Accuracy of gradient diffusion method for susceptibility testing of dalbavancin and comparators.

OBJECTIVES: This multicenter study aimed to assess the performances of gradient diffusion (GD) method in comparison to broth microdilution (BMD) method for susceptibility testing of dalbavancin, daptomycin, vancomycin, and teicoplanin. METHODS: Minimum Inhibitory Concentrations (MICs) were retrospectively determined concomitantly by BMD and GD methods, for 93 staphylococci and enterococci isolated from clinical samples. BMD was considered as the gold standard. Essential (EA) and categorical agreements (CA) were calculated. Discordant categorical results were categorized as major (ME) and very major errors (VME). RESULTS: EA and CA were 95.7% and 96.8%, 82.8% and 100%, 97.8% and 96.8%, and 94.6% and 95.7% for dalbavancin, daptomycin, vancomycin, and teicoplanin respectively. Concerning dalbavancin, 3 ME without any VME were observed and discrepancies were low (≤ to 2 two-fold dilutions) between both methods. VME were noted in 1 and 3 cases for vancomycin and teicoplanin, respectively, and resulted from 1 two-fold dilution discrepancy in each case. EA was lower for daptomycin. When they were discrepant, BMD MICs were systematically higher than GD ones. Nevertheless, no categorical discrepancy was noted. CONCLUSIONS: GD appears as an acceptable and convenient alternative for dalbavancin, vancomycin, and teicoplanin MICs determination. Our study also emphasizes how achieving accurate daptomycin MICs remains challenging.

Superlocalization of Excitons in Carbon Nanotubes at Cryogenic Temperature.

At cryogenic temperature and at the single emitter level, the optical properties of single-wall carbon nanotubes depart drastically from that of a one-dimensional (1D) object. In fact, the (usually unintentional) localization of excitons in local potential wells leads to nearly 0D behaviors such as photon antibunching, spectral diffusion, inhomogeneous broadening, etc. Here, we present a hyperspectral imaging of this spontaneous exciton localization effect at the single nanotube level using a super-resolved optical microscopy approach. We report on the statistical distribution of the trap localization, depth, and width. We use a quasi-resonant photoluminescence excitation approach to probe the confined quantum states. Numerical simulations of the quantum states and exciton diffusion show that the excitonic states are deeply modified by the interface disorder inducing a remarkable discretization of the excitonic absorption spectrum and a quenching of the free 1D exciton absorption.

Can real-time polymerase chain reaction allow a faster recovery of hospital activity in cases of an incidental discovery of carbapenemase-producing Enterobacteriaceae and vancomycin-resistant Enterococci carriers?

BACKGROUND: Detection of faecal carriers of carbapenemase-producing Enterobacteriaceae (CPE) and vancomycin-resistant Enterococci (VRE) has become a routine medical practice in many countries. In an outbreak setting, several public health organizations recommend three-weekly rectal screenings to rule-out acquisition in contact patients. This strategy, associated with bed closures and reduction of medical activity for a relatively long time, seems costly. AIM: The objective of this study was to test the positive and negative predictive values of reverse transcription polymerase chain reaction (RT-PCR; GeneXpert®) carried-out at Day 0, compared with conventional three-weekly culture-based rectal screenings, in identifying, among contact patients, those who acquired CPE/VRE. METHODS: A multicentre retrospective study was conducted from January2015 to October2018. All contact patients (CPs) were included identified from index patients (IPs) colonized or infected with CPE/VRE, incidentally discovered. Each CP was investigated at Day 0 by PCR (GeneXpert®), and by the recommended three-weekly screenings. FINDINGS: Twenty-two IPs and 159 CPs were included. An average of 0.77 secondary cases per patient was noted, with a mean duration of contact of 10 days (range 1-64). Among the 159 CPs, 16 (10%) had a CPE/VRE-positive culture during the monitoring period. Rectal screenings were positive at Day 0 (10 patients), Day 7 (two patients), Day 14 (four patients). Thirteen of 16 patients with positive culture had a positive PCR at Day 0. Overall, a concordance of 97.5% (155/159) was observed between the three-weekly screenings and Day 0 PCR results. When performed on CPs at Day 0 of the identification of an IP, PCR (GeneXpert®) allowed the reduction in turnaround time by five to 27 days, compared to three-weekly screenings. Positive predictive value and negative predictive value were 100% and 98%, respectively. CONCLUSIONS: The use of RT-PCR (GeneXpert®) can avoid the three-weekly rectal samplings needed to rule-out acquisition of CPE/VRE.

Be careful about MICs to amoxicillin for patients with Streptococci-related infective endocarditis.

