1,721,006 research outputs found
Efficacia degli inibitori di pompe di efflusso in associazione alla claritromicina in isolati clinici di Mycobacterium avium subsp. hominissuis
Full text linkMycobacterium avium subsp. hominissuis (MAH) è uno dei micobatteri non tubercolari di maggiore rilevanza clinica, rappresentando quello più spesso isolato in soggetti con gravi patologie croniche dell’apparato respiratorio. Inoltre, MAH può causare infezioni polmonari o disseminate in pazienti con immunodeficienza acquisita (AIDS) e in altri soggetti immunodepressi. Recenti dati epidemiologici mostrano un considerevole incremento della prevalenza delle infezioni da MAH in Italia, come pure in molti altri paesi del resto del mondo. Le infezioni causate da MAH sono difficili da trattare, a causa dell’intrinseca multi-farmaco resistenza del microrganismo. La claritromicina (CLA) rappresenta il principale farmaco di prima linea impiegato nel trattamento delle infezioni da MAH, verso il quale però il micobatterio può sviluppare resistenza compromettendone l’efficacia. Uno dei principali meccanismi responsabili di tale resistenza è dato dalla presenza di pompe di efflusso che determinano l’estrusione del farmaco dall’interno della cellula micobatterica.
Lo scopo del presente studio è stato quello di valutare l’attività antimicrobica di inibitori delle pompe di efflusso (EPI) in associazione alla CLA su isolati clinici di MAH.
Materiali e Metodi
Sono stati selezionati 4 ceppi di MAH resistenti alla CLA e, come controllo, 6 ceppi sensibili. Tutti gli isolati provenivano dal laboratorio di micobatteriologia dell’Azienda Ospedaliera Universitaria Pisana. Tali ceppi sono stati esaminati mediante un saggio colorimetrico in microdiluizione su piastra denominato “REsazurin Microtiter Assay” (REMA) per valutare la minima concentrazione inibente (MIC) della CLA da sola e in presenza di diverse concentrazioni di ciascuno dei seguenti EPI: berberina (BER), piperina (PIP), tetrandrina (TET) e carbonil cianuro m-clorofenil idrazone (CCCP).
Risultati
I ceppi resistenti hanno mostrato per la CLA una MIC ≥ 256 g/ml e i ceppi sensibili una MIC compresa tra 1 e 4g/ml. L’utilizzo degli EPI in associazione alla CLA ha ridotto nella quasi totalità dei ceppi resistenti la MIC della CLA. Infatti, la BER e il CCCP hanno determinato una riduzione della MIC fino a 10 diluizioni scalari, la TET fino a 9 e la PIP fino a 6. In particolare, in un isolato resistente, l’impiego della CLA in combinazione con ciascuno dei quattro EPI ha evidenziato una riduzione della MIC tale da rendere il ceppo sensibile. Come atteso, anche in tutti i ceppi di controllo gli EPI hanno ridotto la MIC della CLA.
Conclusioni
I risultati ottenuti in questo studio, se pur relativi a un numero limitato di ceppi, confermano che gli EPI testati (BER, PIP, TET e CCCP), in associazione con la CLA, aumentano l’efficacia del farmaco; in particolare, è emerso che la BER ed il CCCP sono gli EPI più efficaci. Tali dati suggeriscono quindi l’importanza del ruolo degli EPI nel trattamento delle infezioni causate da MAH
Increase in non-tuberculous mycobacteria isolated from humans in Tuscany, Italy, from 2004 to 2016
No full textIntroduction: Non-tuberculous mycobacteria (NTM) include all Mycobacterium species other than Mycobacterium tuberculosis complex and Mycobacterium leprae. NTM are a group of over 150 environmental species; they are generally endowed with low pathogenicity to human, however some species are associated with a variety of human diseases: respiratory tract infection are the most frequent, followed by lymphadenitis in children, disseminated infections in severely immunocompromised patients and skin infections. In Italy, the prevalence of NTM in human infections is largely unknown. The aim of the present survey is to report the epidemiology and recent trend of NTM infections in a region of central Italy, Tuscany, over the last 13 years, and provide a review of the recent literature on NTM isolation rates in different geographic regions.
Materials and Methods: The complete collection of NTM strains isolated from 50.150 clinical specimens at the Laboratory of Clinical Mycobacteriology of Pisa University Hospital, Italy, from 1 January 2004 to 31 December 2016 was included.
