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Chunlei Chen,1,* Qingmiao Shi,1,* Xinjun Hu,2 Xiaojing Liu,1,3 Yi Liu,1 Ruishan Liu1 1Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, The First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou, People’s Republic of China; 2Department of Infectious Diseases, The First Affiliated Hospital, College of Clinical Medicine, Henan University of Science and Technology, Luoyang, People’s Republic of China; 3Department of Structure and Morphology, Jinan Microecological Biomedicine Shandong Laboratory, Jinan, People’s Republic of China*These authors contributed equally to this workCorrespondence: Ruishan Liu, State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, The First Affiliated Hospital, College of Medicine, Zhejiang University, No. 79 Qingchun Road, Hangzhou, Zhejiang, 310000, People’s Republic of China, Tel +86 571 872 364 23, Fax +86 571 872 364 21, Email 924172261@qq.comPurpose: Beta-lactamase-producing Klebsiella pneumoniae is common in the clinic, but research associated with the co-existence of KPC-2, LAP-2, and CTX-M-65 in K. pneumoniae is still rare. In this study, the phenotypic and genetic characteristics of a multidrug-resistant K. pneumoniae strain SJ25 co-harboring blaKPC-2, blaLAP-2, and blaCTX-M-65 with rare ST1469 were investigated.Methods and Results: Antimicrobial susceptibility testing revealed that strain SJ25 was resistant to various common antibiotics, except ciprofloxacin, fosfomycin, colistin, and tigecycline. Whole-genome analysis revealed that strain SJ25 carries a variety of antimicrobial resistance genes and virulence determinants. Plasmid analysis confirmed that the blaKPC-2 and blaCTX-M-65 genes were located on an ~136 kb transferrable IncFII/IncR plasmid and that blaLAP-2 was located on an untypeable plasmid.Conclusion: Our findings emphasized the need for continuous surveillance of β-lactamase-bearing K. pneumoniae in the clinic to control potential dissemination and outbreak.Keywords: Klebsiella pneumoniae, multidrug-resistant, blaKPC-2, blaLAP-2, blaCTX-M-65

Emerging mobile colistin resistance (mcr) genes pose a significant threat to public health for colistin was used as the last resort to treat multidrug-resistant (MDR) pathogenic bacterial infections. Hypervirulent Klebsiella pneumoniae (hvKP) is a clinically significant pathogen resulting in highly invasive infections, often complicated by devastating dissemination. Worryingly, the untreatable and severe infections caused by mcr-harbouring hvKP leave the selection of antibiotics for clinical anti-infective treatment in a dilemma. Herein, we screened 3,461 isolates from a tertiary teaching hospital from November 2018 to March 2021, and an mcr-8.2-harbouring hvKP FAHZZU2591 with a conjugative plasmid was identified from paediatric sepsis. This is the first report of MCR-8-producing hvKP from paediatric sepsis to our best knowledge. The susceptibility, genetic features, and plasmid profiles of the isolate were investigated. Further, we assessed the virulence potential of FAHZZU2591 and verified its pathogenicity and invasive capacity using a mouse model. The phylogenetic analysis of mcr-8-bearing K. pneumoniae revealed that China is the predominant reservoir of the mcr-8 gene, and the clinic is the primary source. Our work highlights the risk for the spread of mcr-positive hvKP in clinical, especially in paediatric sepsis, and the persistent surveillance of colistin-resistance hvKP is urgent.

Emerging mobile colistin resistance (mcr) genes pose a significant threat to public health for colistin was used as the last resort to treat multidrug-resistant (MDR) pathogenic bacterial infections. Hypervirulent Klebsiella pneumoniae (hvKP) is a clinically significant pathogen resulting in highly invasive infections, often complicated by devastating dissemination. Worryingly, the untreatable and severe infections caused by mcr-harboring hvKP lead to the selection of antibiotics for clinical anti-infective treatment in a dilemma. Herein, we screened 3,461 isolates from a tertiary teaching hospital from November 2018 to March 2021, and an mcr-8.2-harboring hvKP FAHZZU2591 with a conjugative plasmid was identified from pediatric sepsis. This is the first report of MCR-8-producing hvKP from pediatric sepsis to our best knowledge. The susceptibility, genetic features, and plasmid profiles of the isolate were investigated. Further, we assessed the virulence potential of FAHZZU2591 and verified its pathogenicity and invasive capacity using a mouse model. The phylogenetic analysis of mcr-8-bearing K. pneumoniae revealed that China is the predominant reservoir of the mcr-8 gene, and the clinic is the primary source. Our work highlights the risk for the spread of mcr-positive hvKP in clinical, especially in pediatric sepsis, and the persistent surveillance of colistin-resistance hvKP is urgent.