BACKGROUND: A variety of microorganisms can cause infective endocarditis (IE), with Staphylococci and Streptococci accounting for the majority of cases. Streptococci are a common cause of community-acquired IE but few studies have focused on this subgroup of endocarditis. METHODS: A retrospective multicentre study was conducted between 2012 and 2017 in 12 hospital centres in France. Data were extracted from the local diagnosis-related group database and matched with microbiological results. After identification, the records were retrospectively analysed. RESULTS: A total of 414 patients with streptococcal endocarditis were included. The patients were predominantly male (72.8%) and the median age was 73.2 years (interquartile range [IQR] 61.3-80.9). The majority of patients (70.6%) had native valve endocarditis. Embolic complications were seen in 38.8% of patients. Viridans group Streptococci (VGS) and bovis-equinus group Streptococci (BGS) accounted for 52.4% and 34.5% of isolated strains, respectively. Minimum inhibitory concentrations (MICs) of amoxicillin were <0.125, 0.125-2 and >2 mg/L for 59.6%, 27% and 1% of isolates, respectively. In-hospital mortality for patients with Streptococci-related IE was 17.8%. In multivariate analysis, the only factor associated with in-hospital mortality was MIC for amoxicillin between 0.25 and 2 mg/L (P = 0.04; OR = 2.23 [95% confidence interval (CI) 1.03-4.88]) whereas performance of cardiac surgery for IE was a protective factor (P = 0.001, OR = 0.23 [95% CI 0.1-0.56]). CONCLUSIONS: IE remains a serious and deadly disease despite recent advances in diagnosis and treatment. Adaptation of antibiotic doses to MICs for amoxicillin and surgery may improve patient outcome.

Impact of intensive care unit relocation and role of tap water on an outbreak of Pseudomonas aeruginosa expressing OprD-mediated resistance to imipenem.

BACKGROUND: To assess the impact of the incidental relocation of an intensive care unit (ICU) on the risk of colonizations/infections with Pseudomonas aeruginosa exhibiting OprD-mediated resistance to imipenem (PA-OprD). AIM: The primary aim was to compare the proportion of PA-OprD among P. aeruginosa samples before and after an incidental relocation of the ICU. The role of tap water as a route of contamination for colonization/infection of patients with PA-OprD was assessed as a secondary aim. METHODS: A single-centre, observational, before/after comparison study was conducted from October 2013 to October 2015. The ICU was relocated at the end of October 2014. All P. aeruginosa-positive samples isolated from patients hospitalized ≥48 h in the ICU were included. Tap water specimens were collected every three months in the ICU. PA-OprD strains isolated from patients and tap water were genotyped using pulse-field gel electrophoresis. FINDINGS: A total of 139 clinical specimens of P. aeruginosa and 19 tap water samples were analysed. The proportion of PA-OprD strains decreased significantly from 31% to 7.7% after the relocation of the ICU (P = 0.004). All PA-OprD clinical specimens had a distinct genotype. Surprisingly, tap water was colonized with a single PA-OprD strain during both periods, but this single clone has never been isolated from clinical specimens. CONCLUSION: Relocation of the ICU was associated with a marked decrease in P. aeruginosa strains resistant to imipenem. The polyclonal character of PA-OprD strains isolated from patients and the absence of tap-water-to-patient contamination highlight the complexity of the environmental impact on the endogenous colonization/infection with P. aeruginosa.

Analysis of the magnetic properties of Ce3Pt23Si11: orthorhombic crystal field and mean-field approximation.

We present here a quantitative analysis of the ground state and magnetic properties of Ce3Pt23Si11, based on a crystalline electric field description within the mean-field approximation. In this face-centered cubic compound, the point group symmetry at the Ce site is orthorhombic. One main difficulty in this low symmetry case is that the CEF potential for Ce3+ ions is determined by five independent parameters, while only two magnetic excitations are observed by inelastic neutron scattering. Moreover the anisotropy of the magnetic susceptibility of the Ce ion, that permits an independent determination of the second-order CEF parameters is hidden by the cubic symmetry of the compound. A specific procedure is developed for this purpose that combines genetic algorithms and more conventional optimization methods. A set of CEF parameters is found that best reproduces the different experimental observations in both the paramagnetic and ferromagnetic phases of Ce3Pt23Si11. The analysis accounts for two seemingly contradictory properties: a strong local anisotropy that aligns the moment along a fourfold axis and a rather weak anisotropy of the bulk magnetization with an easy threefold magnetization axis. Ce3Pt23Si11 is shown to be a model system where single site anisotropies compete within a crystal structure of overall high symmetry.

