Search Results (16)

Legacy sulfur smelting has left behind complex contamination landscapes, yet the spatial structuring of microbial risks and adaptation strategies across soil profiles remains insufficiently understood. Microbial risk genes, including those conferring resistance to antibiotic resistance (ARGs), biocide and metal resistance (BRGs/MRGs), and virulence (VFGs), are increasingly recognized as co-selected under heavy metal stress, posing both ecological and public health concerns. In this study, we integrated geochemical analyses with metagenomic sequencing and functional annotation to jointly characterize the vertical (0–7 m) and horizontal (~2 km) distribution of heavy metals/metalloids, microbial communities, and functional risk genes at a historic smelting site in Zhenxiong, Yunnan. Heavy metals and metalloids such as arsenic (As), chromium (Cr), copper (Cu), and lead (Pb) showed clear accumulation with depth, while significantly lower concentrations were observed in both upstream and downstream locations, revealing persistent vertical and horizontal pollution gradients. Correspondingly, resistance and virulence genes were co-enriched at contaminated sites, suggesting potential co-selection under prolonged stress. LEfSe analysis revealed distinct ecological patterns: vertically, upper layers were dominated by nutrient-cycling and mildly stress-tolerant taxa, while deeper layers favored metal-resistant, oligotrophic, and potentially pathogenic microorganisms; horizontally, beneficial and diverse microbes characterized low-contamination zones, whereas heavily polluted areas were dominated by resistant and stress-adapted genera. These findings provide new insights into microbial resilience and ecological risk under long-term smelting stress. Full article

Concerns about the negative effects of traditional insecticides and increasing insecticide resistance have prompted the exploration of botanical alternatives like essential oils (EOs). The registration of biocides is a mandatory procedure, and some regions have established a special status for compounds that meet specific low-risk criteria, which includes certain EOs. This study aimed to evaluate and compare the efficacy of sixteen EOs, both registered as low-risk biocides and/or standard biocides, against the German cockroach, Blattella germanica. A topical application was performed with undiluted EOs (15 µL) on the dorsal surface of awake cockroaches. The results showed significant variations in efficacy, as follows: thyme, sweet orange, and lavender oils were the most effective, achieving 100% mortality within 24 h and a less than 30 s knockdown effect. In contrast, linseed and cottonseed oils were the least effective, resulting in 70% and 40% 24 h mortality. Remarkably, some EOs registered as low-risk biocides performed as well as the ones registered as standard biocides, suggesting that this category does not have to always be at odds with efficacy. Future research should adopt practical, application-driven approaches to ensure bioinsecticides balance performance and safety, meeting both regulatory and consumer demands. Full article

Due to their antibacterial and antifungal properties, parabens are commonly used as biocides and preservatives in food, cosmetics, and pharmaceuticals. Parabens have been reported to exist in various water matrices at low concentrations, which renders the need for sample preparation before their quantification using analytical techniques. Thus, sample preparation methods such as solid-phase extraction (SPE), rotating-disk sorptive extraction (RDSE), and vortex-assisted dispersive liquid–liquid extraction (VA-DLLE) that are commonly used for parabens extraction and preconcentration have been discussed. As a result of sample preparation methods, analytical techniques now detect parabens at trace levels ranging from µg/L to ng/L. These compounds have been detected in water, air, soil, and human tissues. While the full impact of parabens on human health and ecosystems is still being debated in the scientific community, it is widely recognized that parabens can act as endocrine disruptors. Furthermore, some studies have suggested that parabens may have carcinogenic effects. The presence of parabens in the environment is primarily due to wastewater discharges, which result in widespread contamination and their concentrations increased during the COVID-19 pandemic waves. Neglecting the presence of parabens in water exposes humans to these compounds through contaminated food and drinking water. Although there are reviews that focus on the occurrence, fate, and behavior of parabens in the environment, they frequently overlook critical aspects such as removal methods, policy development, and regulatory frameworks. Addressing this gap, the effective treatment of parabens in water relies on combined approaches that address both cost and operational challenges. Membrane filtration methods, such as nanofiltration (NF) and reverse osmosis (RO), demonstrate high efficacy but are hindered by maintenance and energy costs due to extensive fouling. Innovations in anti-fouling and energy efficiency, coupled with pre-treatment methods like adsorption, help mitigate these costs and enhance scalability. Furthermore, combining adsorption with advanced oxidation processes (AOPs) or biological treatments significantly improves economic and energy efficiency. Integrating systems like O₃/UV with activated carbon, along with byproduct recovery strategies, further advances circular economy goals by minimizing waste and resource use. This review provides a thorough overview of paraben monitoring in wastewater, current treatment techniques, and the regulatory policies that govern their presence. Furthermore, it provides perspectives that are critical for future scientific investigations and shaping policies aimed at mitigating the risks of parabens in drinking water. Full article

