细菌生物膜对尿管相关性尿路感染的影响

目的 探讨细菌生物膜对留置尿管相关性尿路感染的影响。方法 对留置尿管不同时间的43例患者，于撤除尿管时行尿液细菌培养，并采用阿利新蓝-刚果红联合染色和扫描电镜观察尿管细菌生物膜形成情况，分析尿管细菌生物膜形成与尿管细菌培养及抗生素应用情况的关系。结果 留置尿管患者尿管细菌生物膜阳性率，3d组为0（0／4），1周组33．3％（4／12），2周组71．4％（10／14），4周组100．0％（13／13）。应用抗生素组60．6％（20／33），未用抗生素组70．0％（7／10），2组差异无统计学意义，P〉0．05。结论 细菌生物膜形成是留置尿管相关性尿路感染的重要致病因素，抗生素预防治疗效果不明显。缩短尿管留置时间，采用封闭式引流等仍是尿路感染主要的防治方法。     

Inhibition of Pseudomonas aeruginosa biofilm formation on wound dressings

Chronic nonhealing skin wounds often contain bacterial biofilms that prevent normal wound healing and closure and present challenges to the use of conventional wound dressings. We investigated inhibition of Pseudomonas aeruginosa biofilm formation, a common pathogen of chronic skin wounds, on a commercially available biological wound dressing. Building on prior reports, we examined whether the amino acid tryptophan would inhibit P. aeruginosa biofilm formation on the three‐dimensional surface of the biological dressing. Bacterial biomass and biofilm polysaccharides were quantified using crystal violet staining or an enzyme linked lectin, respectively. Bacterial cells and biofilm matrix adherent to the wound dressing were visualized through scanning electron microscopy. d ‐/l ‐tryptophan inhibited P. aeruginosa biofilm formation on the wound dressing in a dose dependent manner and was not directly cytotoxic to immortalized human keratinocytes although there was some reduction in cellular metabolism or enzymatic activity. More importantly, d ‐/l ‐tryptophan did not impair wound healing in a splinted skin wound murine model. Furthermore, wound closure was improved when d ‐/l ‐tryptophan treated wound dressing with P. aeruginosa biofilms were compared with untreated dressings. These findings indicate that tryptophan may prove useful for integration into wound dressings to inhibit biofilm formation and promote wound healing.     

Effects of biofilm formation on haemodialysis monitor disinfection.

BACKGROUND: Biofilms are composed of communities of micro-organisms adhering to essentially any surface. We evaluated whether biofilm formation in the hydraulic circuit of a purposely contaminated haemodialysis monitor would modify the efficacy of different disinfection modalities against bacteria and endotoxin concentrations. METHODS: A water-borne Pseudomonas aeruginosa (109) suspension was recirculated for 1 h and was left standing for 72 h (stationary phase) in the hydraulic circuit of the monitor. The monitor was then washed and disinfected by different physical (heat, 85 degrees C) or chemical (hypochlorite or peracetic acid) disinfection modalities (protocol A). In protocol B, the bacterial suspension was also recirculated for 1 h, but the monitor was then immediately washed and disinfected by different chemical disinfection modalities (hypochlorite or peracetic acid). RESULTS: Biofilm formation was revealed by scanning and confocal laser electron microscopy after the stationary phase (protocol A), but was absent when the monitor was immediately washed and disinfected (protocol B). In the presence of biofilm (protocol A), heat in association with citric acid was the most effective modality for reducing both colony forming units and endotoxin concentrations, whereas heat by itself was the least effective method of disinfection. Dwelling (60 h) with diluted peracetic acid completely prevented the formation of biofilm. In the absence of biofilm (protocol B), chemical disinfection proved to be effective against both colony forming units and endotoxin concentrations. CONCLUSIONS: We found that biofilm formation may markedly reduce the efficacy of presently available disinfection modalities. Therefore, different disinfection modalities and the combined action of descaling (by citric acid) and disinfection (physical/chemical agents) should be used periodically in haemodialysis monitors. In addition, dwelling with diluted peracetic acid should be adopted whenever monitors are not in use.     