[Anti-D prophylaxis in fetal-maternal erythrocyte incompatibility in Tunisia]. / Prophylaxie anti-D dans l'incompatibilité fœto-maternelle érythrocytaire en Tunisie.

Generalization of postnatal prophylaxis using anti-D immunoglobulins decreased the incidence of erythrocyte fetal-maternal incompatibility (EFMI) in the Rhesus system. Few recent studies have investigated the situation of anti-D prophylaxis in Tunisia and its effects on maternal and neonatal health. The aim of this study was therefore to analyze the situation of anti-D prophylaxis in Tunisia to detect defects and propose solutions. We conducted a retrospective descriptive study of IFME cases in the rhesus system in the Department of Medicine and Neonatal Resuscitation of the Tunis Maternity and Neonatology Center (CMNT) during an 8-year period from 1 January 2006 to 31 December 2015. We collected 51 cases of IFME. The prevalence of IFME was 3.4 per 10 000 live births; 41 % of the patients were transferred in utero and they were from the northwest of the country (17 %). The rate of women with a history of at least one spontaneous miscarriage (SCF) was 45 %. In 42 % of the cases, pregnancies were monitored at local clinics. The search for irregular agglutinins (RAI) was performed in 86 % of the women studied. RAI was positive in 97 % of the cases. Anti-D prophylaxis was correctly performed in only 27 % of the cases. The systematic prophylaxis of the third trimester and a systematic Kleihauer test must be combined with postpartum prophylaxis to better identify dysfunctions and improve the application of the recommendations.

Actinobaculum schaalii: A truly emerging pathogen?: Actinobaculum schaalii: un pathogène réellement émergent?

Actinobaculum schaalii is a Gram-positive facultative anaerobe bacillus. It is a commensal organism of the genitourinary tract. Its morphology is nonspecific. Aerobic culture is tedious, and identification techniques have long been inadequate. Thus, A. schaalii has often been considered as a nonpathogen bacterium or a contaminant. Its pathogenicity is now well described in urinary tract infections, and infections in other sites have been reported. This pathogen is considered as an emerging one following the growing use of mass spectrometry identification. In this context, the aim of our study was to evaluate the number of isolations of A. schaalii before and after the introduction of mass spectrometry in our hospital and to study the clinical circumstances in which isolates were found.

Actinobaculum schaalii est un bacille à Gram positif anaérobie facultatif. Il s'agit d'un germe commensal du tractus génito-urinaire. Sa morphologie est aspécifique. La culture est fastidieuse en aérobiose et les techniques d'identification ont longtemps été insuffisantes. De ce fait, il a souvent été considéré comme un germe non pathogène ou un contaminant. Sa pathogénicité est aujourd'hui bien décrite dans les infections urinaires, mais des infections au niveau d'autres sites ont été rapportées. Ce pathogène considéré comme émergent, voit en réalité son nombre d'isolats augmenter depuis l'introduction de la spectrométrie de masse. Dans ce contexte, le but de notre étude est d'évaluer le nombre d'isolements d'Actinobaculum schaalii avant et après l'introduction de la spectrométrie de masse dans notre centre hospitalier et d'étudier les circonstances cliniques dans lesquelles ces isolats ont été retrouvés.

Reduced risk of relapse after long-term nucleos(t)ide analogue consolidation therapy for chronic hepatitis B.

BACKGROUND: Before stopping nucleos(t)ide analogue (NA) treatment in chronic hepatitis B (CHB), 6-12 months of consolidation therapy is recommended. AIM: To investigate the effect of consolidation therapy on off-treatment outcomes in CHB patients. METHODS: We included 94 patients who stopped NA after at least 1 year of therapy. Patients could be HBeAg-positive or HBeAg-negative at start-of-treatment, but were HBeAg-negative and had undetectable HBV DNA at time of discontinuation. Consolidation therapy was defined as treatment after the first undetectable HBV DNA (and HBeAg loss for HBeAg-positive patients) until NA cessation. RESULTS: At 3 years, 74% of the start-of-treatment HBeAg-positive and 75% of the start-of-treatment HBeAg-negative patients developed HBV DNA >2000 IU/mL at a single time point, whereas a persistent virological relapse (≥2 tests of HBV DNA >2000 IU/mL 6 months apart within 1 year) developed in 49% of the start-of-treatment HBeAg-positive and 53% of the start-of-treatment HBeAg-negative patients. For both HBeAg-positive and HBeAg-negative patients, consolidation therapy of ≥3 years was associated with lower persistent virological relapse rates compared to <1 year (1-year relapse rate: 25% vs. 54%; P = 0.063 and 24% vs. 57%; P = 0.036, respectively). At 3 years, 9% of the HBeAg-positive and 14% of the HBeAg-negative patients became HBsAg-negative. Prolonged consolidation therapy increased the likelihood of HBsAg loss. Two cirrhotic patients developed hepatic decompensation but both recovered. CONCLUSIONS: After nucleos(t)ide analogue discontinuation, relapse was common in patients with chronic hepatitis B. Prolongation of consolidation therapy beyond 3 years decreased the risk of persistent virological relapse and increased the likelihood of HBsAg loss.

