The environmental role of carbapenemase-producing Enterobacteriaceae (CPE) acquisition and infection in human disease has been described but not thoroughly investigated. We aimed to assess the ...occurrence of CPE in nearshore aquatic bodies.
Enterobacteriaceae were cultured from coastal and estuary water near Netanya, Israel in June and July of 2018. Bacteria were identified by VITEK2® and their antimicrobial susceptibility was tested according to the CLSI guidelines. Enterobacteriaceae genomes were sequenced to elucidate their resistome and carbapenemase types.
Among other clinically relevant bacteria, four CPE (three Enterobacter spp and one Escherichia coli isolate) were isolated from two river estuaries (Poleg and Alexander Rivers) and coastal water at a popular recreational beach (Beit Yanai). Molecular analysis and genome sequencing revealed the persistent presence of rare beta-lactamase resistance genes, including bla
and a previously unknown bla
allele, which were not found among the local epidemiological strains. Genome comparisons revealed the high identity of riverine and marine CPE that were cultivated one month apart.
We show that CPE contamination was widespread in nearshore marine and riverine habitats. The high genome-level similarity of riverine and marine CPEs, isolated one month apart, hints at the common source of infection. We discuss the clinical implications of these findings and stress the urgent need to assess the role of the aquatic environment in CPE epidemiology.
Coastal waters are subject to many sources of organic matter, such as land runoff, industrial and urban waste, rivers and atmospheric depositions. Semi-volatile organic compounds (SVOC) are ...frequently found next to coastal and urban areas. Depending on the specific physical properties of each compound in the SVOC group, these compounds may be adsorbed to particulate matter, evaporate to the atmosphere or accumulate in the sea's uppermost layer - the Sea surface microlayer (SML). Since many of these compounds present health risks, understanding the mechanisms that control the SVOC environmental concentration is crucial, especially in coastal waters.
This study assesses for the first time, the origin of monocyclic aromatic hydrocarbons (MAH) and aliphatic SVOC, as well as their distribution pattern in the SML and the sea sub surface layer (SSL) of the Haifa (Israel) coastal waters during 2015. Seasonal analysis of the SML and SSL showed high prevalence of several SVOC members, including BTEX, phthalates, trimethyl-benzene and monoterpenes. Concentrations of the BTEX group were elevated in the SSL particulate (>0.2 μm) and the SML free fractions (<0.2 μm), while only minor to nil levels were found in the SSL free fraction. Total phthalates were recorded in all sea layers, yet were found in higher concentrations in the SML's particulate and free fractions. The distribution of these molecules was linked to the presence of SML polysaccharides that showed elevated concentrations in the rainy season. Phthalates are rapidly transported to the SML in this area and have the potential of either aggregating or dissolving in the water column. We conclude that when examining the dominant MAH distribution, low-molecular weight phthalates enrichment takes place in the SML despite their higher solubility compared to the BTEX group. BTEX molecules have potentially elevated emission rates from SML particulate matter, with low adsorption to particulate matter and very low water solubility in the SSL. These observations may be linked to the low affinity of BTEX molecules to local particulate matter and to the low Henry coefficient (KH). Molecules like low-molecular weight phthalates (higher KH than BTEX), can be found in all water layers, but tend to concentrate in the SML and may also become airborne (though to a lower extent in the gas phase) via aerosol forming processes. Finally, while atmospheric depositions were found to be the major source of BTEX components in 2015, phthalates originated from urban runoff, the Kishon River as well as atmospheric depositions. These results may explain the long term presence of phthalates in aqueous form and the chronic BTEX evaporation in this coastal area.
•Phthalates concentrated in the particulate and free forms at the SML of Haifa coast.•BTEX and similar molecules concentrated in the free form at the SML and in the particulate form at the SSL of Haifa coast.•Elevated levels of BTEX and extreme concentrations of phthalates were recorded in aerosol particles, loading the SML.•Airborne particles might load the SML with monocyclic aromatic molecules.•Urban runoff reaching Haifa's coastline, supply high concentrations of organic matter including extreme levels of phthalates.•Slicks formed following urban drainage water discharge, included high levels of polysaccharides and extreme levels of phthalates in crude SML samples.
