Treated-wastewater (TW) irrigation transfers antibiotic-resistant bacteria (ARB) to soil, but persistence of these bacteria is generally low due to resilience of the soil microbiome. Nonetheless, ...wastewater-derived bacteria and associated antibiotic resistance genes (ARGs) may persist below detection levels and potentially proliferate under copiotrophic conditions. To test this hypothesis, we exposed soils from microcosm, lysimeter, and field experiments to short-term enrichment in copiotroph-stimulating media. In microcosms, enrichment stimulated growth of multidrug-resistant Escherichia coli up to 2 weeks after falling below detection limits. Lysimeter and orchard soils irrigated in-tandem with either freshwater or TW were subjected to culture-based, qPCR and shotgun metagenomic analyses prior, and subsequent, to enrichment. Although native TW- and freshwater-irrigated soil microbiomes and resistomes were similar to each other, enrichment resulted in higher abundances of cephalosporin- and carbapenem-resistant Enterobacteriaceae and in substantial differences in the composition of microbial communities and ARGs. Enrichment stimulated ARG-harboring Bacillaceae in the freshwater-irrigated soils, whereas in TWW-irrigated soils, ARG-harboring γ-proteobacterial families Enterobacteriaceae and Moraxellaceae were more profuse. We demonstrate that TW-derived ARB and associated ARGs can persist at below detection levels in irrigated soils and believe that similar short-term enrichment strategies can be applied for environmental antimicrobial risk assessment in the future.
Wastewater (WW) reuse is expected to be increasingly indispensable in future water management to mitigate water scarcity. However, this increases the risk of antibiotic resistance (AR) dissemination ...via irrigation. Herein, a conventional (chlorination) and an advanced oxidation process (heterogeneous photocatalysis (HPC)) were used to disinfect urban WW to the same target of Escherichia coli <10 CFU/100 mL and used to irrigate lettuce plants (Lactuca sativa) set up in four groups, each receiving one of four water types, secondary WW (positive control), fresh water (negative control), chlorinated WW, and HPC WW. Four genes were monitored in water and soil, 16S rRNA as an indicator of total bacterial load, intI1 as a gene commonly associated with anthropogenic activity and AR, and two AR genes bla OXA‑10 and qnrS. Irrigation with secondary WW resulted in higher dry soil levels of intI1 (from 1.4 × 104 copies/g before irrigation to 3.3 × 105 copies/g after). HPC-treated wastewater showed higher copy numbers of intI1 in the irrigated soil than chlorination, but the opposite was true for bla OXA‑10. The results indicate that the current treatment is insufficient to prevent dissemination of AR markers and that HPC does not offer a clear advantage over chlorination.
AbstractA large-scale comprehensive survey of indicator bacteria, pathogen viruses, coliphages, microbial source tracking (MST) indicators, and antibiotic resistance genes was carried out in the ...Shafdan soil aquifer treatment (SAT) of the Tel Aviv, Israel area. The study reveals complete elimination of pathogen viruses—enterovirus, adenovirus, norovirus, parechovirus, and coliphage—and of the bacterial indicators total and fecal coliforms, fecal streptococcus, and microbial source tracking (MST) Bacteroides already in the vadose zone below the percolation basins. Trace levels of antibiotic resistance genes (ARGs) were detected in the recovery wells, but these were also detected in wells not impacted by effluent, suggesting that these genes are associated with native aquifer bacterial communities. This is the first comprehensive survey describing four types of microbial indicators—bacteria, pathogenic viruses, coliphages, and MST—for SAT research, and the first to address the occurrence of antibiotic resistance genes in SAT systems. The results should provide guidance to regulatory agencies regarding the attainable efficiency of optimally designed and operated SAT systems and the monitoring point locations. Most of the pathogen removal occurs in the vadose zone underneath the basins, which can be monitored more rapidly than the water quality in the recovery wells.
Plasmids harboring
genes confer resistance to low fluoroquinolone concentrations. These genes are of significant clinical, evolutionary and environmental importance, since they are widely distributed ...in a diverse array of natural and clinical environments. We previously extracted and sequenced a large (∼185 Kbp)
-harboring plasmid, and several small (∼8 Kbp)
-harboring plasmids, from
isolates from municipal wastewater biosolids, and hypothesized that these plasmids provide host bacteria a selective advantage in wastewater treatment plants (WWTPs) that often contain residual concentrations of fluoroquinolones. The objectives of this study were therefore to determine the effect of residual fluoroquinolone concentrations on the growth kinetics of
plasmid-harboring bacteria; and on the copy number of
plasmids and expression of
genes. Electrotransformants harboring either one of the two types of plasmids could grow at ciprofloxacin concentrations exceeding 0.5 μg ml
, but growth was significantly decreased at concentrations higher than 0.1 μg ml
. In contrast, plasmid-free strains failed to grow even at 0.05 μg ml
. No differences were observed in plasmid copy number under the tested ciprofloxacin concentrations, but
expression increased incrementally from 0 to 0.4 μg ml
, suggesting that the transcription of this gene is regulated by antibiotic concentration. This study reveals that wastewater-derived
plasmids confer a selective advantage in the presence of residual fluoroquinolone concentrations and provides a mechanistic explanation for this phenomenon.
