医院保洁员针刺伤情况的调查分析及其防护措施

目的通过对医院保洁员针刺伤情况的调查,分析原因,以提高其自我防护意识。方法采用自行设计的有关医院保洁员针刺伤防护意识调查表,对第二军医大学东方肝胆医院50名保洁员进行问卷调查,并对出现的问题进行分析。结果82％的医院保洁员在工作期间曾发生过针刺伤,68％的医院保洁员被隐藏在敷料里或废弃物里的注射器针头刺伤,78％的保洁员未按正确的程序对针刺伤进行处理,98％的医院保洁员在被针刺伤后未进行血液检测和未上报相关机构。结论医院保洁员对针刺伤防护意识薄弱,对医院感染知识缺乏了解,应重视并加强医院保洁员对医院感染知识、针刺伤防护知识的培训及正确处理针刺伤步骤的学习,以提高其自我防护意识,减少医院保洁员针刺伤的发生。     

Biofilm Formation and Effect of Caspofungin on Biofilm Structure of Candida Species Bloodstream Isolates

Candida biofilms are microbial communities, embedded in a polymeric matrix, growing attached to a surface, and are highly recalcitrant to antimicrobial therapy. These biofilms exhibit enhanced resistance against most antifungal agents except echinocandins and lipid formulations of amphotericin B. In this study, biofilm formation by different Candida species, particularly Candida albicans, C. tropicalis, and C. parapsilosis, was evaluated, and the effect of caspofungin (CAS) was assessed using a clinically relevant in vitro model system. CAS displayed in vitro activity against C. albicans and C. tropicalis cells within biofilms. Biofilm formation was evaluated after 48 h of antifungal drug exposure, and the effects of CAS on preformed Candida species biofilms were visualized using scanning electron microscopy (SEM). Several species-specific differences in the cellular morphologies associated with biofilms were observed. Our results confirmed the presence of paradoxical growth (PG) in C. albicans and C. tropicalis biofilms in the presence of high CAS concentrations. These findings were also confirmed by SEM analysis and were associated with the metabolic activity obtained by biofilm susceptibility testing. Importantly, these results suggest that the presence of atypical, enlarged, conical cells could be associated with PG and with tolerant cells in Candida species biofilm populations. The clinical implications of these findings are still unknown.Candida species are opportunistic pathogens that cause superficial and systemic diseases in critically ill patients (8, 22, 44) and are associated with high mortality rates (35%) and costly treatments (8, 19). They rank among the four most common causes of bloodstream infection in U.S. hospitals, surpassing gram-negative rods in incidence (6, 17).Recent studies suggest that the majority of disease produced by this pathogen is associated with a biofilm growth style (7, 16, 28, 48). Biofilms are self-organized communities of microorganisms that grow on an abiotic or biotic surface, are embedded in a self-produced matrix consisting of an extracellular polymeric substance (14, 15, 55), and when associated with implanted medical devices are commonly refractive to antimicrobial therapy.As opportunistic pathogens, Candida species are able to attach to polymeric surfaces and generate a biofilm structure, protecting the organisms from the host defenses and antifungal drugs (11, 16, 45, 48). Candida biofilms are more resistant than their planktonic counterparts to various antifungal agents, including amphotericin B (AMB), fluconazole, itraconazole, and ketoconazole (20, 38, 50). However, the molecular basis for the antifungal resistance of biofilm-related organisms is not completely understood.The complex architecture of Candida biofilms observed both in vitro and in vivo suggests that morphological differentiation to produce hyphae plays an important role in biofilm formation and maturation (7, 32, 33). Baillie and Douglas demonstrated that although mutant cells fixed in either a hyphal or a yeast form can develop into biofilms, the hyphal structure is the essential element for providing the integrity and multilayered architecture of a biofilm (4). It has been reported that Candida parapsilosis, C. glabrata, and C. tropicalis biofilms are not as large as those generated by C. albicans; however, further structural analysis studies are needed to describe biofilm formation by these organisms (30, 31).The mechanisms responsible for the resistance characteristics displayed by Candida biofilms are unclear. Possible mechanisms include a decreased growth rate; nutrient limitation of cells in the biofilm; expression of resistance genes, particularly those encoding efflux pumps; increased cell density; cell aging; or the presence of “persister” cells in the biofilm (1, 3, 5, 29, 34, 36, 38, 43, 46, 48, 50, 51).The echinocandins are a novel class of semisynthetic amphiphilic lipopeptides that display important antifungal activity. The echinocandins that are presently marketed are caspofungin (CAS), micafungin, and anidulafungin. The echinocandins show considerable efficacy in vitro and in vivo in the treatment of candidemia and invasive candidiasis (25, 27, 42). CAS is the first antifungal agent to be licensed that inhibits the synthesis of β-1,3-glucan, the major structural component of Candida cell walls; glucan synthesis might prove to be a particularly effective target for biofilms (29, 31, 38, 48, 50). The paradoxical attenuation of antifungal activity at high echinocandin concentrations is a phenomenon that usually occurs with C. albicans isolates and appears to be specific to CAS among echinocandins. The cells surviving at high concentrations appear to be subject to some drug effect, showing evidence of slowed growth in the presence of CAS (53, 54). Recent studies have described this effect in Candida species biofilms (24, 37, 47); however, we are not aware of studies that have elucidated the effect of CAS on Candida biofilm structure. The present study was designed to (i) characterize the in vitro biofilm growth of Candida species bloodstream isolates and (ii) use scanning electron microscopy (SEM) to obtain visual evidence of the effect of CAS on biofilm morphology changes associated with paradoxical growth (PG).     

