decreased with the augmentation of the frequency in the range of 585-1140 kHz. It was also found that the initial rate of the sonolytic degradation of FSM increased with the increase of its initial concentration (2, 5, 10, 15 and 20 mg/L). The most significant degradation was achieved in acidic conditions at pH 2, while in terms of saturating gas, the rate of FSM degradation decreased in the order of Ar > air > N2. The FSM degradation experiments with radical scavengers showed that the diuretic molecule degraded mainly at the interfacial region of the bubble by hydroxyl radical attack. Additionally, in terms of acoustic conditions, the sono-degradation of 30.24 µmol L-1 of FSM solution demonstrate an optimal performance at 585 kHz and 4.3 W/cm2, the results indicated that even if the ultrasonic action eliminated the total concentration of FSM within 60 min, a low degree of mineralization was obtained due to the by-products formed during the sono-oxidation process. The ultrasonic process transforms FSM into biodegradable and environmentally friendly organic by-products that could be treated in a subsequent biological treatment. Besides, the efficiency of the sonolytic degradation of FSM in real environmental matrices such as natural mineral water and seawater was demonstrated. Consequently, the sonochemical advanced oxidation process represent a very interesting technique for the treatment of water contaminated with FSM.

Impact of parabens on drinking water bacteria and their biofilms: The role of exposure time and substrate materials

Parabens have been detected in drinking water (DW) worldwide, however, their impact on DW microbial communities remains to be explored. Microorganisms can easily adapt to environmental changes. Therefore, their exposure to contaminants of emerging concern, particularly parabens, in DW distribution systems (DWDS) may affect the microbiological quality and safety of the DW reaching the consumers tap. This work provides a pioneer evaluation of the effects of methylparaben (MP), propylparaben (PP), butylparaben (BP), and their combination (MIX), in bacterial biofilms formed on different surfaces, representative of DWDS materials - high-density polyethylene (HDPE), polypropylene (PPL) and polyvinyl chloride (PVC). Acinetobacter calcoaceticus and Stenotrophomonas maltophilia, isolated from DW, were used to form single and dual-species biofilms on the surface materials selected. The exposure to MP for 7 days caused the most significant effects on biofilms, by increasing their cellular culturability, density, and thickness up to 233%, 150%, and 224%, respectively, in comparison to non-exposed biofilms. Overall, more pronounced alterations were detected for single biofilms than for dual-species biofilms when HDPE and PPL, demonstrating that the surface material used affected the action of parabens on biofilms. Swimming motility and the production of virulence factors (protease and gelatinase) by S. maltophilia were increased up to 141%, 41%, and 73%, respectively, when exposed to MP for 7 days. The overall results highlight the potential of parabens to interfere with DW bacteria in planktonic state and biofilms, and compromise the DW microbiological quality and safety.

Landfill leachate treatment by a combination of a multiple plant hybrid constructed wetland system with a solar photoFenton process in a raceway pond reactor

The sustainable and green treatment of landfill leachate (LL), produced by municipal solid waste, represents one of the most relevant challenges in the integrated waste management systems. Accordingly, in this work a green solution was investigated by coupling an innovative hybrid constructed wetland (HCW) to a solar photo-Fenton (SPF) process. A multiple layers HCW pilot plant including different medium substrates (sand, solid compost and carriers) and plant species (Phragmites australis, Arundo donax and A. plinii) was designed. The HCW was functionalised with compost tea solution to simultaneously provide high nutrient content for plants and increase the microorganism biodiversity. Process efficiency was investigated using different real LLs (young and mature) in terms of chemical oxygen demand (COD), nitrogen compounds, chlorides and metals. Removals in the range 75-95% were observed for all the parameters after ten days of leachate recirculation in the pilot plant. Subsequently, the SPF process was carried out in a raceway pond reactor (RPR) as polishing step, significantly improving COD removal (further 49%). HCW combined with SPF in RPR would allow to meet the corresponding limits according to the final use/fate of the effluent by modulating the main parameters of the process.

Versatility of Stenotrophomonas maltophilia: Ecological roles of RND efflux pumps

S. maltophilia is a widely distributed bacterium found in natural, anthropized and clinical environments. The genome of this opportunistic pathogen of environmental origin includes a large number of genes encoding RND efflux pumps independently of the clinical or environmental origin of the strains. These pumps have been historically associated with the uptake of antibiotics and clinically relevant molecules because they confer resistance to many antibiotics. However, considering the environmental origin of S. maltophilia, the ecological role of these pumps needs to be clarified. RND efflux systems are highly conserved within bacteria and encountered both in pathogenic and non-pathogenic species. Moreover, their evolutionary origin, conservation and multiple copies in bacterial genomes suggest a primordial role in cellular functions and environmental adaptation. This review is aimed at elucidating the ecological role of S. maltophilia RND efflux pumps in the environmental context and providing an exhaustive description of the environmental niches of S. maltophilia. By looking at the substrates and functions of the pumps, we propose different involvements and roles according to the adaptation of the bacterium to various niches. We highlight that i°) regulatory mechanisms and inducer molecules help to understand the conditions leading to their expression, and ii°) association and functional redundancy of RND pumps and other efflux systems demonstrate their complex role within S. maltophilia cells. These observations emphasize that RND efflux pumps play a role in the versatility of S. maltophilia.

