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Objectives: To evaluate a new tool for the early diagnosis of tuberculosis., Methods: A total of 374 smear-negative clinical specimens from patients with suspected tuberculosis were evaluated using a new procedure consisting of a preliminary step of culture in broth bottles followed by the detection of Mycobacterium tuberculosis complex (Mtb) and rifampicin resistance by the Xpert MTB/RIF assay (XMTB-RIF)., Results: A total of 30 Mtb strains were isolated, all susceptible to rifampicin. When broth cultures were subjected to XMTB-RIF analysis after 15 days of incubation, sensitivity, specificity, PPV, and NPV were each 100% when compared with liquid culture., Conclusion: The XMTB-RIF assay used in 15-day broth cultures may provide a final culture result for smear-negative specimens. This process, combined with clinical signs, may contribute to rapidly diagnosing tuberculosis and also to the early reevaluation of empirical antituberculosis treatment., (Copyright © 2018. Published by Elsevier Masson SAS.)

High permittivity SrTiO 3 for the realization of all-dielectric metamaterials operating at terahertz frequencies was fabricated. A comparison of different processing methods demonstrates that Spark Plasma Sintering is the most effective sintering process to yield high density ceramic with high permittivity. We compare this sintering process with two other processes. The fabricated samples are characterized in the low frequency and in the terahertz frequency ranges. Their relative permittivities are compared with that of a reference SrTiO 3 single crystal. The permittivity of the sample fabricated by Spark Plasma Sintering is as high as that of the single crystal. The role of the signal-to-noise ratio in the measurements at terahertz frequency is detailed.

The interplay between membrane permeability alterations and the enzymatic barrier contributes to Klebsiella pneumoniae multidrug resistance. We assessed the specific effect of the efflux levels of the main efflux pumps (AcrAB and OqxAB), alone and associated with the loss of the main porins (OmpK35 and OMPK36), on the activity of various antibiotics by constructing a set of K. pneumoniae isogenic strains, including strains with plasmid-mediated β-lactamases (DHA-1, CTX-M-15, and OXA-48). The two pumps contributed to intrinsic chloramphenicol resistance and AcrAB to that of nalidixic acid and cefoxitin, whereas they had no impact on the activity of the other 11 antibiotics tested. We confirmed the expulsion of these three antibiotics by the two overproduced pumps and that of tigecycline by overproduced AcrAB, and showed that overproduced AcrAB also expelled ertapenem, piperacillin, ceftolozane, and ceftazidime. The sole loss of porins did not significantly affect the activity of the tested antibiotics, except ertapenem. The effect of efflux increases and porin loss on β-lactam activity was the highest in plasmid-mediated β-lactamase-producing strains. Thus, DHA-1-producing strains became non-susceptible (NS) to (i) ertapenem when there was an increase in efflux or porin loss, (ii) imipenem and ceftazidime+avibactam when the two mechanisms were associated, and (iii) temocillin when AcrAB was overproduced. The CTX-M-15-producing strains became NS to (i) ertapenem when there was no porin, (ii) ceftolozane+tazobactam when there was either overproduced OqxAB or porin loss, and (iii) temocillin when AcrAB was overproduced. OXA-48-producing strains known to be NS to temocillin were also NS to ceftolozane and they became NS to imipenem when the two pumps were overproduced or there was porin loss. Overall, this study shows that the balance between influx and efflux differentially modulates the activity of the tested antibiotics, an important point for evaluating the activity of future antibiotics or new combinations.

Natural diamonds contain mineral and fluid inclusions that record diamond growth conditions. Replicating the growth of inclusion-bearing diamonds in a laboratory is therefore a novel diagnostic tool to constrain the conditions of diamond formation in Earth's lithosphere. By determining the carbon isotopic fractionation during diamond growth in fluids or melts, our laboratory experiments revealed that lithospheric monocrystalline and fibrous and coated diamonds grow similarly from redox reactions at isotopic equilibrium in water and carbonate-rich fluids or melts, and not from native carbon. These new results explain why most of the lithospheric diamonds are characterized by a common carbon isotopic fingerprint, inherited from their common parent fluids and not from the mantle assemblage.