Cytotoxicity of synthesized Iron Oxide nanoparticles: toward novel biomarkers of colon cancer.

In this paper we present the preliminary results of a novel biological analysis platform for early colon cancer detection using magnetic separation of magnetized markers. The platform consists of a microfluidic structure integrated with biosensors. Super-Paramagnetic Iron Oxide nanoparticles (SPIO-NPs) were functionalized with purified DNA Aptamer and their synthesis is described. In this paper, we also present the physicochemical results of the synthesized SPIO/Au-NPs characterized by TEM and XRD. Toxicity of our synthesized biomarkers on HCT116 cell line is discussed. Based on our findings, a concentration of 1mg/ml of our biomarkers added to 5 × 105 cells per well has no effect the viability of the human cells even after 24 hours.

Large magnetovolume effects due to transition from the ferromagnetic to antiferromagnetic state in Hf0.825Ta0.175Fe2 intermetallic compound.

Intrinsic magnetic properties and magnetovolume effects have been investigated for the Hf0.825Ta0.175Fe2 itinerant-electron system, which exhibits a temperature-induced first-order transition from the ferromagnetic (FM) to the antiferromagnetic (AFM) state. The spontaneous volume magnetostriction contraction due to this transition from the high-volume FM state to the low-volume AFM state is about 0.66%. Applying a magnetic field increases significantly the FM-AFM transition temperature T(FM-AFM), with a rate of 7.2 K T(-1). At temperatures T > T(FM-AFM) a first-order metamagnetic transition between the AFM and FM states has been observed from isothermal magnetization curves, a result attributed to the itinerant-electron character of the Fe magnetism. This AFM-FM transition is accompanied by a huge field-induced volume magnetostriction. The change in ΔV/V due to the AFM-FM transition is about 0.75%.

CeB6 macroscopically revisited.

Magnetic susceptibility anisotropy and high sensitivity magnetostriction measurements are used to investigate the symmetry of CeB(6) ordered states. The antiferromagnetic state is confirmed as tetragonal, but no deviation from the cubic symmetry is observed in the so-called antiferroquadrupolar phase, where only volume effects are detected. In this phase, the temperature dependence of the strain field susceptibilities is typical of nonordered quadrupoles. Moreover, while an antiferroquadrupolar order should be cubic, this symmetry is incompatible with the (½½½) ordering wave vector. The antiferroquadrupolar description of CeB(6) phase II is clearly inconsistent, and an alternative model, based on a unidimensional representation of the cube, has to be sought.

Silent myocardial ischaemia and risk factors in a diabetic Afro-Caribbean population.

AIMS: In Guadeloupe, an island in the French West Indies, diabetes has a prevalence recently reported to be 10%. Myocardial ischaemia is more frequently silent in diabetics, and needs to be screened for and monitored, once identified. This study aimed to evaluate the prevalence of silent myocardial ischaemia (SMI) in a diabetic population and to analyze its associated cardiovascular risk (CVR) factors. METHODS: This was a cross-sectional study of 147 patients with associated CVR factors, defined according to the 2004 SFC/ALFEDIAM guidelines. Exercise stress tests, myocardial performance imaging and stress echocardiography were performed. Ancova and logistic regression were used in the statistical analyses. RESULTS: The patients' mean age was 62 years, and 53% were male. Mean duration of diabetes was 14 years. Overall, 23.1% had SMI, and these patients more frequently had a personal history of cardiovascular disease vs those without SMI. On multivariate logistic-regression analyses, the adjusted odds ratios of SMI were significantly increased in patients with a personal history of cardiovascular disease (4.36, 95% CI: 1.36-13.96; P=0.01) and left ventricular hypertrophy (LVH) (2.46, 95% CI: 1.03-5.86; P=0.04). CONCLUSION: The prevalence of SMI in our Afro-Caribbean diabetic population was 23.1%. Searching for a personal history of cardiovascular disease and LVH may help to identify patients who need to be screened for SMI.