Global transcriptional and translational regulation of Sphingomonas melonis TY in response to hyperosmotic stress

Hyperosmotic stress is one of the most ubiquitous stress factors in microbial habitats and impairs the efficiency of bacteria performing vital biochemical tasks. Sphingomonas serves as a 'superstar' of plant defense and pollutant degradation, and is widely existed in the environment. However, it is still unclear that how Sphingomonas sp. survives under hyperosmotic stress conditions. In this study, multiomics profiling analysis was conducted with S. melonis TY under hyperosmotic conditions to investigate the intracellular hyperosmotic responses. The transcriptome and proteome revealed that sensing systems, including most membrane protein coding genes were upregulated, genes related to two-component systems were tiered adjusted to reset the whole system, other stress response regulators such as sigma-70 were also significantly tiered upregulated. In addition, transport systems together with compatible solute biosynthesis related genes were significantly upregulated to accumulate intracellular nutrients and compatible solutes. When treated with hyperosmotic stress, redox-stress response systems were triggered and mechanosensitive channels together with ion transporters were induced to maintain cellular ion homeostasis. In addition, cellular concentration of c-di-guanosine monophosphate synthetase (c-di-GMP) was reduced, followed by negative influences on genes involved in flagellar assembly and chemotaxis pathways, leading to severe damage to the athletic ability of S. melonis TY, and causing detachments of biofilms. Briefly, this research revealed a comprehensive response mechanism of S. melonis TY exposure to hyperosmotic stress, and emphasized that flagellar assembly and biofilm formation were vulnerable to hyperosmotic conditions. Importance. Sphingomonas, a genus with versatile functions survives extensively, lauded for its prominent role in plant protection and environmental remediation. Current evidence shows that hyperosmotic stress as a ubiquitous environmental factor, usually threatens the survival of microbes and thus impairs the efficiency of their environmental functions. Thus, it is essential to explore the cellular responses to hyperosmotic stress. Hence, this research will greatly enhance our understanding of the global transcriptional and translational regulation of S. melonis TY in response to hyperosmotic stress, leading to broader perspectives on the impacts of stressful environments.

Novel method in emerging environmental contaminants detection: Fiber optic sensors based on microfluidic chips

Recently, human industrial practices and certain activities have caused the widespread spread of emerging contaminants throughout the environmental matrix, even in trace amounts, which constitute a serious threat to human health and environmental ecology, and have therefore attracted the attention of research scholars. Different traditional techniques are used to monitor water pollutants, However, they still have some disadvantages such as high costs, ecological problems and treatment times, and require technicians and researchers to operate them effectively. There is therefore an urgent need to develop simple, inexpensive and highly sensitive methods to sense and detect these toxic environmental contaminants. Optical fiber microfluidic coupled sensors offer different advantages over other detection technologies, allowing manipulation of light through controlled microfluidics, precise detection results and good stability, and have therefore become a logical device for screening and identifying environmental contaminants. This paper reviews the application of fiber optic microfluidic sensors in emerging environmental contaminant detection, focusing on the characteristics of different emerging contaminant types, different types of fiber optic microfluidic sensors, methodological principles of detection, and specific emerging contaminant detection applications. The optical detection methods in fiber optic microfluidic chips and their respective advantages and disadvantages are analyzed in the discussion. The applications of fiber optic biochemical sensors in microfluidic chips, especially for the detection of emerging contaminants in the aqueous environment, such as personal care products, endocrine disruptors, and perfluorinated compounds, are reviewed. Finally, the prospects of fiber optic microfluidic coupled sensors in environmental detection and related fields are foreseen.

An Overview of the Impact of Pharmaceuticals on Aquatic Microbial Communities

Pharmaceuticals are present as pollutants in several ecosystems worldwide. Despite the reduced concentrations at which they are detected, their negative impact on natural biota constitutes a global concern. The consequences of pharmaceuticals' presence in water sources and food have been evaluated with a higher detail for human health. However, although most of the pharmaceuticals detected in the environment had not been designed to act against microorganisms, it is of utmost importance to understand their impact on the environmental native microbiota. Microbial communities can suffer serious consequences from the presence of pharmaceuticals as pollutants in the environment, which may directly impact public health and ecosystem equilibrium. Among this class of pollutants, the ones that have been studied in more detail are antibiotics. This work aims to provide an overview of the impacts of different pharmaceuticals on environmental biofilms, more specifically in biofilms from aquatic ecosystems and engineered water systems. The alterations caused in the biofilm function and characteristics, as well as bacteria antimicrobial tolerance and consequently the associated risks for public health, are also reviewed. Despite the information already available on this topic, the need for additional data urges the assessment of emerging pollutants on microbial communities and the potential public health impacts.

Acanthamoeba and a bacterial endocytobiont isolated from recreational freshwaters

The quality of many freshwater environments is impacted by human activities, so that many rivers may represent a vehicle for the transmission of health-related microorganisms. This work aimed to isolate and identify genetically free-living amoeba (FLA) of the genus Acanthamoeba from a recreational river in Salta, Argentina, and isolate, if possible, an endocytobiont. Sampling took place at four points (P1-P4) throughout the river in the winter and the summer seasons. Free-living amoebae and Acanthamoeba were recovered from 20-L water concentrated through an ultrafiltration system. Isolation was performed in agar plates, confirmation of Acanthamoeba genus by PCR, and fellow identification and classification based on their sequence analyses. High concentrations of indicator bacteria were found especially in P2, which is intensively used for recreation. Out of a total of 29 FLA isolations, 9 were identified as Acanthamoeba genotype T4 subtype A, the most frequent genotype found in nature and associated with causing human disease. From an axenic culture of Acanthamoeba spp. (KY751412), a bacterial endocytobiont was isolated, and identified as Stenotrophomonas maltophilia. The endocytobiont showed resistance and intermediate resistance to a wide range of widely used antibiotics. Results were in concordance with the cosmopolitan behavior of Acanthamoeba, and showed the importance of studying this group of amoebae and related microorganisms in recreational environments.

