This study investigated the in vitro susceptibility of ceftobiprole and its potential synergistic activity in combination with other antimicrobials against 46 selected Gram-positive pathogens ...displaying resistance or decrease susceptibility to several drugs. The gradient-cross method was used to assess synergism between ceftobiprole and daptomycin, levofloxacin, linezolid, rifampicin and piperacillin/tazobactam. Time-kill curves were performed for seven representative isolates. Ceftobiprole MICs ranged from 0.25–6 mg/L for staphylococci; 4–≥32 mg/L for Enterococcus faecalis, and 0.38–≥32 mg/L for E. faecium. Ceftobiprole plus daptomycin was synergistic against all isolates. Ceftobiprole plus linezolid was synergistic against 4 isolates belonging to different species. Ceftobiprole plus levofloxacin was synergistic only against enterococci. In conclusion, ceftobiprole exhibited a potent in vitro antibacterial activity and exhibited synergy with daptomycin against all Gram-positive isolates, despite their antibiotic resistance phenotypes. The use of ceftobiprole in combination may provide a promising alternative therapy for the treatment of resistant Gram-positive infections.
•High in-vitro activity of ceftobiprole against Gram-positive isolates.•Synergistic activity was observed with daptomycin against all resistance phenotypes.•Promising alternative drug for the treatment of resistant Gram-positive strains.
The High Agri Valley (southern Italy) is one of the largest intermontane basin of the southern Apennines affected by intensive agricultural and industrial activities. The study of groundwater ...chemical features provides much important information useful in water resource management. In this study, hydrogeochemical investigations coupled with multivariate statistics, saturation indices, and stable isotope composition (δD and δ18O) were conducted in the High Agri Valley to determine the chemical composition of groundwater and to define the geogenic and anthropogenic influences on groundwater quality. Twenty-four sampling point ( including well and spring waters) have been examined. The isotopic data revealed that groundwater has a meteoric origin. Well waters, located on recent alluvial-lacustrine deposits in shallow porous aquifers at the valley floor, are influenced by seasonal rainfall events and show shallow circuits; conversely, spring waters from fissured and/or karstified aquifers are probably associated to deeper and longer hydrogeological circuits. The R-mode factor analysis shows that three factors explain 94% of the total variance, and F1 represents the combined effect of dolomite and silicate dissolution to explain most water chemistry. In addition, very low contents of trace elements were detected, and their distribution was principally related to natural input. Only two well waters, used for irrigation use, show critical issue for NO3- concentrations, whose values are linked to agricultural activities. Groundwater quality strongly affects the management of water resources, as well as their suitability for domestic, agricultural, and industrial uses. Overall, our results were considered fulfilling the requirements for the inorganic component of the Water Framework Directive and Italian legislation for drinking purposes. The water quality for irrigation is from “good to permissible” to “excellent to good” although salinity and relatively high content of Mg2+ can occasionally be critical.
In this study Cr(tot), Cr(VI), major and trace elements were determined in groundwater of northern sector of the Pollino Massif (southern Italy). The investigated area is characterized by ophiolitic ...rocks consisting of metabasites, shales and calcschists and fractured serpentinites. Two main hydro-facies were observed, reflecting low temperature water–rock interaction. The Mg-HCO
3
hydrofacies is due to the weathering of serpentinites, Ca-HCO
3
groundwaters are linked to the interaction with calcschist and metabasites. High Cr(VI) concentrations were detected, exceeding the maximum admissible concentrations by Italian regulation, due to the release of Cr(III) from ophiolitic rocks into water and its oxidation to the hexavalent state. Remediation tests were carried out using two synthetized nanomaterials, Fe(0) and magnetite, characterized by a mean size lower than 50 nm. The experiments were conducted at fixed nanoparticles/Cr(VI) molar ratio and according to previous studies. In addition, the kinetic data were interpreted with a suitable mathematical model.
Weathering of outcrops of ultramafic rocks (remnants of ancient oceanic crust) is a source of biologically toxic trace elements, particularly first row transition elements. The Cr and Ni ...concentrations of serpentinite and metabasite outcrops in the northern sector of the Pollino massif (Lucanian Apennines, southern Italy) are hundreds of orders of magnitude higher than those of the upper continental crust. In this region, exposed intermediate to lower crustal rocks are significantly enriched in Ni, Cr, and V relative to the average upper continental crust. We evaluate the levels and distributions of trace elements of environmental concern, including Cr (as total dissolved Cr and Cr(VI)), V, Mn, Fe, Ni, Cu, Zn, As, Pb, and U, in spring waters from the northern sector of the Pollino massif.