Reuse of municipal wastewater is a growing global trend, but currently there is lack of consensus regarding the potential dissemination of antibiotic resistance elements by treated wastewater ...irrigation. We tracked intI1, a proxy for anthropogenic pollution, and an assemblage of antibiotic resistance genes associated with mobile elements and/or wastewater (blaGES, blaOXA2, blaOXA10, blaTEM, blaCTX-M-32 and qnrS) in treated wastewater effluents, effluent stabilization reservoirs, and along irrigation water-soil-crop continua in experimental lysimeters and large-scale commercial fields. While several of the targeted antibiotic resistance genes were profuse in effluents, there was almost no correlation between gene abundance in irrigation water and those detected in soil, and no evidence of systematic gene transfer to irrigated soil or crops. In contrast, soil intI1 abundance correlated strongly to irrigation water levels in lysimeters and sandy field soils, but this was not the case for clay-rich soils or for most of the analyzed crops, suggesting that intI1 may not always be a reliable marker for tracking the impact of treated wastewater irrigation. We hypothesize that "ecological boundaries" expedited by biotic and abiotic factors constrain dissemination of antibiotic resistance elements, and assert that a more holistic perception of these factors is crucial for understanding and managing antibiotic resistance dissemination.
Display omitted
•We targeted antibiotic resistance genes (ARGs) in effluents and irrigated fields.•blaOXA and blaGES genes were strongly linked to treated wastewater effluents.•Effluent storage in reservoirs substantially reduced ARG abundance.•intI1 distribution in irrigated soil was only partially linked to water quality.•Ecological barriers seem to restrict ARG dissemination to irrigated soil and crops.
Bloodstream infection (BSI) caused by carbapenem-resistant
(KP) poses significant challenges, particularly when the infecting isolate carries multiple antimicrobial resistance (AMR) ...genes/determinants. This study, employing short- and long-read whole-genome sequencing, characterizes six New Delhi metallo-β-lactamase (NDM) 1 and KP carbapenemase (KPC) 3 co-producing KP isolates, the largest cohort investigated in Europe to date. Five sequence type (ST) 512 and one (ST11) isolates were recovered from patients who developed BSI from February to August 2022 or February 2023 at two different hospitals in Rome, Italy. Phylogenetic analysis revealed two distinct clusters among ST512 isolates and a separate cluster for the ST11 isolate. Beyond
and
, various AMR genes, indicative of a multidrug resistance phenotype, including colistin resistance, were found. Each cluster-representative ST512 isolate harbored a
plasmid (IncC) and a
plasmid IncFIB(pQil)/IncFII(K), while the ST11 isolate harbored a
plasmid IncFII(pKPX1) and a
plasmid IncFIB(K)/IncFII(K). The
plasmids carried genes conferring resistance to clinically relevant antimicrobial agents, and the aminoglycoside resistance gene
(
')-
was found on different plasmids. Colistin resistance-associated
/
gene mutations were present in all isolates, and the yersiniabactin-encoding
gene was unique to the ST11 isolate. In conclusion, our findings provide insights into the genomic context of
/
carbapenemase-producing KP isolates.IMPORTANCEThis study underscores the critical role of genomic surveillance as a proactive measure to restrict the spread of carbapenemase-producing KP isolates, especially when key antimicrobial resistance genes, such as
/
, are plasmid borne. In-depth characterization of these isolates may help identify plasmid similarities contributing to their intra-hospital/inter-hospital adaptation and transmission. Despite the lack of data on patient movements, it is possible that carbapenem-resistant isolates were selected to co-produce KP carbapenemase and New Delhi metallo-β-lactamase via plasmid acquisition. Studies employing long-read whole-genome sequencing should be encouraged to address the emergence of KP clones with converging phenotypes of virulence and resistance to last-resort antimicrobial agents.
•The performance of the SOLARIS concentrator are presented and discussed as function of the direct normal irradiance.•The performance have been estimated as function of the number of residential ...utilities, considering an entire year.•The optimal number of utilities connected to the SOLARIS was found considering both the energy and economic point of view.•The optimal size of electric and thermal storage have been defined.•The maximum capital cost of the system has been estimated in order to achieve a roi in ten or twelve years.
The research on photovoltaic conversion is continuously overtaking technological challenges and modern PV cells can nowadays be efficiently combined with solar concentrators. In this paper a new photovoltaic solar concentrator model based on non-imaging optics and embedding high efficiency multi-junctions cells is presented. The concentrator has been optimized to maximize the electricity production but it is thought to work in cogeneration to allow also for thermal energy by recovering the residual heat, since an active cooling system for the cells is necessary. The efficiency enhancement is obtained thanks to the high matching between the collected solar irradiance and the receiver electrical features.
