Bacterial Biofilm Formation Using PCL/Curcumin Electrospun Fibers and Its Potential Use for Biotechnological Applications

Electrospun nanofibers are used for many applications due to their large surface area, mechanical properties, and bioactivity. Bacterial biofilms are the cause of numerous problems in biomedical devices and in the food industry. On the other hand, these bacterial biofilms can produce interesting metabolites. Hence, the objective of this study is to evaluate the efficiency of poly (Ɛ- caprolactone)/Curcumin (PCL/CUR) nanofibers to promote bacterial biofilm formation. These scaffolds were characterized by scanning electron microscopy (SEM), which showed homogeneous fibers with diameters between 441–557 nm; thermogravimetric analysis and differential scanning calorimetry (TGA and DSC) demonstrated high temperature resilience with degradation temperatures over >350 °C; FTIR and ¹H-NMR serve as evidence of CUR incorporation in the PCL fibers. PCL/CUR scaffolds successfully promoted the formation of Escherichia coli, Staphylococcus aureus and Pseudomonas aeruginosa biofilms. These results will be valuable in the study of controlled harvesting of pathogenic biofilms as well as in metabolites production for biotechnological purposes.     

Nitric oxide production by polymorphonuclear leucocytes in infected cystic fibrosis sputum consumes oxygen

Chronic Pseudomonas aeruginosa lung infection in cystic fibrosis (CF) patients is characterized by persisting mucoid biofilms in hypoxic endobronchial mucus. These biofilms are surrounded by numerous polymorphonuclear leucocytes (PMNs), which consume a major part of present molecular oxygen (O₂) due to production of superoxide (O₂⁻). In this study, we show that the PMNs also consume O₂ for production of nitric oxide (NO) by the nitric oxide synthases (NOS) in the infected endobronchial mucus. Fresh expectorated sputum samples (n = 28) from chronically infected CF patients (n = 22) were analysed by quantifying and visualizing the NO production. NO production was detected by optode measurements combined with fluorescence microscopy, flow cytometry and spectrophotometry. Inhibition of nitric oxide synthases (NOS) with N^G-monomethyl-L-arginine (L-NMMA) resulted in reduced O₂ consumption (P < 0·0008, n = 8) and a lower fraction of cells with fluorescence from the NO-indicator 4-amino-5-methylamino-2′,7′-difluorofluorescein diacetate (DAF-FM) (P < 0·002, n = 8). PMNs stained with DAF-FM and the superoxide indicator hydroethidine (HE) and host cells with inducible NOS (iNOS) were identified in the sputum. In addition, the production of the stable end-products of NO in CF sputum was correlated with the concentration of PMNs; NO₃⁻ (P < 0·04, r = 0·66, n = 10) and NO₂⁻ (P< 0·006, r = 0·78, n = 11). The present study suggests that besides consumption of O₂ for production of reactive oxygen species, the PMNs in CF sputum also consume O₂ for production of NO.     

Bone morphogenetic protein 4 inhibits liposaccharide‐induced inflammation in the airway

Bone morphogenetic protein 4 (BMP4) is a multifunctional growth factor that belongs to the TGF‐β superfamily. The role of BMP4 in lung diseases is not fully understood. Here, we demonstrate that BMP4 was upregulated in lungs undergoing lipopolysaccharide (LPS)‐induced inflammation, and in airway epithelial cells treated with LPS or TNF‐α. BMP4 mutant (BMP4^+/?) mice presented with more severe lung inflammation in response to LPS or Pseudomonas aeruginosa, and lower bacterial load compared with that in BMP4^+/+ mice. Knockdown of BMP4 by siRNA increased LPS and TNF‐α‐induced IL‐8 expression in 16HBE human airway epithelial cells and in primary human bronchial epithelial cells. Similarly, peritoneal macrophages from BMP4^+/? mice produced greater levels of TNF‐α and keratinocyte chemoattractant (KC) upon LPS treatment compared with cells from BMP4^+/+ mice. Administration of exogenous BMP4 attenuated the upregulation of TNF‐α, IL‐8, or KC induced by LPS and/or TNF‐α in airway epithelial cells, and peritoneal macrophages. Finally, partial deficiency of BMP4 in BMP4^+/? mice protected the animals from restrictive lung function reduction upon chronic LPS exposure. These results indicate that BMP4 plays an important anti‐inflammatory role, controlling the strength and facilitating the resolution of acute lung inflammation; yet, BMP4 also contributes to lung function impairment during chronic lung inflammation.     

碳青霉烯类抗生素耐药菌的治疗选择

多重耐药菌在全球范围内的快速增长和流行日益严重,给临床治疗带来严峻挑战,直接影响患者预后,造成严重的社会和经济负担。最严重的泛耐药菌铜绿假单胞菌、产碳青霉烯酶肺炎克雷伯菌和鲍曼不动杆菌使抗生素的治疗选择濒临绝望的境地。为应对多重耐药菌,在加强耐药监测指导临床治疗的同时,也在不断探讨新的治疗措施。本文对目前国内外碳青霉烯类抗生素耐药菌的流行状况和治疗新进展进行阐述。     

糖尿病足溃疡感染多重耐药铜绿假单胞菌的危险因素及预后分析

目的 探讨糖尿病足溃疡（DFU）感染多重耐药铜绿假单胞菌（MDRPA）的危险因素及其对预后的影响. 方法 将117例DFU感染铜绿假单胞菌（PA）患者根据是否感染MDRPA分为非MDR-PA（N-MDRPA）组和MDRPA组,分析DFU感染MDRPA的危险因素及其对预后的影响. 结果 入院前抗生素应用史、入院前因同一溃疡住院史和骨髓炎是DFU患者感染MDRPA的独立危险因素.MDRPA组较N-MDRPA组截肢/趾率高（32.6％ vs 16.2％,P＜0.05）,治愈率低（20.9％vs41.9％,P＜0.05）. 结论 入院前抗生素应用史、入院前因同一溃疡住院史和骨髓炎是DFU患者感染MDRPA的独立危险因素.MDRPA可导致创面预后差,增加截肢/趾风险.     