Background: Carbapenemase-producing Enterobacteriaceae (CPE) are difficult to identify among carbapenem non-susceptible Enterobacteriaceae (NSE). We designed phenotypic strategies giving priority to high sensitivity for screening putative CPE before further testing., Methods: Presence of carbapenemase-encoding genes in ertapenem NSE (MIC > 0.5 mg/l) consecutively isolated in 80 French laboratories between November 2011 and April 2012 was determined by the Check-MDR-CT103 array method. Using the Mueller-Hinton (MH) disk diffusion method, clinical diameter breakpoints of carbapenems other than ertapenem, piperazicillin+tazobactam, ticarcillin+clavulanate and cefepime as well as diameter cut-offs for these antibiotics and temocillin were evaluated alone or combined to determine their performances (sensitivity, specificity, positive and negative likelihood ratios) for identifying putative CPE among these ertapenem-NSE isolates. To increase the screening specificity, these antibiotics were also tested on cloxacillin-containing MH when carbapenem NSE isolates belonged to species producing chromosomal cephalosporinase (AmpC) but Escherichia coli., Results: Out of the 349 ertapenem NSE, 52 (14.9%) were CPE, including 39 producing OXA-48 group carbapenemase, eight KPC and five MBL. A screening strategy based on the following diameter cut offs, ticarcillin+clavulanate <15 mm, temocillin <15 mm, meropenem or imipenem <22 mm, and cefepime <26 mm, showed 100% sensitivity and 68.1% specificity with the better likelihood ratios combination. The specificity increased when a diameter cut-off <32 mm for imipenem (76.1%) or meropenem (78.8%) further tested on cloxacillin-containing MH was added to the previous strategy for AmpC-producing isolates., Conclusion: The proposed strategies that allowed for increasing the likelihood of CPE among ertapenem-NSE isolates should be considered as a surrogate for carbapenemase production before further CPE confirmatory testing.

Sequence type 131 (ST131) is a predominant lineage among extraintestinal pathogenic Escherichia coli. It plays a major role in the worldwide dissemination of E. coli producing extended-spectrum β-lactamases (ESBLs). Here we describe the long-term epidemiology of this clonal group in a French university hospital, where the incidence of ESBL-producing E. coli has increased from 0.018 case per 1000 patient-days in the year 2000 to 0.50 case per 1000 patient-days in 2014. The first of the 141 ST131 isolates was recovered in 2006, and the ST131 clonal group accounted for 18.1% of total ESBL-producing E. coli over the whole period (2000-2014). Subclonal typing showed that 75.9% (107/141) of ST131 isolates were H30, of which 81.3% (87/107) were H30-Rx. The large majority (137/141) of ESBLs produced were of the CTX-M group, with 94 CTX-M-15, 19 CTX-M-1, 10 CTX-M-27, 8 CTX-M-14 and four other CTX-M types (n = 6). Pulsed-field gel electrophoresis (PFGE) analysis showed high diversity, which increased during the course of the study. The 141 ST131 isolates clustered in 53 pulsotypes (PTs), with 2 dominant PTs (PT14 and PT13) with 36 and 17 isolates, respectively. These findings showed that ST131 was a predominant clone among ESBL-producing E. coli in our hospital, even though it only accounted for <20%. Moreover, ST131 should be regarded not as a unified entity but as a cluster of distinct clonal subsets even if the increase in resistance within ST131 has a strong clonal basis, being attributable mainly to the spread of C1/H30-R and C2/H30-Rx clades., (Copyright © 2016 Elsevier B.V. and International Society of Chemotherapy. All rights reserved.)

Background: Adult skeletal muscles are composed of slow and fast myofiber subtypes which each express selective genes required for their specific contractile and metabolic activity. Six homeoproteins are transcription factors regulating muscle cell fate through activation of myogenic regulatory factors and driving fast-type gene expression during embryogenesis., Results: We show here that Six1 protein accumulates more robustly in the nuclei of adult fast-type muscles than in adult slow-type muscles, this specific enrichment takes place during perinatal growth. Deletion of Six1 in soleus impaired fast-type myofiber specialization during perinatal development, resulting in a slow phenotype and a complete lack of Myosin heavy chain 2A (MyHCIIA) expression. Global transcriptomic analysis of wild-type and Six1 mutant myofibers identified the gene networks controlled by Six1 in adult soleus muscle. This analysis showed that Six1 is required for the expression of numerous genes encoding fast-type sarcomeric proteins, glycolytic enzymes and controlling intracellular calcium homeostasis. Parvalbumin, a key player of calcium buffering, in particular, is a direct target of Six1 in the adult myofiber., Conclusions: This analysis revealed that Six1 controls distinct aspects of adult muscle physiology in vivo, and acts as a main determinant of fast-fiber type acquisition and maintenance.

