Prevalence and Antimicrobial Resistance Diversity of Salmonella Isolates in Jiaxing City, China.

Nontyphoidal Salmonella (NTS) is a cause of foodborne diarrheal diseases worldwide. Important emerging NTS serotypes that have spread as multidrug-resistant high-risk clones include S. Typhimurium monophasic variant and S. Kentucky. In this study, we isolated Salmonella in 5019 stool samples collected from patients with clinical diarrhea and 484 food samples. Antibiotic susceptibility testing and whole-genome sequencing were performed on positive strains. The detection rates of Salmonella among patients with diarrhea and food samples were 4.0% (200/5019) and 3.1% (15/484), respectively. These 215 Salmonella isolates comprised five main serotypes, namely S. Typhimurium monophasic variant, S. Typhimurium, S. London, S. Enteritidis, and S. Rissen, and were mainly resistant to ampicillin, tetracycline, chloramphenicol, and trimethoprim/sulfamethoxazole. The MDR rates of five major serotypes were 77.4%, 56.0%, 66.7%, 53.3%, and 80.0%, respectively. The most commonly acquired extended-spectrum ß-lactamase-encoding genes were blaTEM-1B, blaOXA-10, and blaCTX-M-65. The S. Typhimurium monophasic variant strains from Jiaxing City belonged to a unique clone with broad antibiotic resistance. S. Kentucky isolates showed the highest drug resistance, and all were MDR strains. The discovery of high antibiotic resistance rates in this common foodborne pathogen is a growing concern; therefore, ongoing surveillance is crucial to effectively monitor this pathogen.

Characteristics of Two mcr-1-Harboring IncHI2 Plasmids from Clinical Salmonella Isolates in Jiaxing City.

Salmonella is a primary cause of foodborne diseases, and the increasing prevalence of mcr-1-carrying plasmids, which confer colistin resistance to Salmonella, poses significant global health concerns. As the frequency of occurrence of the mcr-1 gene is increasing globally, we studied the prevalence of mcr-1 in clinical Salmonella isolates by analyzing 195 clinical strains isolated in 2020. Of the 195 Salmonella isolates, 41 isolates were resistant to colistin. We found mcr-1 in two strains (Salmonella Typhimurium ZJJX20006 and Salmonella Kentucky ZJJX20014), which we analyzed in detail via whole-genome sequencing and antibiotic susceptibility testing. Two strains displayed resistance to ampicillin, ampicillin-sulbactam, tetracycline, chloramphenicol, and cotrimoxazole, while ZJJX20006 displayed resistance to colistin and ZJJX20014 was sensitive. Genomic analysis revealed that these strains had plasmid-encoded mcr-1 in IncHI2 plasmids, which were not similar to the mcr-1-IncX4 identified in 2016. These two strains also harbored other drug resistance genes, including blaOXA-1 and blaCTX-M-14. Our findings may help clarify the molecular mechanisms of mcr-1 dissemination among Salmonella strains in Jiaxing City and offer insights into the evolution of mcr-1 in Salmonella.

Mechanisms of calcium sulfate in alleviating cadmium toxicity and accumulation in pak choi seedlings.

Gypsum (calcium sulfate dihydrate, CaSO4 ·2H2O) is commonly applied to improve soil quality and nutrient supply. Previous studies also suggested it is a cost-effective soil amendment in alleviating cadmium (Cd) toxicity and accumulation in plants. The aim of this study was to investigate how this is achieved. We used pak choi as our research material because it is a popular vegetable in Asia, and as a leafy vegetable, it accumulates higher Cd level than other types of vegetable. Under Cd stress, application of CaSO4 promoted pak choi seedling growth, decreased the oxidative stress in roots, reduced Cd accumulation, and enhanced the photosynthesis in shoots. We revealed the inhibition of Cd2+ absorption by CaSO4 is largely due to the competition between Ca2+ and Cd2+ for ion channels or transporter. Moreover, under Cd stress, CaSO4 facilitated the sulphate assimilation, increased the biosynthesis of phytochelatins, and activated the expression of transporters for vacuolar sequestration. Together, CaSO4 could benefit plant growth and enhance Cd tolerance by suppressing Cd root uptake and lowering the Cd content in cytoplasm.

Directly patternable, highly conducting polymers for broad applications in organic electronics.

Postdeposition solvent annealing of water-dispersible conducting polymers induces dramatic structural rearrangement and improves electrical conductivities by more than two orders of magnitude. We attain electrical conductivities in excess of 50 S/cm when polyaniline films are exposed to dichloroacetic acid. Subjecting commercially available poly(ethylene dioxythiophene) to the same treatment yields a conductivity as high as 250 S/cm. This process has enabled the wide incorporation of conducting polymers in organic electronics; conducting polymers that are not typically processable can now be deposited from solution and their conductivities subsequently enhanced to practical levels via a simple and straightforward solvent annealing process. The treated conducting polymers are thus promising alternatives for metals as source and drain electrodes in organic thin-film transistors as well as for transparent metal oxide conductors as anodes in organic solar cells and light-emitting diodes.

Characterization and theory of electrocatalysts based on scanning electrochemical microscopy screening methods.

A strategy for finding new electrocatalysts for the oxygen reduction reaction (ORR) in acidic solutions is outlined and illustrated with results for Pd-Co catalysts. This is based on establishing guidelines for selecting test systems, rapid preparation of arrays, and rapid screening by scanning electrochemical microscopy. Promising candidates are further tested as supported electrocatalysts by larger scale electrochemical methods and in fuel cells, with optimization of the composition and structure. Those that emerge are characterized by a variety of methods, including X-ray diffraction, scanning electron microscopy, and X-ray photoemission spectroscopy. Finally, density functional theory is used for detailed calculations of oxygen adsorption and dissociation on the material and provides better guidelines for further testing.

Monomeric Titanium(IV) Azides as a New Route to Titanium Nitride.

The reaction of Ti(NMe(2))(4) with 2 equiv of Me(3)SiN(3) in toluene solution affords a dark red polymeric material of composition [Ti(NMe(2))(2)(N(3))(2)](n) (1). If the reaction is carried out in pyridine (py) solution, dark red, crystalline [Ti(NMe(2))(2)(N(3))(2)(py)(2)] (2) is formed. Analogous reactions of Ti(NMe(2))(4) with 2 or 1 equiv of Me(3)SiN(3) in the presence of 1 equiv of bipyridyl (bipy) in toluene solution afford brown crystals of [Ti(NMe(2))(2)(N(3))(2)(bipy)] (3) and dark red crystals of [Ti(NMe(2))(3)(N(3))(bipy)] (4), respectively. Crystallographic data for 2: orthorhombic, C222(1), a = 7.120(1) Å, b = 15.899(3) Å, c = 16.946(4) Å, V = 1918.3(6) Å(3), rho = 1.310 g/cm(3), Z = 4. Crystallographic data for 3: monoclinic, I2/a, a = 7.358(2) Å, b = 16.808(4) Å, c = 14.837(6) Å, beta = 95.40(2) degrees, V = 1826.8(1) Å(3), rho = 1.368 g/cm(3), Z = 4. Crystallographic data for 4: monoclinic, P2(1)/c, a = 15.682(2) Å, b = 8.814(1) Å, c = 15.128(1) Å, beta = 108.39(1) degrees, V = 1984.2(4) Å(3), rho = 1.267 g/cm(3), Z = 4. Compounds 1 and 2 deposit thin films of titanium nitride (TiN) on silica and/or nickel substrates in the temperature range 300-400 degrees C. The TiN films deposited from precursor 2 are superior to those deposited from 1.