Update on biofilm infections in the urinary tract

Purpose

Biofilm infections have a major role in implants or devices placed in the human body. As part of the endourological development, a great variety of foreign bodies have been designed, and with the increasing number of biomaterial devices used in urology, biofilm formation and device infection is an issue of growing importance.

Methods

A literature search was performed in the Medline database regarding biofilm formation and the role of biofilms in urogenital infections using the following items in different combinations: ??biofilm,?? ??urinary tract infection,?? ??bacteriuria,?? ??catheter,?? ??stent,?? and ??encrustation.?? The studies were graded using the Oxford Centre for Evidence-based Medicine classification.

Results

The authors present an update on the mechanism of biofilm formation in the urinary tract with special emphasis on the role of biofilms in lower and upper urinary tract infections, as well as on biofilm formation on foreign bodies, such as catheters, ureteral stents, stones, implants, and artificial urinary sphincters. The authors also summarize the different methods developed to prevent biofilm formation on urinary foreign bodies.

Conclusions

Several different approaches are being investigated for preventing biofilm formation, and some promising results have been obtained. However, an ideal method has not been developed. Future researches have to aim at identifying effective mechanisms for controlling biofilm formation and to develop antimicrobial agents effective against bacteria in biofilms.     

Clinician perceptions of wound biofilm

In wound care today, biofilm is a subject area of great interest and debate. There is an increasing awareness that biofilm exists in the majority of non‐healing wounds, and that it is implicated in both recalcitrance and infection. Together with the presence of devitalised host tissue, biofilm is recognised as a component of the wound environment that requires removal to enable wound progression. However, uncertainty exists among wound care practitioners regarding confirmation of the presence of biofilm, and how best to remove biofilm from a non‐healing wound. While recent efforts have been taken to assist practitioners in signs and symptoms of wound biofilm, continuing research is required to characterise and confirm wound biofilm. This research was conducted as part of a market research process to better understand the knowledge levels, experiences, clinical awareness and impact of biofilm in wound care, which was undertaken across the USA and Europe. While knowledge levels and experiences vary from country to country, certain wound characteristics were consistently associated with the presence of biofilm.     

感染人工关节周围生物膜对细菌影响的研究

感染人工关节周围生物膜对细菌影响的研究吴宇黎王继芳卢世璧感染是人工关节置换术后最严重的并发症之一。根据Ｇｒｉｓｔｉｎａ等的统计,全髋关节置换术后感染率为０．１％～１％,全膝关节置换术为１％～４％,而全肘关节置换术则为４％～４７％〔１〕。感染一旦发生,...     

鲍曼不动杆菌生物被膜形成能力与被膜相关基因及耐药性的关系

目的 探讨临床分离的鲍曼不动杆菌生物被膜形成能力与相关基因及耐药性的关系.方法 收集南充市中心医院嘉陵院区2018年1月至6月的临床分离鲍曼不动杆菌共40株,采用Vitek-2全自动微生物分析系统测定临床菌株对13种常用抗菌药物的最低抑菌浓度(MIC);采用结晶紫染色法测定临床菌株生物被膜形成能力;采用PCR法检测生物...     

Methods for biofilm analysis on silicone tubing of dialysis machines

We describe an analytical protocol to study biofilms that develop inside silicone tubing of dialysis machines. This protocol has been set up with the help of a dynamic testing device reproducing dialysis conditions. The methodology includes direct microscopic observation, biofilm removal with an original mechanical biofilm scraper, quantitative analysis with culturable and total bacteria counting, and endotoxin level measurement using the LAL chromogenic kinetic assay. The analytical protocol has been assessed on 13 different clinical tubing samples. Most samples were contaminated by adherent cells and the thickest biofilms were found at the connection between the dialysis water distribution loop and the dialysis machine. The less contaminated samples had been removed from dialysis machines that were decontaminated with citric acid and autoclaving, showing the importance of the decontamination procedure for the prevention of biofilm development. This article shows that easy, rapid, reproducible, and economical methods are applicable for a routine analysis of biofilms that develop on dialysis systems and should be included in the regular control of the microbiological quality of dialysis liquids.     