Diffraction is the ultimate limit at which details of objects can be resolved in conventional optical spectroscopy and imaging systems. In the THz spectral range, spectroscopy systems increasingly rely on ultra-broadband radiation (extending over more 5 octaves) making a great challenge to reach resolution limited by diffraction. Here, we propose an original easy-to-implement wavefront manipulation concept to achieve ultrabroadband THz spectroscopy system with diffraction-limited resolution. Applying this concept to a large-area photoconductive emitter, we demonstrate diffraction-limited ultra-broadband spectroscopy system up to 14.5 THz with a dynamic range of 10(3). The strong focusing of ultrabroadband THz radiation provided by our approach is essential for investigating single micrometer-scale objects such as graphene flakes or living cells, and besides for achieving intense ultra-broadband THz electric fields.

Background: Chromosomal class A β-lactamases have been characterized in Raoultella ornithinolytica and Raoultella planticola. The purpose of this study was to characterize that of Raoultella terrigena., Materials and Methods: The blaTER-1 gene of R. terrigena strain ATCC33257(T) was cloned (pACter-1) and sequenced. It was then used to detect the bla gene of strains BM 85 01 095 and SB2796. The hypermutable Escherichia coli strain AB1157 mutS::Tn10 was transformed with pACter-1 and mutants growing on plates containing>2mg/L ceftazidime were studied. Notably, the impact of mutations only observed in the promoter region on β-lactam resistance was assessed by site-directed mutagenesis experiments., Results: R. terrigena strains ATCC33257(T) and BM 85 01 095 had the same bla gene and deduced protein (TER-1) whereas there were 3 substitutions in those of strain SB2796 (TER-2). Class A β-lactamases TER showed 78%, 69.9% and 38.7% identity with PLA or ORN, TEM-1 and KOXY, respectively. Compared with TEM-1, TER-1 and TER-2 showed 2 particular substitutions, Leu75Pro and Glu240Asn demonstrated to be involved in the inherent β-lactam resistance profile of R. terrigena. TER-1 (pI of 7.6) had a high activity against penicillin G and a significantly low one against amoxicillin. Substitution G/T observed in the -35 region of the blaTER gene harbored by strains growing in the presence of≥2mg/L ceftazidime was shown to be responsible for this growth., Conclusion: TER is a new class A β-lactamase belonging to functional group 2b., (Copyright © 2015. Published by Elsevier SAS.)

Background: Environmental conditions early in life may imprint the circadian system and influence response to environmental signals later in life. We previously determined that a large springtime increase in solar insolation at the onset location was associated with a younger age of onset of bipolar disorder, especially with a family history of mood disorders. This study investigated whether the hours of daylight at the birth location affected this association., Methods: Data collected previously at 36 collection sites from 23 countries were available for 3896 patients with bipolar I disorder, born between latitudes of 1.4 N and 70.7 N, and 1.2 S and 41.3 S. Hours of daylight variables for the birth location were added to a base model to assess the relation between the age of onset and solar insolation., Results: More hours of daylight at the birth location during early life was associated with an older age of onset, suggesting reduced vulnerability to the future circadian challenge of the springtime increase in solar insolation at the onset location. Addition of the minimum of the average monthly hours of daylight during the first 3 months of life improved the base model, with a significant positive relationship to age of onset. Coefficients for all other variables remained stable, significant and consistent with the base model., Conclusions: Light exposure during early life may have important consequences for those who are susceptible to bipolar disorder, especially at latitudes with little natural light in winter. This study indirectly supports the concept that early life exposure to light may affect the long term adaptability to respond to a circadian challenge later in life., (Copyright © 2015 Elsevier Ltd. All rights reserved.)

