乳杆菌非益生作用研究进展

胃肠道菌群在维持能量代谢、营养吸收、免疫系统构建以及病原微生物抵抗方面起着重要作用。乳杆菌是胃肠道内常见菌,经常作为益生菌用于抗生素导致的相关性腹泻等疾病的预防和治疗。然而,近年来乳杆菌致病的病例报道屡见不鲜。有研究表明,胃癌患者中乳杆菌的定植数量明显增多。乳杆菌可以通过增加外源性乳酸、N 亚硝基化合物和活性氧的产生以及促进非幽门螺杆菌的致癌致病菌的定植等一系列机制参与胃癌的发生和发展。本文综述乳杆菌的益生作用和非益生作用(包括致炎和致癌),探讨其致病机制,以期为临床上乳杆菌的合理使用提供理论依据。     

乳杆菌对致病假单胞菌的抑制作用研究进展*

假单胞菌污染事件在临床就医和日常饮食中频发,屡次产生致病、致死等恶劣后果,有效抑制致病假单胞菌并降低其耐药性作为解决该问题的关键手段,是目前的研究重点。相关研究表明益生菌等天然活性成分对假单胞菌产生多方面影响,以应用范围最广的益生菌——乳杆菌为例,综合国内外最新研究进展,论述了乳杆菌对假单胞菌的生物膜结构、生长活性、生物毒性、黏附细胞表面能力及被假单胞菌感染后的小鼠等产生的影响。深入挖掘乳杆菌等益生菌及其代谢产物成分的作用机制,是防治假单胞菌等微生物污染和感染的关键。     

脆弱拟杆菌的研究进展

脆弱拟杆菌是定殖于哺乳动物肠道中的共生菌,同时也是临床感染病例中常见的条件致病菌。本文从致病及益生特性两大方面综述脆弱拟杆菌的研究现状,着重讨论了脆弱拟杆菌作为潜在益生菌在预防和治疗糖尿病及免疫性疾病中所起的重要作用,从而为筛选及应用益生脆弱拟杆菌菌株提供一定的参考。     

益生菌对16种抗生素的耐药性分析

目的评估市场常见益生菌对临床常用抗生素的体外耐药情况,为临床预防抗生素相关性肠道菌群紊乱和抗生素相关性腹泻提供参考。方法分离培养9种益生菌制剂中的20株益生菌,采用浓度梯度试条法(E-test)测定益生菌对16种抗生素的最低抑菌浓度(MIC)。结果细菌类益生菌对一些口服抗生素敏感,其中枯草芽胞杆菌、保加利亚乳杆菌、长双歧杆菌、婴儿双歧杆菌和嗜热链球菌对12种以上的抗生素敏感;屎肠球菌只对5种抗生素敏感,而真菌类益生菌如布拉酵母CNCM I-745则对16种抗生素均具有耐药性。结论细菌类益生菌和真菌类益生菌表现出不同的抗生素敏感性,在临床预防和治疗抗生素相关性腹泻时应注意益生菌与抗生素的合理使用。     

益生菌抑制致病菌作用的机制研究进展

致病菌引起的各种胃肠道疾病对人类健康造成危害,应用益生菌制剂防治致病菌感染,具有安全和减少耐药性等优点,为控制致病菌感染性疾病提供了新的途径。主要从益生菌与致病菌竞争黏附位点、与致病菌的共聚作用及其产生的抗菌物质三个方面综述益生菌抑制致病菌的作用机制。     

唾液乳杆菌的研究进展

唾液乳杆菌属于乳杆菌科、乳杆菌属,广泛地存在于人和动物的肠道。近年来,唾液乳杆菌作为益生菌广泛用于人和动物益生菌制剂的生产。在分析与唾液乳杆菌相关的文献和生物信息数据的基础上,就唾液乳杆菌的生物学特征、作用机制、应用及发展前景进行了简要综述,为唾液乳杆菌的研究提供参考。     

基于群体感应抑制肠道致病菌的研究进展

群体感应(quorum sensing,QS)是依赖于自诱导剂的产生、释放和识别的微生物细胞间的通讯过程,在微生物生长过程中起重要作用。在肠道环境中,鼠伤寒沙门氏菌、霍乱弧菌、艰难梭菌、大肠杆菌等肠道致病菌感染宿主机体,影响宿主机体的正常免疫代谢过程,引发急性肠胃炎、痢疾等疾病。传统治疗方案中,抗生素可以应对肠道致病菌引起的并发性感染,但抗生素的滥用会导致细菌出现多重耐药性,且耐药性会在遗传水平上发生迁移和突变。近年来,越来越多的研究表明,可以通过操纵QS系统来调控菌体生物膜形成、毒力因子产生和耐药性抑制等行为。该文首先对几种典型菌体QS系统的工作路径进行了总结;并综述了几种常见的肠道致病菌的QS治疗策略,以期为肠道疾病的新型治疗方案和相关的肠道致病菌抑制剂的开发提供一定的参考。     

