Identification of neurological complications in childhood influenza: a random forest model.

BACKGROUND: Among the neurological complications of influenza in children, the most severe is acute necrotizing encephalopathy (ANE), with a high mortality rate and neurological sequelae. ANE is characterized by rapid progression to death within 1-2 days from onset. However, the knowledge about the early diagnosis of ANE is limited, which is often misdiagnosed as simple seizures/convulsions or mild acute influenza-associated encephalopathy (IAE). OBJECTIVE: To develop and validate an early prediction model to discriminate the ANE from two common neurological complications, seizures/convulsions and mild IAE in children with influenza. METHODS: This retrospective case-control study included patients with ANE (median age 3.8 (2.3,5.4) years), seizures/convulsions alone (median age 2.6 (1.7,4.3) years), or mild IAE (median age 2.8 (1.5,6.1) years) at a tertiary pediatric medical center in China between November 2012 to January 2020. The random forest algorithm was used to screen the characteristics and construct a prediction model. RESULTS: Of the 433 patients, 278 (64.2%) had seizures/convulsions alone, 106 (24.5%) had mild IAE, and 49 (11.3%) had ANE. The discrimination performance of the model was satisfactory, with an accuracy above 0.80 from both model development (84.2%) and internal validation (88.2%). Seizures/convulsions were less likely to be wrongly classified (3.7%, 2/54), but mild IAE (22.7%, 5/22) was prone to be misdiagnosed as seizures/convulsions, and a small proportion (4.5%, 1/22) of them was prone to be misdiagnosed as ANE. Of the children with ANE, 22.2% (2/9) were misdiagnosed as mild IAE, and none were misdiagnosed as seizures/convulsions. CONCLUSION: This model can distinguish the ANE from seizures/convulsions with high accuracy and from mild IAE close to 80% accuracy, providing valuable information for the early management of children with influenza.

Near-freezing temperature suppresses avocado (Persea americana Mill.) fruit softening and chilling injury by maintaining cell wall and reactive oxygen species metabolism during storage.

To enhance the postharvest quality of avocado (Persea americana Mill.) fruit, this study investigates alterations in cell wall metabolism and reactive oxygen species (ROS) metabolism during near-freezing temperature (NFT) storage, and explores their impact on fruit softening. The fruit was stored at 25 °C, 5 °C, 2 °C, and NFT, respectively. NFT storage retarded firmness loss and chilling injury in comparison with 25 °C, 5 °C, and 2 °C. NFT storage delayed the decrease of ionic-soluble pectin (ISP) and cellulose (CLL) contents by suppressing cell wall degradation enzyme activities. Correlation analysis showed that cell wall degradation enzyme activities were positively correlated to rates of ethylene release and respiration. Moreover, NFT storage maintained higher levels of DPPH and ABTS scavenging abilities, activities of superoxide dismutase, peroxidase, and catalase, as well as ascorbate-glutathione cycle (ascorbic acid, glutathione, glutathione disulfide, ascorbate peroxidase, cycle-related enzymes), thereby inhibited the increase of ROS content, malondialdehyde content, and cell membrane permeability. Fruit firmness and chilling injury were correlated with the contents of hydrogen (H2O2), superoxide anion (O2.-), ISP, and CLL. These results suggested that NFT could suppress fruit softening and chilling injury by inhibiting cell wall degradation through delaying respiration and ethylene production and suppressing ROS production via activation of antioxidant systems, thereby maintaining quality and prolonged storage life during avocado fruit storage.

Two new rare-earth oxyborates Ba4BiTbO(BO3)4 and Ba1.54Sr2.46BiTbO(BO3)4 and luminescence properties of the Ba4BiTb1-xEuxO(BO3)4 phosphors.