十二指肠乳头切开术联合内镜下乳头气囊扩张术用于胆总管结石取石的效果

目的：探讨十二指肠乳头切开术（endoscopic sphincterotomy,EST）联合内镜下乳头气囊扩张术（endoscopic papillary balloon dilation,EPBD）用于胆总管结石取石的疗效及安全性.方法：选择2011年2月-2013年2月收治的164例接受内镜取石治疗的胆总管结石患者,其中82例患者采用EST联合EPBD取石（EST＋ EPBD组）,其余82例患者采用EST取石（EST组）,比较2组患者取石时间、碎石率、一次性结石取净率及并发症（出血、消化道穿孔、急性胰腺炎、高淀粉酶血症、胆管炎）发生率.结果：EST＋ EPBD组取石时间为（39.4±11.2）min,低于EST组[（45.2±20.5） min],差异有统计学意义（P＜0.05）;EST＋ EPBD组一次性结石取净率为95.1％（78/82）,高于EST组[90.2％ （74/82）],差异无统计学意义（P＞0.05）;EST＋ EPBD组碎石率为9.8％（8/82）,低于EST组[21.9％ （18/82）],差异有统计学意义（P＜0.05）;EST＋ EPBD组总的并发症发生率为21.9％（18/82）,高于EST组[20.7％ （17/82）],差异无统计学意义（P＞0.05）.结论：EST联合EPBD用于胆总管结石取石安全、有效,可较EST缩短取石时间、降低碎石率.     

医院清洁工和护工洗手依从性影响因素分析

目的了解医院清洁工和护工洗手依从性的影响因素。方法应用自行设计的调查问卷,对某院102名清洁工和生活护工进行洗手依从性调查,并对其相关因素进行多因素分析。结果102名调查对象中,洗手依从性高者仅有28名,大多数医院清洁工和护工对手卫生的认识程度低;多因素分析结果显示：影响其洗手依从性的因素包括文化程度、性别、手卫生知识认知程度、个人生活习惯和对交叉感染源的认知。结论医院清洁工和护工的洗手依从性差,文化程度越低、对手卫生的认知程度越低、对交叉感染源认识程度越低,洗手依从性越低。     

高分子材料的表面菌膜

背景：医疗器械尤其是高分子介入性导管引起的导管相关型感染是院内感染的主要途径之一,而导致人体感染的真正原因是器械或导管表面形成了菌膜。目的：对菌膜的形成机制,影响菌膜形成和发展的因素以及当前抑制菌膜形成的常用方法进行综述。方法：以＂菌膜,生物膜,生物被膜＂,＂高分子,塑料,橡胶＂和＂biofilm,polymer,plastics,rubber＂为检索词在medline、life sciences、Toxline plus、Derwent drug file、CBMDisc、CMCC等数据库和www.ncbi.nlm.nih.gov、www.uspto.gov、www.patent.com.cn等网站进行检索,得到相关国内外文献214篇。排除陈旧和内容类似文献,选择43篇文献进行综述。结果与结论：目前对菌膜在高分子器械表面形成过程和形成机制已经基本阐述清晰,但迄今为止,菌膜的研究多集中从微生物学、医学、基因角度进行,对菌膜的防治也是直接从利用抗生素的抑制方面考虑,文章着重从材料角度探讨抑制菌膜的可能途径及其在临床应用的可能性。     

高分子材料的表面菌膜

背景:医疗器械尤其是高分子介入性导管引起的导管相关型感染是院内感染的主要途径之一,而导致人体感染的真正原因是器械或导管表面形成了菌膜.目的:对菌膜的形成机制,影响菌膜形成和发展的因素以及当前抑制菌膜形成的常用方法进行综述.方法:以"菌膜,生物膜,生物被膜","高分子,塑料,橡胶"和"biofilm,polymer,plastics,rubber"为检索词在medline、life sciences、Toxline plus、Derwent drug file、CBMDisc、CMCC等数据库和www.ncbi.nlm.nih.gov、www.uspto.gov、www.patent.com.cn等网站进行检索,得到相关国内外文献214篇.排除陈旧和内容类似文献,选择43篇文献进行综述.结果与结论:目前对菌膜在高分子器械表面形成过程和形成机制已经基本阐述清晰,但迄今为止,菌膜的研究多集中从微生物学、医学、基因角度进行,对菌膜的防治也是直接从利用抗生素的抑制方面考虑,文章着重从材料角度探讨抑制菌膜的可能途径及其在临床应用的可能性.     