On the ferromagnetic structure of the intermetallic borocarbide TbCo(2)B(2)C.

Based on magnetization, specific heat, magnetostriction and neutron-diffraction studies on single-crystal TbCo(2)B(2)C, it is found out that the paramagnetic properties, down to liquid nitrogen temperatures, are well described by a Curie-Weiss behavior of the Tb(3+) moments. Furthermore, below T(c) = 6.3 K, the Tb sublattice undergoes a ferromagnetic (FM) phase transition with the easy axis being along the (100) direction and, concomitantly, the unit cell undergoes a tetragonal-to-orthorhombic distortion. The manifestation of an FM state in TbCo(2)B(2)C is unique among all other isomorphous borocarbides, in particular TbNi(2)B(2)C (T(N) = 15 K, incommensurate modulated magnetic state) even though the Tb ions in both isomorphs have almost the same crystalline electric field properties. The difference among the magnetic modes of these Tb-based isomorphs is attributed to a difference in their exchange couplings which are in turn caused by a variation in their lattice parameters and in the position of their Fermi levels.

Surrogate markers of resectability in patients undergoing exploration of potentially resectable pancreatic adenocarcinoma.

Despite extensive preoperative staging, a significant number of pancreatic cancers are unresectable at surgical exploration. Patients undergoing pancreatic exploration with a view to resection were studied and comparisons are then made between those undergoing resection and a bypass procedure to identify surrogate markers of unresectability. One hundred thirteen consecutive patients underwent pancreatic exploration for head-of-pancreas (HOP) adenocarcinoma with curative intent. Fifty-five underwent pancreaticoduodenectomy and 58 underwent a bypass procedure. Student's t test, receiver operator characteristics (ROC) and logistic regression were used to compare the predictive value of preoperative patient variables collected retrospectively. The bypass group had a significantly higher median CA19.9 than the resection group (P = 0.003). Platelet count and neutrophil-lymphocyte ratio (NLR) were also significantly different (P = 0.013 and P = 0.026, respectively). ROC analysis indicated that age < or =65, platelet count >297 x 10(9)/l, CA19.9 < or =473 Ku/l, and CA19.9-bilirubin ratio were predictive variables for resectable disease. NLR and CA19.9-bilirubin ratio had specificity values of 92.9 and 97.0%, respectively. From logistic regression, a raised CA19.9 was found to be an independent risk factor for unresectable disease (P = 0.031). A significant proportion of patients with HOP adenocarcinoma are understaged preoperatively. Preoperative serology including platelet count, NLR, CA19.9, and CA19.9-bilirubin ratio may be used as additional discriminators of resectability particularly for high-risk patients.

Influence of post-treatment delay on the evaluation of the response to focused ultrasound surgery of breast cancer by dynamic contrast enhanced MRI.

The assessment of the effectiveness of MRI-guided focused ultrasound surgery (MRIgFUS) of breast carcinomas can be performed by dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) parameters which monitor the presence of residual tumour. The aim of this study was to evaluate the effect of the post-treatment delay on this assessment. DCE-MRI data were acquired immediately and 3-14 days after MRIgFUS treatment of 26 tumours (<7 days, n = 6; = or > ge;7 days, n = 20). The percentage of residual tumour was determined histologically on the resected mass and correlated with two DCE-MRI parameters: increase in signal intensity (ISI) and positive enhancement integral (PEI). No correlation could be found between DCE-MRI data acquired immediately after treatment and the percentage of residual tumour. Good correlation coefficients were found for data acquired several days after treatment (ISI, r = 0.749; PEI, r = 0.778). However, they were higher when the post-treatment time interval was 7 days or more (ISI, r = 0.962; PEI, r = 0.934). These results suggest that a post-treatment delay of 7 days is necessary for the accurate assessment of the presence of residual tumour by DCE-MRI parameters.

[Review: genetics of familial dilated cardiomyopathy]. / Mise au point sur la génétique de la cardiomyopathie dilatée familiale.

Dilated cardiomyopathy is the most frequent cardiomyopathy. Twenty to 35% of dilated cardiomyopathies are familial. The transmission of the disease is most frequently dominant autosomic. Dilated cardiomyopathy is genetically heterogeneous. Hence, mutations have been identified on 14 genes, and 9 loci have been associated to familial dilated cardiomyopathy. The incriminated mechanisms in the pathogeny of dilated cardiomyopathy include mutations on proteins of the sarcomere, the cytosqueletton, the nuclear membrane or involved in calcium signaling. This review indicates the genes and proteins implicated in the pathogeny of familial dilated cardiomyopathy, and their potential clinical effects.