Oriented Epitaxial Growth of Mixed-Dimensional van der Waals Heterostructures with One-Dimensional (1D) Bi2S3 Nanowires and Two-Dimensional (2D) WS2 Monolayers for Performance-Enhanced Photodetectors.

The synthesis of mixed-dimensional van der Waals heterostructures with controlled alignment by chemical vapor deposition (CVD) technique remains a big challenge due to the complex epitaxial growth mechanism. Herein, we report the epitaxial growth of mixed-dimensional Bi2S3/WS2 heterostructures by a two-step CVD method. Bi2S3 crystals grown on 2D WS2 monolayers exhibit 1D feature with the preferred orientation, indicating a strong epitaxial growth behavior at the 1D/2D interface. Furthermore, the heterostructure was carefully characterized by transmission electron microscopy, which reveals the preferential growth of Bi2S3 nanowires along the zigzag edge of WS2 monolayers. The experimental results are also consistent with the theoretical calculations by DFT, where the preferred orientation possesses minimal surface energy. The strong interaction between Bi2S3 and WS2 enables efficient charge transfer of photogenerated carriers at the heterointerface, which leads to a largely improved light harvesting capability with the highest responsivity of ∼48.1 AW-1 and detectivity of ∼5.9 × 1012 Jones.

Self-Trapped Exciton Emission in Highly Polar 0D Hybrid Ammonium/Hydronium-Based Perovskites Triggered by Antimony Doping.

Various monovalent cations are employed to construct metal halide perovskites with various structures and functionalities. However, perovskites based on highly polar A-site cations have seldom been reported. Here, a novel hybrid 0D (NH4)x(OH3)3-xInCl6 perovskite with highly polar hydronium OH3+ cations is introduced in this study. Upon doping with Sb3+, hybrid 0D (NH4)x(OH3)3-xInCl6 single crystals exhibited highly efficient broadband yellowish-green (550 nm) and red (630 nm) dual emissions with a PLQY of 86%. The dual emission arises due to Sb3+ occupying two sites within the crystal lattice that possess different polarization environments, leading to distinct Stokes shift energies. The study revealed that lattice polarity plays a significant role in the self-trapped exciton emission of Sb3+-doped perovskites, contributing up to 25% of the Stokes shift energy for hybrid 0D (NH4)x(OH3)3-xInCl6:Sb3+ as a secondary source, in addition to the Jahn-Teller deformation. These findings highlight the potential of Sb3+-doped perovskites for achieving tunable broadband emission and underscore the importance of lattice polarity in determining the emission properties of perovskite materials.

NiFe LDH/Fe2O3/Ni3S2 Heterostructure with a Superhydrophilic/Superaerophobic Surface for Solar-Driven Electrolytic Water Splitting.

The development of a bifunctional electrocatalyst with high efficiency, high stability, and low cost is of great significance in practical applications of electrocatalytic water splitting. Herein, a self-supporting bifunctional electrocatalyst with a NiFe layered double hydroxide/Fe2O3/Ni3S2 heterostructure (NiFe LDH/Fe2O3/Ni3S2/IF) for hydrogen evolution and oxygen evolution reactions (HER/OER) is synthesized by the self-corrosion of iron foam (IF) and hydrothermal strategies. The constructed NiFe LDH/Fe2O3/Ni3S2/IF hierarchical heterostructure was not only beneficial to expose active sites and promote charge/mass transfer but also generate a superhydrophilic/superaerophobic surface, thereby accelerating the reaction kinetics to improve the HER/OER activity. Therefore, NiFe LDH/Fe2O3/Ni3S2/IF exhibited superior overpotentials of 226.2 and 162.8 mV for the OER and HER at 100 mA cm-2, respectively. NiFe LDH/Fe2O3/Ni3S2/IF was employed as both the cathode and the anode to assemble a device for overall water splitting and displayed a voltage of 1.55 V at 10 mA cm-2. The overall water splitting device was coupled with a solar cell to simulate a solar-powered water splitting system, resulting in a superior solar-to-hydrogen conversion efficiency of 15.16%. This work can promote the development of clean energy sources such as solar hydrogen production.

Toward an Ideal Light Source for Indoor Photosynthesis: Broadband Red Emission in Zero-Dimensional Hafnium-Based Metal Halide (TPP)2HfCl6·4C2H3N:Sb3.