Inhibition of Porphyromonas gingivalis Biofilm by Oxantel

Porphyromonas gingivalis is a major pathogen of chronic periodontitis and exists in a biofilm on the surface of the tooth root. Oxantel, a cholinergic anthelmintic and fumarate reductase inhibitor, significantly inhibited biofilm formation by P. gingivalis and disrupted established biofilms at concentrations below its MIC against planktonic cells. Oxantel was more effective against P. gingivalis in biofilm than metronidazole, a commonly used antibiotic for periodontitis.Periodontitis is a chronic inflammatory disease of the supporting tissues of the teeth and is estimated to affect around 30% of the adult population, with severe forms affecting 5 to 10% (19). Porphyromonas gingivalis, a Gram-negative, asaccharolytic anaerobe that relies on the catabolism of amino acids for the production of metabolic energy, is considered to be a major pathogen in chronic periodontitis. P. gingivalis and other oral bacterial species exist in vivo as a biofilm called subgingival plaque that is accreted to the surface of the tooth root. Sessile P. gingivalis cells can release antigens, toxins, and hydrolytic enzymes, such as lipopolysaccharide, proteinases, and hemagglutinins, that stimulate a host immune response. However, the host response is not very effective at eliminating bacteria within biofilms, and a chronic inflammatory response results in tissue destruction and ultimately tooth loss (13).Fumarate respiration is the most widespread type of anaerobic respiration (12). In a previous comparative proteomic analysis of P. gingivalis, 2.9- and 4.0-fold reductions of two components of the trimeric P. gingivalis fumarate reductase (Frd) complex (FrdA and FrdB, respectively) were observed during heme-limited growth of the bacterium (6). The lower abundance of the Frd complex correlated with the diminished growth (6). Smith et al. (22) showed that the Frd activity of the anaerobe Campylobacter jejuni was higher in cultures growing exponentially than in cultures that had entered the stationary growth phase. The Frd enzyme complex is required for the growth of Bacteroides fragilis in heme-limited media and to enable colonization of murine stomachs by Helicobacter pylori (1, 2, 8). Together, these findings suggest that Frd activity may limit bacterial growth, which could make it an attractive new therapeutic target to control P. gingivalis infection, especially as the Frd complex is absent in humans (11, 23).Cholinergic anthelmintics, such as oxantel, thiabendazole, and morantel, which are used for the treatment of intestinal parasites like the whipworm Trichocephalus trichiurus, are known fumarate reductase inhibitors (5, 7, 10, 21). In this study, we determined the inhibitory effects of these anthelmintics on the planktonic and biofilm growth of P. gingivalis.     

细菌生物被膜的防治进展

细菌生物被膜（bacterialbiofilm,BF）是指多个细菌不可逆地黏附于机体或物体表面,被自身细胞分泌的基质所包裹,能表达一套与浮游细菌不同的基因,即一个新的表型。它是细菌的三维聚集体,在许多生物医学材料相关性感染和慢性感染疾病中起着重要作用,所致疾病迁延不愈,是医学工作者面临的巨大挑战。因此,如何防止其形成和有效清除已形成的生物被膜,在临床实践中至关重要。现对细菌生物被膜的防治综述如下。     

Effects of Bacteriocins on Methicillin-Resistant Staphylococcus aureus Biofilm

Control of biofilms formed by microbial pathogens is an important subject for medical researchers, since the development of biofilms on foreign-body surfaces often causes biofilm-associated infections in patients with indwelling medical devices. The present study examined the effects of different kinds of bacteriocins, which are ribosomally synthesized antimicrobial peptides produced by certain bacteria, on biofilms formed by a clinical isolate of methicillin-resistant Staphylococcus aureus (MRSA). The activities and modes of action of three bacteriocins with different structures (nisin A, lacticin Q, and nukacin ISK-1) were evaluated. Vancomycin, a glycopeptide antibiotic used in the treatment of MRSA infections, showed bactericidal activity against planktonic cells but not against biofilm cells. Among the tested bacteriocins, nisin A showed the highest bactericidal activity against both planktonic cells and biofilm cells. Lacticin Q also showed bactericidal activity against both planktonic cells and biofilm cells, but its activity against biofilm cells was significantly lower than that of nisin A. Nukacin ISK-1 showed bacteriostatic activity against planktonic cells and did not show bactericidal activity against biofilm cells. Mode-of-action studies indicated that pore formation leading to ATP efflux is important for the bactericidal activity against biofilm cells. Our results suggest that bacteriocins that form stable pores on biofilm cells are highly potent for the treatment of MRSA biofilm infections.     

