抗结核药品对肠道菌群的改变及其对机体的影响

肠道菌群的结构和代谢产物与人体互相作用,维持肠道屏障稳态,促进全身营养代谢与免疫平衡,参与多种系统及组织、器官的病理生理过程,在结核感染、发病、治疗及转归过程中发挥重要作用,但是抗结核药品对肠道菌群的影响研究刚刚起步。作者综述肠道菌群在肠道屏障稳态中的作用,进而梳理和总结抗结核药品对肠道菌群影响的研究成果,并最终扩展至相关临床问题,讨论肠道菌群改变对机体的广泛影响。     

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.     

恶性血液病患者肺部感染病原学及药敏分析

目的研究恶性血液病患者肺部感染时病原学分布及药敏情况。方法对135例血液恶性肿瘤住院患者的痰细菌培养及药敏试验结果进行回顾性分析。结果 135例恶性血液病患者痰标本分布为:革兰氏阴性菌66.2%,其中铜绿假单胞菌16.9%,嗜麦芽假单胞菌7.7%,肺炎克雷伯杆菌13.8%,鲍曼不动杆菌9.2%;革兰氏阳性菌18.5%,以金黄色葡萄球菌为主,占12.3%;真菌15.4%。药敏试验显示革兰氏阴性菌对广谱抗菌素产生耐药,中性粒细胞的下降与感染密切相关。结论临床上一方面应加强支持治疗,改善机体免疫力,缓解粒细胞缺乏,另一方面,应积极开展痰细菌培养和药敏试验,合理使用抗生素,减少耐药菌株的产生,可联合抗霉菌治疗。     

Trends in bacterial resistance in a tertiary university hospital over one decade

The objective of this study was to investigate bacterial resistance trends, infection sites and the relationship between resistance and admittance to the intensive care unit (ICU). A total of 53,316 bacteria identified between 1999 and 2008 were evaluated. Multidrug resistance was characterized when gram-negative bacilli (GNB) presented resistance to two or more classes of antibiotics. Gram-positive cocci (CPC) were assessed for resistance to penicillin, oxacillin and vancomycin. GNB were the most common (66.1%) isolate. There was a 3.7-fold overall increase in multidrug resistant GNB over the study period; Acinetobacter baumanii and Staphylococcus aureus were the most prevalent. Highest increases were recorded for Klebsiella pneumoniae (14.6-fold) and enterococci (73-fold). The resistance rates for GNB and GPC were 36% and 51.7%, respectively. Most multidrug resistant GNB and GPC were recovered from ICU patients (p-value < 0.001). Vancomycin-resistant enterococci were isolated during this decade with an increase of 18.7% by 2008. These data confirm the worldwide trend in multidrug bacterial resistance.