Microbiota,infecciones gastrointestinales,inflamación de bajo grado y antibioticoterapia en el síndrome de intestino irritable. Una revisión basada en evidencias

BackgroundPost-infectious irritable bowel syndrome (PI-IBS) prevalence, small intestinal bacterial overgrowth (SIBO), altered microbiota, low-grade inflammation, and antibiotic therapy in IBS are all controversial issues.AimsTo conduct an evidence-based review of these factors.MethodsA review of the literature was carried out up to July 2012, with the inclusion of additional articles as far as August 2013, all of which were analyzed through the Oxford Centre for Evidence-Based Medicine (OCEBM) system.Results1. There is greater SIBO probability in IBS when breath tests are performed, but prevalence varies widely (2-84%). 2. The gut microbiota in individuals with IBS is different from that in healthy subjects, but a common characteristic present in all the patients has not been established. 3. The incidence and prevalence of PI-IBS varies from 9-10% and 3-17%, respectively, and the latter decreases over time. Bacterial etiology is the most frequent but post-viral and parasitic cases have been reported. 4. A sub-group of patients has increased enterochromaffin cells, intraepithelial lymphocytes, and mast cells in the intestinal mucosa, but no differences between PI-IBS and non-PI-IBS have been determined. 5. Methanogenic microbiota has been associated with IBS with constipation. 6. Rifaximin at doses of 400 mg TID/10 days or 550 mg TID/14 days is effective treatment for the majority of overall symptoms and abdominal bloating in IBS. Retreatment effectiveness appears to be similar to that of the first cycle.ConclusionsFurther studies are required to determine the nature of the gut microbiota in IBS and the differences in low-grade inflammation between PI-IBS and non-PI-IBS. Rifaximin has shown itself to be effective treatment for IBS, regardless of prior factors.     

鲍曼不动杆菌及其耐药基因的检测

目的：探索一种检测鲍曼不动杆菌及其耐药基因的新方法。方法首先对近几年医院内鲍曼不动杆菌的耐药情况进行分析,选择临床上治疗鲍曼不动杆菌的首选药,再采用聚合酶链反应对鲍曼不动杆菌及其突变株进行检测。结果鲍曼不动杆菌对亚胺培南的耐药率最低,为9.37%,OXA-51基因扩增结果与细菌培养相符,OXA-23基因扩增与鲍曼不动杆菌耐亚胺培南的结果相符。结论采用PCR法对OXA-51基因扩增可以检测是否存在鲍曼不动杆菌,采用PCR法对OXA-23基因扩增可以检测鲍曼不动杆菌是否存在亚胺培南耐药性。从而快速检测鲍曼不动杆菌及其耐药基因,指导临床用药。     

流动采血车内空气菌落检测分析

目的分析采血车内消毒效果并加强管理。方法收集我站2012年3月～2013年2月流动采血车消毒后的空气菌落,计算其菌群数量,消毒方法为次氯酸钠溶液合并紫外线照射消毒。结果6、7月份有菌群数量超标现象,且发现霉菌。结论流动采血车的消毒效果与环境、季节、工作人员操作等有关,临床应该针对性的加强管理。     

Bacterial imaging with photostable upconversion fluorescent nanoparticles

Autofluorescence, photodamage and photobleaching are often encountered when using downconverting fluorophores and fluorescent proteins for bacteria labeling. These caveats represent a serious limitation when trying to map bacteria dissemination for prolonged periods. Upconversion nanoparticles (UCNs), which are able to convert low energy near-infrared (NIR) excitation light into higher energy visible or NIR light, can address these limitations. These particles' unique optical properties translate into attractive advantages of minimal autofluorescence, reduced photodamage, deeper tissue penetration and prolonged photostability. Here, we report a UCN-based bacteria labeling strategy using Escherichia coli as prototypic bacteria. A comparative analysis highlighted the superior photostability of UCN-labeled bacteria over green fluorescent protein-expressing bacteria. Infection study of UCN-labeled bacteria in dendritic cells indicated co-localization of the UCN signal with bacterial position for up to 6 h post-infection. Furthermore, long-term monitoring of the same infected cells demonstrated the potential to utilize photostable UCN-based imaging for bacterial trafficking purposes.     

Cloning and characterization of two different ficolins from the giant freshwater prawn Macrobrachium rosenbergii

Ficolins, a kind of lectin containing collagen-like and fibrinogen-related domains (FReDs, also known as FBG or FREP), are involved in the first line of host defense against pathogens. In this study, two ficolins, namely, MrFico1 and MrFico2, from the giant freshwater prawn Macrobrachium rosenbergii were identified. In contrast to other ficolins, these two ficolins have no collagen-like domain, but such ficolins contain a coiled region and a FReD domain. Phylogenetic analysis showed that MrFico1 and MrFico2, together with two ficolin-like proteins from Pacifastacus leniusculus, belonged to one group. Quantitative RT-PCR (qRT-PCR) showed that both MrFico1 and MrFico2 were expressed in hepatopancreas, stomach and intestine, with the highest expression in stomach for MrFico1, compared to the highest expression in hepatopancreas for MrFico2. qRT-PCR analysis also showed that MrFico1 was obviously upregulated upon Vibrio anguillarium challenge, while MrFico2 was upregulated after challenged by V. anguillarium or white spot syndrome virus. Bacterium-binding experiment showed that MrFico1 and MrFico2 could bind to different microbes, and sugar-binding assay revealed that these two ficolins could also bind to lipopolysaccharide and peptidoglycan, the glycoconjugates of bacteria surface. Moreover, these two ficolins could agglutinate bacteria in a calcium-dependent manner, and the results of bacteria clearance experiment showed that both ficolins could facilitate the clearance of injected bacteria in the prawn. Our results suggested that MrFico1 and MrFico2 may function as pattern-recognition receptors in the immune system of M. rosenbergii.     

