968 resultados para Introduced organisms -- Catalonia


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The measurement of mesozooplankton biomass in the ocean requires the use of analytical procedures that destroy the samples. Alternatively, the development of methods to estimate biomass from optical systems and appropriate conversion factors could be a compromise between the accuracy of analytical methods and the need to preserve the samples for further taxonomic studies. The conversion of the body area recorded by an optical counter or a camera, by converting the digitized area of an organism into individual biomass, was suggested as a suitable method to estimate total biomass. In this study, crustacean mesozooplankton from subtropical waters were analyzed, and individual dry weight and body area were compared. The obtained relationships agreed with other measurements of biomass obtained from a previous study in Antarctic waters. Gelatinous mesozooplankton from subtropical and Antarctic waters were also sampled and processed for body area and biomass. As expected, differences between crustacean and gelatinous plankton were highly significant. Transparent gelatinous organisms have a lower dry weight per unit area. Therefore, to estimate biomass from digitized images, pattern recognition discerning, at least, between crustaceans and gelatinous forms is required.

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[EN] Mesozooplankton organisms (>250 μm) were sampled at two stations (inner and outer Bay) in the Bay of Cádiz between May and July 2008. Samples were analysed by means of a semi-automated technique in order to give a preliminary view of the mesoozooplankton community structure in the Bay, based on taxonomic diversity and biomass distribution among size classes. The abundance of organisms increased from May to July in accordance with the increase in temperature and Chlorophyll a (Chla) concentrations. Abundances were higher in the outer Bay station, where Chla concentrations are greater and the water column is more stable. The community changed from being meroplankton- to holoplankton-based due to an increase of Calanoida and especially Cladocera individuals (mainly Peniliaavirostris), which are known to peak acutely in the summer. The analysis of Normalised Biomass-Size spectra revealed fairly steep slopes (average -1.3) and relatively high departures from steady state (r2 = 0.8 – 0.94), expectable in a coastal system such as the Bay of Cádiz were disturbance factors are introduced from benthic and tidal processes, together with anthropogenic pressure.

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[EN] Background: The paradox of health refers to the improvement in objective measures of health and the increase in the reported prevalence of chronic conditions. The objective of this paper is to test the paradox of health in Catalonia from 1994 to 2006. Methods: Longitudinal cross-sectional study using the Catalonia Health Interview Survey of 1994 and 2006. The approach used was the three-fold Blinder - Oaxaca decomposition, separating the part of the differential in mean visual analogue scale value (VAS) due to group differences in the predictors (prevalence effect), due to differences in the coefficients (severity effect), and an interaction term. Variables included were the VAS value, education level, labour status, marital status, all common chronic conditions over the two cross-sections, and a variable for non-common chronic conditions and other conditions. Sample weights have been applied. Results: Results show that there is an increase in mean VAS for men aged 15-44, and a decrease in mean VAS for women aged 65-74 and 75 and more. The increase in mean VAS for men aged 15-44 could be explained by a decrease in the severity effect, which offsets the increase in the prevalence effect. The decrease in mean VAS for women aged 65-74 and 75 and more could be explained by an increase in the prevalence effect, which does not offset the decrease in the severity effect. Conclusions: The results of the present analysis corroborate the paradox of health hypothesis for the population of Catalonia, and highlight the need to be careful when measuring population health over time, as well as their usefulness to detect population's perceptions.

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Trabajo realizado por: Maldonado, F.; Packard, T.; Gómez, M.; Santana Rodríguez, J. J