Results: In our setting, in the period 2004-2016 a total of 215 patients had cultures positive for NTM. The number of NTM isolates increased considerably from 5 isolates in 2004 to 36 in 2016; a sharp increase occurred in the last 5 years. Overall, 18 NTM species were isolated; the most common were M. avium, M. intracellulare and M. gordonae detected in respectively in 37.7%, 15.8% and 13.5% of NTM patients. Notably, M. kansasii, a pulmonary pathogen not reported before 2012, was repeatedly isolated in the last 5 years, representing 7,1% of total NTM isolates. In general, NTM isolates were largely prevalent in people older than 60 (59.5%); patients aged 1-10 year-old almost exclusively yielded M. avium and M. intracellulare. Of the 215 NTM clinical isolates, 77.2% were from respiratory specimens, 10.7% from lymph nodes, 2.3% from blood (yielding exclusively M. avium), and the remaining 9.8% from other clinical specimens.
Conclusions: The present study provides a snapshot of the prevalent NTM species in our setting and shows an increase in NTM isolation rate, which is in keeping with the general increase in NTM infections reported worldwide in the past two decades, although the distribution of the NTM prevalent species differs by geographic region
Stable water isotope as foundamental tool in karst aquifer studies: some results from isotopic applications in the Apuan Alps carbonatic complexes (NW Tuscany)
Full text linkThe management and protection of water resources in karst environment require detailed knowledge of the aquifer system which can be obtained through a multidisciplinary approach, including not only hydrogeological/structural assessment, but also the use of tools not commonly used in hydrogeology, as the isotope ratios.
In the present work some examples of isotopic applications on karst aquifers are discussed in relation to hydrogeological studies carried out in the Carrione Stream, Frigido River, and Versilia River catchments (Apuan Alps, Tuscany). In particular, during such studies the isotopic ratios 18O / 16O and 2H / 1H of the water molecule, mainly, and 13C / 12C of inorganic carbon in solution were used.
The isotopic data, and their comparison with the hydrogeological and structural-geological ones, were useful: to obtain information about the hydrodynamic conditions in the aquifer; to define the recharge area of main springs; and to identify different circulation systems drained by closing springs which have similar chemistry.
The obtained results confirm that in karst systems, where it is often difficult to carry out conventional hydrogeological surveys, the isotopic instruments have a fundamental role in the study of water circulation
Protection of Groundwater Resources: Worldwide Regulations and Scientific Approaches
No full textThe increasing role of groundwater in municipal water networks in many countries of the world makes the protection of groundwater resources an essential practice for safeguarding drinking water supplies. Several scientific-technical approaches are adopted worldwide to face this issue. In addition, some countries mainly depend on groundwater also for non-domestic use, making this topic even more critical. This chapter provides an overview of the main directives and their related technical aspects, concerning the protection zones of groundwater sources for human consumption. The main results of a multidisciplinary study are also presented, highlighting how the knowledge of physical and chemical aspects of groundwater bodies is a fundamental tool for protecting this vital resource and assuring its availability for the future generations
A multidisciplinary approach in defining the hydrogeological model of the carbonate aquifer system in the Versilia River basin (Tuscany, Italy)
No full textA hydrogeological study was carried out on important fractured/karst aquifer systems located in the Versilia River basin (Tuscany, Italy), in order to optimize the groundwater resources management. The main aim was the individuation of the feeding areas of the most important springs by means of a multidisciplinary approach using geological, hydrogeological and geochemical-isotopic tools. Some hydrogeological sections were elaborated in order to define the geometry of the main hydrostructures and to individuate possible groundwater divides. The elaboration of geochemical data allowed at identifying 3 main chemical facies: Ca-HCO3, Ca-SO4 and Na-Cl. The first two highlight the interaction of water with limestone/dolostone and carbonate-evaporite rocks for a time sufficient to acquire these chemical compositions and to achieve saturation/supersaturation in calcite and dolomite. The Na-Cl groundwater shows low salinity and a composition similar to rainwater, indicating a circulation in rocks containing minerals not very reactive and/or short interaction time with carbonate rocks. These two main types of water-rock interaction are confirmed by the isotopic ratio δ13C: for the Ca-HCO3 and Ca-SO4 types, δ13C value requires a significant contribution of carbon derived from dissolution of calcite, while for Na-Cl water, δ13C values are consistent with the addition of biogenic CO2 in rainwater. Stable water isotopes (δ18O and δ2H) confirm that groundwaters have a meteoric origin and that the wide