With suitable electron-phonon coupling strength, a near-unity broadband photoluminescence quantum yield (PLQY) can be achieved in organic-inorganic hybrid metal halides (OIHMHs) via self-trapped exciton (STE) emission. However, it is still challenging to obtain high-quality red emission from OIHMHs with a desirable emission wavelength and high chemical stability, which hinders their practical application in high-performance displays, plant-growth lighting, and biomedical imaging. Herein, a series of hafnium-based zero-dimensional (TPP)2HfCl6·4C2H3N (TPP: tetraphenylphosphonium) single crystals with different Sb3+ doping levels are synthesized. The Sb3+-doped (TPP)2HfCl6·4C2H3N shows dual-band red emission with a full width at half-maximum of 178 nm and a high PLQY of 91.09%. This broad dual-band emission originates from dopant-induced extrinsic free excitons and STEs. Furthermore, (TPP)2HfCl6·4C2H3N:Sb3+ was employed as a luminescence converter in a light-emitting diode (LED) for plant growth regulation. A correlated color temperature of 4055 K and a color rendering index of 82.13 were achieved upon excitation of the LED at 365 nm. These results provide fundamental perspectives on the emission behavior of Sb3+-doped OIHMHs and illustrate their promise for use in plant-growth lighting.

A photoelectrochemical aptasensor based on W6+-doped carbon nitride with carbon-rich structure for sensitive detection of diazinon.

A photoelectrochemical (PEC) aptasensor us reported based on W6+-doped carbon nitride with carbon-rich structure (WCCN). WCCN exhibited excellent photoelectric conversion performance owing to the carbon-rich structure and W6+ doping. C atoms can replace the center N/edge N atoms to form a carbon-rich structure, improving the insufficient light absorption of CN in the visible region. Also, W6+ doping forms a directional electron transfer channel, achieving the efficient separation and transport of carriers. W6+ doping and carbon-rich structure can promote the generation, transfer, and separation of photogenerated carriers, further enhancing PEC performance. The fabricated PEC aptasensor based on WCCN demonstrated a wide detection range (3.92 ~ 588 pg L-1), a low detection limit (1.31 pg L-1, S/N = 3), good reproducibility, selectivity, stability, and practical application in actual water samples. This work explores the modification strategy of element doping for carbon nitride with high photoelectric property and offers a cost-effective and simplified method for the detection of pesticide residues.

Development of a label-free photoelectrochemical immunosensor for novel astrovirus detection.

Since 2017, an infectious goose gout disease characterized by urate precipitation in viscera, mainly caused by novel goose astrovirus (GoAstV) infection, has emerged in the main goose-producing region of China. The current challenge in managing goose gout disease is largely due to the absence of a rapid and efficient detection method for the GoAstV pathogen. Notably, the potential application of immunosensors in detecting GoAstV has not yet been explored. Herein, a label-free PEC immunosensor was fabricated by using purchased TiO2 as the photoactive material and antibody against GoAstV P2 proteins as the specific recognition element. First, we successfully expressed the capsid spike domain P2 protein of ORF2 from GoAstV CHSH01 by using the pET prokaryotic expression system. Meanwhile, the polyclonal antibody against GoAstV capsid P2 protein was produced by purified protein. To our knowledge, this is the first establishment and preliminary application of the label-free photoelectrochemical immunosensor method in the detection of AstV. The PEC immunosensor had a linear range of 1.83 fg mL-1 to 3.02 ng mL-1, and the limit of detection (LOD) was as low as 0.61 fg mL-1. This immunosensor exhibited high sensitivity, great specificity, and good stability in detecting GoAstV P2 proteins. To evaluate the practical application of the immunosensor in real-world sample detection, allantoic fluid from goose embryos was collected as test samples. The results indicated that of the eight positive samples, one false negative result was detected, while both negative samples were accurately detected, suggesting that the constructed PEC immunosensor had good applicability and practical application value, providing a platform for the qualitative detection of GoAstV.

Co-Delivery of Gemcitabine and Honokiol by Lipid Bilayer-Coated Mesoporous Silica Nanoparticles Enhances Pancreatic Cancer Therapy via Targeting Depletion of Tumor Stroma.