The aim of the paper is the definition of the number of residential utilities connected to the system in order to minimize the exchange of energy with the network and also the use of auxiliary boiler. Also the optimal size of electric and thermal storage to be integrated to the concentrator, has been determined as function of the number of utilities.
To achieve these goals a parametric analysis has been carried out by the use of an in-house-developed calculation code considering a whole year of operation in order to estimate the energy fluxes and the economic performance. Furthermore, the maximum capital cost of the system has been estimated in order to achieve a return on the investment in ten or twenty years.
According to the Authors’ knowledge, the novelty of this study regards the implementation of this kind of photovoltaic solar concentrator – for combined heat and power production – in a residential application.
The Vimos VLT deep survey Garilli, B.; Le Fèvre, O.; Guzzo, L. ...
Astronomy and astrophysics (Berlin),
08/2008, Letnik:
486, Številka:
3
Journal Article
Recenzirano
Odprti dostop
Context. The VVDS-Wide survey has been designed to trace the large-scale distribution of galaxies at z similar to 1 on comoving scales reaching similar to 100 h super(-1) Mpc, while providing a good ...control of cosmic variance over areas as large as a few square degrees. This is achieved by measuring redshifts with VIMOS at the ESO VLT to a limiting magnitude I AB = 22.5, targeting four independent fields with sizes of up to 4 deg super(2) each. Aims. We discuss the survey strategy which covers 8.6 deg super(2) and present the general properties of the current redshift sample. This includes 32 734 spectra in the four regions, covering a total area of 6.1 deg super(2) with a sampling rate of 22 to 24%. This paper accompanies the public release of the first 18 143 redshifts of the VVDS-Wide survey from the 4 deg super(2) contiguous area of the F22 field at RA = 22\rm phi . Methods. We have devised and tested an objective method to assess the quality of each spectrum, providing a compact figure-of-merit. This is particularly effective in the case of long-lasting spectroscopic surveys with varying observing conditions. Our figure of merit is a measure of the robustness of the redshift measurement and, most importantly, can be used to select galaxies with uniform high-quality spectra to carry out reliable measurements of spectral features. We also use the data available over the four independent regions to directly measure the variance in galaxy counts. We compare it with general predictions from the observed galaxy two-point correlation function at different redshifts and with that measured in mock galaxy surveys built from the Millennium simulation. Results. The purely magnitude-limited VVDS Wide sample includes 19 977 galaxies, 304 type I AGNs, and 9913 stars. The redshift success rate is above 90% independent of magnitude. A cone diagram of the galaxy spatial distribution provides us with the current largest overview of large-scale structure up to z similar to 1, showing a rich texture of over- and under-dense regions. We give the mean N (z) distribution averaged over 6.1 deg super(2) for a sample limited in magnitude to I AB = 22.5. Comparing galaxy densities from the four fields shows that in a redshift bin Delta z = 0.1 at z similar to 1 one still has factor-of-two variations over areas as large as similar to 0.25 deg super(2). This level of cosmic variance agrees with that obtained by integrating the galaxy two-point correlation function estimated from the F22 field alone. It is also in fairly good statistical agreement with that predicted by the Millennium simulations. Conclusions. The VVDS WIDE survey currently provides the largest area coverage among redshift surveys reaching z similar to 1. The variance estimated over the survey fields shows explicitly how clustering results from deep surveys of even 1 deg super(2) size should be interpreted with caution. The survey data represent a rich data base to select complete sub-samples of high-quality spectra and to study galaxy ensemble properties and galaxy clustering over unprecedented scales at these redshifts. The redshift catalog of the 4 deg super(2) F22 field is publicly available at http://cencosw.oamp.fr.
We derive the mass-metallicity relation of star-forming galaxies up to $z\sim0.9$, using data from the VIMOS VLT Deep Survey. Automatic measurement of emission-line fluxes and equivalent widths have ...been performed on the full spectroscopic sample. This sample is divided into two sub-samples depending on the apparent magnitude selection: wide ($I_{\mathrm{AB}}<22.5$) and deep $I_{\mathrm{AB}}<24$). These two samples span two different ranges of stellar masses. Emission-line galaxies have been separated into star-forming galaxies and active galactic nuclei using emission line ratios. For the star-forming galaxies the emission line ratios have also been used to estimate gas-phase oxygen abundance, using empirical calibrations renormalized in order to give consistent results at low and high redshifts. The stellar masses have been estimated by fitting the whole spectral energy distributions with a set of stellar population synthesis models. We assume at first order that the shape of the mass-metallicity relation remains constant with redshift. Then we find a stronger metallicity evolution in the wide sample as compared to the deep sample. We thus conclude that the mass-metallicity relation is flatter at higher redshift. The observed flattening of the mass-metallicity relation at high redshift is analyzed as an evidence in favor of the open-closed model.
PDF
