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.     

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。     

2016-2018年清镇市第一人民医院铜绿假单胞菌的分布及耐药性分析

目的 探讨2016-2018年清镇市第一人民医院铜绿假单胞菌感染的临床分布特征及耐药性变迁,为临床合理选用抗生素治疗提供参考。方法 收集2016-2018年清镇市第一人民医院临床标本中铜绿假单胞菌的检出情况、病区分布、标本来源及药敏结果等资料,并进行统计分析。结果 共分离出铜绿假单胞菌215株,以痰液标本来源为主,占84.2%,感染病区以呼吸内科、ICU和神经外科占前3位,分别占33.9%、18.1%、17.7%。铜绿假单胞菌对复方新诺明、氨苄西林、头孢唑林、氨苄西林/舒巴坦和头孢曲松的耐药率在90.0%以上,对阿米卡星的耐药率最低。与2016年相比较,2018年铜绿假单胞菌对哌拉西林、头孢他啶、哌拉西林/他唑巴坦、头孢吡肟的耐药率呈下降趋势,对庆大霉素、妥布霉素、阿米卡星、环丙沙星、左氧氟沙星、亚胺培南的耐药率呈上升趋势。结论 2016-2018年铜绿假单胞菌对多种抗生素耐药呈上升趋势,临床应加强铜绿假单胞菌感染监控及耐药性监测,密切关注耐药性变迁,合理选用抗生素治疗。     

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。     

下呼吸道感染患者铜绿假单胞菌分离株氨基糖苷类耐药相关基因分析

目的探讨分离自下呼吸道感染患者的氨基糖苷类耐药铜绿假单胞菌的耐药机制。方法从下呼吸道感染患者痰液中分离出52株对氨基糖苷类耐药的铜绿假单胞菌,PCR法检测6种氨基糖苷类修饰酶(AMEs)基因,并检测其中泛耐药菌的6种16S rRNA甲基化酶基因(以下简称甲基化酶基因)。对阳性产物测序加以证实。结果 52株铜绿假单胞菌中检出4种AMEs基因[aac(3)-Ⅱ、aac(6’)-Ⅰb、aac(6’)-Ⅱ和ant(2″)-Ⅰ],AMEs基因总检出率为92.3%。泛耐药菌中检出1种甲基化酶基因(rmtB)。16株高水平泛耐药菌中rmtB基因的检出率为81.3%。结论分离自下呼吸道感染患者的氨基糖苷类耐药铜绿假单胞菌中AMEs基因携带率高,其对氨基糖苷类耐药与aac(3)-Ⅱ、aac(6’)-Ⅰb、aac(6’)-Ⅱ和ant(2″)-Ⅰ有关;对氨基糖苷类高水平泛耐药主要与甲基化酶基因rmtB有关。     

Favorable outcome in a renal transplant recipient with donor-derived infection due to multidrug-resistant Pseudomonas aeruginosa

Most cases of donor-derived infection due to Pseudomonas aeruginosa reported in the literature are associated with vascular dehiscence, all of which resulted either in death or graft failure requiring graft removal. We report the successful treatment of donor-derived infection due to multidrug-resistant P. aeruginosa in a 64-year-old male who presented with bacteremia and peritransplant renal fluid collection after undergoing deceased-donor renal transplantation. As a result of the report of positive donor cultures by the host Organ Procurement Organization, the infection was promptly identified by blood cultures drawn before appearance of symptoms. Surveillance blood cultures in recipients are not usually recommended. However, they should be done if donor cultures turn positive. Therefore, it is crucial to perform cultures in donors and to closely follow them up for early identification and prompt treatment of donor-transmitted infections due to organisms like P. aeruginosa that can be graft and/or life threatening.