The use of traditional biocidal products in cultural heritage has suffered a slowdown due to the risks related to human health and the environment. Thus, many studies have been carried out with the aim of testing innovative and environmentally friendly alternatives. In this framework, this review attempts to provide an overview of some novel potential products with biocidal action, tested to counteract the process of degradation of paper and stone materials due to microbial activity, keeping in mind the sustainability criteria. In particular, we have focused our attention on the testing of nanotechnologies, essential oils, DES (deep eutectic solvents) with low toxicity, and colloidal substances for conservation purposes. Full article

Worldwide, the need for thermal insulation materials used to increase the energy performance of buildings and ensure indoor thermal comfort is constantly growing. There are several traditional, well-known and frequently used thermal insulation materials on the building materials market, but there is a growing trend towards innovative materials based on agro-industrial waste. This paper analyses the performance of 10 such innovative thermal insulation materials obtained by recycling cellulosic and/or animal waste, using standardised testing methods. More precisely, thermal insulation materials based on the following raw materials were analysed: cellulose acetate, cigarette filter manufacturing waste; cellulose acetate, cigarette filter manufacturing waste and cigarette paper waste; cellulose acetate, waste from cigarette filter manufacturing, waste cigarette paper and waste aluminised paper; cellulose from waste paper (two types made by two independent manufacturers); wood fibres; cellulose from cardboard waste; cellulose from waste cardboard, poor processing, inhomogeneous product; rice husk waste and composite based on sheep wool, recycled PET fibres and cellulosic fibres for the textile industry. The analysis followed the performance in terms of thermal insulating quality, evidenced by the thermal conductivity coefficient (used as a measurable indicator) determined for both dry and conditioned material at 50% RH, in several density variants, simulating the subsidence under its own weight or under various possible stresses arising in use. The results showed in most cases that an increase in material density has beneficial effects by reducing the coefficient of thermal conductivity, but exceptions were also reported. In conjunction with this parameter, the analysis of the 10 types of materials also looked at their moisture sorption/desorption capacity (using as a measurable indicator the amount of water stored by the material), concluding that, although they have a capacity to regulate the humidity of the indoor air, under low RH conditions the water loss is not complete, leaving a residual quantity of material that could favour the development of mould. Therefore, the impact on indoor air quality was also analysed by assessing the risk of mould growth (using as a measurable indicator the class and performance category of the material in terms of nutrient content conducive to the growth of microorganisms) under high humidity conditions but also the resistance to the action of two commonly encountered moulds, Aspergillus niger and Penicillium notatum. The results showed a relative resistance to the action of microbiological factors, indicating however the need for intensified biocidal treatment. Full article

Mesoporous silica engineered nanomaterials are of interest to the industry due to their drug-carrier ability. Advances in coating technology include using mesoporous silica nanocontainers (SiNC) loaded with organic molecules as additives in protective coatings. The SiNC loaded with the biocide 4,5-dichloro-2-octyl-4-isothiazolin-3-one (DCOIT), i.e., SiNC-DCOIT, is proposed as an additive for antifouling marine paints. As the instability of nanomaterials in ionic-rich media has been reported and related to shifting key properties and its environmental fate, this study aims at understanding the behaviour of SiNC and SiNC-DCOIT in aqueous media with distinct ionic strengths. Both nanomaterials were dispersed in (i) low- (ultrapure water—UP) and (ii) high- ionic strength media—artificial seawater (ASW) and f/2 medium enriched in ASW (f/2 medium). The morphology, size and zeta potential (ζP) of both engineering nanomaterials were evaluated at different timepoints and concentrations. Results showed that both nanomaterials were unstable in aqueous suspensions, with the initial ζP values in UP below −30 mV and the particle size varying from 148 to 235 nm and 153 to 173 nm for SiNC and SiNC-DCOIT, respectively. In UP, aggregation occurs over time, regardless of the concentration. Additionally, the formation of larger complexes was associated with modifications in the ζP values towards the threshold of stable nanoparticles. In ASW, SiNC and SiNC-DCOIT formed aggregates (<300 nm) independently of the time or concentration, while larger and heterogeneous nanostructures (>300 nm) were detected in the f/2 medium. The pattern of aggregation detected may increase engineering nanomaterial sedimentation rates and enhance the risks towards dwelling organisms. Full article