The adaptive evolution of large asexual populations is generally characterized by competition between clones carrying different beneficial mutations. Interference slows down the adaptation speed and makes the theoretical description of the dynamics more complex with respect to the successional occurrence and fixation of beneficial mutations typical of small populations. A simplified modeling framework considering multiple beneficial mutations with equal and constant fitness advantage is known to capture some of the essential features of laboratory evolution experiments. However, in these experiments the relative advantage of a beneficial mutation is generally dependent on the genetic background. In particular, the general pattern is that, as mutations in different loci accumulate, the relative advantage of new mutations decreases, a trend often referred to as "diminishing return" epistasis. Here, we propose a phenomenological model that generalizes the fixed-advantage framework to include this negative epistasis in a simple way. We evaluate analytically as well as with direct simulations the quantitative consequences of diminishing returns on the evolutionary dynamics. The speed of adaptation decreases in time and reaches a limit value corresponding to neutral evolution in the long time limit. This corresponds to an increase of the diversity in terms of "classes of mutation" in the population. Finally, we show how the model can be compared with dynamic data on fitness and number of beneficial mutations from laboratory evolution experiments., (Copyright © 2014 Elsevier Ltd. All rights reserved.)

The giant plasticity of [Formula: see text]He crystals has been explained as a consequence of the large mobility of their dislocations. Thus, the mechanical properties of dislocation free crystals should be quite different from those of usual ones. In 1996-1998, Ruutu et al. published crystal growth studies showing that, in their helium 4 crystals, the density of screw dislocations along the c-axis was less than 100 per cm[Formula: see text], sometimes zero. We have grown helium 4 crystals using similar growth speeds and temperatures, and extracted their dislocation density from their mechanical properties. We found dislocation densities that are in the range of 10[Formula: see text]-10[Formula: see text] per cm[Formula: see text], that is several orders of magnitude larger than Ruutu et al. Our tentative interpretation of this apparent contradiction is that the two types of measurements are somewhat indirect and concern different types of dislocations. As for the dislocation nucleation mechanism, it remains to be understood.

Purpose: Two common approaches to identify subgroups of patients with bipolar disorder are clustering methodology (mixture analysis) based on the age of onset, and a birth cohort analysis. This study investigates if a birth cohort effect will influence the results of clustering on the age of onset, using a large, international database., Methods: The database includes 4037 patients with a diagnosis of bipolar I disorder, previously collected at 36 collection sites in 23 countries. Generalized estimating equations (GEE) were used to adjust the data for country median age, and in some models, birth cohort. Model-based clustering (mixture analysis) was then performed on the age of onset data using the residuals. Clinical variables in subgroups were compared., Results: There was a strong birth cohort effect. Without adjusting for the birth cohort, three subgroups were found by clustering. After adjusting for the birth cohort or when considering only those born after 1959, two subgroups were found. With results of either two or three subgroups, the youngest subgroup was more likely to have a family history of mood disorders and a first episode with depressed polarity. However, without adjusting for birth cohort (three subgroups), family history and polarity of the first episode could not be distinguished between the middle and oldest subgroups., Conclusion: These results using international data confirm prior findings using single country data, that there are subgroups of bipolar I disorder based on the age of onset, and that there is a birth cohort effect. Including the birth cohort adjustment altered the number and characteristics of subgroups detected when clustering by age of onset. Further investigation is needed to determine if combining both approaches will identify subgroups that are more useful for research., (Copyright © 2014 Elsevier Masson SAS. All rights reserved.)

The prevalence of Escherichia coli sequence type 131 (ST131) and its subclone H30 was assessed among a collection of 490 E. coli isolated in 2013 in a French university hospital. The prevalence of ST131 was 4% among bloodstream isolates (regardless of antimicrobial resistance) and 17.2% among extended-spectrum β-lactamase (ESBL)-producing isolates. Although a much lower prevalence of ST131 was found among bloodstream E. coli isolates compared with other countries, a large predominance of H30 subclone within ST131 was confirmed. It was also confirmed that, among ESBL-producing E. coli, ST131 isolates were more frequently resistant to amoxicillin/clavulanic acid, ceftazidime, fluoroquinolones and aminoglycosides than non-ST131 isolates., (Copyright © 2014 Elsevier B.V. and the International Society of Chemotherapy. All rights reserved.)