Single crystals of two new terbium oxyborates Ba4BiTbO(BO3)4 and Ba1.54Sr2.46BiTbO(BO3)4 were obtained by the high-temperature solution method. They crystallize in the hexagonal P63/mmc group (Z = 2) with lattice parameters of a = 5.41865(9) Å, c = 26.3535(5) Å, V = 670.12(3) Å3 and a = 5.36534(19) Å, c = 26.0661(10) Å, V = 649.83(5) Å3, respectively. Their crystal structures feature two kinds of layers: [Tb(BO3)2]n3n- formed by corner-sharing TbO6 octahedra and BO3 triangles, as well as [Bi(BO3)2O]n5n- consisting of Bi2O13 dimers and BO3 groups, with alkali-earth cations sitting inside and between the layers. In addition, solid solutions of Ba4BiTb1-xEuxO(BO3)4 (0 ≤ x ≤ 0.2) were prepared via the solid-state reaction method. The obtained products were characterized by powder XRD, SEM, IR/Raman, XPS, DRS, and luminescence spectroscopy. It was found that as the Eu3+ doped content varies from x = 0 to 0.2, the emission color of the Ba4BiTb1-xEuxO(BO3)4 phosphors can be adjusted from cyan to near-white and then to orange-red or from green to orange and then to red under the excitation of 349 and 377 nm, respectively. Furthermore, the emission intensities and chromaticity coordinates were found to be sensitive to the temperature for the phosphor Ba4BiTb0.999Eu0.001O(BO3)4 upon 377 nm excitation. The above results demonstrate that Ba4BiTb1-xEuxO(BO3)4 phosphors have potential as multifunctional materials for solid-state lighting and temperature sensing applications.

First report of Botryosphaeria dothidea causing fruit rot on Chinese olive (Canarium album Raeusch.) in Guangdong province of China.

Chinese olive (Canarium album Raeusch.) is a traditional Chinese medicinal plant, mainly cultivated in Guangdong and Fujian provinces in China (Lai et al. 2022). In October 2023, Chinese olive fruit spots were observed in all the Chinese olive orchards surveyed in Chaozhou city (23.75°N, 116.67°E) of Guangdong, with an incidence up to 15%. Early disease symptoms on fruits appeared as circular or irregular, dark brown to black spots with yellowish lesions, and later the spots slowly coalesced to form large necrotic areas, which seriously affected the fruit marketability. To isolate the causal agent, small pieces (~0.3 mm2) of fruit tissue were excised from the lesion margins, and surface-disinfested with 75% (v/v) ethanol for 1 min, followed by 1% NaClO for 3 min, and rinsed three times with sterile water. The pieces were then placed on potato-dextrose-agar (PDA) and incubated at 27°C. Ultimately, four fungal isolates were obtained with similar morphology phenotypes, colonies initially appeared white with irregular margins and after 4-6 days turned dark gray gradually with dense aerial myceliu. Microscopy revealed conidia were single-celled, hyaline, aseptate, fusiform to subclavate, and measured 18.1-22.5 µm × 6.4-9.3 µm (19.8 × 7.4 m on average, n = 30), which were consistent with those descriptions of Botryosphaeria dothidea (Vasic et al. 2013; Zhang et al. 2023). To further identity the isolates, partial sequences of ribosomal transcribed spacer (ITS), translation elongation factor 1-α (TEF1-α), and ß-tubulin (TUB2) genes were amplified using primers ITS1/ITS5, TEF-F/R, TUB2-F/R, respectively (Xu et al., 2023; Hong et al. 2006). The sequences of four isolates were identical, and those of representative strain GDCZ-1 were deposited in GenBank (ITS, OR584295; TEF1-α, OR685157; TUB2, OR685158). Using Neighbor-Joining algorithm, phylogenetic tree based on concatenated sequences of ITS, TEF1-α, and TUB2 showed that GDCZ-1 clustered with B. dothidea. To fulfill Koch's postulates, pathogenicity tests were performed on healthy Chinese olive fruits using the needle-prick inoculation method. The fruits were wounded with a sterile needle at the equatorial area (depth of 3-4 mm), and inoculated with 10 µL of spore suspension (106 /mL). The control fruits were inoculated with sterile water. Inoculated fruits were placed in sterile plastic containers to maintain high relative humidity (almost 100%) and incubated at 27°C. After 4 days, the inoculated fruits showed similar symptoms with those observed in the field infected fruits, while the control remained asymptomatic. Pathogen re-isolated from the inoculated fruits showed identical morphological characteristics to the original isolate GDCZ-1. As far as we know, fruit rot caused by Alternaria alternata has been recently reported on C. album in China (Shao et al. 2024). To our knowledge, this is the first report of B. dothidea causing fruit rot disease on C. album in Guangdong. Our report will provide crucial information for studying the epidemiology and management of this disease.