The major solutes in the spring waters from this region are Mg-HCO3 and Ca-HCO3. The Mg-HCO3 type waters are produced mainly through the interaction of meteoric waters with serpentinites, whereas the Ca-HCO3 type waters are produced through the interaction of meteoric waters with Ca-rich rocks (i.e., carbonate rocks, calc-schists, and metabasites). Thermodynamic evaluation indicates that in the MgO–SiO2–Al2O3–H2O system, waters flowing in serpentinites fall in the kaolinite field, close to the kaolinite–Mg-vermiculite phase boundary. This result arises because kaolinite is a relatively early reaction product, which is consumed to produce Mg-vermiculite and further Mg-saponite. In the CaO–SiO2–Al2O3–H2O system, Ca-HCO3 type waters fall either in the field of gibbsite or kaolinite, depending on dissolved silica.
Chromium (VI) contamination associated with local mineralogy and with maximum admissible concentration >5μgL−1 was observed for nine springs (both Mg-HCO3 and Ca-HCO3 type waters). The Cr(VI)-rich Ca-HCO3 springs are not located in serpentinites. However, some of these waters likely acquire their high Cr levels from interacting with serpentinite clasts, as in the case of springs flowing through conglomerates. In addition, Cr(VI) contamination is not limited to waters interacting with serpentinites or serpentinite clasts, because in one case weathering of garnet-rich gneiss is responsible for the release of significant amounts of Cr(VI) in solution.
Finally, studies are needed to address the potential health risks associated with the observed high concentrations of Cr(VI) in waters from the Pollino massif area. A mode-of-action analysis is needed to evaluate adverse health risks associated with exposure to Cr(VI) in drinking water, especially as Cr contamination is not limited to springs flowing through serpentinites.
► Serpentinite, metabasite, and garnet-rich gneiss in the Pollino massif, Italy. ► Distributions of Cr(VI) in spring waters. ► Springs waters in the Pollino massif are either Mg-HCO3 or Ca-HCO3. ► Cr(VI) contamination in springs of both Mg-HCO3 and Ca-HCO3 type. ► Contamination is not confined to springs which flow through serpentinites.
Sedimentary (pedogenic) and hydrothermal Mn ores are hosted by a volcanic succession in south-western Sardinia. The sedimentary Mn ores are characterized by chondrite-normalized Ce anomalies (Ce/Ce*) ...of 1.08–3.40, whereas the hydrothermal Mn ores have Ce anomalies of 0.35–3.15.
The presence of both negative and positive Ce anomalies in the hydrothermal Mn ores is related to the remobilization of rare earth elements (REEs) within the hydrothermal system, which occurred via the dissolution and redistribution of REE-bearing accessory minerals by mineralizing fluids. The REEs were removed from wall-rocks and redeposited within the Mn ores as apatite, monazite, and cerianite, which have textures characteristic of growth into a Mn-oxide matrix during mineralization. In addition, the redistribution of cerium led to a progressive increase in the magnitude of the Ce anomaly from E to W, suggesting that mineralizing fluids moved along an E–W-striking fault close to the Mn ore.
In the sedimentary Mn ores, the spatial variability of Ce/Ce* values probably relates to changes in the deposition environment, from organic-rich to organic-poor. Positive Ce anomalies with Ce/Ce* values of 1.08–1.75 are associated with samples from thick sedimentary layers within a paleosoil or samples from veins related to paleosoils, and potentially formed in a environment where organic speciation of the REEs acted to limit cerianite precipitation. Conversely, spheroidal concretions of Mn-oxides within pumice and ash layers have larger positive Ce anomalies (Ce/Ce*>2.5) and likely formed in an organic-free environment matter, with REE speciation in circulating fluids dominated by inorganic species.
Finally, given the large range in Ce/Ce* ratios of Mn ores, we stress the need to carefully consider sampling methodologies, to ensure the accurate interpretation and determination of ore deposit models, the identification of mechanisms involved in Ce distribution, and the relationships between Ce and Mn phases.
► Sedimentary and hydrothermal Mn ores in SW Sardinia ► Generation of Ce anomalies ► Ce/Ce* fluctuations.
In this paper we provide a geochemical investigation on 34 groundwater samples in the Mt. Vulture volcanic aquifer representing one of the most important groundwater resources of the southern Italy ...pumped for drinking and irrigation supply. The present study includes the first data on the abundance and mobility of minor and trace elements and the thermodynamic considerations on water–rock interaction processes in order to evaluate the conditions of alkali basalt weathering by waters enriched in magma-derived CO
2. The results highlight the occurrence of two hydrofacies: bicarbonate alkaline-earth and alkaline waters deriving from low-temperature leaching of volcanic rocks of Mt. Vulture, and bicarbonate-sulfate-alkaline waters (high-salinity waters) related to prolonged water circulation in alkali and feldspathoids-rich pyroclastic layers interbedded with clay deposits. The Al-normalized relative mobility (RM) of metals in Vulture's aquifer varies over a wide range (10
−
1
<
RM
<
10
4), confirming that the basalt weathering is not a congruent and isochemical process. Chemical equilibrium studies show that the bicarbonate alkaline-earth and alkaline waters, having a short interaction with silicate minerals, plot very close to the kaolinite–smectite stability boundary, whereas the high-salinity waters fall in the stability field of smectite and muscovite because of prolonged interaction with alkali and feldspathoids-rich pyroclastic layers. Overall, for the bicarbonate alkaline-earth and alkaline waters, the release of toxic metals in solutions is related to the spatial variation of host-rock geochemistry, the high-salinity waters, collected near urban areas, show values higher than legal limits for Ni and As, likely as a consequence of anthropogenic contribution.