Distribution and characteristics of carbapenem-resistant and extended-spectrum β-lactamase (ESBL) producing Escherichia coli in hospital effluents, sewage treatment plants, and river water in an urban area of Japan

Occurrence of profiles of the carbapenem-resistant Escherichia coli (CRE-E) and extended-spectrum β-lactamase (ESBL)-producing Escherichia coli (ESBL-E) in an urban river in a sub-catchment of the Yodo River Basin, one of the representative water systems of Japan was investigated. We conducted seasonal and year-round surveys for the antimicrobial-resistant bacteria (AMRB) and antimicrobial-resistance genes (AMRGs) in hospital effluents, sewage treatment plant (STP) wastewater, and river water; subsequently, contributions to wastewater discharge into the rivers were estimated by analyses based on the mass flux. Furthermore, the characteristics of AMRB in the water samples were evaluated on the basis of antimicrobial susceptibility tests. CRE-E and ESBL-E were detected in all water samples with mean values 11 and 1900 CFU/mL in the hospital effluent, 58 and 4550 CFU/mL in the STP influent, not detected to 1 CFU/mL in the STP effluent, and 1 and 1 CFU/mL in the STP discharge into the river, respectively. Contributions of the pollution load derived from the STP effluent discharged into the river water were 1 to 21%. The resistome profiles for bla_IMP, bla_TEM, and bla_CTX-M genes in each water sample showed that AMRGs were not completely removed in the wastewater treatment process in the STP, and the relative abundances of bla_IMP, bla_TEM, and bla_CTX-M genes were almost similar (P<0.05). Susceptibility testing of antimicrobial-resistant E. coli isolates showed that CRE-E and ESBL-E detected in wastewaters and river water were linked to the prevalence of AMRB in clinical settings. These results suggest the importance of conducting environmental risk management of AMRB and AMRGs in the river environment. To our knowledge, this is the first detailed study that links the medical environment to CRE-E and ESBL-E for evaluating the AMRB and AMRGs in hospital effluents, STP wastewater, and river water at the basin scale on the basis of mass flux as well as the contributions of CRE-E and ESBL-E to wastewater discharge into the river.

The impact of synthetic musk compounds in biofilms from drinking water bacteria

Musk fragrances have been detected in drinking water (DW) at trace concentrations. However, their impact on the microbial quality of DW has been disregarded. This work provides a pioneer evaluation of the effects of two synthetic musks contaminants, tonalide (AHTN) and galaxolide (HHCB), in microbial biofilms formed on two different surfaces, polyvinyl chloride (PVC) and stainless steel AISI 316 (SS316). Three bacterial species isolated from DW (Acinetobacter calcoaceticus, Burkholderia cepacia and Stenotrophomonas maltophilia), were used to develop 7-day-old single and mixed species biofilms. The impact of musks was assessed directly on biofilms but also on the bacteria motility, biofilm formation ability and biofilm susceptibility to chlorination. AHTN musk caused the most remarkable effects by increasing the cellular density and viability of mixed biofilms, and the extracellular polysaccharides content of biofilms on SS316. Most of the alterations caused by the direct exposure of biofilms to musks were observed when SS316 was used as an adhesion surface. In contrast, the ability to form biofilms and their susceptibility to chlorine were more affected for bacteria from HHCB-exposed biofilms on PVC. The overall results demonstrate that the presence of musks at residual concentrations influences DW bacterial dynamics, with the potential to impact the DW quality and safety. The type of plumbing material may further impact the effects of musks.

Emerging contaminants of high concern for the environment: Current trends and future research

Wastewater is contaminated water that must be treated before it may be transferred into other rivers and lakes in order to prevent further groundwater pollution. Over the last decade, research has been conducted on a wide variety of contaminants, but the emerging contaminants are those caused primarily by micropollutants, endocrine disruptors (EDs), pesticides, pharmaceuticals, hormones, and toxins, as well as industrially-related synthetic dyes and dye-containing hazardous pollutants. Most emerging pollutants did not have established guidelines, but even at low concentrations they could have harmful effects on humans and aquatic organisms. In order to combat the above ecological threats, huge efforts have been done with a view to boosting the effectiveness of remediation procedures or developing new techniques for the detection, quantification and efficiency of the samples. The increase of interest in biotechnology and environmental engineering gives an opportunity for the development of more innovative ways to water treatment remediation. The purpose of this article is to provide an overview of emerging sources of contaminants, detection technologies, and treatment strategies. The goal of this review is to evaluate adsorption as a method for treating emerging pollutants, as well as sophisticated and cost-effective approaches for treating emerging contaminants.