Comparative physiological and transcriptome analysis provide insights into the inhibitory effect of osthole on Penicillium choerospondiatis.

Blue mold induced by Penicillium choerospondiatis is a primary cause of growth and postharvest losses in the fruit of Phyllanthus emblica. There is an urgent need to explore novel and safe fungicides to control this disease. Here, we demonstrated osthole, a natural coumarin compound isolated from Cnidium monnieri, exhibited a strong inhibitory effect on mycelia growth, conidial germination rate and germ tube length of P. choerospondiatis, and effectively suppressed the blue mold development in postharvest fruit of P. emblica. The median effective concentration of osthole was 9.86 mg/L. Osthole treatment resulted in cellular structural disruption, reactive oxygen species (ROS) accumulation, and induced autophagic vacuoles containing cytoplasmic components in fungal cells. Transcriptome analysis revealed that osthole treatment led to the differentially expressed genes mainly enriched in the cell wall synthesis, TCA cycle, glycolysis/ gluconeogenesis, oxidative phosphorylation. Moreover, osthole treatment led to increase genes expression involved in peroxisome, autophagy and endocytosis. Particularly, the autophagy pathway related genes (PcATG1, PcATG3, PcATG15, PcATG27, PcYPT7 and PcSEC18) were prominently up-regulated by osthole. Summarily, these results revealed the potential antifungal mechanism of osthole against P. choerospondiatis. Osthole has potentials to develop as a natural antifungal agent for controlling blue mold disease in postharvest fruits.

Polaronic Nonlinear Optical Response and All-Optical Switching Based on an Ionic Metal Oxide.

It has been well-established that light-matter interactions, as manifested by diverse linear and nonlinear optical (NLO) processes, are mediated by real and virtual particles, such as electrons, phonons, and excitons. Polarons, often regarded as electrons dressed by phonons, are known to contribute to exotic behaviors of solids, from superconductivity to photocatalysis, while their role in materials' NLO response remains largely unexplored. Here, the NLO response mediated by polarons supported by a model ionic metal oxide, TiO2, is examined. It is observed that the formation of polaronic states within the bandgap results in a dramatic enhancement of NLO absorption coefficient by over 130 times for photon energies in the sub-bandgap regions, characterized by a 100 fs scale ultrafast response that is typical for thermalized electrons in metals. The ultrafast polaronic NLO response is then exploited for the development of all-optical switches for ultrafast pulse generation in near-infrared (NIR) fiber lasers and modulation of optical signal in the telecommunication band based on evanescent interaction on a planar waveguide chip. These results suggest that the polarons supported by dielectric ionic oxides can fill the gaps left by dielectric and metallic materials and serve as a novel platform for nonlinear photonic applications.

The relationship between insulin resistance, serum alkaline phosphatase, and left ventricular dysfunction following myocardial infarction.

The occurrence of heart failure following acute myocardial infarction (AMI) significantly increases the risk of post-infarction mortality. Alkaline phosphatase (AP) is considered to be an independent predictor of cardiovascular disease (CVD) and adverse outcomes. Furthermore, in recent years, alkaline phosphatase has been associated with insulin resistance (IR). Our aim was to investigate the correlation between IR substitutes (triglyceride-glucose (TyG) index, triglyceride to high-density lipoprotein cholesterol (TG/HDL-C) ratio), AP, and LV dysfunction in patients admitted after AMI. The retrospective study included 810 patients who underwent coronary angiography for myocardial infarction at the First Hospital of Hebei Medical University from August 2018 to December 2021. Patients were categorized into three groups based on their serum AP levels. Clinical characteristics at admission, cardiac echocardiography findings, coronary angiography results, and biochemical markers such as serum AP levels and triglycerides (TG) were recorded during hospitalization. Left ventricular ejection fraction (LVEF) was assessed using cardiac echocardiography conducted from the time of admission until the coronary angiography procedure. A total of 774 patients with AMI were included in this study. The TyG index is significantly correlated with the TG/HDL-C ratio. (R = 0.739, P < 0.001). Binary logistic regression analysis revealed that elevated serum AP (OR 2.598, 95% CI 1.331-5.071, P = 0.005), presence of the left anterior descending (LAD) artery as the infarct-related artery (IRA) (OR 2.452, 95% CI 1.352-4.449, P = 0.003), and triglyceride (TG) levels (OR 0.652, 95% CI 0.429-0.992, P = 0.046) were protective risk factor for an admission LVEF < 40% following AMI. The serum alkaline phosphatase and LAD as IRA are independent risk factors for severe reduction in LVEF during hospitalization for AMI. Conversely, triglyceride are independent protective factor for severe reduction in LVEF during AMI hospitalization.