正确看待阴道乳杆菌在难治性阴道炎治疗中的应用

正常阴道内虽然有多种微生物存在,但这些微生物与宿主阴道环境之间相互依赖、相互制约,达到动态的生态平衡,并不致病。乳杆菌是维持女性阴道微生态平衡的主要微生物,它在维持阴道酸性环境和拮抗病原体方面起着重要作用。大部分阴道感染可以用抗生素治愈,然而很多时候由于治疗不规范造成病情延误或反复发作,最终发展为难治性阴道炎。补充乳杆菌可能恢复正常的阴道微生态平衡,从而对难治性阴道炎的治疗起到积极作用。本综述主要探讨了乳杆菌制剂在难治性阴道炎治疗中的临床应用及使用方式的选择,包括抗菌药物与乳杆菌制剂联合应用、抗菌药物与乳杆菌制剂序贯疗法及阴道菌群移植等。

     

益生菌辅助治疗牙周病的研究进展

牙周病是累及牙周支持组织的慢性感染性疾病。牙菌斑生物膜中的微生物及其代谢产物是其必不可少的始动因素,可导致口腔微生态失衡和宿主免疫反应,最终引起牙周病的发生发展。目前,牙周病的基础治疗主要是机械清除牙菌斑生物膜和牙石,但治疗效果具有局限性。益生菌通过产生抑菌物质、刺激局部免疫反应、与致病菌争夺黏膜受体和营养物质,从而改善口腔微生态平衡,促进牙周病的治疗。本文就近年来益生菌在牙周病治疗上的实验和临床研究、作用机制、安全性等进行综述,为将来益生菌辅助治疗牙周病的应用提供参考。     

鲍曼不动杆菌疫苗的研究进展

鲍曼不动杆菌为不动杆菌属中最常见的一种革兰阴性杆菌,同时也是医院获得性感染的主要致病菌之一。由于其广泛的耐药性,普通抗生素对其治疗效果已不明显。近年来,国内外学者尝试通过研制抗菌疫苗的手段来防治鲍曼不动杆菌感染,主要有灭活全菌体疫苗、外膜囊泡、重组蛋白亚单位疫苗、荚膜多糖候选疫苗、联合疫苗等。现就鲍曼不动杆菌疫苗的研究进展进行了综述。     

细菌生物被膜分散及分子调控机制研究进展

生物被膜分散(Biofilm Dispersal)是生物被膜发展后期细菌响应营养物、低浓度的一氧化氮、D-氨基酸、自诱导肽(Autoinducing Peptide,AIP)、酰基高丝氨酸内酯(Acyl Homoserine Lactones,AHL)、腺苷三磷酸(Adenosine Triphosphate,ATP)等信号变化而做出的一种程序性反应,有利于细菌从恶劣的生物被膜内部环境中脱离出来寻找新的定殖位点。此外,由生物被膜引起的细菌短暂的抗生素耐受性在分散过程中会恢复正常水平,这有助于治疗由致病菌引起的难治愈的生物被膜相关疾病。目前生物被膜分散的相关研究正处于起步阶段,本文希望通过综述生物被膜分散现象、信号分子及调控机制,可以更好地了解细菌生物被膜分散对于防控病原微生物和应用有益微生物的重要意义。     

Bacteriophages and Lysins in Biofilm Control

To formulate the optimal strategy of combatting bacterial biofilms, in this review we update current knowledge on the growing problem of biofilm formation and its resistance to antibiotics which has spurred the search for new strategies to deal with this complication. Based on recent findings, the role of bacteriophages in the prevention and elimination of biofilm-related infections has been emphasized. In vitro, ex vivo and in vivo biofilm treatment models with single bacteriophages or phage cocktails have been compared. A combined use of bacteriophages with antibiotics in vitro or in vivo confirms earlier reports of the synergistic effect of these agents in improving biofilm removal. Furthermore, studies on the application of phage-derived lysins in vitro, ex vivo or in vivo against biofilm-related infections are encouraging. The strategy of combined use of phage and antibiotics seems to be different from using lysins and antibiotics. These findings suggest that phages and lysins alone or in combination with antibiotics may be an efficient weapon against biofilm formation in vivo and ex vivo, which could be useful in formulating novel strategies to combat bacterial infections. Those findings proved to be relevant in the prevention and destruction of biofilms occurring during urinary tract infections,orthopedic implant-related infections, periodontal and peri-implant infections. In conclusion, it appears that most efficient strategy of eliminating biofilms involves phages or lysins in combination with antibiotics, but the optimal scheme of their administration requires further studies.     