Syndecan-1 (SDC1) modified lipid bilayer (LB)-coated mesoporous silica nanoparticles (MSN) to co-deliver gemcitabine (GEM) and honokiol (HNK) were prepared for the targeting treatment of pancreatic cancer. The encapsulation efficiencies of GEM and HNK in SDC1-LB-MSN-GEM/HNK were determined to be 60.3 ± 3.2% and 73.0 ± 1.1%. The targeting efficiency of SDC1-LB-MSN-GEM/HNK was investigated in BxPC-3 cells in vitro. The fluorescence intensity in the cells treated with SDC1-LB-MSN-Cou6 was 2-fold of LB-MSN-Cou6-treated cells, which was caused by SDC1/IGF1R-mediated endocytosis. As anticipated, its cytotoxicity was significantly increased. Furthermore, the mechanism was verified that SDC1-LB-MSN-HNK induced tumor cell apoptosis through the mitochondrial apoptosis pathway. Finally, the biodistribution, tumor growth inhibition, and preliminary safety studies were performed on BALB/c nude mice bearing BxPC-3 tumor models. The tumor growth inhibition index of SDC1-LB-MSN-GEM/HNK was 56.19%, which was 1.45-fold and 1.33-fold higher than that of the free GEM/HNK and LB-MSN-GEM/HNK treatment groups, respectively. As a result, SDC1-LB-MSN-GEM/HNK combined advantages of both GEM and HNK and simultaneously targeted and eliminated pancreatic cancerous and cancer-associated stromal cells. In summary, the present study demonstrated a new strategy of synergistic GEM and HNK to enhance the therapeutic effect of pancreatic cancer via the targeting depletion of tumor stroma.

A Fluorinated Imide-Functionalized Arene Enabling a Wide Bandgap Polymer Donor for Record-Efficiency All-Polymer Solar Cells.

All-polymer solar cells (all-PSCs) present compelling advantages for commercial applications, including mechanical durability and optical and thermal stability. However, progress in developing high-performance polymer donors has trailed behind the emergence of excellent polymer acceptors. In this study, we report a new electron-deficient arene, fluorinated bithiophene imide (F-BTI) and its polymer donor SA1, in which two fluorine atoms are introduced at the outer ß-positions in the thiophene rings of BTI to fine-tune the energy levels and aggregation of the resulting polymers. SA1 exhibits a deep HOMO level of -5.51 eV, a wide bandgap of 1.81 eV and suitable miscibility with the polymer acceptor. Polymer chains incorporating F-BTI result in a highly ordered π-π stacking and favorable phase-separated morphology within the all-polymer active layer. Thus, SA1 : PY-IT-based all-PSCs exhibit an efficiency of 16.31 % with excellent stability, which is further enhanced to a record value of 19.33 % (certified: 19.17 %) by constructing ternary device. This work demonstrates that F-BTI offers an effective route for developing new polymer materials with improved optoelectronic properties, and the emergence of F-BTI will change the scenario in terms of developing polymer donor for high-performance and stable all-PSCs.

P-Orbital Bismuth Single-Atom Catalyst for Highly Effective Oxygen Electroreduction in Quasi-Solid Zinc-Air Batteries.

P-block metals have gradually been utilized to synthesize non-noble-metal catalysts for oxygen reduction reaction (ORR) due to the easily tunable localized p-orbitals and resulted versatile electronic structures. The high-density single-atom bismuth sites (Bi-NC) anchored onto nitrogen-doped three-dimensional porous carbon are proved to possess significant electrocatalytic ORR performance. Theoretical calculations unveil positively charged bismuth centers prominently improved the adsorption capacity of N-doped carbon to O2 . The p orbitals of Bi sites within Bi-NC easily generate hybrid states with p orbitals of O2 , thus promoting charge transfer and ultimately reducing the energy barrier of ORR. Benefiting from p-orbital electrons regulation of bismuth atoms, Bi-NC exhibit ORR half-wave potential of 0.86 V (vs RHE). Additionally, both liquid and quasi-solid zinc-air batteries with Bi-NC as air-cathodes achieve higher power density and specific capacity than 20 wt% Pt/C, and comparable stability and round-trip efficiency with 20 wt% Pt/C. The discovery sheds light on the theoretical and practical guidance for p-block metallic single-atom catalysts.

Comparative transcriptomics and co-expression networks reveal cultivar-specific molecular signatures associated with reproductive-stage cold stress in rice.