Clinical Characteristics and Prognosis of Bloodstream Infection with Carbapenem-Resistant Pseudomonas aeruginosa in Patients with Hematologic Malignancies.

Objective: To analyze the clinical characteristics and prognostic risk factors of carbapenem-resistant Pseudomonas aeruginosa (CRPA) bloodstream infections in patients with hematologic malignancies. Methods: Medical records and drug susceptibility data of patients with hematologic malignancies complicated by CRPA bloodstream infections admitted to the Cancer Hospital of Zhengzhou University between January 1, 2018, and December 31, 2022, were retrospectively analyzed. Results: A total of 64 patients were included in the study, with a mortality rate of 37.5% (24/64) at 28 days after the occurrence of CRPA bloodstream infection. In Cox regression analysis, an absolute neutrophil count <0.5×109/L at discharge (HR 0.039, 95% CI 0.006 ~ 0.258, p=0.001), admission to the intensive care unit (HR 7.546, 95% CI 1.345 ~ 42.338, p= 0.022), and a higher Pitt bacteremia score (HR 0.207, 95% CI 0.046 ~ 0.939, p = 0.041) were independent risk factors associated with 28-day mortality. Survival analysis showed that patients receiving ceftazidime-avibactam-based (HR 0.368, 95% CI 0.107~ 1.268, p = 0.023) or polymyxin B (HR 2.561, 95% CI 0.721 ~ 9.101, p = 0.015) therapy had a higher survival rate. Conclusion: Patients with hematologic neoplasms had high mortality from CRPA bloodstream infections, and admission to the intensive care unit, higher Pitt bacteremia score (PBS) scores, granulocyte deficiency, and granulocyte deficiency at discharge were independently associated with higher mortality. Early anti-infective treatment with ceftazidime-avibactam or polymyxin B may improve the clinical prognosis of patients.

Identification of Two Novel Carbapenemase-Encoding Hybrid Plasmids Harboring blaNDM-5 and blaKPC-2 in a Clinical ST11-KL47 Klebsiella pneumoniae.

Background: Emergence of blaKPC and blaNDM co-harboring Klebsiella pneumoniae has escalated the threat of Carbapenem-resistant Klebsiella pneumoniae (CRKP) to healthcare. It remains unknown the prevalence and molecular characteristics of CRKP co-producing KPC and NDMs carbapenemases in Henan. Methods and Results: Twenty-seven CRKP strains isolated from different times were selected randomly in affiliated cancer hospital of Zhengzhou University from January 2019 to January 2021, among which one KPC-2 and NDM-5 positive CRKP named K9 was isolated from an abdominal pus sample of a 63-year-old male patient with leukemia. Sequencing of K9 determined that K9 belonged to ST11-KL47, which is resistant to antibiotics such as meropenem, ceftazidime-avibactam and tetracycline. K9 carried two different plasmids that contained blaNDM-5 and blaKPC-2. Both plasmids were shown to be novel hybrid plasmids and IS26 played an important role in generation of two plasmids. Gene blaKPC-2 was flanked by the NTEKPC-Ib-like genetic structure (IS26-ΔTn3-ISKpn8-blaKPC-2-ISKpn6-IS26) and was located on a conjugative IncFII/R/N type hybrid plasmid. Conclusion: The resistance gene blaNDM-5 located on a region organized as IS26-blaNDM-5-ble-trpF-dsbD-ISCR1-sul1-aadA2-dfrA12-IntI1-IS26 was carried by a phage-plasmid. We described a clinical CRKP co-producing KPC-2 and NDM-5 and emphasized an urgent need to control their further spread.