Acaricides are hypothesized to reduce human risk of exposure to tick-borne pathogens by decreasing the abundance and/or infection prevalence of the ticks that serve as vectors for the pathogens. Acaricides targeted at reservoir hosts such as small mammals are expected to reduce infection prevalence in ticks by preventing their acquisition of zoonotic pathogens. By reducing tick abundance, reservoir-targeted or broadcast acaricides could reduce tick infection prevalence by interrupting transmission cycles between ticks and their hosts. Using an acaricide targeted at small-mammal hosts (TCS bait boxes) and one sprayed on low vegetation (Met52 fungal biocide), we tested the hypotheses that infection prevalence of blacklegged ticks with zoonotic pathogens would be more strongly diminished by TCS bait boxes, and that any effects of both acaricidal treatments would increase during the four years of deployment. We used a masked, placebo-controlled design in 24 residential neighborhoods in Dutchess County, New York. Analyzing prevalence of infection with Borrelia burgdorferi, Anaplasma phagocytophilum, and Babesia microti in 5380 nymphal Ixodes scapularis ticks, we found little support for either hypothesis. TCS bait boxes did not reduce infection prevalence with any of the three pathogens compared to placebo controls. Met52 was associated with lower infection prevalence with B. burgdorferi compared to placebo controls but had no effect on prevalence of infection with the other two pathogens. Although significant effects of year on infection prevalence of all three pathogens were detected, hypothesized cumulative reductions in prevalence were observed only for B. burgdorferi. We conclude that reservoir-targeted and broadcast acaricides might not generally disrupt pathogen transmission between reservoir hosts and tick vectors or reduce human risk of exposure to tick-borne pathogens. Full article

Organotin compounds (OTCs) are a commercially important group of organometallic compounds of tin used globally as polyvinyl chloride stabilizers and marine antifouling biocides. Worldwide use of OTCs has resulted in their ubiquitous presence in ecosystems across all the continents. OTCs have metabolic and endocrine disrupting effects in marine and terrestrial organisms. Thus, harmful OTCs (tributyltin) have been banned by the International Convention on the Control of Harmful Antifouling Systems since 2008. However, continued manufacturing by non-member countries poses a substantial risk for animal and human health. In this study, structural binding of common commercial OTCs, tributyltin (TBT), dibutyltin (DBT), monobutyltin (MBT), triphenyltin (TPT), diphenyltin (DPT), monophenyltin (MPT), and azocyclotin (ACT) against sex-steroid nuclear receptors, androgen receptor (AR), and estrogen receptors (ERα, ERβ) was performed using molecular docking and MD simulation. TBT, DBT, DPT, and MPT bound deep within the binding sites of AR, ERα, and Erβ, showing good dock score, binding energy and dissociation constants that were comparable to bound native ligands, testosterone and estradiol. The stability of docking complex was shown by MD simulation of organotin/receptor complex with RMSD, RMSF, Rg, and SASA plots showing stable interaction, low deviation, and compactness of the complex. A high commonality (50–100%) of interacting residues of ERα and ERβ for the docked ligands and bound native ligand (estradiol) indicated that the organotin compounds bound in the same binding site of the receptor as the native ligand. The results suggested that organotins may interfere with the natural steroid/receptor binding and perturb steroid signaling. Full article

