大肠埃希菌高耐药率回顾性分析

目的了解和分析天津市泰达医院大肠埃希菌耐药情况,指导临床合理使用抗菌药物。方法对2010年至2012年间从临床标本中分离的859株大肠埃希菌的耐药情况进行回顾性总结分析。结果 859株大肠埃希菌对多种抗菌药物均产生不同程度的耐药性,其中对氨苄西林的耐药率达到85.0%,对碳青霉烯类抗菌药物如亚胺培南及四代头孢菌素的耐药率均低于5%。结论天津市泰达医院分离的大肠埃希菌存在严重的耐药性,耐药率达到50%的有11种,原因是滥用抗生素,应加强其耐药性监测,合理规范使用抗生素。     

242例住院病人院内感染与抗菌药物使用情况的流行病学调查

目的研究了242例住院病人院内感染与抗菌药物使用情况的流行病学。方法随机抽取湖北省孝感市中心医院2008年2月—2013年2月242例院内感染患者,观察院内感染患者病原体感染类型、抗菌药物的使用变化情况。结果肺炎克雷伯菌、大肠埃希氏菌、铜绿假单胞菌是感染病原体常见类型,约占总类型的50%;单联、二联抗菌药物使用次数比重显著提高,四联及多联抗菌药物使用次数比重显著降低,均具有统计学意义(P0.05)。结论加强患相关病原体检测、合理使用抗菌药物是改善院内感染的重要趋势。     

化学发光磁酶免疫法检测O157∶H7大肠埃希菌

O157∶H7大肠埃希菌是一种致病力非常强的微生物.近年来,陆续有其引起食物中毒事件的报道.1996年日本发生O157∶H7大肠埃希菌食物中毒的爆发流行,感染病例逾万人,死亡9例.2001年我国江苏及安徽等地也发生了肠出血性O157∶H7大肠埃希菌所引发的感染性腹泻事件.目前O157∶H7大肠埃希菌实验室常规检测方法为分离培养计数法,此法费时费力,需要几天的时间才能得到检测结果[1,2],缺乏应对突发事件的能力,因此亟需开发快速检测技术.近年来,多种微生物快速检测技术如ELISA法[3]、热解质谱测定法[4]、多聚酶链反应[5]、荧光成像技术[6]、生物发…     

呼吸内科下呼吸道感染细菌分布及其耐药性分析

目的探析呼吸内科下呼吸道感染细菌分布及其耐药性。方法选择湖北省孝感市中心医院呼吸内科收治1 537例下呼吸道感染患者,行痰液培养明确细菌分布并进行药敏试验掌握抗菌药物耐药情况。结果 1 537例患者共得到672份(43.72%)阳性标本,所获得菌株共782例,其中546例(69.82%)为革兰阴性球菌、157(20.08%)为革兰阳性球菌、79例(10.10%)为真菌。金黄色葡萄球菌、表皮葡萄球菌、肺炎链球菌主要对万古霉素、呋喃妥因、亚胺培南等有较高耐药性。结论革兰阴性球菌为下呼吸道感染最常见病原菌,包括铜绿假单胞菌、鲍式不动杆菌等,耐药分析显示金黄色葡萄球菌、表皮葡萄球菌、肺炎链球菌主要对万古霉素、呋喃妥因、亚胺培南、左氧氟沙星等耐药性高,临床用药时需予以注意。     

番石榴叶提取物的鉴定及其抗菌作用

采用纸片扩散法对番石榴叶提取物进行体外抗菌试验研究,以了解其抗菌谱.结果表明番石榴叶提取物中存在有效抗菌成分,其中以乙醇提取物中白念珠菌、甲醇提取物中大肠埃希菌高度敏感.     

头孢孟多酯钠的LC-MS分析

头孢孟多酯钠(cefamandole nafate)是头孢孟多(cefamandole)的前体药物,头孢孟多对多数革兰氏阳性球菌有较强的抗菌作用,用于敏感菌所致的肺部感染、尿路感染、胆道感染等.     