An image-based 384-well high-throughput screening method for the discovery of biofilm inhibitors in Vibrio cholerae

Bacterial biofilms are assemblages of bacterial cells and extracellular matrix that result in the creation of surface-associated macrocolony formation. Most bacteria are capable of forming biofilms under suitable conditions. Biofilm formation by pathogenic bacteria on medical implant devices has been linked to implant rejection in up to 10% of cases, due to biofilm-related secondary infections. In addition, biofilm formation has been implicated in both bacterial persistence and antibiotic resistance. In this study, a method has been developed for the discovery of small molecule inhibitors of biofilm formation in Vibrio cholerae, through the use of high-throughput epifluorescence microscopy imaging. Adaptation of a strategy for the growth of bacterial biofilms in wellplates, and the subsequent quantification of biofilm coverage within these wells, provides the first example of an image-based 384-well format system for the evaluation of biofilm inhibition in V. cholerae. Application of this method to the high-throughput screening of small molecule libraries has lead to the discovery of 29 biofilm lead structures, many of which eliminate biofilm formation without altering bacterial cell viability.     

抗菌肽的抗生物膜机理研究进展

生物膜,也称为生物被膜,是指附着于有生命或无生命物体表面被细菌胞外大分子包裹的有组织的细菌群体。与浮游菌相比,生物膜内的细菌对抗生素的耐受性提高了10–1000倍,是造成目前细菌耐药的主要原因之一。作为一种新型抗菌制剂,抗菌肽的使用为生物膜感染的治疗提供了一种新的思路和手段。抗菌肽在抑制生物膜形成、杀灭生物膜内细菌以及消除成熟生物膜的过程中发挥了独特的优势。文中分析了近30年的数据,从细菌生物膜的结构入手,对抗菌肽可能的抗生物膜机理进行了综述,以期为抗菌肽临床治疗生物膜感染提供一定参考。     

Molecular mechanisms of compounds affecting bacterial biofilm formation and dispersal

Bacteria can switch between planktonic forms (single cells) and biofilms, i.e., bacterial communities growing on solid surfaces and embedded in a matrix of extracellular polymeric substance. Biofilm formation by pathogenic bacteria often results in lower susceptibility to antibiotic treatments and in the development of chronic infections; thus, biofilm formation can be considered an important virulence factor. In recent years, much attention has been directed towards understanding the biology of biofilms and towards searching for inhibitors of biofilm development and of biofilm-related cellular processes. In this report, we review selected examples of target-based screening for anti-biofilm agents: We focus on inhibitors of quorum sensing, possibly the most characterized target for molecules with anti-biofilm activity, and on compounds interfering with the metabolism of the signal molecule cyclic di-GMP metabolism and on inhibitors of DNA and nucleotide biosynthesis, which represent a novel and promising class of biofilm inhibitors. Finally, we discuss the activation of biofilm dispersal as a novel mode of action for anti-biofilm compounds.     

A Modified CDC Biofilm Reactor to Produce Mature Biofilms on the Surface of PEEK Membranes for an In Vivo Animal Model Application

Biofilm-related infections have become a major clinical concern. Typically, animal models that involve inoculation with planktonic bacteria have been used to create positive infection signals and examine antimicrobial strategies for eradicating or preventing biofilm-related infection. However, it is estimated that 99.9% of bacteria in nature dwell in established biofilms. As such, open wounds have significant potential to become contaminated with bacteria that reside in a well-established biofilm. In this study, a modified CDC biofilm reactor was developed to repeatably grow mature biofilms of Staphylococcus aureus on the surface of polyetheretherketone (PEEK) membranes for inoculation in a future animal model of orthopaedic implant biofilm-related infection. Results indicated that uniform, mature biofilms repeatably grew on the surface of the PEEK membranes.     

Applications of sequencing technology in clinical microbial infection

Infectious diseases are a type of disease caused by pathogenic microorganisms. Although the discovery of antibiotics changed the treatment of infectious diseases and reduced the mortality of bacterial infections, resistant bacterial strains have emerged. Anti‐infective therapy based on aetiological evidence is the gold standard for clinical treatment, but the time lag and low positive culture rate of traditional methods of pathogen diagnosis leads to relative difficulty in obtaining the evidence of pathogens. Compared with traditional methods of pathogenic diagnosis, next‐generation and third‐generation sequencing technologies have many advantages in the detection of pathogenic microorganisms. In this review, we mainly introduce recent progress in research on pathogenic diagnostic technology and the applications of sequencing technology in the diagnosis of pathogenic microorganisms. This review provides new insights into the application of sequencing technology in the clinical diagnosis of microorganisms.     