The folate receptor is overexpressed in a broad spectrum of malignant tumors and represents an attractive target for selective
delivery of anticancer agents to folate receptor–expressing tumors. This ...study examines folate-lipid conjugates as a means
of enhancing the tumor selectivity of liposome-encapsulated drugs in a mouse lymphoma model. Folate-derivatized polyethylene
glycol (PEG 3350 )-distearoyl-phosphatidylethanolamine was post-loaded at various concentrations into the following preparations: radiolabeled
PEGylated liposomes, PEGylated liposomes labeled in the aqueous compartment with dextran fluorescein, and PEGylated liposomal
doxorubicin (PLD, Doxil). We incubated folate-targeted radiolabeled or fluorescent liposomes with mouse J6456 lymphoma cells
up-regulated for their folate receptors (J6456-FR) to determine the optimal ligand concentration required in the lipid bilayer
for liposomal cell association, and to examine whether folate-targeted liposomes are internalized by J6456-FR cells in suspension.
Liposomal association with cells was quantified based on radioactivity and fluorescence-activated cell sorting analysis, and
internalization was assessed by confocal fluorescence microscopy. We found an optimal ligand molar concentration of ∼0.5%
using our ligand. A substantial lipid dose-dependent increase in cell-associated fluorescence was found in folate-targeted
liposomes compared with nontargeted liposomes. Confocal depth scanning showed that a substantial amount of the folate-targeted
liposomes are internalized by J6456-FR cells. Binding and uptake of folate-targeted PLD by J6456-FR cells were also observed
in vivo after i.p. injection of folate-targeted PLD in mice bearing ascitic J6456-FR tumors. The drug levels in ascitic tumor cells
were increased by 17-fold, whereas those in plasma were decreased by 14-fold when folate-targeted PLD were compared with nontargeted
PLD in the i.p. model. Folate-targeted liposomes represent an attractive approach for the intracellular delivery of drugs
to folate receptor–expressing lymphoma cells and seem to be a promising tool for in vivo intracavitary drug targeting. Mol Cancer Ther 2006;5(4):818–24
Submarine groundwater discharge (SGD) has been shown to be an important source of nutrients in coastal environments, especially nitrogen and silica, and thereby relive nutrient limitation to ...phytoplankton. Here, we followed autotrophic microbial biomass, activity, and community composition at a site strongly influenced by SGD and a nearby nutrients-poor reference site at the oligotrophic Israeli shallow rocky coast southeastern Mediterranean Sea (SEMS) between 2011 and 2019. The surface water at the SGD-affected area had significantly higher NO
3
+ NO
2
(∼10-fold) and Si(OH)
4
(∼2-fold) levels compared to the reference site, while no significant differences were observed for PO
4
or NH
4
. This resulted in a significant increase in algae biomass (∼3.5-fold), which was attributed to elevated
Synechococcus
(∼3.5-fold) and picoeukaryotes (∼2-fold) at the SGD-affected site, and in elevated primary production rates (∼2.5-fold). Contrary to most SGD-affected coastal areas, diatoms biomass remained unchanged between sites, despite the elevated N and Si, suggesting the dominance of picophytoplankton over microphytoplankton at the SEMS. DNA sequencing of the 16S and 18S rDNA supported these findings. These results highlight the influence of SGD on shallow-water microbial populations. Our observations are consistent with recent studies showing that phytoplankton along the Israeli coast are likely nitrogen + silica limited, and may have important ecological and regulatory implications for environmental policy and management of coastal aquifers.