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Introduction 1.1 Occurrence of polycyclic aromatic hydrocarbons (PAH) in the environment Worldwide industrial and agricultural developments have released a large number of natural and synthetic hazardous compounds into the environment due to careless waste disposal, illegal waste dumping and accidental spills. As a result, there are numerous sites in the world that require cleanup of soils and groundwater. Polycyclic aromatic hydrocarbons (PAHs) are one of the major groups of these contaminants (Da Silva et al., 2003). PAHs constitute a diverse class of organic compounds consisting of two or more aromatic rings with various structural configurations (Prabhu and Phale, 2003). Being a derivative of benzene, PAHs are thermodynamically stable. In addition, these chemicals tend to adhere to particle surfaces, such as soils, because of their low water solubility and strong hydrophobicity, and this results in greater persistence under natural conditions. This persistence coupled with their potential carcinogenicity makes PAHs problematic environmental contaminants (Cerniglia, 1992; Sutherland, 1992). PAHs are widely found in high concentrations at many industrial sites, particularly those associated with petroleum, gas production and wood preserving industries (Wilson and Jones, 1993). 1.2 Remediation technologies Conventional techniques used for the remediation of soil polluted with organic contaminants include excavation of the contaminated soil and disposal to a landfill or capping - containment - of the contaminated areas of a site. These methods have some drawbacks. The first method simply moves the contamination elsewhere and may create significant risks in the excavation, handling and transport of hazardous material. Additionally, it is very difficult and increasingly expensive to find new landfill sites for the final disposal of the material. The cap and containment method is only an interim solution since the contamination remains on site, requiring monitoring and maintenance of the isolation barriers long into the future, with all the associated costs and potential liability. A better approach than these traditional methods is to completely destroy the pollutants, if possible, or transform them into harmless substances. Some technologies that have been used are high-temperature incineration and various types of chemical decomposition (for example, base-catalyzed dechlorination, UV oxidation). However, these methods have significant disadvantages, principally their technological complexity, high cost , and the lack of public acceptance. Bioremediation, on the contrast, is a promising option for the complete removal and destruction of contaminants. 1.3 Bioremediation of PAH contaminated soil & groundwater Bioremediation is the use of living organisms, primarily microorganisms, to degrade or detoxify hazardous wastes into harmless substances such as carbon dioxide, water and cell biomass Most PAHs are biodegradable unter natural conditions (Da Silva et al., 2003; Meysami and Baheri, 2003) and bioremediation for cleanup of PAH wastes has been extensively studied at both laboratory and commercial levels- It has been implemented at a number of contaminated sites, including the cleanup of the Exxon Valdez oil spill in Prince William Sound, Alaska in 1989, the Mega Borg spill off the Texas coast in 1990 and the Burgan Oil Field, Kuwait in 1994 (Purwaningsih, 2002). Different strategies for PAH bioremediation, such as in situ , ex situ or on site bioremediation were developed in recent years. In situ bioremediation is a technique that is applied to soil and groundwater at the site without removing the contaminated soil or groundwater, based on the provision of optimum conditions for microbiological contaminant breakdown.. Ex situ bioremediation of PAHs, on the other hand, is a technique applied to soil and groundwater which has been removed from the site via excavation (soil) or pumping (water). Hazardous contaminants are converted in controlled bioreactors into harmless compounds in an efficient manner. 1.4 Bioavailability of PAH in the subsurface Frequently, PAH contamination in the environment is occurs as contaminants that are sorbed onto soilparticles rather than in phase (NAPL, non aqueous phase liquids). It is known that the biodegradation rate of most PAHs sorbed onto soil is far lower than rates measured in solution cultures of microorganisms with pure solid pollutants (Alexander and Scow, 1989; Hamaker, 1972). It is generally believed that only that fraction of PAHs dissolved in the solution can be metabolized by microorganisms in soil. The amount of contaminant that can be readily taken up and degraded by microorganisms is defined as bioavailability (Bosma et al., 1997; Maier, 2000). Two phenomena have been suggested to cause the low bioavailability of PAHs in soil (Danielsson, 2000). The first one is strong adsorption of the contaminants to the soil constituents which then leads to very slow release rates of contaminants to the aqueous phase. Sorption is often well correlated with soil organic matter content (Means, 1980) and significantly reduces biodegradation (Manilal and Alexander, 1991). The second phenomenon is slow mass transfer of pollutants, such as pore diffusion in the soil aggregates or diffusion in the organic matter in the soil. The complex set of these physical, chemical and biological processes is schematically illustrated in Figure 1. As shown in Figure 1, biodegradation processes are taking place in the soil solution while diffusion processes occur in the narrow pores in and between soil aggregates (Danielsson, 2000). Seemingly contradictory studies can be found in the literature that indicate the rate and final extent of metabolism may be either lower or higher for sorbed PAHs by soil than those for pure PAHs (Van Loosdrecht et al., 1990). These contrasting results demonstrate that the bioavailability of organic contaminants sorbed onto soil is far from being well understood. Besides bioavailability, there are several other factors influencing the rate and extent of biodegradation of PAHs in soil including microbial population characteristics, physical and chemical properties of PAHs and environmental factors (temperature, moisture, pH, degree of contamination). Figure 1: Schematic diagram showing possible rate-limiting processes during bioremediation of hydrophobic organic contaminants in a contaminated soil-water system (not to scale) (Danielsson, 2000). 1.5 Increasing the bioavailability of PAH in soil Attempts to improve the biodegradation of PAHs in soil by increasing their bioavailability include the use of surfactants , solvents or solubility enhancers.. However, introduction of synthetic surfactant may result in the addition of one more pollutant. (Wang and Brusseau, 1993).A study conducted by Mulder et al. showed that the introduction of hydropropyl-ß-cyclodextrin (HPCD), a well-known PAH solubility enhancer, significantly increased the solubilization of PAHs although it did not improve the biodegradation rate of PAHs (Mulder et al., 1998), indicating that further research is required in order to develop a feasible and efficient remediation method. Enhancing the extent of PAHs mass transfer from the soil phase to the liquid might prove an efficient and environmentally low-risk alternative way of addressing the problem of slow PAH biodegradation in soil.