Background: Klebsiella pneumoniae is an important multidrug-resistant (MDR) pathogen, causing both community- and healthcare-associated infections. The resistance is due to the continuous accumulation of multiple antibiotic-resistance-genes (ARGs) through spontaneous genomic mutations and the acquisition of conjugative plasmids. This study presents antibiotics resistance genes, plasmids replicons, and virulence genes of K. pneumoniae isolates from clinical specimens in a tertiary hospital, Mwanza, Tanzania. Methods: Whole genome sequencing (WGS) of 34 K. pneumoniae was performed, using an Illumina NextSeq 500, followed by in silco analysis. Results: A total of 34 extended-spectrum beta-lactamase-producing K. pneumoniae, isolated from blood samples from neonatal units were whole-genome sequenced. Of these, 28 (82.4%) had an identified sequence type (ST), with ST14 (39.3%, n = 11) being frequently identified. Moreover, 18 (52.9%) of the bacteria harbored at least one plasmid, from which a total of 25 plasmid replicons were identified with a predominance of IncFIB(K) 48.0% (n = 12). Out of 34 sequenced K. pneumoniae, 32 (94.1%) were harboring acquired antibiotic/biocides-resistance-genes (ARGs) with a predominance of bla_CTX-M-15 (90.6%), followed by oqxB (87.5%), oqxA (84.4%), bla_TEM-1B (84.4%) and sul2 (84.4%). Interestingly, we observed the ColRNAI plasmid-replicon (n = 1) and qacE gene (n = 4) for the first time in this setting. Conclusion: Global high-risk clones of K. pneumoniae isolates carry multiple ARGs in multiple plasmid-replicons. Findings from this study warrant genomic-based surveillance to monitor high-risk global clones, epidemic plasmids and ARGs in low- and middle-income countries. Full article

Mosquitoes breeding in urban sewage infrastructure are both a source of nuisance to the local population and a public health risk, given that biting mosquitoes can transmit pathogenic organisms to humans. The increasing presence of the invasive mosquito species Aedes albopictus in European cities has further exacerbated the problems already caused by native Culex pipiens. We tested the effectiveness of modifications to sewage structures as an alternative to the use of biocides to prevent mosquito breeding. The placing of a layer of concrete at the bottom of sand sewers to prevent water accumulation completely eliminated mosquito reproduction, and so eliminates the need for biocides in modified structures. Sewer modification is thus a valid low-cost alternative for mosquito control. Full article

The presence of virulence genes, phylogenetic relationships, biofilm formation index (BFI), and ultrastructure in S. Minnesota at different temperatures (4, 25, and 36 °C) were analyzed. In addition, the ability of biocidal agents (chlorhexidine1%, sodium hypochlorite 1%, and peracetic acid 0.8%) to inhibit biofilms formed by 20 strains isolated from broiler slaughter plants from two Brazilian companies in 2009, 2010, and 2014 was determined. The presence of specific genes was evaluated by PCR and phylogeny between strains by pulsed-field gel electrophoresis. The BFI was determined using tryptone soy broth with 5% of chicken juice, and its structure was observed by scanning electron microscopy. The presence of specific genes indicated that S. Minnesota has the potential to cause disease in humans, adapting to adverse conditions. Temperatures of 25 and 36 °C favored biofilm formation, although at 4 °C, there was still biomass that could contaminate the final product. Tolerance to all biocides was identified in 12/20 (60%), representing a real risk of adaptation mechanisms development, especially regarding to resistance to sodium hypochlorite. Phylogenetic analysis indicated cross-contamination and spread among companies, which was probably related to biofilms formation. Results show the necessity of attention to this serovar considering its resistance to sodium hypochlorite, including the need for rigorous control, adopting low temperatures to prevent biofilms formation in the poultry industry. Full article

Rare sugars are monosaccharides with a limited availability in the nature and almost unknown biological functions. The use of industrial enzymatic and microbial processes greatly reduced their production costs, making research on these molecules more accessible. Since then, the number of studies on their medical/clinical applications grew and rare sugars emerged as potential candidates to replace conventional sugars in human nutrition thanks to their beneficial health effects. More recently, the potential use of rare sugars in agriculture was also highlighted. However, overviews and critical evaluations on this topic are missing. This review aims to provide the current knowledge about the effects of rare sugars on the organisms of the farming ecosystem, with an emphasis on their mode of action and practical use as an innovative tool for sustainable agriculture. Some rare sugars can impact the plant growth and immune responses by affecting metabolic homeostasis and the hormonal signaling pathways. These properties could be used for the development of new herbicides, plant growth regulators and resistance inducers. Other rare sugars also showed antinutritional properties on some phytopathogens and biocidal activity against some plant pests, highlighting their promising potential for the development of new sustainable pesticides. Their low risk for human health also makes them safe and ecofriendly alternatives to agrochemicals. Full article