KEY MESSAGE: The resistance of Huaidao5 results from the high constitutive expression of tolerance genes, while that of Huaidao9 is due to the cold-induced resistance in flag leaves and panicles. The regulation mechanism of rice seedlings' cold tolerance is relatively clear, and knowledge of its underlying mechanisms at the reproductive stage is limited. We performed differential expression and co-expression network analyses to transcriptomes from panicle and flag leaf tissues of a cold-tolerant cultivar (Huaidao5), and a sensitive cultivar (Huaidao9), under reproductive-stage cold stress. The results revealed that the expression levels of genes in stress-related pathways such as MAPK signaling pathway, diterpenoid biosynthesis, glutathione metabolism, plant-pathogen interaction and plant hormone signal transduction were constitutively highly expressed in Huaidao5, especially in panicles. Moreover, the Hudaidao5's panicle sample-specific (under cold) module contained some genes related to rice yield, such as GW5L, GGC2, SG1 and CTPS1. However, the resistance of Huaidao9 was derived from the induced resistance to cold in flag leaves and panicles. In the flag leaves, the responses included a series of stress response and signal transduction, while in the panicles nitrogen metabolism was severely affected, especially 66 endosperm-specific genes. Through integrating differential expression with co-expression networks, we predicted 161 candidate genes (79 cold-responsive genes common to both cultivars and 82 cold-tolerance genes associated with differences in cold tolerance between cultivars) potentially affecting cold response/tolerance, among which 85 (52.80%) were known to be cold-related genes. Moreover, 52 (65.82%) cold-responsive genes (e.g., TIFY11C, LSK1 and LPA) could be confirmed by previous transcriptome studies and 72 (87.80%) cold-tolerance genes (e.g., APX5, OsFbox17 and OsSTA109) were located within QTLs associated with cold tolerance. This study provides an efficient strategy for further discovery of mechanisms of cold tolerance in rice.

Long-term improvement of sediment in situ restoration and REDOX characteristics by Vallisneria natans coupling with carbon fiber.

China is conducting ecological restoration work in urban water bodies. Under anoxic and anaerobic conditions, pollutants transform and produce odorous and black substances, deteriorating the water quality, which is a significant problem in urban water bodies. Vallisneria natans has received widespread attention for its applications in water treatment and restoration. However, the efficiency by which V. natans reduces water pollution and allows sediment remediation requires further improvement. Therefore, in this study, we investigated the effect of V. natans coupled with carbon fiber on the restoration of water bodies and sediment compared with the control group that grew V. natans without carbon fiber. The oxidation-reduction potential (ORP) was selected as the main evaluation index for the water and sediment. Dissolved oxygen in the water and total organic carbon and total nitrogen (TN) in the sediment were also evaluated. V. natans coupled with carbon fiber significantly increased the ORP; that of surface sediment increased by 50 % and that of the water body increased by 60 % compared with the sediment without any bioremediation. Chemical oxygen demand, total phosphorous, and TN in water decreased by 61.2 %, 22.9 %, and 48.3 %, respectively. These results indicate that planting V. natans with carbon fiber can reduce pollutants in water (including humus) and sediments, effectively improving ORP in water and sediment.

Improved the in-situ remediation effect of benthic microbial electrochemical system by optimizing the anode structure.

Six 60-L benthic microbial electrochemical systems (BMESs) were built for the bioremediation of river sediment. Carbon mesh anodes with honeycomb-structure supports were compared with horizontal anodes, and the system was tested using different cover depths and anode densities. The pollutant removal, electricity generation, and electrochemistry of the six BMES with different anodes was examined using the Ashi River (Harbin, China) as a case study. Total organic carbon and total nitrogen removal from sediments in BMES with Honeycomb-structure anodes were 20-30% and 20-33% higher for the other reactors. The maximum power densities of 43.2 mW m-2 was obtained in BMES. The maximum power densities in BMES with honeycomb-structure anodes were 10-40% higher than that of BMESs with horizontal anode reactors.

Zero-Dimensional Organic-Inorganic Hybrid Copper-Based Halides with Highly Efficient Orange-Red Emission.