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Synthetic biology has recently had a great development, many papers have been published and many applications have been presented, spanning from the production of biopharmacheuticals to the synthesis of bioenergetic substrates or industrial catalysts. But, despite these advances, most of the applications are quite simple and don’t fully exploit the potential of this discipline. This limitation in complexity has many causes, like the incomplete characterization of some components, or the intrinsic variability of the biological systems, but one of the most important reasons is the incapability of the cell to sustain the additional metabolic burden introduced by a complex circuit. The objective of the project, of which this work is part, is trying to solve this problem through the engineering of a multicellular behaviour in prokaryotic cells. This system will introduce a cooperative behaviour that will allow to implement complex functionalities, that can’t be obtained with a single cell. In particular the goal is to implement the Leader Election, this procedure has been firstly devised in the field of distributed computing, to identify the process that allow to identify a single process as organizer and coordinator of a series of tasks assigned to the whole population. The election of the Leader greatly simplifies the computation providing a centralized control. Further- more this system may even be useful to evolutionary studies that aims to explain how complex organisms evolved from unicellular systems. The work presented here describes, in particular, the design and the experimental characterization of a component of the circuit that solves the Leader Election problem. This module, composed of an hybrid promoter and a gene, is activated in the non-leader cells after receiving the signal that a leader is present in the colony. The most important element, in this case, is the hybrid promoter, it has been realized in different versions, applying the heuristic rules stated in [22], and their activity has been experimentally tested. The objective of the experimental characterization was to test the response of the genetic circuit to the introduction, in the cellular environment, of particular molecules, inducers, that can be considered inputs of the system. The desired behaviour is similar to the one of a logic AND gate in which the exit, represented by the luminous signal produced by a fluorescent protein, is one only in presence of both inducers. The robustness and the stability of this behaviour have been tested by changing the concentration of the input signals and building dose response curves. From these data it is possible to conclude that the analysed constructs have an AND-like behaviour over a wide range of inducers’ concentrations, even if it is possible to identify many differences in the expression profiles of the different constructs. This variability accounts for the fact that the input and the output signals are continuous, and so their binary representation isn’t able to capture the complexity of the behaviour. The module of the circuit that has been considered in this analysis has a fundamental role in the realization of the intercellular communication system that is necessary for the cooperative behaviour to take place. For this reason, the second phase of the characterization has been focused on the analysis of the signal transmission. In particular, the interaction between this element and the one that is responsible for emitting the chemical signal has been tested. The desired behaviour is still similar to a logic AND, since, even in this case, the exit signal is determined by the hybrid promoter activity. The experimental results have demonstrated that the systems behave correctly, even if there is still a substantial variability between them. The dose response curves highlighted that stricter constrains on the inducers concentrations need to be imposed in order to obtain a clear separation between the two levels of expression. In the conclusive chapter the DNA sequences of the hybrid promoters are analysed, trying to identify the regulatory elements that are most important for the determination of the gene expression. Given the available data it wasn’t possible to draw definitive conclusions. In the end, few considerations on promoter engineering and complex circuits realization are presented. This section aims to briefly recall some of the problems outlined in the introduction and provide a few possible solutions.

