血流感染病原菌的分布及耐药性分析

目的分析血流感染病原菌的分布及耐药性,为临床医师选择抗菌药物提供参考。方法收集2011年1月1日-2016年12月31日血培养标本,采用Bac T/Alert 3D 120型全自动血培养分析仪进行培养,所有分离菌株采用Vitek2-compact系统进行鉴定及药敏试验。数据分析采用Whonet 5.6软件。结果 5,122份血培养标本共检出病原菌874株,阳性率为17.1%。其中革兰阳性球菌596株,占68.2%,革兰阴性杆菌265株,占30.3%,真菌属13株,占1.5%。革兰阳性菌不同菌种的耐药谱明显不同,耐甲氧西林金黄色葡萄球菌(meticillin-resistant Staphylococcus aureus,MRSA)和耐甲氧西林凝固酶阴性葡萄球菌(meticillin-resistant coagulase-negative staphylococci,MRCNS)的检出率分别为14.3%和80.6%,未发现对万古霉素耐药的菌株;肠球菌属中亦未检出对万古霉素和替考拉宁耐药的菌株,其中屎肠球菌对所测试的抗菌药物的耐药性大多数高于粪肠球菌。大肠埃希菌和肺炎克雷伯菌中产超广谱β-内酰胺酶(extendedspectrumβ-lactamases,ESBLs)菌株分别占35.7%和25.5%;发现1株对亚胺培南耐药的肺炎克雷伯菌。铜绿假单胞菌对所测试抗菌药物的耐药率均低于42.9%;鲍曼不动杆菌对头孢哌酮/舒巴坦和阿米卡星的耐药率分别为26.1%和30.8%,对其他抗菌药物的耐药率均大于53.8%。凝固酶阴性葡萄球菌(coagulase-negative staphylococci,CNS)既是血流感染病原菌,也是最常见的污染菌。结论临床医师应严格执行无菌操作,降低血培养污染率。治疗血流感染前,应积极寻找原发病灶和病原菌,做到合理使用抗菌药物,降低患者的死亡率。

Spatio-temporal variation of soil CO_(2) concentration in Loess Area of northwestern Shanxi Province,China

CO_(2) released by soil serves as an important link between terrestrial ecosystems and atmospheric CO_(2), whose small chang‐es may significantly affect the global carbon cycle. In order to reveal the spatio-temporal variations of CO_(2) concentrations in deep loess, this paper takes Qingliangsi Gully watershed in northwestern Shanxi Province, China as an example to sys‐tematically study soil CO_(2)concentration and its spatio-temporal variations and carbon sink significance under different watershed locations and different land use types. Results show that: (1) The release potential of the loess soil is larger in the depth range of 2 m, which is much more likely to be the CO_(2) release area. (2) Grassland and forest are more advanta‐geous in terms of soil microbial activity and soil carbon reserve compared with farmland. In addition, the change of land use type from farmland to grassland can increase soil organic carbon reserve, which is of far-reaching significance to the global carbon cycle. This is especially true in an area like the Loess Plateau with densely covered hills, gullies, and serious soil erosion in an area of 64×104 km2. (3) In the study area, the diurnal concentration of soil CO_(2) at different depths shows a weak "high-low-high-low" trend from 08:00 to 07:00 next day;and in deep soil it has a lag time compared with the daily change of temperature, generally about 4−12 h, which may be caused largely by the more compact loess structure. It is worth pointing out that the Loess Plateau in China, with a thickness of the loess of tens to hundreds of meters, has the most abundant soil resources in the world, and also stores a large amount of terrestrial soil carbon, which carries the hope of promoting the research of global carbon cycle.