铜绿假单胞菌褐藻胶合成抑制剂筛选模型的建立

目的 建立以铜绿假单胞菌（Pseudomonas aeruginosa）乙酰化褐藻胶的合成为靶向的筛选模型,用于筛选抑制铜绿假单胞菌褐藻胶合成的活性分子。 方法 分别建立铜绿假单胞菌双层平板筛选模型和PalgD-GFP 荧光分子模型,从海洋微生物代谢产物中筛选抑制铜绿假单胞菌乙酰化褐藻胶合成的活性分子。 结果 利用2个筛选模型筛选300余种化合物,获得2种抑制铜绿假单胞菌合成褐藻胶的化合物,且化合物的抑制作用具有浓度依赖性,验证了模型的可行性和有效性。 结论 2种模型结合,可以高效、准确地筛选目标化合物,为解决细菌耐药问题提供了1种有效的手段。     

铜绿假单胞菌耐药性分析及分子流行病学研究简

目的 分析铜绿假单胞菌（PA）耐药现状及耐药基因情况.方法收集2009~2012年临床分离的PA 305株.K-B法进行药敏试验,并检出产ESBLs菌株及耐碳青霉烯的PA,用聚合酶链反应（PCR）对产ESBLs菌株进行TEM、SHV、CTX-M基因检测,对耐碳青霉烯PA进行VIM、IPM、OXA-23基因检测.结果 3年中PA对亚胺培南、美罗培南、头孢他啶、左氧的耐药率呈上升趋势,氨曲南、阿米卡星的耐药率呈下降趋势,305株PA中共检出48株产ESBLs,57株耐碳青霉烯.PCR检测出5株PA含TEM基因,2株含SHV基因.CTX-M、VIM、IPM、OXA-23基因检测均为阴性.结论 产ESBLs是我院耐药PA的重要原因,耐碳青霉烯的PA不含VIM、IPM、OXA-23基因.     

铜绿假单胞菌外排泵系统及其抑制剂的研究进展

铜绿假单胞菌是院内感染常见的条件致病菌,随着临床抗生素的广泛应用和不合理应用,耐药率呈逐年增高趋势。主动外排泵系统是铜绿假单胞菌耐药的重要机制。本文通过总结近年来发表的文献,对铜绿假单胞菌外排泵系统的结构、底物及其外排泵抑制剂作用机制及分类进行综述。     

手术切口感染铜绿假单胞菌的MBLs基因检测和耐药性分析

目的研究住院患者手术切口感染铜绿假单胞菌的耐药性,并对碳青霉烯类耐药株进行分型和金属-内酰胺酶基因检测。方法分离自患者手术切口感染的铜绿假单胞菌186株,以铜绿假单胞菌ATCC27853,大肠埃希菌ATCC25922作为质控菌株,采用常见的8种抗生素进行药敏试验;利用ERIC-PCR对碳青霉烯类耐药株铜绿假单胞菌进行分型;利用IMP-PCR和VIM-PCR检测金属β-内酰胺酶基因。结果 186株铜绿假单胞菌对8种抗生素的耐药率分别为：庆大霉素和哌拉西林36.02%,阿米卡星和左氧氟沙星34.95%,美罗培南32.80%,环丙沙星32.26%,头孢吡肟27.42%,头孢他啶25.27%,其中62株耐碳青霉烯类铜绿假单细胞菌对美罗培南耐药率98.4%,且全部为多重耐药（MDR）,占总数的33.3%。11株为泛耐药株（PDR）,占总数的6%。4株VIM2型铜绿假单胞菌和1株IMP-25亚型金属β-内酰胺酶基因检测阳性。讨论随着近年来抗生素的频繁使用铜绿假单胞菌不断产生新的耐药株,并检出1株IMP-25亚型,这对研究铜绿假单胞菌的耐药性和流行病学特点具有重要意义。     

新型尿苷肽类化合物Sansanmycin P的提取分离、结构鉴定及活性研究

目的从放线菌 Streptomyces sp SS 发酵液中分离新型活性尿苷肽类似物。方法发酵液经 D4006大孔吸附树脂、DEAE-葡聚糖凝胶及制备液相分离纯化,获得单一化合物;根据 UV、MS、MS/MS、1D 和2D NMR 确定化合物结构,并进行抗菌活性研究。结果分离纯化得到1个 N-末端含有1-甲基-6-羟基四氢异喹啉的尿苷肽类化合物 Sansanmycin P。初步体外抗菌活性,抗铜绿假单胞菌 MIC 〉32μg/ml,抗结核杆菌 MIC 〉32μg/ml。结论 Sansanmycin P 为全新结构 Sansanmycins 类似物,具有一定抗结核杆菌和铜绿假单胞菌活性。