A new melilite-type rare-earth borate CdTbGaB2O7 and multicolor tunable emission in the CdTb1-xSmxGaB2O7 (0 ≤ x ≤ 0.2) phosphors.

A new mixed metal borate, CdTbGaB2O7, was successfully synthesized using the high-temperature solution method and its crystal structure was determined by single-crystal X-ray diffraction with the following unit-cell data: P4̄21m, a = b = 7.3487(1) Å, c = 4.7247(1) Å, V = 255.150(9) Å3, and Z = 2. It belongs to a new member of the melilite family, which features a 3D framework consisting of alternately stacked [Ga(B2O7)]n5n- tetrahedral layers and (Cd2+/Tb3+) cationic layers that are interconnected via B(Ga)-O-(Cd/Tb) bridges. In addition, the solid solutions of CdTb1-xSmxGaB2O7 (0 ≤ x ≤ 0.2) were prepared via the solid-state reaction method. The combined techniques of XRD, SEM, IR/Raman, XPS and PLE/PL were employed to characterize the products. It was found that the CdTb1-xSmxGaB2O7 phosphors simultaneously showed green emission of Tb3+ at 545 nm and orange emission of Sm3+ at 603 nm under excitation at 370 nm. The emission color can be adjusted from green to orange-red by varying the Sm3+ doped content via an energy transfer mechanism. For CdTb0.995Sm0.005GaB2O7, a QY of 13.22% was obtained, and its emission intensity at 423 K was 94% of that at 303 K. These results show that the prepared materials can act as potential color-tunable phosphors for UV w-LEDs.

Testis cell pyroptosis mediated by CASP1 and CASP4: possible sertoli cell-only syndrome pathogenesis.

BACKGROUND: Sertoli cell-only syndrome (SCOS) is the most serious pathological type of non-obstructive azoospermia. Recently, several genes related to SCOS have been identified, including FANCM, TEX14, NR5A1, NANOS2, PLK4, WNK3, and FANCA, but they cannot fully explain the pathogenesis of SCOS. This study attempted to explain spermatogenesis dysfunction in SCOS through testicular tissue RNA sequencing and to provide new targets for SCOS diagnosis and therapy. METHODS: We analyzed differentially expressed genes (DEGs) based on RNA sequencing of nine patients with SCOS and three patients with obstructive azoospermia and normal spermatogenesis. We further explored the identified genes using ELISA and immunohistochemistry. RESULTS: In total, 9406 DEGs were expressed (Log2|FC|≥ 1; adjusted P value < 0.05) in SCOS samples, and 21 hub genes were identified. Three upregulated core genes were found, including CASP4, CASP1, and PLA2G4A. Thus, we hypothesized that testis cell pyroptosis mediated by CASP1 and CASP4 might be involved in SCOS occurrence and development. ELISA verified that CASP1 and CASP4 activities in the testes of patients with SCOS were significantly higher than those in patients with normal spermatogenesis. Immunohistochemical results showed that CASP1 and CASP4 in the normal spermatogenesis group were mainly expressed in the nuclei of spermatogenic, Sertoli, and interstitial cells. CASP1 and CASP4 in the SCOS group were mainly expressed in the nuclei of Sertoli and interstitial cells because of the loss of spermatogonia and spermatocytes. CASP1 and CASP4 expression levels in the testes of patients with SCOS were significantly higher than those in patients with normal spermatogenisis. Furthermore, the pyroptosis-related proteins GSDMD and GSDME in the testes of patients with SCOS were also significantly higher than those in control patients. ELISA also showed that inflammatory factors (IL-1 ß, IL-18, LDH, and ROS) were significantly increased in the SCOS group. CONCLUSIONS: For the first time, we found that cell pyroptosis-related genes and key markers were significantly increased in the testes of patients with SCOS. We also observed many inflammatory and oxidative stress reactions in SCOS. Thus, we propose that testis cell pyroptosis mediated by CASP1 and CASP4 could participate in SCOS occurrence and development.

Structural Engineering of Hierarchical Aerogels Hybrid Networks for Efficient Thermal Comfort Management and Versatile Protection.