In vitro Antibiosis of Chlorella vulgaris Extract against the Phytopathogen, Stenotrophomonas maltophilia

The aim of the current study was to evaluate the antibacterial activity of Chlorella vulgaris extracts against Stenotrophomonas maltophilia CSK1 isolated from a diseased cucumber fruit. To this end, water, methanol and ethanol were used separately as solvents to extract the active compounds from the dried Chlorella vulgaris. S. maltophilia CSK1 was identified using the 16S rRNA gene sequencing at 99.93% of identity level. The identity of the bacterial strain CSK1 was confirmed by phylogenetic analyses. CSK1 was clearly clustered with the reference strain, S. maltophilia MTCC 434 (JALV01000036). The antibiosis of the extract against S. maltophilia CSK1 was estimated using agar well diffusion method. Unlike water and ethanolic extracts, the methanolic one exhibited an inhibition of CSK1 (zone of inhibition 13.4 mm), indicating the antimicrobial activity of this extract. No zone of inhibition was formed around ethanolic and water extracts, indicating that both exhibited no-observed effect against the growth of CSK1. This can be attributed to the active constituents in the extract which may varies based on various factors including the polarity of solvent used in the extraction process. The inhibitory effect of the methanolic extract against the S. maltophilia CSK1 obtained from the diseased cucumber fruit could open the door for potential application of such active ingredient within this extract against this bacteria in future.

Synthetic Musk Fragrances in Water Systems and Their Impact on Microbial Communities

The presence of emerging contaminants in aquatic systems and their potential effects on ecosystems have sparked the interest of the scientific community with a consequent increase in their report. Moreover, the presence of emerging contaminants in the environment should be assessed through the “One-Health” approach since all the living organisms are exposed to those contaminants at some point and several works already reported their impact on ecological interactions. There are a wide variety of concerning emerging contaminants in water sources, such as pharmaceuticals, personal care products, house-care products, nanomaterials, fire-retardants, and all the vast number of different compounds of indispensable use in routine tasks. Synthetic musks are examples of fragrances used in the formulation of personal and/or house-care products, which may potentially cause significant ecotoxicological concerns. However, there is little-to-no information regarding the effect of synthetic musks on microbial communities. This study reviews the presence of musk fragrances in drinking water and their impact on aquatic microbial communities, with a focus on the role of biofilms in aquatic systems. Moreover, this review highlights the research needed for a better understating of the impact of non-pharmaceutical contaminants in microbial populations and public health.

The effect of a novel anticonvulsant chemical Q808 on gut microbiota and hippocampus neurotransmitters in pentylenetetrazole-induced seizures in rats

Background

The gut microbiota can modulate brain function and behavior and is increasingly recognized as an important factor in mediating the risk of epilepsy and the effects of seizure interventions. Drug therapy is one of the factors that influence the composition of the intestinal microbiota. Q808 is an innovative chemical with strong anticonvulsant activity and low neurotoxicity. However, studies evaluating the effect of Q808 on gut microbial communities are lacking. In this study, we aimed to evaluate the anticonvulsant activity of Q808 on a pentylenetetrazol (PTZ)—induced seizure model and analyze and compare the intestinal microbiota composition of non-PTZ vehicle control group, the PTZ-induced seizure model rats with and without Q808, through 16S rDNA sequencing. Neurotransmitter levels in the hippocampus were quantitatively estimated using HPLC–MS.

Results

The results suggest that Q808 effectively alleviates seizures in chronic PTZ-kindled model rats. Additionally, based on the analyzed abundance of the gut microbiota, dysbacteriosis of model rats was found to be corrected after Q808 treatment at the phylum level. The unique bacterial taxa (e.g., Lactobacillus) that are associated with acetylcholine production, were significantly increased. Several short-chain fatty acids (SCFAs)-producing bacteria, including Roseburia, Alloprevptella, Prevotellaceae_NK3B31_group, Prevotellaceae_UCG-001, and Prevotella_9, were enriched. In the hippocampus, the contents of acetylcholine increased, whereas the levels of 3-methoxytyramine, glutamine, and 5-hydroxyindole acetic acid (5-HIAA) decreased after Q808 treatment.

Conclusions

This study demonstrates that Q808 can be used to remodel the dysbiosis of the gut microbiome and influence neurotransmitter levels in the hippocampus of PTZ-induced seizure model rats. We hope that these novel findings prompt further research on the interaction between gut microbiota and seizures and the mechanism of Q808.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12868-022-00690-3.

Advanced catalytic oxidation coupled to biological systems to treat pesticide-contaminated water: A review on technological trends and future challenges

This article had the one and only objective of consolidating the couplings of advanced oxidation processes and biological systems in the decontamination of wastewater with pesticide content reported in the Scopus and Web of Science databases, through a critical analysis of which have been the most used, what methodologies have been implemented to develop them, identifying the objectives of each work, determining the success of the research and where the main niches of knowledge are, which can lead to the generation of new scientific knowledge as well as future trends. A co-occurrence analysis was carried out through the VOSViewer software to determine the most associated key words with the treatment configurations described above. Fenton and Photo-Fenton processes, heterogeneous photocatalysis TiO₂/UV, electrocatalysis, ozonization and a particular case of hydrodynamic cavitation-ozone as main advanced oxidation processes, together with advanced biological processes such as sequential batch bioreactor (SBR), membrane bioreactor (MBR), mobile bed biofilm reactor (MBBR); biodegradability and toxicity tests with bacterial strains and surface wetlands, whose treatment philosophy is activated sludge. The main future trends are the reuse of treated wastewater, the analysis and control of costs towards the efficient use of resources and the primary study of the byproducts generated in advanced oxidation to improve the efficiencies in the coupling.