Although the failure of antibiotic treatment is normally attributed to resistance, tolerance and persistence display a significant role in the lack of response to antibiotics. Due to the fact that several nosocomial pathogens show a high level of tolerance and/or resistance to chlorhexidine, in this study we analyzed the molecular mechanisms associated with chlorhexidine adaptation in two clinical strains of Klebsiella pneumoniae by phenotypic and transcriptomic studies. These two strains belong to ST258-KPC3 (high-risk clone carrying β-lactamase KPC3) and ST846-OXA48 (low-risk clone carrying β-lactamase OXA48). Our results showed that the K. pneumoniae ST258-KPC3CA and ST846-OXA48CA strains exhibited a different behavior under chlorhexidine (CHLX) pressure, adapting to this biocide through resistance and tolerance mechanisms, respectively. Furthermore, the appearance of cross-resistance to colistin was observed in the ST846-OXA48CA strain (tolerant to CHLX), using the broth microdilution method. Interestingly, this ST846-OXA48CA isolate contained a plasmid that encodes a novel type II toxin/antitoxin (TA) system, PemI/PemK. We characterized this PemI/PemK TA system by cloning both genes into the IPTG-inducible pCA24N plasmid, and found their role in persistence and biofilm formation. Accordingly, the ST846-OXA48CA strain showed a persistence biphasic curve in the presence of a chlorhexidine-imipenem combination, and these results were confirmed by the enzymatic assay (WST-1). Full article

Biocides are non-agricultural chemical agents for the prevention of unhygienic pests. The worldwide demand for biocidal products has been rapidly increasing. Meanwhile, biocides have been causing negative health effects for decades, resulting in public health scares. Therefore, governments around the world have tried to strictly control biocides, and it is necessary to prioritize the health risks of biocides for efficient management. Chemical ranking and scoring (CRS) methods have been developed for the effective management of chemicals. However, existing methods do not use suitable variables to evaluate biocides, thus possibly underestimating or overestimating the actual health risks. We developed a new CRS method that reflects the exposure and toxicity characteristics of biocides. Eleven indicators were chosen as appropriate for prioritizing biocides, and scoring based on the globally harmonized system of classification and labeling of chemicals (GHS) improved the efficiency of the method. Correlations between individual indicators in this study were low (−0.151–0.325), indicating that each indicator was independent and well-chosen for prioritizing biocides. The effect of each indicator on the total score showed that carcinogenicity, mutagenicity, and reproductive toxicity (CMR) chemicals ranked high with r = 0.558. This result demonstrated that the most dangerous toxicants should play a more decisive role in the top ranking than the others. We expect that our method can be efficiently used to screen regulated biocides by prioritizing their health hazards, thus leading to better policy decision making about biocide use. Full article

The influence of the strain on the ability of Salmonella enterica to form biofilms on polystyrene was investigated by confocal laser scanning microscopy. The effects of sodium hypochlorite with 10% active chlorine (SHY; 25,000, 50,000, or 100,000 ppm), and benzalkonium chloride (BZK; 1000, 5000, or 10,000 ppm) on twenty-four-hour-old biofilms was also determined. The biofilms of ten Salmonella enterica isolates from poultry (S. Agona, S. Anatum, S. Enteritidis, S. Hadar, S. Infantis, S. Kentucky, S. Thompson, S. Typhimurium, monophasic variant of S. Typhimurium 1,4,(5),12:i:-, and S. Virchow) were studied. Biofilms produced by S. Anatum, S. Hadar, S. Kentucky, and S. Typhimurium showed a trend to have the largest biovolume and the greatest surface coverage and thickness. The smallest biofilms (P < 0.01) in the observation field (14.2 × 10³ µm²) were produced by S. Enteritidis and S. 1,4,(5),12:i:- (average 12.9 × 10³ ± 9.3 × 10³ µm³) compared to the rest of the serotypes (44.4 × 10³ ± 24.7 × 10³ µm³). Biovolume and surface coverage decreased after exposure for ten minutes to SHY at 50,000 or 100,000 ppm and to BZK at 5000 or 10,000 ppm. However, the lowest concentrations of disinfectants increased biovolume and surface coverage in biofilms of several strains (markedly so in the case of BZK). The results from this study suggest that the use of biocides at low concentrations could represent a public health risk. Further research studies under practical field conditions should be appropriate to confirm these findings. Full article