Graphene has been proposed as a particularly attractive material for the achievement of strong optical nonlinearities, in particular generation of terahertz radiation. However, owing to the particular symmetries of the C-lattice, second-order nonlinear effects such as difference-frequency or rectification processes are predicted to vanish in a graphene layer for optical excitations (ℏω ≫ 2EF) involving the two relativistic dispersion bands. Here we experimentally demonstrate that graphene excited by femtosecond optical pulses generate a coherent THz radiation ranging from 0.1 to 4 THz via a second-order nonlinear effect. We fully interpret its characteristics with a model describing the electron and hole states beyond the usual massless relativistic scheme. This second-order nonlinear effect is dynamical photon drag, which relies on the transfer of light momentum to the carriers by the ponderomotive electric and magnetic forces. The model highlights the key roles of next-C-neighbor couplings and of unequal electron and hole lifetimes in the observed second-order response. Finally, our results indicate that dynamical photon drag effect in graphene can provide emission up to 60 THz, opening new routes for the generation of ultrabroadband terahertz pulses.

Objectives: To determine proportions and incidence rates of Enterobacteriaceae producing carbapenemase among those non-susceptible (NS) to carbapenems in France., Methods: From November 2011 to April 2012, 71 laboratories recorded non-duplicate Enterobacteriaceae clinical isolates NS to at least one carbapenem and the total number of isolates of the different species. Carbapenem MICs were determined by broth microdilution and the β-lactamase content by DNA microarray., Results: During the study period, the 71 laboratories identified 133 244 Enterobacteriaceae isolates, of which 846 (0.63%) were NS to at least one carbapenem. Carbapenem-NS isolates accounted for 0.07% (61/90 148) among Escherichia coli isolates, 1.1% (111/10 436) among Klebsiella pneumoniae, 8.2% (492/5971) among Enterobacter cloacae and 4.0% (84/2104) among Enterobacter aerogenes. Among the 541 available carbapenem-NS isolates, 222 (including 63 randomly selected E. cloacae) were further analysed after confirmation of carbapenem non-susceptibility. None of the Enterobacter spp. isolates produced carbapenemase. Among the other species, 28 isolates produced carbapenemases (22 OXA-48, 4 KPC and 2 NDM), accounting for an estimated proportion of carbapenemase-producing isolates of 0.08% for all species, 0.01% for E. coli and 0.27% for K. pneumoniae. The incidence-density rate in the participating hospitals was 0.0041 per 1000 hospital-days and the incidence rate was 0.0027 per 100 admissions., Conclusions: The incidence-density rate of carbapenemase-producing isolates per 1000 hospital-days was low and 30-fold lower than that of carbapenem-NS isolates (0.125) and almost 300-fold lower than that of ESBL-producing isolates (1.104) in these French hospitals., (© The Author 2014. Published by Oxford University Press on behalf of the British Society for Antimicrobial Chemotherapy. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.)

In 2008, a previously unknown Escherichia coli clonal group, sequence type 131 (ST131), was identified on three continents. Today, ST131 is the predominant E. coli lineage among extraintestinal pathogenic E. coli (ExPEC) isolates worldwide. Retrospective studies have suggested that it may originally have risen to prominence as early as 2003. Unlike other classical group B2 ExPEC isolates, ST131 isolates are commonly reported to produce extended-spectrum β-lactamases, such as CTX-M-15, and almost all are resistant to fluoroquinolones. Moreover, ST131 E. coli isolates are considered to be truly pathogenic, due to the spectrum of infections they cause in both community and hospital settings and the large number of virulence-associated genes they contain. ST131 isolates therefore seem to contradict the widely held view that high levels of antimicrobial resistance are necessarily associated with a fitness cost leading to a decrease in pathogenesis. Six years after the first description of E. coli ST131, this review outlines the principal traits of ST131 clonal group isolates, based on the growing body of published data, and highlights what is currently known and what we need to find out to provide public health authorities with better information to help combat ST131., (Copyright © 2014, American Society for Microbiology. All Rights Reserved.)