Biofilm Changes of Clinically Isolated Coagulase Negative Staphylococci

Proceedings of the National Academy of Sciences, India Section B: Biological Sciences - Coagulase Negative Staphylococci (CoNS) are remarkable for the heterogeneity in the chemical composition and...     

Role of Mutation in Pseudomonas aeruginosa Biofilm Development

The survival of bacteria in nature is greatly enhanced by their ability to grow within surface-associated communities called biofilms. Commonly, biofilms generate proliferations of bacterial cells, called microcolonies, which are highly recalcitrant, 3-dimensional foci of bacterial growth. Microcolony growth is initiated by only a subpopulation of bacteria within biofilms, but processes responsible for this differentiation remain poorly understood. Under conditions of crowding and intense competition between bacteria within biofilms, microevolutionary processes such as mutation selection may be important for growth; however their influence on microcolony-based biofilm growth and architecture have not previously been explored. To study mutation in-situ within biofilms, we transformed Pseudomonas aeruginosa cells with a green fluorescent protein gene containing a +1 frameshift mutation. Transformed P. aeruginosa cells were non-fluorescent until a mutation causing reversion to the wildtype sequence occurs. Fluorescence-inducing mutations were observed in microcolony structures, but not in other biofilm cells, or in planktonic cultures of P. aeruginosa cells. Thus microcolonies may represent important foci for mutation and evolution within biofilms. We calculated that microcolony-specific increases in mutation frequency were at least 100-fold compared with planktonically grown cultures. We also observed that mutator phenotypes can enhance microcolony-based growth of P. aeruginosa cells. For P. aeruginosa strains defective in DNA fidelity and error repair, we found that microcolony initiation and growth was enhanced with increased mutation frequency of the organism. We suggest that microcolony-based growth can involve mutation and subsequent selection of mutants better adapted to grow on surfaces within crowded-cell environments. This model for biofilm growth is analogous to mutation selection that occurs during neoplastic progression and tumor development, and may help to explain why structural and genetic heterogeneity are characteristic features of bacterial biofilm populations.     

中国生物被膜相关研究文献分析

目的分析1997～2007年我国生物被膜相关研究文献，为我国抗感染领域科研工作者确定研究课题、利用和探索文献提供参考与借鉴。方法检索《中国医院知识仓库》、《中文科技期刊数据库》收录的生物被膜研究文献，采用文献计量学方法，对纳入研究文献的年份分布、作者单位、基金资助、研究内容等进行统计分析，并评价纳入研究中的随机对照试验的质量。结果我国生物被膜研究总文献量为491篇，纳入符合标准文献240篇；高等院校是该领域的主导力量；我国生物被膜的研究菌种集中于铜绿假单胞菌、葡萄球菌，并且主要以体外模型为主；对生物被膜的防控仍较多关注于现有抗菌药物的利用。纳入的研究中仅有4篇RCT，且方法学质量均为c级。结论我国生物被膜研究能够紧跟国际步伐，但结合工程学、材料学、免疫学等各个学科领域研究的广度和深度还需加强。     

Oxantel Disrupts Polymicrobial Biofilm Development of Periodontal Pathogens

Bacterial pathogens commonly associated with chronic periodontitis are the spirochete Treponema denticola and the Gram-negative, proteolytic species Porphyromonas gingivalis and Tannerella forsythia. These species rely on complex anaerobic respiration of amino acids, and the anthelmintic drug oxantel has been shown to inhibit fumarate reductase (Frd) activity in some pathogenic bacteria and inhibit P. gingivalis homotypic biofilm formation. Here, we demonstrate that oxantel inhibited P. gingivalis Frd activity with a 50% inhibitory concentration (IC₅₀) of 2.2 μM and planktonic growth of T. forsythia with a MIC of 295 μM, but it had no effect on the growth of T. denticola. Oxantel treatment caused the downregulation of six P. gingivalis gene products and the upregulation of 22 gene products. All of these genes are part of a regulon controlled by heme availability. There was no large-scale change in the expression of genes encoding metabolic enzymes, indicating that P. gingivalis may be unable to overcome Frd inhibition. Oxantel disrupted the development of polymicrobial biofilms composed of P. gingivalis, T. forsythia, and T. denticola in a concentration-dependent manner. In these biofilms, all three species were inhibited to a similar degree, demonstrating the synergistic nature of biofilm formation by these species and the dependence of T. denticola on the other two species. In a murine alveolar bone loss model of periodontitis oxantel addition to the drinking water of P. gingivalis-infected mice reduced bone loss to the same level as the uninfected control.