Antimicrobial Susceptibility of Persister Biofilm Cells of Bacillus cereus and Pseudomonas fluorescens

The present study evaluates the antimicrobial susceptibility of persister cells of Bacillus cereus and Pseudomonas fluorescens after their regrowth in suspension and as biofilms. Two conventional (benzalkonium chloride-BAC and peracetic acid-PAA) and two emerging biocides (glycolic acid-GA and glyoxal-GO) were selected for this study. Persister cells resulted from biofilms subjected to a critical treatment using the selected biocides. All biocide treatments developed B. cereus persister cells, except PAA that effectively reduced the levels of vegetative cells and endospores. P. fluorescens persister cells comprise viable and viable but non-culturable cells. Afterwards, persister cells were regrown in suspension and in biofilms and were subjected to a second biocide treatment. In general, planktonic cultures of regrown persister cells in suspension lost their antimicrobial tolerance, for both bacteria. Regrown biofilms of persister cells had antimicrobial susceptibility close to those regrown biofilms of biocide-untreated cells, except for regrown biofilms of persister P. fluorescens after BAC treatment, which demonstrated increased antimicrobial tolerance. The most active biocide against persister cells was PAA, which did not promote changes in susceptibility after their regrowth. In conclusion, persister cells are ubiquitous within biofilms and survive after critical biocide treatment. The descendant planktonic and biofilms populations showed similar properties as the original ones.

Innovative Perspectives on Biofilm Interactions in Poultry Drinking Water Systems and Veterinary Antibiotics Used Worldwide

Prudent use of antibiotics in livestock is widely considered to be important to prevent antibiotic resistance. This study aimed to evaluate the interactions between biofilms and veterinary antibiotics in therapeutic concentrations administrated via drinking water through a standardized experimental setup. In this context, two biofilms formed by pseudomonads (Pseudomonas (P.) aeruginosa or P. fluorescens) and a susceptible Escherichia (E.) coli strain were developed in a nutrient-poor medium on the inner surface of polyvinyl chloride pipe pieces. Subsequently, developing biofilms were exposed to sulfadiazine/trimethoprim (SDZ/TMP) or tylosin A (TYL A) in dosages recommended for application in drinking water for 5 or 7 days, respectively. Various interactions were detected between biofilms and antibiotics. Microbiological examinations revealed that only TYL A reduced the number of bacteria on the surface of the pipes. Additionally, susceptible E. coli survived both antibiotic treatments without observable changes in the minimum inhibitory concentration to 13 relevant antibiotics. Furthermore, as demonstrated by HPLC-UV, the dynamics of SDZ/TMP and TYL A in liquid media differed between the biofilms of both pseudomonads over the exposure period. We conclude that this approach represents an innovative step toward the effective evaluation of safe veterinary antibiotic use.

Machine Learning Approach to Predict Quality Parameters for Bacterial Consortium-Treated Hospital Wastewater and Phytotoxicity Assessment on Radish, Cauliflower, Hot Pepper, Rice and Wheat Crops

Raw hospital wastewater is a source of excessive heavy metals and pharmaceutical pollutants. In water-stressed countries such as Pakistan, the practice of unsafe reuse by local farmers for crop irrigation is of major concern. In our previous work, we developed a low-cost bacterial consortium wastewater treatment method. Here, in a two-part study, we first aimed to find what physico-chemical parameters were the most important for differentiating consortium-treated and untreated wastewater for its safe reuse. This was achieved using a Kruskal–Wallis test on a suite of physico-chemical measurements to find those parameters which were differentially abundant between consortium-treated and untreated wastewater. The differentially abundant parameters were then input to a Random Forest classifier. The classifier showed that ‘turbidity’ was the most influential parameter for predicting biotreatment. In the second part of our study, we wanted to know if the consortium-treated wastewater was safe for crop irrigation. We therefore carried out a plant growth experiment using a range of popular crop plants in Pakistan (Radish, Cauliflower, Hot pepper, Rice and Wheat), which were grown using irrigation from consortium-treated and untreated hospital wastewater at a range of dilutions (turbidity levels) and performed a phytotoxicity assessment. Our results showed an increasing trend in germination indices and a decreasing one in phytotoxicity indices in plants after irrigation with consortium-treated hospital wastewater (at each dilution/turbidity measure). The comparative study of growth between plants showed the following trend: Cauliflower > Radish > Wheat > Rice > Hot pepper. Cauliflower was the most adaptive plant (PI: −0.28, −0.13, −0.16, −0.06) for the treated hospital wastewater, while hot pepper was susceptible for reuse; hence, we conclude that bacterial consortium-treated hospital wastewater is safe for reuse for the irrigation of cauliflower, radish, wheat and rice. We further conclude that turbidity is the most influential parameter for predicting bio-treatment efficiency prior to water reuse. This method, therefore, could represent a low-cost, low-tech and safe means for farmers to grow crops in water stressed areas.

Isolation and characterization of a strain with high microbial attachment in aerobic granular sludge

Aerobic granule is a special microbial aggregate associated with biofilm structure. The formation of aerobic granular sludge is primarily depending on its bacterial community and relevant microbiological properties. In this experiment, a strain with high microbial attachment was isolated from aerobic granular sludge, and the detailed characteristics were examined. Its high attachment ability could reach 2.34 (OD_600nm), while other low attachment values were only around 0.06-0.32, which indicated a big variation among the different bacteria. The strain exhibited a very special morphology with many fibric fingers under SEM observation. A distinctive behaviour was to form a spherical particle by themselves, which would be very beneficial for the formation and development of granular sludge. The EPS measurement showed that its PN content was higher than low attachment bacteria, and 3D-EEM confirmed that there were some different components. Based on the 16S rRNA analysis, it was identified to mostly belong to Stenotrophomonas. Its augmentation to particle sludge cultivation demonstrated that the strain could significantly promote the formation of aerobic granule. Conclusively, it was strongly suggested that it might be used as a good and potential model strain or chassis organism for the aerobic granular sludge formation and development.

