Performance Analysis of a Compression Scheme for Highly Dense Cluster-Based Wireless Sensor Network

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Impact of contrast injection and stent-graft implantation on reproducibility of volume measurements in semiautomated segmentation of abdominal aortic aneurysm on computed tomography

Purpose To assessthe impact of contrast injection and stent-graft implantation on feasibility, accuracy, and reproducibilityof abdominal aortic aneurysm (AAA) volume and maximaldiameter (D-max) measurements using segmentation software. Materials and methods CT images of 80 subjects presentingAAA were divided into four equal groups: with or without contrast enhancement, and with or without stent-graft implantation. Semiautomated software was used to segment the aortic wall, once by an expert and twice by three readers. Volume and D-max reproducibility was estimated by intraclass correlation coefficients (ICC), and accuracy was estimated between the expert and the readers by mean relative errors. Results All segmentations were technically successful. Themean AAA volume was 167.0±82.8 mL and the mean D-max 55.0±10.6 mm. Inter- and intraobserver ICCs for volume andD-max measurements were greater than 0.99. Mean relative errors between readers varied between −1.8±4.6 and 0.0± 3.6 mL. Mean relative errors in volume and D-max measurements between readers showed no significant difference between the four groups (P≥0.2). Conclusion The feasibility, accuracy, and reproducibility of AAA volume and D-max measurements using segmentation software were not affected by the absence of contrast injection or the presence of stent-graft

Co-occurrence of carbapenemase encoding genes in Acinetobacter baumannii, a dream or reality?

International audienceBackground: Acinetobacter baumannii is an important opportunistic pathogen that is rapidly evolving towards multidrug resistance and is responsible for life-threatening infections. Carbapenems are commonly used to treat A. baumannii infections but the emergence of carbapenemase encoding genes, such as bla(OXA-23-like), bla(OXA-24-like), bla(OXA-58-like), and bla(NDM) has been reported. Moreover, several studies have reported the co-occurrence of two distinct carbapenemases in some isolates. The aim of the present study is to demonstrate whether the phenomenon of co-occurrence of two distinct carbapenemase encoding genes in a single isolate still exists. Results: We studied six strains of A. baumannii including one harboring bla(OXA-23-like) and bla(OXA-24-like) genes and five with bla(OXA-23-like) and bla(NDM) genes. One colony of each strain was inoculated in sterile water and diluted ten-fold. Each dilution was cultivated on trypticase soy agar plates for 24 h at 37 degrees C and the isolated bacteria were analyzed. For two of the six tested strains, we identified two different populations of A. baumannii, each with a different carbapenemase, genes encoding aminoglycoside modifying enzymes, resistance phenotype, and clonal type. In addition, the two different populations had the same aspect on the agar plate. Conclusions: Here, we demonstrate that A. baumannii infections could be linked to multiple clones harboring different carbapenemase encoding genes in the same sample. In addition, we describe an easy method of verifying the presence of co-occurrence of carbapenemase in one isolate

A Novel Probability Function for Energy-Efficient Clustering Protocol in Wireless Sensor Networks

International audienceWireless Sensor Networks (WSNs) are composed of tiny sensor nodes, which are capable of sensing and processing data from inaccessible environments and communicating them to the end-user for further analysis. The main requirement of energy-constrained wireless sensor networks is to offer a long network lifetime. Thus, conceiving energy efficient protocols is a major challenge for WSNs. Energy-aware protocols therefore become crucial in designing viable WSNs that can live for a long time. We propose in this paper a novel probability function for energy-efficient clustering protocols in wireless sensor networks. The proposed probability function considers, in addition to the information about the residual energy of the nodes, the specific network topology characteristics, such as the connectivity degree, in the selection process of the cluster heads. We incorporate the proposed function in the energy-efficient HEED protocol. Simulation results show that, in addition to a considerable energy saving, the proposed probability function increases the packet delivery compared to the classical HEED

Characterisation of bla(OXA)(-538), a new variant of bla(OXA-48), in Shewanella xiamenensis isolated from river water in Algeria

International audienceObjectives: In this study, the presence of carbapenemase genes in Shewanella xiamenensis strains isolated from river water in Bejaia, Algeria, was investigated. Methods: Four isolates of S. xiamenensis were isolated from water from Soummam River. The isolates were identified by matrix-assisted laser desorption/ionisation time-of-flight mass spectrometry (MALDI-TOF/MS) and sequencing of the 16S rRNA and gyrB genes. Isolates were subjected to antimicrobial susceptibility testing. Carbapenemase production was screened using phenotypic tests. PCR and sequencing were used to identify carbapenemase genes in the isolates. The genetic context of the bla(OXA-48-like )gene was investigated by sequencing the whole genome of strain AS58. Results: All four S. xiamenensis strains harboured bla(OXA-48-like) genes. They exhibited different resistance patterns and had imipenem minimum inhibitory concentrations (MICs) of >= 0.5 mg/L. Sequencing of bla(OXA-48-like) genes from the S. xiamenensis isolates showed that two strains harboured bla(OXA-181), one strain harboured bla(OXA-199) and one strain exhibited a new variant of the bla(OXA-48-like) gene, named bla(OXA-538). This new variant shared 98% nucleotide identity with bla(OXA-162), with three amino acid changes (G201A, A213G and I219F). Conjugation assays with Escherichia coli J53 recipient were performed but no transconjugants were obtained. Analysis of the genome of AS58 Touati strain confirmed the chromosomal location of the bla(OXA-538) gene. Conclusion: This study showed that environmental water holds a diversity of S. xiamenensis strains harbouring bla(OXA-48-like) genes and may play an important role in the dissemination and spread of these genes from the environment to humans. (C) 2017 International Society for Chemotherapy of Infection and Cancer. Published by Elsevier Ltd. All rights reserved

Genomic characterization of Citrobacter freundii strains coproducing OXA-48 and VIM-1 carbapenemase enzymes isolated in leukemic patient in Spain

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