range of values essentially depends on the different average altitude of feeding zone. Comparing the geological and hydrogeological features with the results of the geochemical processing, it is reasonable to assume that: the Na-Cl springs are representative of the superficial circuits, with small feeding zones and very low residence times in aquifer; whereas the Ca-HCO3 and Ca-SO4 springs are representative of relatively deep circuits developed in extensive aquifers with high permeability. The first type of springs was used to obtain the relationship between the δ18O ratio and the altitude of rainwater infiltration. Taking into account that they drain a small basin and considering the regulator effect of the aquifers, the isotopic composition of these springs are very similar to the annual average isotopic values of the local meteoric water. This relationship was used to evaluate the average altitude of the feeding area of the second type of springs. All these elements, and some tracer test results available in literature, allowed us to delimit the hydrogeological basins likely drained by the most important springs under study. In addition, for each hydrogeological system, a simplified water balance using meteorological data and the effective infiltration coefficients reported in the literature was performed, verifying that the delimited catchment areas are entirely consistent with the flow rate data of the springs
Hydrogeological and geochemical features of the sandy unconfined aquifer between Marina di Pisa and Calambrone (NW Tuscany) affected by seawater intrusion
No full textEvaluation of Xpert MTB/RIF Ultra assay for rapid diagnosis of pulmonary and extra-pulmonary tuberculosis in an Italian center
Full text linkAbstract not availabl
L’acqua sulle Alpi Apuane: risorsa pregiata e fattore di rischio
No full textNegli ultimi anni, le risorse idriche sotterranee stanno acquisendo sempre più importanza a seguito della continua crescita demografica e quindi dell’aumento della richiesta di acqua potabile. In questo contesto, le Alpi Apuane risultano di particolare interesse grazie alla presenza di ingenti risorse idriche ospitate in acquiferi carsici e caratterizzate da una buona qualità. Molte sorgenti che scaturiscono nell’area apuana vengono da tempo captate per uso idropotabile, tuttavia la loro tutela è messa fortemente a rischio anche dalla presenza di numerose attività antropiche impattanti, quali le aree estrattive, nonché dai cambiamenti climatici in atto. Per una corretta gestione e salvaguardia di tale preziosa risorsa è necessario disporre di elevate conoscenze del sistema ambiente che possono essere raggiunte solo attraverso studi integrati multidisciplinari. Questo articolo vuole offrire una breve panoramica delle conoscenze attuali acquisite mediante l’utilizzo di metodologie geologiche, idrogeologiche e geochimiche isotopiche. Gli studi effettuati hanno permesso di ottenere già importanti risultati: individuare i diversi sistemi acquiferi che alimentano le principali sorgenti delle Alpi Apuane; Comprendere le condizioni idrodinamiche degli acquiferi e di conseguenza le loro condizioni di vulnerabilità sia all’inquinamento che ai cambiamenti climatici; individuare le aree di alimentazione delle principali sorgenti con il fine di definirne le zone di protezione. I cambiamenti climatici attesi, fra i quali l’aumento della frequenza ed intensità degli eventi estremi, avrà inevitabilmente conseguenze anche sull’area apuana e sulle sue risorse, con impatto sull’incremento del dissesto idrogeologico e sulla potenziale diminuzione delle risorse idriche. Ciò rende sempre più indifferibile l’aumento della conoscenza sul territorio, sulle sue risorse e sulle sue esigenze, e in secondo luogo una presa di coscienza definitiva da parte della popolazione e soprattutto degli enti che ne sono preposti alla gestione.In recent years, groundwater is becoming increasingly important as a result of the continuous population growth and the consequent increase in drinking water. In this context, the Apuan Alps are of particular interest thanks to the presence of large, good quality water resources hosted in karst aquifers. Many springs in the Apuan area have long been captured for drinking water use, but their protection is also strongly jeopardised by the presence of numerous anthropogenic activities, such as mining, as well as climate change. In order to correctly manage and safeguard this precious resource, an in-depth knowledge of the environmental system is necessary, which can only be acquired through integrated multidisciplinary studies. This article aims to provide a brief overview of the current knowledge
acquired by means of geological, hydrogeological and isotopic geochemical methodologies. The studies carried out have already obtained important results: identification of the different aquifer systems feeding the main springs of the Apuan Alps; an understanding of the hydrodynamic conditions of the aquifers and consequently their vulnerability to both pollution and climate change; identification of the feeding areas of the main springs with the aim of defining their protection zones. The expected climate changes, among which the increase in the frequency and intensity of extreme events, will inevitably have effects on the Apuan area and its resources too, with an impact on the increase in hydrogeological instability and potential decrease in water resources. This makes the increase in knowledge about the territory, its resources and its needs more and more urgent. In addition, it is necessary to raise awareness among the population and, above all, the authorities responsible for its management