Antimicrobial Activity of Non-steroidal Anti-inflammatory Drugs on Biofilm: Current Evidence and Potential for Drug Repurposing

It has been demonstrated that some non-steroidal anti-inflammatory drugs (NSAIDs), like acetylsalicylic acid, diclofenac, and ibuprofen, have anti-biofilm activity in concentrations found in human pharmacokinetic studies, which could fuel an interest in repurposing these well tolerated drugs as adjunctive therapies for biofilm-related infections. Here we sought to review the currently available data on the anti-biofilm activity of NSAIDs and its relevance in a clinical context. We performed a systematic literature review to identify the most commonly tested NSAIDs drugs in the last 5 years, the bacterial species that have demonstrated to be responsive to their actions, and the emergence of resistance to these molecules. We found that most studies investigating NSAIDs' activity against biofilms were in vitro, and frequently tested non-clinical bacterial isolates, which may not adequately represent the bacterial populations that cause clinically-relevant biofilm-related infections. Furthermore, studies concerning NSAIDs and antibiotic resistance are scarce, with divergent outcomes. Although the potential to use NSAIDs to control biofilm-related infections seems to be an exciting avenue, there is a paucity of studies that tested these drugs using appropriate in vivo models of biofilm infections or in controlled human clinical trials to support their repurposing as anti-biofilm agents.

Environmental and health impacts of contaminants of emerging concerns: Recent treatment challenges and approaches

In the past few decades, new contaminants of emerging concern (CECs) in the air, water, and soil have gained significant attention due to their adverse impact on human health and the environment. The sources of CECs have been identified in different forms from domestic and industrial activities such as personal care products and pharmaceuticals. It has been established that aqueous medium plays a major role in the dissemination of various contaminants, like drinking water, reservoirs, lakes, rivers and waste with water medium. There remains inadequate technology for the treatment of CECs in the wastewater systems. Though different techniques have advanced for the treatment of CECs, they still pose a severe threat to human health and disturb the ecological balance. In this review, the characteristics, recent technologies, risk assessment and management of CECs have been discussed. The primary aim is to highlight the new innovative and cost-effective technologies for the remediations of CECs in all forms. Biochar is readily and economically available in abundance and an economical adsorbent with 100% adsorptive removal for H₂PO₄^-. The bibliometric analysis also performed to understand the emerging research trends on the treatment techniques, which can help in developing a guiding pathway to modern research in academia and industry.

Advances in the Microbiology of Stenotrophomonas maltophilia

Stenotrophomonas maltophilia is an opportunistic pathogen of significant concern to susceptible patient populations. This pathogen can cause nosocomial and community-acquired respiratory and bloodstream infections and various other infections in humans. Sources include water, plant rhizospheres, animals, and foods. Studies of the genetic heterogeneity of S. maltophilia strains have identified several new genogroups and suggested adaptation of this pathogen to its habitats. The mechanisms used by S. maltophilia during pathogenesis continue to be uncovered and explored. S. maltophilia virulence factors include use of motility, biofilm formation, iron acquisition mechanisms, outer membrane components, protein secretion systems, extracellular enzymes, and antimicrobial resistance mechanisms. S. maltophilia is intrinsically drug resistant to an array of different antibiotics and uses a broad arsenal to protect itself against antimicrobials. Surveillance studies have recorded increases in drug resistance for S. maltophilia, prompting new strategies to be developed against this opportunist. The interactions of this environmental bacterium with other microorganisms are being elucidated. S. maltophilia and its products have applications in biotechnology, including agriculture, biocontrol, and bioremediation.

Discrepant roles of a quorum quenching bacterium (Rhodococcus sp. BH4) in growing dual-species biofilms

Quorum quenching (QQ) is a promising alternative method for biofilm control. However, a largely unexplored issue is the mechanism through which QQ bacteria interact with biofilm-forming bacteria. Here, we explore inter-species interactions during biofilm development (using 96-well polystyrene plates in a static incubator) between the QQ bacterium Rhodococcus sp. BH4 and sludge bacteria. Experimental results revealed that strain BH4 provoked both competitive (76%) and cooperative (24%) interactions (P < 0.05) in dual-species biofilms after 24 h of incubation (mature biofilm), implying that signal destruction by strain BH4 was strain-dependent. Besides hike in the biofilm biomass (~21%), amount of extracellular polymeric substances (EPS) (25-30 times) and particle size (3.5 times) in the Serratia sp. JSB1 biofilm were increased by str. BH4. This suggests that strain BH4 may only have quenching effects against certain bacteria, and that such effects are overlooked at the community level. Taken together, present results imply that in a given biofilm community, not all QS-bacteria interact similarly with Rhodococcus sp. BH4, either because QS-bacteria are tolerant of strain BH4 or QS-bacteria have more than one mechanism for biofilm development. Overall, the QQ-strategy alone seems ineffective at controlling biofilm development, although it may be used in combination with other strategies.