In recent years, growing concerns regarding energy efficiency and heat mitigation, along with the critical goal of carbon neutrality, have drawn human attention to the zero-energy-consumption cooling technique. Passive daytime radiative cooling (PDRC) can be an invaluable tool for combating climate change by dispersing ambient heat directly into outer space instead of just transferring it across the surface. Although significant progress has been made in cooling mechanisms, materials design, and application exploration, PDRC faces challenges regarding functionality, durability, and commercialization. Herein, a silica nanofiber aerogels (SNAs) functionalized poly(vinylidene fluoride-co-hexafluoropropene) (P(VDF-HFP)) membrane (SFP membrane), inspired by constructional engineering is constructed. As-prepared membranes with flexible network structure combined hierarchical structure design and practicability principal. As the host material for thermal comfort management (TCM) and versatile protection, the SFP membrane features a large surface area, porous structure, and a robust skeleton that can render excellent mechanical properties. Importantly, the SFP membrane can keep exceptional solar reflectivity (0.95) and strong mid-infrared emittance (0.98) drop the temperature to 12.5 °C below ambient and 96 W m-2 cooling power under typical solar intensities over 910 W m-2 . This work provides a promising avenue for high performance aerogel membranes that can be created for use in a wide variety of applications.

Multiple Lytic Bone Lesions Mimicking Langerhans Cell Histiocytosis: A Case of Infantile Mendelian Susceptibility to Mycobacterial Disease due to STAT1 Deficiency.

We present the first infantile disseminated Bacillus Calmette-Guérin (BCG) disease case with STAT1 deficiency, which is manifested by multiple Langerhans cell histiocytosis-like osteolytic lesions. The diagnosis of BCG-induced osteomyelitis was not initially considered until the additional biopsy revealing granulomatous inflammation, a key pathological diagnostic component for mycobacterial infection.

Optimization Method of an Antibreast Cancer Drug Candidate Based on Machine Learning.

Breast cancer is a common but serious and even lethal disease. Fortunately, compared with other cancers, breast cancer treatments currently are relatively well developed. The use of specific drugs is typically essential in the majority of breast cancer treatment strategies. Given the aforementioned factors, it is important to continue researching effective antibreast cancer drug design. Machine learning-based computer-aided drug design is currently a common practice in both drug industries and academic institutes. According to the characteristics of breast cancer, we selected multiple candidate compounds; based on the corresponding molecular descriptors, biological activities, and pharmacokinetic properties, a dataset of inhibition potency and pharmacokinetic properties paired with multiple features of compounds was constructed. On this basis, the random forest method was utilized to choose greater-influenced feature embeddings; thus, 224 main operating variables were selected for further analysis; we then employed the efficient MobileNetV3 deep neural network as the backbone to establish the prediction models for the inhibition potency and pharmacokinetic properties of the compounds. After data preprocessing, the weights are obtained by training on the refined dataset. Finally, we define an optimization problem to discover compounds with the best properties. The problem is solved using the genetic algorithm with the acquired prediction model, and the solution value for the corresponding operating variables with the best clinical properties in theory is then obtained. Analysis demonstrates that our approach could be used to aid the screening process of antibreast cancer drug candidates.

A new rare-earth oxyborate Ba3BiPbEuO(BO3)4 and the luminescence properties of the Ba3BiPbY1-xEuxO(BO3)4 phosphors.

A new rare-earth oxyborate Ba3BiPbEuO(BO3)4 was prepared, and its crystal structure was established by the single-crystal X-ray diffraction method with the following structural data: P63/mmc, a = 5.4305(1) Å, c = 26.3501(3) Å, V = 672.96(3) Å3 and Z = 2. This is a layered material containing two types of layers: one is formed by corner-sharing EuO6 octahedra and BO3 triangles and the other is composed of corner- or edge-sharing (Bi/Pb)O7 hexagonal pyramids and BO3 triangles. These layers and their equivalent partners are alternately stacked along the c-axis, with Ba2+ cations situated in between and within the layers. Furthermore, the phase composition, morphology, and IR, Raman, XPS, and UV-vis absorption spectra of this compound were studied. In addition, solid solutions of Ba3BiPbY1-xEuxO(BO3)4 (0 ≤ x ≤ 1) were prepared via the solid-state reaction method and their photoluminescence properties were investigated. Ba3BiPbYO(BO3)4 and Ba3BiPbEuO(BO3)4 showed blue and reddish-orange luminescence when excited at 242 and 394 nm, respectively. By doping Eu3+ into the Ba3BiPbYO(BO3)4 matrix and changing the Eu3+ doping concentration, luminescence color tunability from blue to orange-red was realized in Ba3BiPbY1-xEuxO(BO3)4 phosphors under excitation at 331 nm. This kind of material with color variability may have potential application in field-emission displays.