Protective Effect of Levilactobacillus brevis Against Yersinia enterocolitica Infection in Mouse Model via Regulating MAPK and NF-κB Pathway

Probiotics and Antimicrobial Proteins - Although the use of the probiotic bacterium Lactobacillus for the treatment and prevention of diseases caused by various pathogenic bacteria has received...     

Effect of bacteriocin and exopolysaccharides isolated from probiotic on <Emphasis Type="Italic">P. aeruginosa</Emphasis> PAO1 biofilm

Microorganisms develop biofilms on indwelling medical devices and are associated with biofilm-related infections, resulting in substantial morbidity and mortality. Therefore, to prevent and control biofilm-associated infections, the present study was designed to assess the anti-biofilm potential of postbiotics derived from probiotic organisms against most prevalent biofilm-forming Pseudomonas aeruginosa PAO1. Eighty lactic acid bacteria isolated from eight neonatal fecal samples possessed antibacterial activity against P. aeruginosa PAO1. Among these, only four lactic acid bacteria produced both bacteriocin and exopolysaccharides but only one isolate was found to maximally attenuate the P. aeruginosa PAO1 biofilm. More specifically, the phenotypic and probiotic characterization showed that the isolated lactic acid bacteria were gram positive, non-motile, and catalase and oxidase negative; tolerated acidic and alkaline pH; has bile salt concentration; showed 53% hydrophobicity; and was found to be non-hemolytic. Phylogenetically, the organism was found to be probiotic Lactobacillus fermentum with accession no. KT998657. Interestingly, pre-coating of a microtiter plate either with bacteriocin or with exopolysaccharides as well as their combination significantly (p < 0.05) reduced the number of viable cells forming biofilms to 41.7% compared with simultaneous coating of postbiotics that had 72.4% biofilm-forming viable cells as observed by flow cytometry and confocal laser scanning microscopy. Therefore, it can be anticipated that postbiotics as the natural biointerventions can be employed as the prophylactic agents for medical devices used to treat gastrointestinal and urinary tract infections.     

阴道中益生特性乳杆菌的分离与功能评价

目的 分离健康女性阴道中的乳杆菌并鉴定其益生特性,为开发治疗妇科疾病的复方益生菌制剂提供新型菌株。方法 采集健康女性阴道分泌物并分离筛选乳杆菌,通过16S rDNA序列分析鉴定乳杆菌分离株,并对其产酸性能、产H2O2能力、抑菌能力、产生物膜能力进行检测。结果 从50名健康女性阴道内共分离出179株乳杆菌,其中卷曲乳杆菌101株、詹氏乳杆菌42株、格氏乳杆菌26株、植物乳杆菌5株、唾液乳杆菌3株以及干酪乳杆菌2株。179株乳杆菌中有146株具有产酸能力,发酵液pH值的最低的5株菌分别为卷曲乳杆菌J3、卷曲乳杆菌J8、詹氏乳杆菌J87,植物乳杆菌J75以及格氏乳杆菌J35,其pH分别为4.20、4.23、4.24、4.26及4.36;产H2O2弱阳性菌株有87株、阳性有37株、强阳性有9株,这9株菌分别为卷曲乳杆菌J3、卷曲乳杆菌J8、卷曲乳杆菌J20、詹氏乳杆菌J87,詹氏乳杆菌J90、詹氏乳杆菌J15、格氏乳杆菌J11、植物乳杆菌J75、植物乳杆菌J69以及植物乳杆菌J40;能拮抗大肠埃希菌的菌株有115株、拮抗金黄色葡萄球菌的有84株、拮抗白假丝酵母的有52株;经统计,对三者同时有拮抗作用且作用最强的只有6株,分别为卷曲乳杆菌J3、卷曲乳杆菌J50、卷曲乳杆菌J62、詹氏乳杆菌J87、詹氏乳杆菌J16和格氏乳杆菌J66;不同乳杆菌产生物膜能力数值范围在1.0~5.4,卷曲乳杆菌、詹氏乳杆菌、干酪乳杆菌的生物被膜形成能力显著高于其他三种菌（P<0.05）。在全部179株菌中,卷曲乳杆菌J3和詹氏乳杆菌J87既具有强的产酸能力和产过氧化氢能力,又有较强抑菌活性,同时产生物膜能力也最强。结论 卷曲乳杆菌J3和詹氏乳杆菌J87具有优良的生物学特性,有望成为用于治疗妇科疾病微生态制剂的备选菌株。