Emerging roles for the intestinal microbiome in epilepsy

The gut microbiome is emerging as a key regulator of brain function and behavior and is associated with symptoms of several neurological disorders. There is emerging evidence that alterations in the gut microbiota are seen in epilepsy and in response to seizure interventions. In this review, we highlight recent studies reporting that individuals with refractory epilepsy exhibit altered composition of the gut microbiota. We further discuss antibiotic treatment and infection as microbiome-related factors that influence seizure susceptibility in humans and animal models. In addition, we evaluate how the microbiome may mediate effects of the ketogenic diet, probiotic treatment, and anti-epileptic drugs on reducing both seizure frequency and severity. Finally, we assess the open questions in interrogating roles for the microbiome in epilepsy and address the prospect that continued research may uncover fundamental insights for understanding risk factors for epilepsy, as well as novel approaches for treating refractory epilepsy.

Influence of surface copper content on Stenotrophomonas maltophilia biofilm control using chlorine and mechanical stress

This work aimed to evaluate the action of materials with different copper content (0, 57, 96 and 100%) on biofilm formation and control by chlorination and mechanical stress. Stenotrophomonas maltophilia isolated from drinking water was used as a model microorganism and biofilms were developed in a rotating cylinder reactor using realism-based shear stress conditions. Biofilms were characterized phenotypically and exposed to three control strategies: 10 mg l^-1 of free chlorine for 10 min, an increased shear stress (a fluid velocity of 1.5 m s^-1 for 30s), and a combination of both treatments. These shock treatments were not effective in biofilm control. The benefits from the use of copper surfaces was found essentially in reducing the numbers of non-damaged cells. Copper materials demonstrated better performance in biofilm prevention than chlorine. In general, copper alloys may have a positive public health impact by reducing the number of non-damaged cells in the water delivered after chlorine exposure.

Structure-Dependent Inhibition of Stenotrophomonas maltophilia by Polyphenol and Its Impact on Cell Membrane

As natural occurring antimicrobial substances, phenolic compounds have been used to inhibit various bacteria. Stenotrophomonas maltophilia 4–1, a strain isolated from food, exhibited spoilage potential in vitro with proteolysis and lipolysis at 25°C. The present study evaluated the antibacterial properties of 13 polyphenols on S. maltophilia 4–1, and selected 6 compounds (ferulic acid, p-coumaric acid, caffeic acid, chlorogenic acid, (−)-epigallocatechin, and phloretin) for binary combination treatments. The results revealed that antibacterial activities of polyphenols were structure-dependent, and cinnamic acid showed strong inhibitory effects, with a minimum inhibitory concentration (MIC) of 0.125 mg/mL. Importantly, we did not observe any obvious synergistic effects across all binary combinations. The antibacterial mechanism of cinnamic acid was related to membrane damage, caused by the loss of cell membrane integrity and alteration of cell morphology. These findings suggest that cinnamic acid is a promising candidate for the control of spoilage bacteria in food.

Adhesion of filamentous fungi isolated from drinking water under different process conditions

Filamentous fungi (ff) are consistently recognized as drinking water (DW) inhabitants, typically harboured in biofilms. Their sessile behaviour is still poorly understood. This study aimed the evaluation of the influence of several abiotic factors (substratum, hydrodynamic conditions and nutrient availability) on biofilm formation by Penicillium brevicompactum and P. expansum isolated from DW. Fungal adhesion was quantified on high density polyethylene (HDPE) and polyvinyl chloride (PVC) surfaces using synthetic tap water (STW) and R2A broth, under stagnant or agitated (25 and 150 rpm) conditions. Fungal spore numbers were assessed after staining with Calcofluor White MR2 and epifluorescence microscopy. The surface charge and physicochemical properties of spores were characterized for a mechanistic understanding on the adhesion process. The adhesion kinetics of spores was represented accurately by the Logistic model, in which adhesion increased with time until a maximum level attained before spore germination (8 h after incubation). In general, P. brevicompactum demonstrated to adhere in a higher extent than P. expansum (12 × 10⁴ spores/cm²vs 1.7 × 10⁴ spores/cm²). Moreover, fungal adhesion was potentiated under stagnation and using R2A broth. HDPE and PVC allowed spore adhesion at similar extents. Adhesion predictions based on the extended Derjaguin, Landau, Verwey and Overbeek (XDLVO) theory corroborated the experimental results, highlighting the role of physicochemical surface properties on the adhesion of spores. These results allowed to refine a model for ff biofilm formation. The overall results help to understand key aspects determining the presence of P. brevicompactum and P. expansum biofilms in DW, where stagnant conditions and the presence of nutrients should be avoided to prevent ff biofilm formation.

Prolonged exposure of Stenotrophomonas maltophilia biofilms to trace levels of clofibric acid alters antimicrobial tolerance and virulence

The presence of pharmaceuticals in water sources, including in drinking water (DW), is increasingly being recognized as an emerging and global concern for the environment and public health. Based on the principles of the "One Health" initiative, the present work aims to understand the effects of clofibric acid (CA), a lipid regulator, on the behavior of a selected bacterium isolated from drinking water (DW). Biofilms of the opportunistic pathogen Stenotrophomonas maltophilia were exposed to CA for 12 weeks at 170 and 17000 ng/L. The effects of CA were evaluated on planktonic S. maltophilia susceptibility to chlorine and antibiotics (amoxicillin, ciprofloxacin, erythromycin, kanamycin, levofloxacin, oxacillin, spectinomycin, tetracycline and trimethoprim-sulfamethoxazole), biofilm formation, motility, siderophores production and on the adhesion and internalization of the human colon adenocarcinoma cell line (HT-29). It was found that CA did not affect planktonic S. maltophilia tolerance to chlorine exposure. Additionally, no effects were observed on biofilm formation, motility and siderophores production. However, biofilms formed after CA exposure were more tolerant to chlorine disinfection and lower CFU reductions were obtained. Of additional concern was the effect of CA exposure on S. maltophilia increased tolerance to erythromycin. CA exposure also slightly reduced S. maltophilia ability to invade HT-29 cells. In conclusion, this work reinforces the importance of studying the effects of non-antibiotic contaminants on the behavior of environmental microorganisms, particularly their role as drivers affecting resistance evolution and selection.