Lead-free metal halides are promising luminescent materials with low non-toxicity, tunable emission, and high luminescence quantum yield (PLQY). The development of red light-emitting materials with high PLQY to meet the color coordinate requirements for light-emitting diode (LED) lighting and wide color gamut displays remains a major scientific challenge. Herein, novel lead-free copper-based halide materials are reported. PEA4 Cu4 I4 is an efficient orange-red broad emission with a highest PLQY of 73.6%. All three materials, namely, those of ((R)-(+)-α-PEA)4 Cu4 I4 , ((S)-(-)-α-PEA)4 Cu4 I4 , and (ß-PEA)4 Cu4 I4 with zero-dimensional structures have large exciton binding energies and Huang-Rhys factors, thus causing efficient self-trapped exciton emissions. A prototypical orange-red LED device is fabricated successfully that demonstrates the potential of copper-based halide materials in lighting and display applications.

Identification of a novel plasmid-mediated tigecycline resistance-related gene, tet(Y), in Acinetobacter baumannii.

OBJECTIVES: To characterize a novel plasmid-mediated tigecycline resistance-related gene, tet(Y), in a clinical Acinetobacter baumannii isolate from China. METHODS: The tet(Y)-encoded tigecycline-resistant A. baumannii 2016GDAB1 was screened through antimicrobial susceptibility testing and WGS. The function of tet(Y) was verified by complementation of tet(Y). The plasmid transferability and stability were detected via plasmid conjugation and in vitro bacterial passaging. The 3D structure of Tet(Y) was predicted and docked using tFold and AutoDock Vina. RESULTS: The tigecycline-resistant A. baumannii 2016GDAB1 was isolated from bronchoalveolar lavage fluid of a patient with hospital-acquired pneumonia. However, this strain did not harbour any common tigecycline resistance genes, determinants or mutations. 2016GDAB1 belongs to the non-epidemic clone ST355 (Oxford scheme), which has been mainly reported in animals. The tet(Y) gene was located on a 72 156 bp plasmid and genomic environment analysis revealed that Tn5393 may play a role in tet(Y) transmission, whereas phylogenetic analysis indicated the origin of tet(Y) as from Aeromonas. Overexpression of tet(Y) resulted in a 2- to 4-fold increase in tigecycline MIC. Introduction of the tet(Y)-harbouring plasmid p2016GDAB1 via electroporation resulted in a 16-fold increase in tigecycline MIC but failed to transfer into the tigecycline-susceptible A. baumannii recipient via conjugation. Isolates carrying the tet(Y) gene were vulnerable to tigecycline pressure and exhibited decreased susceptibility to tigecycline. A tet(Y)-carrying plasmid was stably maintained in the host strains. CONCLUSIONS: This study identified the tigecycline resistance-related gene tet(Y) in A. baumannii. This gene conferred an increased tigecycline MIC and the transposable element Tn5393 may play a role in its transmission across isolates.

Considering the flanking region variants of nonbinary SNP and phenotype-informative SNP to constitute 30 microhaplotype loci for increasing the discriminative ability of forensic applications.

The flanking region variants of nonbinary SNPs and phenotype-informative SNPs (piSNPs) have been observed, which may greatly improve the discriminative ability after constituting microhaplotype. In this study, 30 microhaplotype loci based on the nonbinary SNPs and piSNPs (shown to be related to phenotypes such as hair and eye color) were selected. Genotyping were conducted on 100 unrelated northern Han Chinese, and the 26 populations from the 1000 Genome Project were also included for comparison of populations differentiation. The simulated study was conducted for evaluating the efficiency of kinship testing. These 30 microhaplotype loci we selected had good polymorphism, with a mean effective number of alleles (Ae) of 3.46. The average Ae increase was 1.27 compared with the target SNPs. The populations from the five regions worldwide could also be distinguished using these loci. The results of kinship testing showed that these microhaplotype loci had the similar ability as 15 STR loci of AmpFlSTRR IdentifilerR PCR Amplification Kit to identify the biological parent and a stronger ability to exclude the nonbiological parents. So, these 30 microhaplotype loci may be multifunctional for forensic application, including the ability of personal identification and kinship testing equivalent to 15 STR loci, and the power of ancestry inference for distinguishing the main intercontinental population. Moreover, our selected phenotypic microhaplotype loci may theoretically have phenotype prediction capabilities. But the phenotype prediction efficiency of these phenotypic microhaplotype loci may be worse than that of piSNPs and the detailed prediction accuracy of different populations needs to be further studied.

Clinical and microbiological characteristics of adults with hospital-acquired pneumonia: a 10-year prospective observational study in China.