Differential effects of planktonic and biofilm MRSA on human fibroblasts

Bacteria colonizing chronic wounds often exist as biofilms, yet their role in chronic wound pathogenesis remains unclear. Staphylococcus aureus biofilms induce apoptosis in dermal keratinocytes, and given that chronic wound biofilms also colonize dermal tissue, it is important to investigate the effects of bacterial biofilms on dermal fibroblasts. The effects of a predominant wound pathogen, methicillin‐resistant S. aureus, on normal, human, dermal fibroblasts were examined in vitro. Cell‐culture medium was conditioned with equivalent numbers of either planktonic or biofilm methicillin‐resistant S. aureus and then fed to fibroblast cultures. Fibroblast response was evaluated using scratch, viability, and apoptosis assays. The results suggested that fibroblasts experience the same fate when exposed to the soluble products of either planktonic or biofilm methicillin‐resistant S. aureus, namely limited migration followed by death. Enzyme‐linked immunosorbent assays demonstrated that fibroblast production of cytokines, growth factors, and proteases were differentially affected by planktonic and biofilm‐conditioned medium. Planktonic‐conditioned medium induced more interleukin‐6, interleukin‐8, vascular endothelial growth factor, transforming growth factor‐β1, heparin‐bound epidermal growth factor, matrix metalloproteinase‐1, and metalloproteinase‐3 production in fibroblasts than the biofilm‐conditioned medium. Biofilm‐conditioned medium induced more tumor necrosis factor‐α production in fibroblasts compared with planktonic‐conditioned medium, and suppressed metalloproteinase‐3 production compared with controls.     

Intravascular catheters and biofilm control

Intravascular catheters are the most common cause of nosocomially acquired bloodstream infections. Bacteria found adhering to the intraluminal surfaces of catheters are the principal source and cause of these infections. Adherent bacteria overtime are known to form multicellular communities which become encased within a three dimensional matrix of extracellular polymeric material known as biofilms, which are thought to be responsible for persistent infections. Consequently, a number of technologies have been developed to help prevent and control biofilms in intravascular catheters. One such approach involves impregnating catheter material with antimicrobial agents. Unfortunately these methods are not universally effective in preventing catheter-related biofilm infections. Technologies that utilise antimicrobials, as catheter locks have been shown to have more potential for preventing biofilm formation and reducing the incidences of catheter related bloodstream infections (CRBSI). This article discusses the significance of biofilms in intravascular catheters and determines whether the treatments available today are proving to be effective for controlling biofilms and draws attention to future avenues which are being investigated to control biofilms and therefore CRBSI.     

细菌生物膜与慢性骨髓炎的关系

慢性骨髓炎作为常见的骨科感染性疾病,可导致内固定失败、死骨和窦道形成、长期排脓、甚至最终恶变等严重后果,影响患者的预后和生活质量,造成巨大的医疗和经济负担。骨髓炎的治疗手段由过去的清创术转为现在的清创+Masquelet骨重建术或截骨+Ilizarov骨搬运术,治疗效果显著提升,但缺点是手术次数多、疗程长、手术创伤和风险增加,暨需要新的治疗策略。慢性骨髓炎根治困难的原因包括自体免疫水平紊乱(炎症因子、氧化应激)、局部血供差、耐药细菌出现和细菌生物膜形成等因素,其中细菌生物膜作为细菌在体内的定植存在形式对慢性骨髓炎的影响显著,包括屏障抗生素、抵抗免疫清除、提高细菌耐受性、播散细菌和促进细菌间信号沟通,针对其中的关键因子和通路为靶点进行研究和干预是骨髓炎研究和治疗的热点和趋势。现对研究生物膜与慢性骨髓炎的关系的文献进行综述,便于了解生物膜对慢性骨髓炎的影响机制和相关靶点,为慢性骨髓炎的防治和药物开发提供理论基础。     