► The investigated groundwaters have a bicarbonate alkaline-earth and bicarbonate-sulfate-alkaline composition. ► The former type is due to low-temperature leaching of volcanic rocks and also to the greater dissolved CO
2 rich-gases. ► The latter (high salinity waters) is related to water circulation in feldspathoids-rich pyroclastic layers and clays. ► The Al-normalized relative mobility of metals varies over a wide range (10
−1
<
RM
<
10
4). ► The potentially toxic metals have low concentrations, with the exception of Ni and As contents in high-salinity waters.
This study focuses on a late Cretaceous karst bauxite deposit in the Murge area of the Apulia district, southern Italy. The first analysis of the vertical distributions of a wide range of elements ...(including REEs and selected trace elements) throughout the deposit was shown in order to identify the processes determining element fractionation during the evolution of the bauxite.
The studied karst bauxite deposit exhibits an ooidal texture, is mineralogically homogeneous, and contains higher abundances of boehmite than of hematite, kaolinite, and anatase. The major element composition of the bauxite is dominated by elevated concentrations of SiO2, TiO2, Al2O3, and Fe2O3, and analyses of element mobility within the bauxite indicate that all elements except for Nb and Ni, and to a lesser extent Cr, are depleted relative to the immobile element Ti. R-mode factor analysis revealed a number of key findings: (i) some low-solubility elements (e.g., Zr, Th, Ti, V, Ga) were concentrated in detrital zircon and monazite (Zr, Th), in anatase (Ti, V), and possibly in boehmite and hematite (Ga) during the later stages of bauxitisation; (ii) Fe and Cr were concentrated during wet conditions, whereas Al and Co accumulated during dry conditions; (iii) distributions of the light REEs (LREEs) and the heavy REEs (HREEs) are controlled by the same processes, suggesting that little LREE/HREE fractionation occurred during bauxite formation; and (iv) the behaviour of cerium is different from that of the other REEs, and highly variable cerium anomalies are observed across the deposit, with three characteristic Ce/Ce* maxima with values of >2. Parisite was the only authigenic cerium mineral detected during this study. Thus, we propose a three-step model to explain the distribution of Ce: cerianite is dissolved by cerium reduction, is transported by downward-moving meteoric water (per descensum), and finally parisite is precipitated. This cycle was repeated several times in the Apulian karst bauxite in response to Eh decreases under alkaline conditions, promoted by fluctuations in the groundwater level. Finally, we used the value of the Eu anomaly to discuss the parental affinity or protolith of the bauxite. The value of the Eu anomaly (min. Eu/Eu*=0.76, max. Eu/Eu*=0.89) indicates that the bauxite was not derived from carbonates, but rather, that the majority of the bauxite was influenced by intermediate to mafic magmatic sources. Eu/Eu* vs Sm/Nd diagram suggests that the parental material for the bauxite was derived from a combination of a distant magmatic source and clastic material derived from a continental margin (northern Africa) to the south.
•Geochemistry of Cretaceous karst bauxite of the Apulia district, southern Italy•Minor LREE/HREE fractionation and (La/Yb)ch close to or below the value of the UCC•(La/Yb)ch ratios may depend on fluctuations in soil solution pH•Ce fractionation during groundwater fluctuations under low Eh and alkaline conditions•Bauxite derived likely from a distal magmatic source and a southern clastic source
At Santa Filitica, a Roman settlement in north‐western Sardinia occupied until the ninth century ad, archaeological excavations have found the remnants of a furnace consisting of a semi‐circular base ...made of stony slabs and tiles bound with clay. The furnace is attached to a wall of Roman age. Layers of the sixth century ad, bearing several variously oxidized slags, were found close to the furnace. These findings first testify to an ironworks in Sardinia, within a well‐defined context. XRPD and SEM–EDS mineralogical and textural analyses suggest that the slags derive from a bloomery and smithing work that was the first evidence of this type documented in Sardinia during the Early Middle Ages. Chemical analyses (performed with ICP and INAA) of rare earth elements and trace elements in two slags and in two Sardinian iron deposits allow some conclusions to be drawn on the local provenance of the ore. Our comparison of the Sardinian findings and some slags representative of archaeological smelting sites at the front of Elba island—the largest and longest lived iron‐working sites in the Mediterranean—also improves the methodology with which iron slags derived from different ores are compared.
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