The identification of transcription factor binding sites (TFBSs) on genomic DNA is of crucial importance for understanding and predicting regulatory elements in gene networks. TFBS motifs are commonly described by Position Weight Matrices (PWMs), in which each DNA base pair contributes independently to the transcription factor (TF) binding. However, this description ignores correlations between nucleotides at different positions, and is generally inaccurate: analysing fly and mouse in vivo ChIPseq data, we show that in most cases the PWM model fails to reproduce the observed statistics of TFBSs. To overcome this issue, we introduce the pairwise interaction model (PIM), a generalization of the PWM model. The model is based on the principle of maximum entropy and explicitly describes pairwise correlations between nucleotides at different positions, while being otherwise as unconstrained as possible. It is mathematically equivalent to considering a TF-DNA binding energy that depends additively on each nucleotide identity at all positions in the TFBS, like the PWM model, but also additively on pairs of nucleotides. We find that the PIM significantly improves over the PWM model, and even provides an optimal description of TFBS statistics within statistical noise. The PIM generalizes previous approaches to interdependent positions: it accounts for co-variation of two or more base pairs, and predicts secondary motifs, while outperforming multiple-motif models consisting of mixtures of PWMs. We analyse the structure of pairwise interactions between nucleotides, and find that they are sparse and dominantly located between consecutive base pairs in the flanking region of TFBS. Nonetheless, interactions between pairs of non-consecutive nucleotides are found to play a significant role in the obtained accurate description of TFBS statistics. The PIM is computationally tractable, and provides a general framework that should be useful for describing and predicting TFBSs beyond PWMs.

Thousands of long intergenic non-coding RNAs (lincRNAs) are encoded by the mammalian genome. However, the function of most of these lincRNAs has not been identified in vivo. Here, we demonstrate a role for a novel lincRNA, linc-MYH, in adult fast-type myofiber specialization. Fast myosin heavy chain (MYH) genes and linc-MYH share a common enhancer, located in the fast MYH gene locus and regulated by Six1 homeoproteins. linc-MYH in nuclei of fast-type myofibers prevents slow-type and enhances fast-type gene expression. Functional fast-sarcomeric unit formation is achieved by the coordinate expression of fast MYHs and linc-MYH, under the control of a common Six-bound enhancer.

Background: The onset of bipolar disorder is influenced by the interaction of genetic and environmental factors. We previously found that a large increase in sunlight in springtime was associated with a lower age of onset. This study extends this analysis with more collection sites at diverse locations, and includes family history and polarity of first episode., Methods: Data from 4037 patients with bipolar I disorder were collected at 36 collection sites in 23 countries at latitudes spanning 3.2 north (N) to 63.4 N and 38.2 south (S) of the equator. The age of onset of the first episode, onset location, family history of mood disorders, and polarity of first episode were obtained retrospectively, from patient records and/or direct interview. Solar insolation data were obtained for the onset locations., Results: There was a large, significant inverse relationship between maximum monthly increase in solar insolation and age of onset, controlling for the country median age and the birth cohort. The effect was reduced by half if there was no family history. The maximum monthly increase in solar insolation occurred in springtime. The effect was one-third smaller for initial episodes of mania than depression. The largest maximum monthly increase in solar insolation occurred in northern latitudes such as Oslo, Norway, and warm and dry areas such as Los Angeles, California., Limitations: Recall bias for onset and family history data., Conclusions: A large springtime increase in sunlight may have an important influence on the onset of bipolar disorder, especially in those with a family history of mood disorders., (Copyright © 2014 Elsevier B.V. All rights reserved.)

Nonequilibrium patterns in open systems are ubiquitous in nature, with examples as diverse as desert sand dunes, animal coat patterns such as zebra stripes, or geographic patterns in parasitic insect populations. A theoretical foundation that explains the basic features of a large class of patterns was given by Turing in the context of chemical reactions and the biological process of morphogenesis. Analogs of Turing patterns have also been studied in optical systems where diffusion of matter is replaced by diffraction of light. The unique features of polaritons in semiconductor microcavities allow us to go one step further and to study Turing patterns in an interacting coherent quantum fluid. We demonstrate formation and control of these patterns. We also demonstrate the promise of these quantum Turing patterns for applications, such as low-intensity ultra-fast all-optical switches.