集成式微流控液滴数字化等温扩增用于尿路感染细菌快速检测

数字化核酸分析技术具有不依赖标准品的绝对定量分析能力,因而有利于实现病原分子的快速诊断。现有的数字化核酸分析方法通常采用离线式分析,操作繁琐且耗时较长,难以满足医疗资源有限情况下的检测需求。本研究建立了一种集成式微流控液滴数字化等温扩增方法。采用的微流控芯片集成了序列液滴核酸提取、负压驱动液滴生成和液滴环介导等温扩增(LAMP)功能,可采用集成化方式在1.5 h内完成细菌核酸数字化分析。此微流控芯片对大肠埃希氏菌的核酸提取效率为93.68%±32.38%;使用注射器负压驱动可在4 min内生成约20000个液滴,液滴体积的相对标准偏差(RSD)小于10%;液滴数字化LAMP检测动态范围跨越4个数量级(2.36×10⁴～1.71×10⁷ CFU/mL)。利用本方法检测尿路感染临床标本(n=13)中的大肠埃希菌,与传统定量培养方法结果相比较,本方法的检测灵敏度和特异性均为100%(K_appa=1,p<0.01)。本方法具有操作简便、定量分析准确的优点,为病原体的现场快速检测提供了一种有力的工具。     

顶空气相色谱法测定阿莫西林中丙酮残留量

阿莫西林为青霉素抗生素,对肺炎链球菌、溶血性链球菌等链球菌属、不产青霉素酶葡萄球菌、粪肠球菌等需氧革兰阳性球菌,大肠埃希菌、奇异变形杆菌、沙门菌属、流感嗜血杆菌、淋病奈瑟菌等需氧革兰阴性菌的不产β内酞胺酶菌株及幽螺杆菌有良好的抗菌活性.     

茚三酮比色法测定头孢羟氨苄

头孢羟氨苄化学名为(6R,7R)-3-甲基-7-[(R)-2-氨基-2-(4-羟基苯基)乙酰氨基]-8-氧代-5-硫杂-1-氮杂双环[4.2.0]辛-2-烯-2-甲酸一水合物,是第一代口服头孢菌素,对产青霉素酶和不产青霉素酶的金葡菌,凝固酶阴性葡萄球菌、肺炎链球菌、A组溶血性链球菌等大部分菌株具有良好的抗菌作用。对大肠埃希菌、奇异变形杆菌、沙门菌属、志贺菌属、流     

蛇床子素酯类衍生物的合成及抗菌活性

为了寻找抗菌活性化合物,以蛇床子素为原料,经氧化、还原、缩合反应制得12个蛇床子素酯类衍生物(Ⅲa-Ⅲl).采用两倍稀释法测试目标化合物对金黄色葡萄球菌(S.aureus)、大肠埃希菌(E.coli)和耐甲氧西林金黄色葡萄球菌(MRSA)的体外抗菌活性.结果 表明,该类衍生物呈现不同程度的抗菌活性,以化合物Ⅲi的活性最...     

Disruption of urogenital biofilms by lactobacilli

The process that changes a relatively sparse vaginal microbiota of healthy women into a dense biofilm of pathogenic and potentially pathogenic bacteria is poorly understood. Likewise, the reverse step whereby an aberrant biofilm is displaced and returns to a healthy lactobacilli dominated microbiota is unclear. In order to study these phenomena, in vitro experiments were performed to examine the structure of biofilms associated with aerobic vaginosis, urinary tract infections, and bacterial vaginosis (BV). Uropathogenic Escherichia coli were able to form relatively thin biofilms within five days (6 μm height), while Atopobium vaginae and Gardnerella vaginalis formed thicker biofilms 12 μm in height within two days. Challenge of E. coli biofilms with lactobacilli did not result in pathogen displacement. However, the resulting thicker lactobacilli infused biofilms, caused significant E. coli killing. E. coli biofilms challenged with secreted products of L. rhamnosus GR-1 caused a marked decrease in cell density, and increased cell death. Similarly challenge of BV biofilms with lactobacilli infiltrated BV biofilms and caused bacterial cell death. Metronidazole produced holes in the biofilm but did not eradicate the organisms. The findings provide some evidence of how lactobacilli probiotics might interfere with an aberrant vaginal microbiota, and strengthen the position that combining probiotics with antimicrobials could better eradicate pathogenic biofilms.     