Anti-cancer drugs in aquatic environment can cause cancer: Insight about mutagenicity in tadpoles

Cyclophosphamide (Cyc) and 5-fluorouracil (5-FU) are two of the most used antineoplastic drugs (AD) in the world. However, their discharge in the environment became a yet-unknown environmental issue that has impact on some groups of animals, such as amphibians. We assessed tadpoles (Lithobates catesbeianus) exposed to environmental concentrations (EC) of Cyc and 5-FU to evaluate whether they can cause morphological and mutagenic changes in them. We defined the following groups: control, positive control (50 mg/L of Cyc), EC-Cyc-I (0.2 μg/L), EC-Cyc-II (0.5 μg/L), EF-Cyc (2.0 μg/L), EC-5-FU-I (13.0 μg/L), EC-5-FU-II (30.4 μg/L) and EF-5-FU (123.5 μg/L). EC groups presented predictive AD concentrations in 10% and 25% hospital-effluent dilutions in water. EF groups met gross hospital-effluent concentrations. Based on our data, ADs caused intestinal changes and influenced the interocular distance in tadpoles after 30-day exposure. We also observed the aneugenic and clastogenic effect of ADs due to the higher frequency of micronucleated and binucleated erythrocytes, and blebbed, multilobulated, notched and kidney-shaped nuclei in animals exposed to them. Based on such changes, we assume that Cyc and 5-FU can trigger malignant cell transformation processes, and cancer, in animals exposed to them, even at low concentrations. Our study is the first to describe that Cyc and 5-FU, spread in the environment, cause damages in non-target organisms opposite to their original end.

Removal of Enteric Pathogens from Real Wastewater Using Single and Catalytic Ozonation

Water scarcity is one of the main problems of this century. Water reclamation appears as an alternative due to the reuse of treated wastewater. Therefore, effluents treatment technologies (activated sludge, rotary biological discs, percolating beds) must be improved since they are not able to remove emerging contaminants such as enteric pathogens (bacteria and virus). These pollutants are difficult to remove from the wastewater and lead to adverse consequences to human health. Advanced oxidation processes, such as single and catalytic ozonation, appear as suitable complements to conventional processes. Catalytic ozonation was carried out using a low-cost material, a volcanic rock. Single and catalytic ozonation were capable of promoting total Escherichia coli removal from municipal wastewater after 90 min of contact. The presence of volcanic rock increases disinfection efficiency since E. coli regrowth was not observed. The identified viruses (Norovirus genotype I and II and JC virus) were completely removed using catalytic ozonation, whereas single ozonation was not able to eliminate JC virus even after 150 min of treatment. The higher performance of the catalytic process can be explained by the formation of hydroxyl radicals, proving that disinfection occurs in the liquid bulk and not due to adsorption at the volcanic rock.

The role of surface copper content on biofilm formation by drinking water bacteria

Copper alloys demonstrated comparable or higher performance than elemental copper in biofilm control. The alloy containing 96% copper was the most promising surface in biofilm control and regrowth prevention.

Environmentally-related contaminants of high concern: Potential sources and analytical modalities for detection, quantification, and treatment

In recent years, emerging contaminants (ECs) of high concern are broadly distributed throughout the environmental matrices because of various industrial practices and anthropogenic inputs, i.e., human-made activities. With ever increasing scientific knowledge, technological advancement, socio-economic awareness, people are now more concern about the widespread distribution of environmentally related ECs of high concern. As, ECs possess serious ecological threats and potential risks to human health and aquatic life, even at minor concentrations. The controlled or uncontrolled discharge and long-term persistence of ECs that includes micro-pollutants, endocrine disruptors (EDs), pesticides, pharmaceuticals, hormones, toxins, and industrially-related synthetic dyes and dyes-containing hazardous pollutants, etc. pose a significant challenge to policy regulators, engineers, and scientific community. The conventional treatment technologies are proved ineffective for the complete elimination and removal of an array of contaminants of emerging environmental concern in various biological and environmental samples. In order to overcome the aforementioned ecological threats, tremendous research efforts have been made to boost the efficiency of remediation techniques or develop new modalities to detect, quantify and treat the samples efficiently. The boom in biotechnology and environmental engineering offers potential opportunities to develop advanced and innovative remediation techniques in the field of water treatment. This review discusses the environmental and health hazards associated with a widespread distribution of micro-pollutants, pesticides, pharmaceuticals, hormones, and industrially-related synthetic dyes and dyes-containing hazardous pollutants, etc. in the water bodies, i.e., surface water, groundwater, and industrial wastewater streams. Life-cycle distribution of emerging (micro)-pollutants with suitable examples from various industrial sources viewpoints is also discussed. The later part of the review focuses on innovative and cost-effective remediation (removal) approaches from phase-changing treatment technologies for these ECs of high concern.