Effects of heat-inactivated Bifidobacterium BB12 on cariogenicity of Streptococcus mutans in vitro

ObjectiveSince some probiotic bacteria are cariogenic themselves, their suitability for caries management is questionable. Inactivated bacteria or their supernatants have been found to exert probiotic effects, whilst having several advantages compared with living bacteria. We hypothesized that viable and heat-inactivated Bifidobacterium animalis BB12 reduces the cariogenicity of Streptococcus mutans (SM) in vitro.DesignWe assessed mono- and mixed species biofilms of SM and viable or heat-inactivated BB12. Biofilms were grown in a continuous-culture-system under cariogenic conditions on smooth proximal enamel or cavitated dentine. For each of eight experimental subsets (4 biofilms × 2 hard-tissue conditions), a total of 32 specimens was used. After 10 days, bacterial numbers of 12 biofilms per group were analysed, and all specimens submitted to transversal microradiography.ResultsMineral loss was higher in cavitated dentine than smooth enamel for all biofilms (p < 0.001, t-test). BB12-monospecies biofilms induced significantly less mineral loss than SM in both enamel (p < 0.05) and dentine (p < 0.001). Viable BB12 did not significantly reduce cariogenicity of SM (p > 0.05), whilst heat-inactivated BB12 decreased cariogenicity of SM in dentinal cavities (p < 0.01). Bacterial numbers were higher on dentine than enamel (p < 0.05), but not significantly influenced by biofilm species (p > 0.05).ConclusionsHeat-inactivated BB12 reduced the cariogenicity of SM in dentinal cavities in vitro. Inactivated probiotics might be suitable for caries control.     

蚊虫的共生菌及其在媒介控制中的应用

许多昆虫与寄生在昆虫体表或肠道细胞中的微生物建立了共生关系。臭虫、蚜虫、猎蝽等昆虫可以依靠非最佳食物为生,这一是由于其特殊的生存环境,还由于其体内的共生微生物可以帮助合成和补充其食物中所缺乏的必需营养物质。蚊虫也与其肠道中共生细菌有着密切的联系。成蚊喜产卵于富舍细菌的水体中,水体细菌成为蚊虫幼虫的重要食物来源。伊蚊和库蚊幼虫正常生长发育不可缺少细菌,在无菌条件下饲养,蚊虫或其他媒介昆虫不能正常发育至成熟或不能传播人畜疾病。该文对蚊虫与细菌的共生现象以及其在以下几方面的应用进行综述,（1）蚊虫共生细菌的分离与鉴定,（2）共生细菌的形成与传代,（3）共生细菌在昆虫中的分布,并讨论了经过遗传改造的蚊虫共生细菌对蚊虫防治及控制疟疾等由昆虫传播的疾病的应用前景。     

SIRT1在呼吸道病原微生物感染中的作用研究进展

SIRT1称为沉默信息调节因子1,是一种烟酰胺腺嘌呤二核苷酸依赖的组蛋白去乙酰化酶,在能量代谢、细胞生长周期调节、DNA损伤修复、抗氧化应激、延缓衰老、抗炎等方面发挥作用.本文结合国内外最新研究报道对SIRT1的抗炎作用信号转导通路进行总结;对细胞水平或动物试验已证实的机体SIRT1在呼吸道病原微生物感染中的作用进行综述.     

细胞因子在晚期肝病合并SBP中的诊断价值

自发性细菌性腹膜炎(SBP)是晚期肝病最常见的并发症之一,由于临床症状多不典型且腹水细菌培养阳性率很低,相当部分的患者得不到及时的诊断或被漏诊。近年来研究发现,某些细胞因子和相关体液成分与SBP发生发展密切相关,文中就目前研究最多的几个细胞因子进行了综述。     

东南沿海海域细菌分布及抗菌药物敏感性研究

目的 了解我国东南沿海海域细菌的种类、分布情况,以及细菌对抗菌药物的敏感性.方法 无菌采集海水,经增菌培养、细菌分离,进行细菌学鉴定和药敏试验.结果 102份海水分离出细菌34种203株;其中弧菌科细菌159株(78.33%),肠杆菌科细菌24株(11.82%),非发酵菌15株(7.39%),革兰阳性球菌3株(1.47%),厌氧菌2株(0.99%).药敏结果显示,157株致病性弧菌对亚胺培南、奈替米星、左氟氧沙星及头孢哌酮-舒巴坦的敏感率为100%,对头孢他啶、头孢噻肟、庆大霉素、环丙沙星、复方磺胺甲唑和替卡西林-克拉维酸的敏感率为90.45%～97.45%,对头孢唑林和氨苄西林的敏感率分别为25.48%和27.39%.结论 东南沿海海域细菌种类繁多、分布广泛,此项研究为该海域海水细菌感染的防治提供了依据.