绿色合成氧化铈构建导尿管抗菌水凝胶涂层

因导尿管引起的微生物感染严重危害患者健康,并容易导致细菌耐药性。基于纳米材料的抗菌涂层是应对导尿管感染的最有效策略之一。本文利用绿色小球藻自身及其分泌物的还原性环境,制备合成高表面活性的纳米氧化铈Bio-CeO₂,能够高效产生活性氧自由基,实现对大肠杆菌、铜绿假单胞菌等致病菌的抑制和杀伤。在这种绿色合成的模拟酶纳米材料基础上,将其与壳聚糖、京尼平等生物基材料协同作用,在导尿管表面构建稳定的抑菌水凝胶涂层。结果显示,包覆有Bio-CeO₂水凝胶抗菌涂层的硅胶导尿管比裸导管的抑菌效果显著增强,尤其是在低浓度的过氧化氢溶液环境下,对铜绿假单胞菌的抑菌效率可提升至54%,这为未来新型广谱抗菌导尿管的设计和感染性疾病的预防控制提供了潜在新材料和技术手段。     

In vitro antibacterial activity of medicinal plant extracts against Escherichia coli strains from human clinical specimens and interactions with antimicrobial drugs

The biological properties of medicinal plants have been documented worldwide for many centuries. We aimed to evaluate interactions between crude extracts from Psidium guajava, Zingiber officinale, Cymbopogon citratus, Caryophyllus aromaticus, Mikania glomerata and Allium sativum samples and antimicrobial drugs against Escherichia coli strains. The susceptibility test performed was disc diffusion, and crude extracts were diluted (%v/v) into Müller-Hinton agar (MHA) at one quarter of the minimal inhibitory concentration for 90% (MIC(90%)) of E. coli strains found previously. Synergistic interactions were observed between C. citratus and polymyxin, and A. sativum extracts and gentamicin. The crude A. sativum extract was the only one that did not show any antagonism with the antimicrobial drugs. The results thus showed the potential use of these medicinal plants against E. coli strains, although antagonism with antimicrobial drugs is a negative aspect in the combined therapy of infectious diseases caused by E. coli.     

Availability of 6-hydroxynicotinic acid for rapid identification of Pseudomonas aeruginosa and Serratia marcescens

Gas chromatography--mass spectrometry has been used to identify specific metabolites produced by Gram-negative bacteria such as Pseudomonas aeruginosa, Serratia marcescens, Klebsiella pneumoniae and Escherichia coli in a defined medium. 6-Hydroxynicotinic acid was detected in spent culture media of Pseudomonas aeruginosa and Serratia marcescens, but could not be detected in those of Klebsiella pneumoniae and Escherichia coli. The production of 6-hydroxynicotinic acid was recognized by the addition of nicotinic acid in urine with Pseudomonas aeruginosa or Serratia marcescens, but not without the addition of nicotinic acid. Among 10(5) Pseudomonas aeruginosa per 1 ml of urine (criteria for the diagnosis of urinary tract infection), 0.15 microgram of 6-hydroxynicotinic acid was detected in urine at 4 h incubation with nicotinic acid at the optimum pH of 6.9, 38 degrees C. The production of 6-hydroxynicotinic acid was proportional to the number of the bacteria and displayed a time dependency. These results suggest that the availability of 6-hydroxynicotinic acid might make for more rapid identification of bacteria than current methods.     

Cranberry derived proanthocyanidins reduce bacterial adhesion to selected biomaterials

Catheter associated urinary tract infections (CAUTI) linked with the uropathogens Escherichia coli (E. coli) and Enterococcus faecalis (E. faecalis) account for the majority of nosocomial infections acquired in the clinical environment. Because these infections develop following initial adhesion of the bacterial pathogens to the catheter surface, there is increased interest in developing effective methods to inhibit attachment of cells to biomaterials used in the manufacture of indwelling devices. High molecular weight proanthocyanidins (PAC) extracted from the North American cranberry (Vaccinium macrocarpon) were examined for their potential to reduce the initial adhesion of uropathogenic bacteria (E. coli CFT073 and E. faecalis 29212) to two model biomaterials, poly(vinyl chloride) (PVC) and polytetrafluoroethylene (PTFE). Well-controlled experiments conducted in a parallel-plate flow chamber (PPFC) demonstrated decreased attachment of both bacteria to PVC and PTFE when either the bacteria, biomaterial or both surfaces were treated with PAC. Most significant inhibition of bacterial adhesion was observed for the condition where both the bacteria and biomaterial surfaces were coated with PAC. Additional experiments conducted with nonbiological model particles demonstrate comparable extents of adhesion inhibition, supporting a nonbiospecific mechanism of PAC action. The results of this study are promising for the implementation of PAC in the clinical milieu for prevention of device associated infection as the proposed functional modification is independent of antibacterial mechanisms that may give rise to resistant strains.     