Analysis of the molecular characteristics of a blaKPC-2-harbouring untypeable plasmid in Serratia marcescens / Análisis de las características moleculares de un plásmido no tipificable que alberga blaKPC-2 en Serratia marcescens

Introduction: Serratia marcescens has attracted increasing attention worldwide as a neglected opportunistic pathogen of public health concern, especially due to its antimicrobial resistance features, which usually cause nosocomial infections in immunocompromised or critically ill patients. Methods: In our study, four carbapenem-resistant Serratia marcescens (CRSM) clinical isolates were characterized in our hospital from February 2018 to May 2018. The conjugation experiment confirmed the transferability of the carbapenem resistance gene. The types of carbapenem resistance genes were detected by PCR. The homology of the strains was analysed by pulsed field gel electrophoresis (PFGE). The characteristics of the plasmid and environment of carbapenem resistance genes were analysed after whole genome sequencing was performed. Then, we compared the amino acid sequence of the replication initiation protein and constructed a dendrogram by the neighbour-joining method. Results: All four isolates showed carbapenem resistance conferred by a blaKPC-2-harbouring plasmid. They had exactly the same bands confirmed by PFGE and were defined as the homologous strains. The blaKPC-2 genes in all of the isolates were located in a 42,742 bp plasmid, which was located in the core region of antibiotic resistance and was composed of Tn3 family transposons, recombinant enzyme genes, ISKpn6 and ISKpn27. The core region of antibiotic resistance formed a ‘Tn3-ISKpn6-blaKPC-ISKpn27-Tn3’ structure, which was an independent region as a movable element belonging to transposon Tn6296 and its derivatives. The plasmid had a similar skeleton to incX6 plasmids and a similar amino acid sequence to the replication initiation protein. The plasmid was defined as an untypeable blaKPC-2-harbouring plasmid named the ‘IncX6-like’ plasmid. Conclusion: The four CRSM isolates were mainly clonally disseminated with a blaKPC-2-harbouring plasmid in our hospital. The pKPC-2-HENAN1602 plasmid...(AU)

Two new rare-earth borates Sr2Tb3B27-δO46 and Ba2Eu3B27-δO46 (δ = 2/3): syntheses, crystal structures, and luminescence properties.

Two new alkali-earth and rare-earth metal borates, Sr2Tb3B27-δO46 and Ba2Eu3B27-δO46 (δ = 2/3), have been prepared by high-temperature solution reactions at 950 °C. The single-crystal XRD analysis showed that the borates crystallize in the rhombohedral space group R3 with the cell parameters a = 7.7468(1) Å, c = 46.3657(5) Å, V = 2409.75(3) Å3, Z = 3 and a = 7.7964(1) Å, c = 46.5086(6) Å, V = 2448.23(7) Å3, Z = 3, respectively, which further confirms that "LnMB9O16" has the right formula of M2Ln3B27-δO46 (δ = 2/3). Their crystal structures consist of 3D networks constructed by Tb(Eu)O6 trigonal prisms, BO3 planar triangles, and BO4 tetrahedra, with large cavities accommodating Sr2+ (Ba2+) cations. Furthermore, the phase composition, morphology, IR, Raman, and XPS spectra as well as photoluminescence properties of these two compounds were studied. Upon excitation by ultraviolet radiation, Sr2Tb3B27-δO46 exhibits the characteristic emission lines originating from Tb3+ corresponding to 5D4-7F6,5,4,3,2,1,0 transitions, whereas Ba2Eu3B27-δO46 displays bright red emission from Eu3+ with four groups of emission bands associated with 5D0 → 7F1,2,3,4 transitions. Both phosphors show stable luminescence and color purity at elevated temperatures. As it may be expected, Sr2Tb3B27-δO46 and Ba2Eu3B27-δO46 (δ = 2/3) are promising green (Tb) and red (Eu) components for use in WLEDs.