Antibiotic resistance (AMR) in pathogens threatens human health worldwide, and antibiotic-resistant bacteria (ARB) are widespread in the environment. In particular, anthropogenically-disturbed rivers ...became reservoirs of ARBs and hotspots of antibiotic resistance gene (ARG) transmission. However, the diversity and sources of ARB, and the mechanisms of ARG transmission are not fully known. Here, we used deep metagenomic sequencing to study the dynamics of pathogens and their antibiotic resistance mechanisms along the Alexander River (Israel), affected by sewage and animal farm runoffs. Putative pathogens such as Aeromicrobium marinum and Mycobacterium massilipolynesiensis were enriched in western stations, following the inputs of polluted Nablus River. Aeromonas veronii was dominant in eastern stations in Spring. Several AMR mechanisms showed distinct patterns in Summer-Spring (dry season) and Winter (rainy season). We found low abundance beta-lactamases conferring carbapenem resistance: e.g., OXA-912 was linked to A. veronii in Spring; OXA-119 and OXA-205 to Xanthomonadaceae in Winter. We classified 33 % of ARG-containing contigs as putative plasmid sequences, indicating the high potential for resistome transmission. A limited number of ARGs were linked to putative phages. Our results suggest that this model river is a hotspot for AMR activity and transmission, and highlight the merit of deep sequencing for AMR discovery.
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•Metagenomics links antibiotic resistance mechanisms, taxonomy and transmission in a model river.•Urban inputs enriched Aeromicrobium marinum and Mycobacterium massilipolynesiensis pathogens.•Aeromonas veronii was dominant in the dry season and encoded OXA-912 beta-lactamase.•33 % of the resistome was linked to putative plasmid sequences, including the A. veronii OXA-912.•We established a state-of-art bioinformatic workflow for resistome interrogation.
Benzene , toluene, ethylbenzene, and xylenes (BTEX) BTEX molecules are toxic components, ubiquitous in the environment, often found in concentrations- a few orders of magnitude higher than the ...well-studied PAHs levels. This fact is demonstrated in either crude oil, fuels, water, and air samples. BTEX studies focus mainly on the airborne levels of these molecules, while their waterborne presence is understudied. In this study, BTEX levels were assessed at Lake Kinneret, Israel. As a result, 0–1.5 ppb of BTEX was recorded in five stations (2021–2022). Elevated BTEX levels (3–10 ppb) were recorded at the northern rivers nourishing this lake, implying the existence of remote polluting sources. Transect air samplings of BTEX conducted at the lake next to the bathing season of 2021 revealed airborne BTEX levels between 0.8 and 10 µg/m
3
, peaking up close to the bathing season, yet inconsistent with the BTEX water level trend. Lake water samples collected next to Tiberias city outfalls following the “Carmel” rainstorm showed elevated concentrations of BTEX up to 35 ppb and PAHs up to 0.47 ppb with an urban isotopic signal. The remote station’s PAHs levels were less than one order of magnitude, with a distinct rural isotopic signal. Additionally, a human-specific microbial marker revealed increased sewer contributions at some of the urbansites. The results of this study show that a wide area dispersion of low atmospheric BTEX levels exists in the lake’s perimeter. The dispersion rate is most likely influenced by season-based factors, e.g., motors and biomass fires. The unstudied waterborne BTEX levels in this lake are influenced by rivers, city runoff, and other yet unknown factors that may contribute to the sedimentation of these components. This process may result in a chronic pollution state. Despite the BTEX’s medium–low solubility and high volatility, its under-evaluated waterborne transportation may lead to high toxic levels following bioaccumulation.