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ZUSAMMENFASSUNG Die vorgelegte Dissertation enthält zwei Teile. Der erste beinhaltet eine Einführung in die Flora Südostasiens und die Untersuchungsgruppe Asteraceae-Senecioneae Cass. mit den Gattungen Cissampelopsis (DC.) Miq., Gynura Cass. und Crassocephalum Moench (Kapitel 1). Der zweite Teil besteht aus drei Manuskripten, die auf originalen Forschungsergebnissen basieren (Kapitel 2-4). In Kapitel 2 wird eine Revision der asiatischen Gattung Cissampelopsis vorgelegt. Die folgenden zwei Sektionen mit zehn Arten und zwei Varietäten werden anerkannt: sect. Buimalia C. Jeffrey & Y. L. Chen mit C. buimalia (Buch.-Ham. ex D. Don) C. Jeffrey & Y. L. Chen, C. erythrochaeta C. Jeffrey & Y. L. Chen und C. calcadensis (Ramasw.) C. Jeffrey & Y. L. Chen sowie sect. Cissampelopsis mit C. glandulosa C. Jeffrey & Y. L. Chen, C. walkeri (Arn.) C. Jeffrey & Y. L. Chen mit var. walkeri und var. floccosa Vanijajiva & Kadereit (var. nov.), C. corifolia C. Jeffrey & Y. L. Chen, C. volubilis (Bl.) Miq, C. ansteadii (Tadul. & Jacob) C. Jeffrey & Y. L. Chen, C. spelaeicola (Van.) C. Jeffrey & Y. L. Chen und C. corymbosa (Wall. ex DC.) C. Jeffrey & Y. L. Chen. Schlüssel, Artbeschreibungen, Fotographien von Blütenmerkmalen und Verbreitungskarten werden präsentiert. Kapitel 3 beinhaltet die Revision der paläotropischen Gattung Gynura. Vierundvierzig Arten werden anerkannt, darunter die folgenden drei Neubeschreibungen: G. davisii Vanijajiva & Kadereit, G. siamensis Vanijajiva & Kadereit und G. villosus Vanijajiva & Kadereit. Gynura dissecta (F. G. Davies) Vanijajiva & Kadereit, G. annua (F. G. Davies) Vanijajiva & Kadereit und G. aurantiaca (Bl) DC. subsp. parviflora (F. G. Davies) Vanijajiva & Kadereit sind Neukombinationen. Ein Schlüssel, Artbeschreibungen und Verbreitungskarten werden vorgelegt. In Kapitel 4 wird eine Analyse von Crassocephalum in Asien, einer aus Afrika eingeschleppten Gattung, präsentiert. Diese Untersuchung basiert auf umfangreicher Feldarbeit, Herbarstudien, Analysen der Pollen- und Samenfertilität, Chromosomenzählungen sowie ITS- und trnL-F-Sequenzen. Die Studie ergab, dass Crassocephalum in Asien mit zwei Arten und deren Hybrid vertreten ist. Die zwei Arten sind C. crepidioides (Benth.) S. Moore und C. rubens (Juss. ex Jacq.) S. Moore, wobei letztere einen Neufund für Asien darstellt. Der Hybrid aus diesen beiden Arten resultiert aus einer Kreuzung von C. crepidioides (2n=40) als weiblichem und C. rubens (2n=40) als männlichem Elter.