Objectives: To determine factors associated with CTX-M-producing ST131 Escherichia coli which is the worldwide predominant lineage among CTX-M-producing E. coli isolates., Methods: Consecutive inpatients with a clinical sample positive for CTX-M-producing E. coli and considered as cases in a previous 8-month (2008-2009) case-control study performed in ten university hospitals in the Paris area were included in the present sub-population study. Patients with a CTX-M-producing ST131 E. coli clinical isolate were compared with those with a CTX-M-producing non-ST131 E. coli clinical isolate with regard to 66 variables. Variables were first compared using univariate logistic regression, then a multivariate analysis using a backward selection with variables with p-value <0.1 in univariate analysis was carried out., Results: Fifty-five patients with a CTX-M-producing ST131 E. coli clinical isolate were compared to 97 patients with a CTX-producing non-ST131 E. coli clinical isolate. Multivariate analysis showed that only previous residence in long term care facilities (OR=4.4; 95% CI=1.3-14.7) was positively associated with a CTX-M-producing ST131 E. coli isolate. However, it also showed that regular consumption of poultry products (OR=0.2; 95% CI=0.1-0.6), having had at least one device in the preceding 6 months (OR=0.3; 95% CI=0.1-0.7) and stay in ICU (OR=0.2; 95% CI=0.05-0.8) were negatively associated with isolation of CTX-M-producing ST131 E. coli from clinical samples., Conclusions: This study provides more insight into the epidemiological features of ST131 and non-ST131 E. coli producing CTX-M enzymes. It shows, for the first time, that isolation of CTX-M-producing ST131 E. coli from clinical samples is not linked to consumption of various foods and confirms that residence in long term care facilities is a predictor of these isolates.

We measure the electric field of a train of modelocked pulses from a quantum cascade laser in the time-domain by electro-optic sampling. The method relies on synchronizing the modelocked pulses to a reference laser and is applied to 15-ps pulses generated by a 2-THz quantum cascade laser. The pulses from the actively modelocked laser are completely characterized in field and in time with a sub-ps resolution, allowing us to determine the amplitude and phase of each cavity mode. The technique can also give access to the carrier-envelope phase of each pulse.

We probed, in the time domain, the THz electromagnetic radiation originating from spins in CdMnTe diluted magnetic semiconductor quantum wells containing high-mobility electron gas. Taking advantage of the efficient Raman generation process, the spin precession was induced by low power near-infrared pulses. We provide a full theoretical first-principles description of spin-wave generation, spin precession, and of emission of THz radiation. Our results open new perspectives for improved control of the direct coupling between spin and an electromagnetic field, e.g., by using semiconductor technology to insert the THz sources in cavities or pillars.

When submitted to large stresses at high temperature, usual crystals may irreversibly deform. This phenomenon is known as plasticity and it is due to the motion of crystal defects such as dislocations. We have discovered that, in the absence of impurities and in the zero temperature limit, helium 4 crystals present a giant plasticity that is anisotropic and reversible. Direct measurements on oriented single crystals show that their resistance to shear nearly vanishes in one particular direction because dislocations glide freely parallel to the basal planes of the hexagonal structure. This plasticity disappears as soon as traces of helium 3 impurities bind to the dislocations or if their motion is damped by collisions with thermal phonons.

Using a superconducting circuit, the Josephson mixer, we demonstrate the first experimental realization of spatially separated two-mode squeezed states of microwave light. Driven by a pump tone, a first Josephson mixer generates, out of quantum vacuum, a pair of entangled fields at different frequencies on separate transmission lines. A second mixer, driven by a π-phase shifted copy of the first pump tone, recombines and disentangles the two fields. The resulting output noise level is measured to be lower than for the vacuum state at the input of the second mixer, an unambiguous proof of entanglement. Moreover, the output noise level provides a direct, quantitative measure of entanglement, leading here to the demonstration of 6 Mebit · s(-1) (mega entangled bits per second) generated by the first mixer.

A novel scheme to achieve mode-locking of a multimode laser is demonstrated. Traditional methods to produce ultrashort laser pulses are based on modulating the cavity gain or losses at the cavity roundtrip frequency, favoring the pulsed emission. Here, we rather directly act on the phases of the modes, resulting in constructive interference for the appropriated phase relationship. This was performed on a terahertz quantum cascade laser by multimode injection seeding with an external terahertz pulse, resulting in phase mode-locked terahertz laser pulses of 9 ps duration, characterized unambiguously in the time domain.

We used a terahertz (THz) quantum cascade laser (QCL) as an integrated injection seeded source and amplifier for THz time-domain spectroscopy. A THz input pulse is generated inside a QCL by illuminating the laser facet with a near-IR pulse from a femtosecond laser and amplified using gain switching. The THz output from the QCL is found to saturate upon increasing the amplitude of the THz input power, which indicates that the QCL is operating in an injection seeded regime.