Analysis of the molecular characteristics of a blaKPC-2-harbouring untypeable plasmid in Serratia marcescens.

INTRODUCTION: Serratia marcescens has attracted increasing attention worldwide as a neglected opportunistic pathogen of public health concern, especially due to its antimicrobial resistance features, which usually cause nosocomial infections in immunocompromised or critically ill patients. METHODS: In our study, four carbapenem-resistant Serratia marcescens (CRSM) clinical isolates were characterized in our hospital from February 2018 to May 2018. The conjugation experiment confirmed the transferability of the carbapenem resistance gene. The types of carbapenem resistance genes were detected by PCR. The homology of the strains was analysed by pulsed field gel electrophoresis (PFGE). The characteristics of the plasmid and environment of carbapenem resistance genes were analysed after whole genome sequencing was performed. Then, we compared the amino acid sequence of the replication initiation protein and constructed a dendrogram by the neighbour-joining method. RESULTS: All four isolates showed carbapenem resistance conferred by a blaKPC-2-harbouring plasmid. They had exactly the same bands confirmed by PFGE and were defined as the homologous strains. The blaKPC-2 genes in all of the isolates were located in a 42,742 bp plasmid, which was located in the core region of antibiotic resistance and was composed of Tn3 family transposons, recombinant enzyme genes, ISKpn6 and ISKpn27. The core region of antibiotic resistance formed a 'Tn3-ISKpn6-blaKPC-ISKpn27-Tn3' structure, which was an independent region as a movable element belonging to transposon Tn6296 and its derivatives. The plasmid had a similar skeleton to incX6 plasmids and a similar amino acid sequence to the replication initiation protein. The plasmid was defined as an untypeable blaKPC-2-harbouring plasmid named the 'IncX6-like' plasmid. CONCLUSION: The four CRSM isolates were mainly clonally disseminated with a blaKPC-2-harbouring plasmid in our hospital. The pKPC-2-HENAN1602 plasmid (CP047392) in our study was first reported in Serratia marcescens, which belongs to an untypeable group named the 'IncX6-like' plasmid. The carbapenem-resistant gene structure surrounding blaKPC-2 as a sole accessory module can be acquired by horizontal gene transfer and might lead to serious nosocomial infection.

IncN1 ST7 Epidemic Plasmid Carrying blaIMP-4 in One ST85-Type Klebsiella oxytoca Clinical Isolate with Porin Deficiency.

PURPOSE: Klebsiella oxytoca is an opportunistic pathogen causing nosocomial infections. This study was designed to characterize the genomic features of a carbapenem-resistant K. oxytoca strain and analyze its molecular characteristics. MATERIALS AND METHODS: The strain wzx-IMP was isolated from the blood of a 2-year-old girl diagnosed with acute myeloid leukemia-M7. Species identification was performed, and the minimal inhibitory concentration of the strain was measured. Multilocus sequence typing was performed to identify the subtypes of K. oxytoca. The transfer capacity of the blaIMP-4-harboring plasmid was investigated by conjugation experiments, and the genome characteristics of the strain were examined using whole-genome sequencing. RESULTS: wzx-IMP belongs to the ST85 type and is resistant to imipenem and meropenem, which harbored the blaIMP-4 gene. The blaIMP-4 gene was located in an IS26-associated class 1 integron of pwzx_IMP, which contains conserved IncN1-type backbone regions with a replication gene and its accessory structure for plasmid replication. The blaIMP-4-carrying plasmid in wzx-IMP was successfully transferred to Escherichia coli EC600 by conjugation. Whole-genome sequencing showed that the wzx-IMP isolate included the blaOXY-1-1 gene, accompanied by OmpK36 absence. CONCLUSION: We report an ST85-type carbapenem-resistant K. oxytoca strain, which produces blaIMP-4 located in an IncN1-type plasmid and accompanied by OmpK36 porin deficiency.