幼儿反复呼吸道感染与头发中微量元素含量关系研究

报道了2886名正常儿童与718例反复呼吸道感染儿童头发中微量元素含量对比研究结果。研究表明,患儿的身高、体重和发Zn明显低于正常儿童,而发Cu、Ca、Pb则明显高于正常和童。因子提取分析显示,Zn和Pb在儿童反复呼吸道感染发病中起非常重要的作用。患反复呼吸道感染儿童约占儿童总数的20％左右。     

Dictamnine Inhibits the Adhesion to and Invasion of Uropathogenic Escherichia Coli (UPEC) to Urothelial Cells

Uropathogenic Escherichia coli (UPEC) is the most common pathogenic bacteria associated with urinary tract infection (UTI). UPEC can cause UTI by adhering to and invading uroepithelial cells. Fimbriae is the most important virulence factor of UPEC, and a potentially promising target in developing novel antibacterial treatments. In this study, the antibacterial properties and effects of the compound dictamnine, extracted from the traditional Chinese medicine Cortex Dictamni, on the bacterial morphology, cell adhesion, and invasion of UPEC were studied. Dictamnine exhibited no obvious antibacterial activity against UPEC, but significantly impeded the ability of UPEC to adhere to and invade uroepithelial cells. RT-qPCR analysis showed that treatment downregulated the expression of type 1 fimbriae, P fimbriae, and curli fimbriae adhesion genes, and also downregulated adhesion-related receptor genes of uroepithelial cells. Transmission electron microscopy showed that dictamnine destroyed the structure of the fimbriae and the surface of the bacteria became smooth. These results suggest that dictamnine may help to prevent UTI by simultaneously targeting UPEC fimbriae and urothelial adhesin receptors, and may have a potential use as a new anti-UPEC drug.     

A single-cell drug efflux assay in bacteria by using a directly accessible femtoliter droplet array

Active efflux of drugs, such as antibiotics, from a cell is one of the major mechanisms that cause multi-drug resistance in bacteria. Here we report a method to assess drug efflux activity in individual Escherichia coli cells enclosed and isolated in a directly accessible femtoliter droplet array with a fluorogenic compound. The inhibitory effect of a chemical compound on an exogenously expressed efflux pump system from pathogenic bacteria was easily detected at the single-cell level. We also present a proof-of-principle experiment to screen for the gene encoding a drug efflux pump by collecting individual droplets containing single cells in which the drug efflux activity was restored after introduction of the exogenous gene from pathogenic bacteria. Our approach will be a useful tool to screen novel pump inhibitors and efflux pump genes, and to overcome infectious diseases caused by multi-drug-resistant bacteria.     

Single-walled carbon nanotubes displaying multivalent ligands for capturing pathogens

A single-walled carbon nanotube was exploited for its semi-flexible pseudo-one-dimensional nanostructure as a unique scaffold to display multivalent carbohydrate ligands, with a specific demonstration showing that galactosylated carbon nanotubes were effective in the capturing of pathogenic Escherichia coli in solution.     

Essential oil analysis and antibacterial activity of Rosmarinus tournefortii from Algeria

The volatile compounds obtained by hydrodistillation of the aerial parts of Rosmarinus tournefortii De Noé. growing wild in the occidental region of Algeria were analyzed by GC/MS. Thirty-six compounds were characterized representing 95.6% of the essential oil, with camphor (37.6%), 1,8-cineole (10.0%), p-cymene-7-ol (7.8%), and borneol (5.4%) as the major components. The antimicrobial activity was evaluated against three pathogenic bacteria: Gram-negative (Escherichia coli and Pseudomonas aeruginosa) and Gram-positive (Staphylococcus aureus). The minimum inhibitory concentration (MIC; mg/mL) was determined by sub-culture on Muller Hinton agar plates. The essential oil exhibited strong antibacterial activity against E. coli and P. aeruginosa, and was also active against Staphylococcus aureus.