烧伤创面常用外用药对鲍氏不动杆菌生物膜内菌的影响

目的 观察烧伤创面常用外用药对鲍氏不动杆菌(AB)游离菌及生物膜内菌的抗菌活性,以及协同应用氨溴索对AB生物膜内菌的影响. 方法 11株AB均分离自2005年8月-2007年4月笔者单位烧伤住院患者创面、呼吸道和血液标本.(1)稀释法测定醋酸磺胺米隆溶液和醋酸氯己定溶液对AB游离菌(敏感株、标准株、耐药株)的MIC和最低杀菌浓度(MBC).(2)以LB或TSB培养液培养AB 12、24、48 h形成生物膜,采用MBC的上述2种外用药分别处理30 min(磺胺米隆组和氯己定组),以不加外用药处理的生物膜作为对照组,激光扫描共聚焦显微镜检测生物膜厚度,计算生物膜内活菌比例.将每个外用药组生物膜混匀并接种于LB培养皿,观察有无细菌生长.(3)另以LB培养液培养AB 48 h形成生物膜,采用MBC的上述2种外用药单独(磺胺米隆组和氯己定组)及分别联合终浓度3.75 mg/mL氨溴索溶液(氨溴索+磺胺米隆组和氨溴索+氯己定组)处理30 min,以不加任何药物处理的生物膜作为对照组,噻唑蓝法检测生物膜内菌增殖情况(数据以吸光度值表示).对数据行单因素方差分析和LSD-t检验. 结果 (1)醋酸磺胺米隆溶液和醋酸氯己定溶液对AB游离菌的MIC分别为25.00、0.03 mg/mL,且每种药物的MIC和MBC相同.(2)各组耐药株生物膜厚度于多数时相点大于敏感株.与对照组比较,2个外用药组各时相点下3种菌株生物膜厚度及膜内活菌比例均有所降低.各外用药组生物膜培养均可见大量细菌生长.(3)对照组耐药株吸光度值为0.776±0.071,磺胺米隆组和氯己定组耐药株吸光度值分别为0.625±0.063、0.420±0.068;氨溴索+磺胺米隆组、氨溴索+氯己定组耐药株吸光度值分别为0.174±0.089、0.178±0.044,显著低于对照组(t值分别为11.823、16.009,P值均为0.000)和对应的单独用药组(t值分别为9.248、6.681,P值均小于0.01). 结论 耐药AB易形成生物膜,并可阻碍创面外用药物对细菌的杀灭作用,联合应用氨溴索与创面外用药能起到协同灭菌作用.     

Lactobacilli: important in biofilm formation on voice prostheses.

OBJECTIVE: We sought to identify bacterial strains responsible for biofilm formation on silicone rubber voice prostheses. STUDY DESIGN: We conducted an analysis of the bacterial population in biofilms on used silicone rubber voice prostheses by using new microbiological methods. METHODS: Two microbiological methods were used: polymerase chain reaction-denaturing gradient gel electrophoresis and fluorescence in situ hybridization. Twenty-six Provox2 and eight Groningen Ultra Low Resistance voice prostheses that were removed because of leakage through the prosthesis or because of increased airflow resistance were used in this study. RESULTS: The results showed that 33 of the 34 explanted voice prosthetic biofilms contained lactobacilli in close association with the Candida sp. present. CONCLUSION: Lactobacilli are general colonizers of tracheoesophageal voice prostheses in vivo, growing intertwined with Candida. This knowledge may be important in the development of new pathways directed to prevent or to influence biofilm formation on tracheoesophageal voice prostheses and elongate their lifespan.     

防治生物膜细菌活性成分的研究进展

近年来抗生物膜细菌活性成分的研究主要集中在化学合成物、天然产物(包括植物中的活性成分和海洋生物活性成分)、生物大分子活性成分等方面,各类别中都具有一定的抑制和(或)杀灭生物膜作用,然而大多数抗生物膜活性成分不足以完全抑制或杀灭生物膜,缺乏广谱抗生物膜制剂,需要对生物膜形成机制认识的不断深入及现代生物医药技术的不断进步。该文对防治生物膜细菌活性成分的研究进行综述,以为下一步研究临床上生物膜细菌形成感染的防治提供依据。