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Different types of proteins exist with diverse functions that are essential for living organisms. An important class of proteins is represented by transmembrane proteins which are specifically designed to be inserted into biological membranes and devised to perform very important functions in the cell such as cell communication and active transport across the membrane. Transmembrane β-barrels (TMBBs) are a sub-class of membrane proteins largely under-represented in structure databases because of the extreme difficulty in experimental structure determination. For this reason, computational tools that are able to predict the structure of TMBBs are needed. In this thesis, two computational problems related to TMBBs were addressed: the detection of TMBBs in large datasets of proteins and the prediction of the topology of TMBB proteins. Firstly, a method for TMBB detection was presented based on a novel neural network framework for variable-length sequence classification. The proposed approach was validated on a non-redundant dataset of proteins. Furthermore, we carried-out genome-wide detection using the entire Escherichia coli proteome. In both experiments, the method significantly outperformed other existing state-of-the-art approaches, reaching very high PPV (92%) and MCC (0.82). Secondly, a method was also introduced for TMBB topology prediction. The proposed approach is based on grammatical modelling and probabilistic discriminative models for sequence data labeling. The method was evaluated using a newly generated dataset of 38 TMBB proteins obtained from high-resolution data in the PDB. Results have shown that the model is able to correctly predict topologies of 25 out of 38 protein chains in the dataset. When tested on previously released datasets, the performances of the proposed approach were measured as comparable or superior to the current state-of-the-art of TMBB topology prediction.

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The introduction of exotic species is one of the most important threats to biodiversity.This phenomenon may cause economic and environmental damage. To prevent these invasions there are institutions like EPPO. Nevertheless, the introduction of exotic pests is an increasing issue, difficult to control. Classic biological control, based on importation of natural enemies from the country of origin, has been successfully used for over 120 years, but it has also raised some criticism. My research work has focused on the study of the new associations occurring between indigenous parasitoids and three exotic pests introduced in Italy and Europe. The three target insects considered were: Cacyreus marshalli Butler (Lepidoptera: Lycaenidae), a pest of Geranium plants; Dryocosmus kuriphilus Yasumatsu (Hymenoptera: Cynipidae), a plague of Castanea sp. and Harmonia axyridis (Pallas) (Coleoptera: Coccinellidae). This ladybug has been introduced as a biological control agent, but since some years it considered as an invasive species. For C. marshalli I performed laboratory tests on acceptance and suitability of immature stages of this butterfly by Exorista larvarum (Diptera: Tachinidae) and Brachymeria tibialis (Hymenoptera: Chalcidicae). The experiments showed that these two parasitoids could be used to contain this pest. For D. kuriphilus I performed field samplings in an infested chestnut area, the samples were maintained in rearing chamber until gall wasp or parasitoids emergence. In the 3-year research many parasitoids of gall wasps were found; one of these, Torymus flavipes (Walker), was found in large number. For H. axyridis the research work included a first phase of field sampling, during which I searched indigenous parasitoids which had adapted to this new host; the only species found was Dinocampus coccinellae (Schrank) (Hymenoptera: Braconidae). Laboratory tests were performed on the wasp rearing, biology and capacity to contain H. axyridis.

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The relatively young discipline of astronautics represents one of the scientifically most fascinating and technologically advanced achievements of our time. The human exploration in space does not offer only extraordinary research possibilities but also demands high requirements from man and technology. The space environment provides a lot of attractive experimental tools towards the understanding of fundamental mechanism in natural sciences. It has been shown that especially reduced gravity and elevated radiation, two distinctive factors in space, influence the behavior of biological systems significantly. For this reason one of the key objectives on board of an earth orbiting laboratory is the research in the field of life sciences, covering the broad range from botany, human physiology and crew health up to biotechnology. The Columbus Module is the only European low gravity platform that allows researchers to perform ambitious experiments in a continuous time frame up to several months. Biolab is part of the initial outfitting of the Columbus Laboratory; it is a multi-user facility supporting research in the field of biology, e.g. effect of microgravity and space radiation on cell cultures, micro-organisms, small plants and small invertebrates. The Biolab IEC are projects designed to work in the automatic part of Biolab. In this moment in the TO-53 department of Airbus Defence & Space (formerly Astrium) there are two experiments that are in phase C/D of the development and they are the subject of this thesis: CELLRAD and CYTOSKELETON. They will be launched in soft configuration, that means packed inside a block of foam that has the task to reduce the launch loads on the payload. Until 10 years ago the payloads which were launched in soft configuration were supposed to be structural safe by themselves and a specific structural analysis could be waived on them; with the opening of the launchers market to private companies (that are not under the direct control of the international space agencies), the requirements on the verifications of payloads are changed and they have become much more conservative. In 2012 a new random environment has been introduced due to the new Space-X launch specification that results to be particularly challenging for the soft launched payloads. The last ESA specification requires to perform structural analysis on the payload for combined loads (random vibration, quasi-steady acceleration and pressure). The aim of this thesis is to create FEM models able to reproduce the launch configuration and to verify that all the margins of safety are positive and to show how they change because of the new Space-X random environment. In case the results are negative, improved design solution are implemented. Based on the FEM result a study of the joins has been carried out and, when needed, a crack growth analysis has been performed.