Hydrodynamic and geochemical behavior of a karst aquifer system exposed to contamination: Analysis of the response of the Moresco Springs (Apuan Alps, Italy) to rainfall
No full textThe Baccatoio Stream basin (Apuan Alps) was subjected to numerous investigations linked to the presence of abandoned mines and related acid mine drainages. This study aims to achieve new insights into water circulation in carbonate aquifers feeding three of the major springs of the area (Moresco springs: VSMOA, VSMOS, VSMOG). VSMOA and VSMOS show evidences of hydraulic connection with Baccatoio stream, contaminated by acid mine drainages. The study focused on springs chemical and isotopic variations induced by a rainfall event. Some general conclusions can be drown: (i) the hydraulic connection between Baccatoio stream and VSMOA-VSMOS seems to be confirmed; (ii) during rainfall events, infiltrated rainwater seem to directly contribute to the perturbation of VSMOA-VSMOS; (iii) different flow fractions feeding VSMOAVSMOS after rainfall pulse were quantified; (iv) VSMOG did not show any perturbation linked to the rainfall
Multidisciplinary approach to provide detailed conceptual model of the aquifer systems: an example in the Versilian coastal plain (NW Tuscany)
No full textDetailed conceptual models of the aquifer systems are an essential base working for groundwater modelling and for a correct groundwater resources management. At the same time the right approach to obtain reliable conceptual models is certainly interdisciplinary, which guarantees the knowledge of geological, hydrogeological and geochemical features of the aquifer systems.
In this contribute an example of multidisciplinary study carried out on the Versilian coastal plain aquifers (NW Tuscany) is presented, underlining as the comparison between geological framework and hydraulic, hydrodynamic, chemical and isotopic data allowed at understanding the feeding mechanism of groundwater flow and at defining the seawater-freshwater mixing process.
The study area has an extension of about 55 kmq and it has delimitated by Poveromo and Motrone ditch, northward and southward respectively, and by shoreline and Apuan Alps, in the western and eastern parts. The Versilian plain constitutes a recent succession of alternating continental and marine deposits. Hydrostratigraphic cross-sections reaching a depth of about 80-100 metres were elaborated. Aquitards/aquicludes are locally interbedded to the prevalent aquifer terms, which are mainly made up by sand and gravel. Gravel is shallow in the inner portion of the plain, where the alluvial fan of Versilia River is present. Seaward gravel deepens and is overlain by sands. For this framework the aquifer results throughout a phreatic monolayer, although the local presence of superficial silty-clayey or peaty deposits may determine confined or semi-confined conditions. Moreover, the presence of a discontinuos subsurface layer of conglomerate and silty-clayley lenses may locally separate the groundwater flow in multiple levels.
In order to achieve the purpose of the present work, multiple types of hydrogeological and hydrodinamics surveys and chemical and isotopic analyses on water samples were performed. In details, two piezometric surveys and physical-chemical analyses (temperature, electrical conductivity, pH, Eh) were carried out in April 2009 (high level condition) and in September 2009 (low level condition). On the whole, 192 wells and 14 stream water points were examined.
Piezometric and iso-conductive maps suggest as the recharge area of the coastal plain is mainly the alluvial fan. Afterwards, more detailed hydrogeochemical analyses were performed. Major elements (Ca, Mg, Na, K, Cl, NO3, SO4, HCO3), some minor elements (Br, F, B, As, Fe, Mn, Pb, Cr, Cu, Ni, Zn) concentration and some isotopic ratios (2H/1H, 18O/16O for water and 13C/12C of total inorganic carbon dissolved) were estimated.
Vertical logs were also performed in order to measure the electrical conductivity and temperature into 10 wells next to the coastline. In addition, in the apex of the fan a long term pumping test was executed, determining the aquifer hydraulic parameters (K, T, S). The last, together with the potentiometric surface, allowed us estimating the groundwater flow rate at the section corresponding to the Versilia River entrance into the plain.
Finally, comparing all data, it was possible to identify the principal component which supplies the coastal aquifer system starting from the upper part of the plain, where the Versilia River feeds the groundwater hosted in its alluvial fan. Secondary contributes are linkable to the local rainfall infiltration, well recognized in the dune sand, and to the groundwater flow coming from some fractured complexes bordering the plain. Freshwater-seawater mixing processes were also individuated
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