Arsenopyrite is a common mineral that is abundant in nonferrous metal tailings. Study of the atomic configuration, chemical state, and morphology of the oxidation products of the arsenopyrite surface is important for enhancing the resource utilization and environmental safety of cementitious backfill. In this paper, the chemical states of the surface atoms of arsenopyrite oxidized with and without water were analyzed by X-ray photoelectron spectroscopy (XPS). The (0 0 1) surface oxidation process of arsenopyrite by oxygen with and without water was characterized using density functional theory (DFT). Results of the XPS analysis showed that water molecules participated in the oxidation reaction and formed a large number of OH structures on the surface of arsenopyrite; the relative content of Sn2−, As(III), and Fe(II) increased significantly. The DFT calculations revealed that oxygen molecules are more easily adsorbed on the As2-Fe2 site by chemical adsorption (Fe2 is the second ortho Fe atom of As2), and water molecules are adsorbed on the Fe2 site by physical adsorption. The oxidation process of the (0 0 1) surface by oxygen can be divided into four stages: adsorption, dissociation, bridging oxygen formation, and desorption of oxidation products; the As2 atom with three coordination sites on the surface of (0 0 1) is oxidized first. In the presence of water, the water molecule dissociates into OH and H, resulting in the hydroxylation of As and Fe atoms on the (0 0 1) surface. Calculation of the energy difference and reaction energy barrier between different reaction steps showed that the participation of water molecules reduces the reaction energy barrier and increases the reaction energy. The oxidation products are derived from the arsenic oxidation of (AsO2) and (HAsO2) types without and with water, and (HAsO2) is easily desorbed from the surface. Water molecules accelerate the surface oxidation of arsenopyrite and cause the surface to form hydroxylated oxidation products.

Graphene quantum dots (GQDs) are one of most promising antioxidants owing to their fascinating properties, including favorable biocompatibility, high antioxidant activity, and low toxicity. In this work, an efficient and rapid approach for preparing GQDs was developed. The graphene oxide (GO) sheet was thoroughly fragmented into the GQDs by the hydroxyl radicals (OH•) generated from a O3/H2O2/UV oxidation reaction. GQDs possessed a large content of sp2-hybridized carbon domains and abundant functional groups in edge. The 1,1-diphenyl-2-picryl-hydrazyl (DPPH•) radical scavenging method and dye decoloration test were used to investigate the antioxidant activity of GQDs, which exhibited high antioxidant activity and great application prospects for corrosion protection, medicinal uses, and the antioxidation of organic dyes.

N,O-acetals are important structures found in many bioactive natural products, and this unique organic functional group can serve as a useful synthetic precursor to the unstable N-acylimines. In this paper, a convenient route to synthesize N-carbamoyl-N,O-acetals and N-acyl-N,O-acetals from enecarbamates and enamides in the presence of alcohols as the solvents and nucleophile sources under Bronsted acid conditions was reported. This strategy could be used to prepare various N,O-acetals from a range of enecarbamates and enamides with light alcohols, and the products are obtained in good yields (52–98%).

The present paper reviewed the food waste management in China,specially analyzed the basic features of food waste,summarized the current disposal technologies,pointed out the present problems,and suggested countermeasures for future in the food waste management of China.Food waste is characterized by high moisture,salinity and organic matter content,which makes it possess duplicity with the perishable and smelly as a waste and the potential as a recycling biotic resource.There is significant spatial and temporal variations in components of food waste from different areas due to geographic differences,eating habits and cultural traditions.Thereby it is usually difficult to process various food waste with a unitary approach.At present,commonly used disposal technologies for food waste include incineration,sanitary landfill,ecofeed,anaerobic digestion,aerobic composting,and vermicomposting.However,incineration is featured with heavy energy consumption because of the high moisture character and sanitary landfill occupies a lot of places with the possibility of the secondary pollution.Other unconventional approaches(except for incineration and sanitary landfill) also have common limitations,such as a long processing period,complex operation,inefficient reclamation and low economic value,when referred to the principle of decrement,innoxiousness,and reclamation.In recent years,more and more attentions have been paid to the food waste reclamation in view of the gradually serious predicament of garbage siege.Nevertheless,the food waste reclamation is still in its infancy with many problems of management and disposal.Above all,it is reported that the amount of food waste generated in China is not less than 60 million tons per year,accounting for 40%—50% of the municipal solid wastes,but the reclamation ratio is extremely low.Moreover,an effective collection system and relevant laws/regulations have not been established.Guangzhou is the only city to issue the Interim Provisions of Garbage Classification Management till the present moment,where refuse sorting is made mandatory for citizens.There is no national law of food waste management in China,and only Xining issued a district law Regulations of Food Waste Management in Xining.Besides,the economic value of the current processing technologies is low at large,and local financial subsidy is requisite to the development of food waste processing technologies and companies which are responsible for food waste disposal.Ultimately,it is difficult to dispose food waste completely using existing technologies,and the liquid of food waste is usually discharged into sewage treatment system.High salinity in the liquid from food waste brings overburdens to the sewage treatment system,not only hindering the growth of microorganism in sewage treatment system,but also corroding relative equipments.All these problems can be broadly grouped into two areas,administrative bottleneck and technical bottleneck.The solution of administrative bottleneck lies in improving management and disposal systems,and all levels of government should pay more attentions and increase investment to the garbage sorting.Whereas the solution of technical bottleneck requires comprehensive use of multiple processing technologies,as well as research and development of new technologies to improve the degree of food waste recycling.And a creative and feasible technology was suggested in the end of this paper,which could be used to recycle food waste efficiently by flies naturrally occurred in organic wastes.