30 research outputs found

    Genotypes and Toxin Gene Profiles of Staphylococcus aureus Clinical Isolates from China

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    A total of 108 S. aureus isolates from 16 major hospitals located in 14 different provinces in China were characterized for the profiles of 18 staphylococcal enterotoxin (SE) genes, 3 exfoliatin genes (eta, etb and etd), and the toxic shock syndrome toxin gene (tsst) by PCR. The genomic diversity of each isolate was also evaluated by pulsed-field gel electrophoresis (PFGE), multilocus sequence typing (MLST), and accessory gene regulator (agr) typing. Of these strains, 90.7% (98/108) harbored toxin genes, in which tsst was the most prevalent toxin gene (48.1%), followed by sea (44.4%), sek (42.6%) and seq (40.7%). The see and etb genes were not found in any of the isolates tested. Because of high-frequency transfer of toxin gene-containing mobile genetic elements between S. aureus strains, a total of 47 different toxin gene combinations were detected, including a complete egc cluster in 19 isolates, co-occurrence of sea, sek and seq in 38 strains, and sec and sel together in 11 strains. Genetic typing by PFGE grouped all the strains into 25 clusters based on 80% similarity. MLST revealed 25 sequence types (ST) which were assigned into 16 clonal complexes (CCs) including 2 new singletons. Among these, 11 new and 6 known STs were first reported in the S. aureus strains from China. Overall, the genotyping results showed high genetic diversity of the strains regardless of their geographical distributions, and no strong correlation between genetic background and toxin genotypes of the strains. For genotyping S. aureus, PFGE appears to be more discriminatory than MLST. However, toxin gene typing combined with PFGE or MLST could increase the discriminatory power of genotyping S. aureus strains

    Automatic extraction of spontaneous cries of preterm newborns in neonatal intensive care units

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    International audienceCry analysis has been proven to be an inescapable tool to evaluate the development of preterm infants. However, to date, only a few authors proposed to automatically extract spontaneous cry events in the real context of Neonatal Intensive Care Units. In fact, this is challenging since a wide variety of sounds can also occur (e.g., alarms, adult voice). In this communication, a new method for spontaneous cry extraction from real life recordings of long duration is presented. A strategy based on an initial segmentation between silence and sound events, followed by a classification of the resulting audio segments into two classes (cry and non-cry) is proposed. To build the classification model, 198 cry events coming from 21 newborns and 439 non-cry events, representing the richness of the clinical sound environment were annotated. Then, a set of features, including Mel-Frequency Cepstral Coefficients, was computed in order to describe each audio segment. It was obtained after Harmonic plus Noise analysis which is commonly used for speech synthesis although never applied for newborn cry analysis. Finally, six machine learning approaches have been compared. K-Nearest Neighbours approach showed an accuracy of 94.1%. To experience the precision of the retained classifier, 412 hours of recordings of 23 newborns were also automatically processed. Results show that despite a difficult clinical context an automatic extraction of cry is achievable. This supports the idea that a new generation of non-invasive monitoring of neuro-behavioral development of premature newborns could emerge. © 2021 European Signal Processing Conference, EUSIPCO. All rights reserved

    Voxyvi: A system for long-term audio and video acquisitions in neonatal intensive care units

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    International audienceBACKGROUND: In the European Union, 300,000 newborn babies are born prematurely every year. Their care is ensured in Neonatal Intensive Care Units (NICU) where vital signs are constantly monitored. In addition, other descriptors such as motion, facial and vocal activities have been shown to be essential to assess neurobehavioral development. AIM: In the scope of the European project Digi-NewB, we aimed to develop and evaluate a new audio-video device designed to non-invasively acquire multi-modal data (audio, video and thermal images), while fitting the wide variety of bedding environment in NICU. METHODS: Firstly, a multimodal system and associated software and guidelines to collect data in neonatal intensive care unit were proposed. Secondly, methods for post-evaluation of the acquisition phase were developed, including the study of clinician feedback and a qualitative analysis of the data. RESULTS: The deployment of 19 acquisition devices in six French hospitals allowed to record more than 500 newborns of different gestational and postmenstrual ages. After the acquisition phase, clinical feedback was mostly positive. In addition, quality of more than 300 recordings was inspected and showed that 77% of the data is exploitable. In depth, the percentage of sole presence of the newborn was estimated at 62% within recordings. CONCLUSIONS: This study demonstrates that audio-video acquisitions are feasible on a large scale in real life in NICU. The experience also allowed us to make a clear observation of the requirements and challenges that will have to be overcome in order to set up audio-video monitoring methods

    A simple, portable, electrochemical biosensor to screen shellfish for vibrio parahaemolyticus

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    An earlier electrochemical mechanism of DNA detection was adapted and specified for the detection of Vibrio parahaemolyticus in real samples. The reader, based on a screen printed carbon electrode, was modified with polylactide-stabilized gold nanoparticles and methylene blue was employed as the redox indicator. Detection was assessed using a microprocessor to measure current response under controlled potential. The fabricated sensor was able to specifically distinguish complementary, non-complementary and mismatched oligonucleotides. DNA was measured in the range of 2.0 × 10−8–2.0 × 10−13 M with a detection limit of 2.16 pM. The relative standard deviation for 6 replications of differential pulse voltammetry (DPV) measurement of 0.2 µM complementary DNA was 4.33%. Additionally, cross-reactivity studies against various other food-borne pathogens showed a reliably sensitive detection of the target pathogen. Successful identification of Vibrio parahaemolyticus (spiked and unspiked) in fresh cockles, combined with its simplicity and portability demonstrate the potential of the device as a practical screening tool
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