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The objective of this theses is to contribute to the wide discussion about the biological control level on the biomineralization operated by calcifying organisms. In particular the intra-crystalline organic matrix associated with different coral species was studied and its role in the process was investigated. The main goals obtained from the research on corals included: (i) the discovery of the species specific role of the intra-crystalline organic matrix molecules in the precipitation of calcium carbonate; (ii) the definition of the role of magnesium ions in the control of the macromolecules assembly/aggregation and in the consequent calcium carbonate polymorphic selectivity; (iii) the discovery that in corals the biomineralization process is not affected by the sea water acidity, as consequence corals are able to construct their skeletons independently from the environmental conditions as far they survive. At the same time, investigations on different kind of vaterite, biogenic and synthetic, were also carried out and confirm the importance of the organism control on the biomineralization process and in particular on the co-existence of different crystalline structures of vaterite for enabling optimization of specific functions, through the employment of OM and acidic macromolecules.

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The marine world is an immense source of biodiversity that provides substances with striking potentials in medicinal chemistry and biotechnology. Sponges (Porifera) are marine animals that represent the most impressive example of organisms possessing the ability to metabolise silica through a family of enzymes known as silicateins. Complex skeletal structures (spicules) made of pure biogenic silica (biosilica) are produced under physiological conditions. Biosilica is a natural material comprising inorganic and organic components with unique mechanical, optical, and physico-chemical properties, including promising potential to be used for development of therapeutic agents in regenerative medicine. Unravelling the intimate physiological mechanisms occurring in sponges during the construction of their siliceous spicules is an on-going project, and several questions have been addressed by the studies proposed by our working group. In this doctoral work, the recombinant DNA technology is exploited for functional and structural characterisation of silicatein. Its precursors are produced as fusion proteins with a chaperone tag (named TF-Ps), and a robust method for the overexpression of native soluble proteins in high concentrations has been developed. In addition, it is observed and proven experimentally that the maturation of silicatein is an autocatalytic event that: (i) can be modulated by rational use of protease inhibitors; (ii) is influenced by the temperature of the environment; (iii) only slightly depends on the pH. In the same experimental framework, observations on the dynamics in the maturation of silicateins allow a better understanding of how the axial filaments form during the early stages of spicule construction. In addition, the definition of new distinct properties of silicatein (termed “structure-guiding” and “structure-forming”) is introduced. By homology models and through comparisons with similar proteins (the cathepsins), domains with significant surface hydrophobicity are identified as potential self-assembly mediators. Moreover, a high-throughput screening showed that TF-Ps could generate crystals under certain conditions, becoming promising for further structural studies. With the goal of optimise the properties of the recombinant silicatein, implementation of new production systems are tried for the first time. Success in the expression of silicatein-type proteins in insect and yeast cells, constitute a promising basis for further development, towards the establishment of an efficient method for the production of a high-value pure and soluble protein.

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We report four epidemiologically unrelated cases of KPC-carrying Klebsiella pneumoniae identified in Switzerland between May 2009 and November 2010. Three cases were transferred from Italy (two KPC-3, one KPC-2) and one from Greece (KPC-2). Resistance to colistin and doxycycline emerged in one KPC-3-carrying K. pneumoniae strain during therapy. These results demonstrate ongoing dissemination of KPC throughout Europe. Rapid and reliable identification of KPC and implementation of control measures is essential to limit spread.