Hospital-acquired pneumonia (HAP) is a significant nosocomial infection; data on the distribution and antimicrobial resistance profiles of HAP in China are limited. We included 2827 adult patients with HAP from the Chinese Antimicrobial Resistance Surveillance of Nosocomial Infections network admitted in 15 Chinese teaching hospitals between 2007 and 2016. Clinical data and antimicrobial susceptibility of isolated pathogens were obtained from the medical records and central laboratory, respectively. Multivariable logistic regression was performed to determine the risk factors for mortality and multidrug resistance (MDR). A total of 386 (13.7%) patients died in the hospital, while 1181 (41.8%) developed ventilator-associated pneumonia (VAP). Active immunosuppressant therapy (OR 1.915 (95% CI 1.475-2.487)), solid tumor (OR 1.860 (95% CI 1.410-2.452)), coma (OR 1.783 (95% CI 1.364-2.333)), clinical pulmonary infection score ≥7 (OR 1.743 (95% CI 1.373-2.212)), intensive care unit stay (OR 1.652 (95% CI 1.292-2.111)), age ≥65 years (OR 1.621 (95% CI 1.282-2.049)), and tracheal cannula insertion (OR 1.613 (95% CI 1.169-2.224)) were independent risk factors for in-hospital mortality. Liver cirrhosis (OR 3.120 (95% CI 1.436-6.780)) and six other variables were independent predictors of MDR. Acinetobacter baumannii (25.6%), Pseudomonas aeruginosa (20.1%), Klebsiella pneumoniae (15.4%), and Staphylococcus aureus (12.6%) were the most common pathogens (MDR prevalence 64.9%). Isolates from VAP patients showed more A. baumannii and less K. pneumoniae and E. coli strains (p < 0.001, respectively) than those from patients without VAP. The proportion of methicillin-resistant S. aureus strains decreased; that of carbapenem-resistant A. baumannii and Enterobacterales strains increased. There had been changes in the antibiotic resistance profiles of HAP pathogens in China. Risk factors for mortality and MDR are important for the selection of antimicrobials for HAP in China.

A photoelectrochemical aptasensor of ciprofloxacin based on Bi24O31Cl10/BiOCl heterojunction.

A photoelectrochemical (PEC) aptasensor was designed and constructed by Bi24O31Cl10/BiOCl heterojunction as a photoelectric active material for realizing the determination of trace ciprofloxacin (CIP) in water. Compared with Bi24O31Cl10, Bi24O31Cl10/BiOCl heterojunction possessed the improvement of light harvesting and the enhancement of photocurrent signal. The formation of heterojunction between Bi24O31Cl10 and BiOCl can accelerate the transportation efficiency and inhibit the recombination rate of photoinduced carriers. Based on the excellent PEC performance, CIP aptamer was introduced on the modified Bi24O31Cl10/BiOCl/indium tin oxide (ITO) electrode for fabricating a PEC aptasensor. Owing to the combination between aptamer and CIP, CIP-aptamer complex can block the transfer of charge, leading to the reduction of photocurrent response. The PEC aptasensor possessed high sensitivity with a wide detection range (5.0~1.0 × 104 ng L-1) and a low detection limit (1.67 ng L-1, S/N = 3). The PEC aptasensor with good selectivity and reproducibility has been applied to the determination of CIP in water.

Evaluation of the in vitro activity of new polymyxin B analogue SPR206 against clinical MDR, colistin-resistant and tigecycline-resistant Gram-negative bacilli.

BACKGROUND: SPR206 is a novel polymyxin analogue. Activity against clinical isolates is little documented. METHODS: A collection of 200 MDR, carbapenem-resistant, tigecycline-resistant, colistin-resistant and non-MDR clinical isolates of Acinetobacter baumannii, Pseudomonas aeruginosa, Klebsiella pneumoniae, Escherichia coli, Enterobacter cloacae and Stenotrophomonas maltophilia was obtained from 50 centres across China (2016-17). All isolates were derived from respiratory tract, urine and blood samples. Strains were purposely selected on the basis of phenotypes, genotypes and specimen origins. MICs of SPR206 and other antimicrobials were determined. RESULTS: SPR206 was active against all bacteria tested except colistin-resistant isolates. The MIC50/90 values of SPR206 for colistin-resistant strains were comparable to known polymyxins (16/128 versus 8/128 mg/L). SPR206 exhibited potent activity against colistin-susceptible OXA-producing A. baumannii (MIC50/90 = 0.064/0.125 mg/L), NDM-producing Enterobacteriaceae (MIC50/90 = 0.125/0.25 mg/L) and KPC-2-producing Enterobacteriaceae (MIC50/90 = 0.125/0.5 mg/L). In fact, SPR206 was the most potent agent tested, with 2- to 4-fold lower MICs than colistin and polymyxin B for A. baumannii, P. aeruginosa and Enterobacteriaceae. Additionally, MIC values of SPR206 (MIC50/90 = 0.064/0.125 mg/L) were 16- to 32-fold lower than those of tigecycline (MIC50/90 = 2/2 mg/L) for tigecycline-susceptible carbapenem-resistant A. baumannii. CONCLUSIONS: SPR206 showed good in vitro activity against MDR, tigecycline-resistant and non-MDR clinical isolates of Gram-negative pathogens. SPR206 also exhibited superior potency to colistin and polymyxin B, with 2- to 4-fold lower MIC50/90 values.