Bio-clickable mussel-inspired peptides improve titanium-based material osseointegration synergistically with immunopolarization-regulation

Upon the osteoporotic condition,sluggish osteogenesis,excessive bone resorption,and chronic inflammation make the osseointegration of bioinert titanium(Ti)implants with surrounding bone tissues difficult,often lead to prosthesis loosening,bone collapse,and implant failure.In this study,we firstly designed clickable mussel-inspired peptides(DOPA-N3)and grafted them onto the surfaces of Ti materials through robust catechol-TiO2 coordinative interactions.Then,two dibenzylcyclooctyne(DBCO)-capped bioactive peptides RGD and BMP-2 bioactive domain(BMP-2)were clicked onto the DOPA-N3-coated Ti material surfaces via bio-orthogonal reaction.We characterized the surface morphology and biocompatibility of the Ti substrates and optimized the osteogenic capacity of Ti surfaces through adjusting the ideal ratios of BMP-2/RGD at 3:1.In vitro,the dual-functionalized Ti substrates exhibited excellent promotion on adhesion and osteogenesis of mesenchymal stem cells(MSCs),and conspicuous immunopolarization-regulation to shift macrophages to alternative(M2)phenotypes and inhibit inflammation,as well as enhancement of osseointegration and mechanical stability in osteoporotic rats.In summary,our biomimetic surface modification strategy by bio-orthogonal reaction provided a convenient and feasible method to resolve the bioinertia and clinical complications of Ti-based implants,which was conducive to the long-term success of Ti implants,especially in the osteoporotic or inflammatory conditions.

Punicalagin ameliorates collagen-induced arthritis by downregulating M1 macrophage and pyroptosis via NF-κB signaling pathway

Rheumatoid arthritis(RA)is a chronic inflammatory disease that eventually leads to disability.Inflammatory cell infiltration,severe joint breaking and systemic bone loss are the main clinical symptoms.In this study,we established a collagen-induced arthritis(CIA)model and found a large number of M1 macrophages and pyroptosis,which are important sources of proinflammatory cytokines.Punicalagin(PUN)is an active substance extracted from pomegranate peel.We found that it inhibited joint inflammation,cartilage damage and systemic bone destruction in CIA mice.PUN effectively alleviated the high expression of inflammatory cytokines in synovial tissue in vivo.PUN treatment shifted macrophages from the M1 phenotype to the M2 phenotype after stimulation with lipopolysaccharide(LPS)and interferon(IFN)-γ.The expression of inducible nitric oxide synthase(i NOS)and other proinflammatory cytokines released by M1 macrophages was decreased in the PUN treatment group.However,simultaneously,the expression of markers of anti-inflammatory M2 macrophages,such as arginase(Arg)-1 and interleukin(IL)-10,was increased.In addition,PUN treatment attenuated pyroptosis by downregulating the expression of NLRP3 and caspase-1,thereby preventing inflammatory cell death resulting from the release of IL-1βand IL-18.Mechanistically,PUN inhibited the activation of receptor activators of the nuclear factor-κB(NF-κB)signaling pathway,which contributes to M1 polarization and pyroptosis of macrophages.We concluded that PUN ameliorated pathological inflammation by inhibiting M1 phenotype polarization and pyroptosis and has great potential as a therapeutic treatment for human RA.

Long-term clinical observation of patients with acute and chronic complete spinal cord injury after transplantation of Neuro Regen scaffold

Spinal cord injury(SCI)often results in an inhibitory environment at the injury site.In our previous studies,transplantation of a scaffold combined with stem cells was proven to induce neural regeneration in animal models of complete SCI.Based on these preclinical studies,collagen scaffolds loaded with the patients’own bone marrow mononuclear cells or human umbilical cord mesenchymal stem cells were transplanted into SCI patients.Fifteen patients with acute complete SCI and 51 patients with chronic complete SCI were enrolled and followed up for 2 to 5 years.No serious adverse events related to functional scaffold transplantation were observed.Among the patients with acute SCI,five patients achieved expansion of their sensory positions and six patients recovered sensation in the bowel or bladder.Additionally,four patients regained voluntary walking ability accompanied by reconnection of neural signal transduction.Among patients with chronic SCI,16 patients achieved expansion of their sensation level and 30 patients experienced enhanced reflexive defecation sensation or increased skin sweating below the injury site.Nearly half of the patients with chronic cervical SCI developed enhanced finger activity.These long-term follow-up results suggest that functional scaffold transplantation may represent a feasible treatment for patients with complete SCI.