Emergence of Hypervirulent Carbapenem-Resistant Klebsiella pneumoniae Coharboring a blaNDM-1-Carrying Virulent Plasmid and a blaKPC-2-Carrying Plasmid in an Egyptian Hospital

The emergence of carbapenem-resistant Klebsiella pneumoniae (CRKP) isolates in Egyptian hospitals has been reported. However, the genetic basis and analysis of the plasmids associated with carbapenem-resistant hypervirulent K. pneumoniae (CR-HvKP) in Egypt have not been presented. Therefore, we attempted to decipher the plasmid sequences that are responsible for transferring the determinants of carbapenem resistance, particularly blaNDM-1 and blaKPC-2. Out of 34 K. pneumoniae isolates collected from two tertiary hospitals in Egypt, 31 were CRKP. Whole-genome sequencing revealed that our isolates were related to 13 different sequence types (STs). The most prevalent ST was ST101, followed by ST383 and ST11. Among the CRKP isolates, one isolate named EBSI036 has been reassessed by Nanopore sequencing. Genetic environment analysis showed that EBSI036 carried 20 antibiotic resistance genes and was identified as a CR-HvKP strain: it harbored four plasmids, namely, pEBSI036-1-NDM-VIR, pEBSI036-2-KPC, pEBSI036-3, and pEBSI036-4. The two carbapenemase genes blaNDM-1 and blaKPC-2 were located on plasmids pEBSI036-1-NDM-VIR and pEBSI036-2-KPC, respectively. The IncFIB:IncHI1B hybrid plasmid pEBSI036-1-NDM-VIR also carried some virulence factors, including the regulator of the mucoid phenotype (rmpA), the regulator of mucoid phenotype 2 (rmpA2), and aerobactin (iucABCD and iutA). Thus, we set out in this study to analyze in depth the genetic basis of the pEBSI036-1-NDM-VIR and pEBSI036-2-KPC plasmids. We report a high-risk clone ST11 KL47 serotype of a CR-HvKP strain isolated from the blood of a 60-year-old hospitalized female patient from the intensive care unit (ICU) in a tertiary care hospital in Egypt, which showed the cohabitation of a novel hybrid plasmid coharboring the blaNDM-1 and virulence genes and a blaKPC-2-carrying plasmid

A Mechanism of the Interdecadal Changes of the Global Low-Frequency Oscillation

Based on the National Center for Environmental Prediction/National Center for Atmospheric Research reanalysis dataset from 1948 to 2009, this study reveals that global low-frequency oscillation features two major temporal bands. One is a quasi-60-day period known as the intraseasonal oscillation (ISO), and the other is a quasi-15-day period known as the quasi-biweekly oscillation (QBWO). After the mid-1970s, both the ISO and QBWO become intensified and more active, and these changes are equivalently barotropic. The primitive barotropic equations are adopted to study the involved mechanism. It reveals that the e-folding time of the least stable modes of both the ISO and QWBO becomes shorter if the model is solved under the atmospheric basic state after the mid-1970s than if solved under the basic state before the mid-1970s. This result suggests that the atmospheric basic flow after the mid-1970s facilitates a more rapid growth of the ISO and QBWO, and thereby an intensification of the low-frequency oscillations at the two bands

Heatwaves Similar to the Unprecedented One in Summer 2021 Over Western North America Are Projected to Become More Frequent in a Warmer World

Abstract Western North America (WNA) experienced an unprecedented heatwave from late June to early July 2021, which lies far outside the historical range. Based on the model outputs from Coupled Model Intercomparison Project Phase 6, we find that the likelihood of a heatwave over WNA similar to the 2021 one increases with global warming. Such a heatwave is projected to occur more frequently with increased extreme temperature and shortened return period. It means that a rare event in the current climate will be a more common event in a warmer climate, especially under a high‐emission scenario like the Shared Socioeconomic Pathways 585 (SSP5‐8.5). Moreover, we show a large expansion of areas over WNA that will break the 2021 record in the future with an increasing level of emission scenario. Nevertheless, some heatwave records west of the Rocky Mountains are still difficult to break, highlighting the specific extremity of the 2021 WNA heatwave

Construction of Chemically Bonded Interface of Organic/Inorganic g-C3N4/LDH Heterojunction for Z-Schematic Photocatalytic H2 Generation

The design and synthesis of a Z-schematic photocatalytic heterostructure with an intimate interface is of great significance for the migration and separation of photogenerated charge carriers, but still remains a challenge. Here, we developed an efficient Z-scheme organic/inorganic g-C3N4/LDH heterojunction by in situ growing of inorganic CoAl-LDH firmly on organic g-C3N4 nanosheet (NS). Benefiting from the two-dimensional (2D) morphology and the surface exposed pyridine-like nitrogen atoms, the g-C3N4 NS offers efficient trap sits to capture transition metal ions. As such, CoAl-LDH NS can be tightly attached onto the g-C3N4 NS, forming a strong interaction between CoAl-LDH and g-C3N4 via nitrogen–metal bonds. Moreover, the 2D/2D interface provides a high-speed channel for the interfacial charge transfer. As a result, the prepared heterojunction composite exhibits a greatly improved photocatalytic H2 evolution activity, as well as considerable stability. Under visible light irradiation of 4 h, the optimal H2 evolution rate reaches 1952.9 μmol g−1, which is 8.4 times of the bare g-C3N4 NS. The in situ construction of organic/inorganic heterojunction with a chemical-bonded interface may provide guidance for the designing of high-performance heterostructure photocatalysts

Artificial Base-Directed In Vivo Formulation of Aptamer–Drug Conjugates with Albumin for Long Circulation and Targeted Delivery

Aptamer–drug conjugates (ApDCs) are potential targeted pharmaceutics, but their clinical applications are hampered by fast clearance in blood. Herein we report the construction of ApDCs modified with artificial base F and the study of biological activities. Two types of F-base-modified ApDCs were prepared, Sgc8-paclitaxel by conjugation and Sgc8-gemcitabine, by automated solid-phase synthesis. In vitro experiments showed that F-base-modified ApDCs retain the specificity of the aptamer to target cells and the biological stability is improved. In vivo studies demonstrated that the circulatory time is increased by up to 55 h or longer, as the incorporated F base leads to a stable ApDC-albumin complex as the formulation for targeted delivery. Moreover, conjugated drug molecules were released efficiently and the drug (paclitaxel) concentration in the tumor site was improved. The results demonstrate that an F-base-directed ApDC-albumin complex is a potential platform for drug delivery and targeted cancer therapy