We report on the resonant emission in coherently driven single semiconductor quantum dots. We demonstrate that an ultraweak nonresonant laser acts as an optical gate for the quantum dot resonant response. We show that the gate laser suppresses Coulomb blockade at the origin of a resonant emission quenching, and that the optically gated quantum dots systematically behave as ideal two-level systems in both regimes of coherent and incoherent resonant emission.

We report on the realization of a high sensitivity RF noise measurement scheme to study small current fluctuations of mesoscopic systems at milli-Kelvin temperatures. The setup relies on the combination of an interferometric amplification scheme and a quarter-wave impedance transformer, allowing the measurement of noise power spectral densities with gigahertz bandwidth up to five orders of magnitude below the amplifier noise floor. We simultaneously measure the high frequency conductance of the sample by derivating a portion of the signal to a microwave homodyne detection. We describe the principle of the setup, as well as its implementation and calibration. Finally, we show that our setup allows to fully characterize a subnanosecond on-demand single electron source. More generally, its sensitivity and bandwidth make it suitable for applications manipulating single charges at GHz frequencies.

We theoretically propose a scheme for a spin quantum bit based on a double quantum dot contacted to ferromagnetic elements. Interface exchange effects enable an all electric manipulation of the spin and a switchable strong coupling to a superconducting coplanar waveguide cavity. Our setup does not rely on any specific band structure and can in principle be realized with many different types of nanoconductors. This allows us to envision on-chip single spin manipulation and readout using cavity QED techniques.

The amplification of spontaneous emission is used to initiate laser action. As the phase of spontaneous emission is random, the phase of the coherent laser emission (the carrier phase) will also be random each time laser action begins. This prevents phase-resolved detection of the laser field. Here, we demonstrate how the carrier phase can be fixed in a semiconductor laser: a quantum cascade laser (QCL). This is performed by injection seeding a QCL with coherent terahertz pulses, which forces laser action to start on a fixed phase. This permits the emitted laser field to be synchronously sampled with a femtosecond laser beam, and measured in the time domain. We observe the phase-resolved buildup of the laser field, which can give insights into the laser dynamics. In addition, as the electric field oscillations are directly measured in the time domain, QCLs can now be used as sources for time-domain spectroscopy.

Although Raoultella planticola and Raoultella ornithinolytica were described more than 20 years ago, identifying them remains difficult. The reliability of the chromosomal bla gene for this identification was evaluated in comparison with that of the 16S rDNA and rpoB genes in 35 Raoultella strains from different origins. Of the 26 strains previously identified as R. planticola by biochemical tests alone or in association with molecular methods, 21 harboured a bla gene with 99.8% identity with the bla gene of two reference R. ornithinolytica strains (bla(ORN) gene) and 5 harboured a bla gene with 99.2% identity with the bla gene of two reference R. planticola strains (bla(PLA) gene). The 9 isolates previously identified as R. ornithinolytica harboured a bla(ORN) gene. The bla gene-based identification was confirmed by 16S rDNA and rpoB sequencing. The 21 isolates newly identified as R. ornithinolytica had a test negative for ornithine decarboxylase (ODC). Molecular experiments suggested one copy of ODC-encoding gene in both ODC-negative R. ornithinolytica and R. planticola strains and two copies in ODC-positive R. orninthinolytica strains. Analysis of the 35 bla genes allowed us (i) to confirm an identity of only 94% between the bla genes of the two Raoultella species while this identity was > 98% for rpoB and > 99% for 16S rDNA genes and (ii) to develop and successfully apply a bla PCR RFLP assay for Raoultella spp. identification. Overall, this study allowed us to discover ODC-negative R. ornithinolytica and to provide a reliable Raoultella identification method widely available as not requiring sequencing equipment.

Although the first reports on extended-spectrum beta-lactamase (ESBL)-producing isolates in long-term-care facilities (LTCFs) appeared 10 years ago, there are still scanty data on this topic. A long-term survey starting in 1993 by the microbial laboratories of the Assistance Publique Hopitaux de Paris and covering 21,000 beds, 7000 of them in LTCFs, indicated that the incidence of ESBL-producing isolates/1000 hospitalisation days in LTCFs increased from 0.07 in 1996 to 0.28 in 2005. Escherichia coli accounted for 80% of ESBL-positive isolates in 2005, whereas it accounted for <45% in 2001. This rise in E. coli with ESBLs reflected clonal spread, as found elsewhere, with CTX-M types now the predominant enzyme types.