In vitro activity of the novel ß-lactamase inhibitor taniborbactam (VNRX-5133), in combination with cefepime or meropenem, against MDR Gram-negative bacterial isolates from China.

OBJECTIVES: To evaluate in vitro activity of the novel ß-lactamase boronate inhibitor taniborbactam (VNRX-5133) combined with cefepime or meropenem against 500 urinary Gram-negative bacilli. METHODS: Cefepime/taniborbactam and 14 comparators were tested by broth microdilution or agar dilution methods. A total of 450 Enterobacteriaceae and 50 Pseudomonas aeruginosa were selected from 2017 to 2019 based on different ß-lactamase-producing or resistance phenotypes. For carbapenem-non-susceptible isolates, the modified carbapenem inactivation method (mCIM), EDTA-CIM (eCIM) and amplification of carbapenemase genes were performed. For NDM-producing isolates and those with cefepime/taniborbactam MICs >8 mg/L, the MICs of meropenem/taniborbactam and/or mutations in PBP3 were investigated. RESULTS: Taniborbactam improved cefepime activity with the same efficiency as avibactam improved ceftazidime activity against 66 KPC-2 producers, 30 non-carbapenemase-producing carbapenem-non-susceptible Enterobacteriaceae and 28 meropenem-susceptible P. aeruginosa. However, cefepime/taniborbactam exhibited more potent activity than ceftazidime/avibactam against 56 ESBL-producing, 61 AmpC-producing, 32 ESBL and AmpC co-producing, 87 NDM-producing and 21 MBL-producing Enterobacteriaceae predicted by phenotypic mCIM and eCIM, 82 Enterobacteriaceae that were susceptible to all tested ß-lactams and 22 carbapenem-non-susceptible P. aeruginosa. A four-amino acid 'INYR' or 'YRIN' insertion, with or without a one/two-amino acid mutation in PBP3, may have caused cefepime/taniborbactam MICs >8 mg/L among 96.6% (28/29) of the NDM-5-producing Escherichia coli, which accounted for the majority of isolates with cefepime/taniborbactam MICs >8 mg/L (76.1%, 35/46). CONCLUSIONS: Taniborbactam's superior breadth of activity, when paired with cefepime or meropenem, suggests these ß-lactam/ß-lactamase inhibitor combinations could be promising candidates for treating urinary tract infections caused by ESBL and/or AmpC, KPC or NDM-producing Enterobacteriaceae or P. aeruginosa.

A photoelectrochemical aptasensor for sensitively monitoring chloramphenicol using plasmon-driven AgNP/BiOCl composites.

A photoelectrochemical (PEC) aptasensor based on silver nanoparticle/BiOCl (AgNP/BiOCl) composites was constructed for detecting chloramphenicol (CAP). The surface-plasmon resonance (SPR) effect of AgNPs can focus the incident light and promote the migration and separation of the photogenerated carriers of AgNP/BiOCl composites. As a result, the AgNP/BiOCl composites showed an enhanced PEC performance compared to that of pure BiOCl. A PEC CAP aptasensor was fabricated using AgNP/BiOCl composites as photoactive materials and a CAP aptamer as a recognition element. The PEC aptasensor exhibited a broad linear response range (0.2 pM-10 nM), a low limit of determination (0.08 pM), satisfactory selectivity, stability, and reproducibility to meet the practical analysis requirements. This work demonstrates that the PEC CAP aptasensor has a promising prospect in environmental assays.