In the last few decades, Endocrine Disrupting Chemicals (EDCs) have taken significant roles in creating harmful effects to aquatic organisms. Many proposed treatment applications are time consuming, ...expensive and focus mainly on waste water treatment plants (WWTP), which are indeed a major aquatic polluting source. Nonetheless, the marine environment is the ultimate sink of many pollutants, e.g. EDCs, and has been largely neglected mainly due to the challenge in treating such salty and immense open natural ecosystems. In this study we describe the bromination and the yet unpresented degradation process of high concentrations (5 mg/L) of phenolic EDCs, by the marine red macroalgaeGracilaria sp. As shown, 17α-Ethinylestradiol (EE2), a well-known contraceptive drug, and one of the most persistent phenol EDCs in the environment, was eliminated from both the medium and tissues of the macroalga, in addition to the degradation of all metabolites as verified by the nil estrogenic activity recorded in the medium. Validation of the proposed bromination-degradation route was reinforced by identifying Bisphenol A (BPA) brominated degradation products only, following 168H of incubation in the presence of Gracilaria sp. As demonstrated in this assay for EE2, BPA and finally for paracetamol, it is likely that the phenol scavenging activity is nonspecific and, thus, possibly even a wider scope of various other phenol-based pollutants might be treated in coastal waters. As far as we know, Gracilaria sp. is the only marine sessile organism able of degrading various phenol based pollutants. The worldwide distribution of many Gracilaria species and their wide aquaculture knowhow, suggest that bioremediation based on these seaweeds is a possible cost effective progressive solution to the treatment of a wide scope of phenols at the marine environment.
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•EE2, BPA and paracetamol were brominated by the red macroalgae Gracilaria sp.•EE2 estrogenic nil activity and BPA brominated degradation products were recorded.•EE2 and BPA degradation was recorded in incubation studies.•Gracilaria sp. mediated bromination, is suspected as a degradation perquisite.•Gracilaria sp. may be used as a cost effective EDCs remedy in marine environments.
Gracilaria sp. showed a fast bromination step, followed by a degradation process of phenolic EDCs. The degradation process was rather unspecific, yet in different time rates.
Two experiments were executed to assess the feasibility of Polychlorinated Biphenyls (PCBs) transfer to fish tissues via MPs as a vector. PCBs that occur in the marine environment were tested for ...their adsorption to four different MP types. PCB congeners showed the highest adsorption levels to Polypropylene homo-polymer. The uptake of PCBs through MP ingestion was tested in an outdoor mesocosm using the herbivorous rabbitfish, Siganus rivulatus in the eastern Mediterranean Sea. Polypropylene homo-polymer particles (0.3–5.0 mm) pre saturated with 11 PCB congeners, in two concentrations (500 ng/g and 5000 ng/g), were mixed with dough and offered to the fish. PCBs were identified after two weeks in fish muscle tissues, but not in the liver. These results suggest that ingestion of contaminated MP by rabbitfish might harm them in the long run, and perhaps even those who consume them on a regular basis, e.g. rabbitfish predators and humans.
•11 PCB congeners had highest adsorption onto polypropylene homo-polymer.•Rabbitfish were offered PCB-laced microplastics to test PCB transfer to tissues.•After two weeks exposure PCBs were found in rabbitfish muscle but not in the liver.
The progressive establishment of gas platforms and increasing petroleum accidents pose a threat to zooplankton communities and thus to pelagic ecosystems. This study is the first to compare the ...impacts of gas-condensate and crude oil on copepod assemblages. We conducted microcosm experiments simulating slick scenarios at five different concentrations of gas-condensate and crude oil to determine and compare their lethal effects and the bioconcentration of low molecular weight polycyclic aromatic hydrocarbons (LMW-PAHs) in eastern Mediterranean coastal copepod assemblages. We found that gas-condensate had a two-times higher toxic effect than crude oil, significantly reducing copepod survival with increased exposure levels. The LMW-PAHs bioconcentration factor was 1–2 orders of magnitude higher in copepods exposed to gas-condensate than in those exposed to crude oil. The median lethal concentration (LC50) was significantly lower in calanoids vs. cyclopoid copepods, suggesting that calanoids are more susceptible to gas-condensate and crude oil pollution, with potential trophic implications.
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•Copepods are more vulnerable to gas-condensate exposure than to crude oil.•Low-weight hydrocarbon concentrations in seawater with condensate were higher than with oil.•Bioconcentration of gas-condensate in copepods was greater than with crude oil.•Cyclopoid copepods are more tolerant to hydrocarbons than calanoid copepods.
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