假体周围高糖环境对葡萄球菌感染影响的实验研究

目的 探讨假体周围高糖环境对葡萄球菌生长和细菌生物膜形成的影响.方法 利用新西兰大白兔建立假体感染的动物模型,分为金黄色葡萄球菌组(金葡菌组,n=40)和表皮葡萄球菌组(表葡菌组,n=60),每组再随机分为实验组和对照组,实验组注入细菌的同时加入0.1ml质量浓度为1%的葡萄糖溶液,对照组加入0.1 ml生理盐水.金葡菌组分别于第2、4、6和8天观察;表葡菌组分别于2、4、6、8、12和16天观察.对不同时间点的膝关节假体感染动物行细菌计数、扫描电镜和组织学观察.结果 金葡菌组第2天实验组和对照组关节液细菌计数差异无统计学意义(P=0.426),注入细菌后第4、6和8天实验组较对照组细菌生长明显增强,差异均有统计学意义(P<0.05).扫描电镜观察第2、4、6天实验组较对照组假体表面黏附细菌明显增多(P<0.05),细菌生物膜生成明显.组织学观察第2天实验组假体周围组织发现细菌,而对照组未发现细菌.表葡菌组第2、4、6、8、12和16天实验组与对照组细菌计数差异均无统计学意义(P>0.05),假体表面黏附细菌没有明显区别(P>0.05).组织学观察第2天实验组和对照组假体周围组织均未发现细菌.结论 假体周围高糖环境对金葡菌感染影响明显,而对表葡菌感染影响不明显.     

噬菌体疗法防治关节假体周围感染研究进展

关节假体周围感染（PJI）指人体关节植入的假体和假体周围存在病原微生物而导致的感染。PJI是髋、膝关节置换术后灾难性的并发症,治疗过程漫长且充满挑战,预后具有不确定性和高风险性。噬菌体是感染细菌、真菌、藻类、放线菌或螺旋体等微生物的病毒的总称,因部分能引起宿主菌的裂解,故称为噬菌体。噬菌体疗法在国外已有较多报道,临床效果显著。该文就噬菌体疗法防治PJI进行综述。     

骨科内置物感染葡萄球菌的研究进展

葡萄球菌是目前医院内最常见的致病菌,也是假体等骨科内置物周围感染的主要致病菌.1997～2005年UK卫生防护机构对手术部位感染的监测数据发现41.4%人工髋关节,33.5%人工膝关节,53%骨折切开复位以及59.1%髋部半关节成形术感染的病原菌为金黄色葡萄球菌.而凝固酶阴性葡萄球菌分别占这些感染的15.1%,20.7%,7.5%及6.3%.陈哲峰等调查国内人工关节术后假体周围感染的细菌学分布表明,金黄色葡萄球菌占总菌株数的34.59%,表皮葡萄球菌占总菌株数的37.48%; 46.7%的金黄色葡萄球菌和85.7%的表皮葡萄球菌株对甲氧西林耐药.     

负压封闭引流结合敏感抗生素治疗假体周围急性感染

目的 :探讨负压封闭引流(vacuum sealing drainage,VSD)结合敏感抗生素治疗假体周围急性感染的疗效。方法:回顾性分析2012年3月至2018年12月采用保留假体的清创、VSD、敏感抗生素治疗11例假体周围急性感染,男7例,女4例;年龄58～88岁,平均72.5岁。髋关节假体周围感染8例,3例出现窦道,膝关节假体周围感染3例。结果:微生物培养阴性2例,阳性9例,金黄色葡萄球菌7例,其中2例耐甲氧西林金黄色葡萄球菌(methicillin-resistant staphylococcus aureus,MRSA),表皮葡萄球菌2例。术后随访8～52个月,平均28个月,1例髋关节假体周围感染清创失败,清创距关节置换时间84 d,行II期人工关节翻修术。10例清创成功。末次随访时,髋关节假体周围感染清创成功患者Harris评分84.1(74～93)分;膝关节假体周围感染者膝关节协会评分(Knee Society score,KSS)84,84,89分。结论:膝关节置换术后1个月内,髋关节置换术后6周内假体周围急性感染,及服用抗凝药物引起假体周围出血伴急性感染,采用保留假体的清创,VSD及敏感抗生素治疗,可获得较满意的效果。     

α-防御素在关节假体周围感染诊断中的作用及应用前景

关节假体周围感染是关节置换术后灾难性的并发症。目前对于关节假体周围感染尚缺乏一种可靠、迅捷、高准确率的诊断方法。美国骨肌系统感染协会(Musculoskeletal Infection Society,MSIS)制定的关节假体周围感染诊断标准获得国内外学者的普遍认可,但其诊断指标相对复杂不便于临床应用。临床上常用血沉、血清CRP、IL-6、降钙素原等实验室指标辅助诊断关节假体周围感染,但这些指标的异常并不完全由关节假体周围感染引起,易受其他炎性因素影响。近年来,滑液生物标志物,尤其是滑液α-防御素对关节假体周围感染的诊断价值逐渐受到重视。本文综合分析目前关于滑液α-防御素的临床研究,就其在关节假体周围感染诊断中的研究现状及临床价值做一综述。     

超声裂解法诊断关节置换术后假体周围感染研究进展

假体周围感染是关节置换术后最具破坏性的并发症之一。及时准确地作出临床诊断, 是治疗假体周围感染的重要环节。然而, 生物膜的形成限制了一些常规检测方法的应用, 大大降低了传统关节滑液培养和假体周围组织培养等方法的检出率。超声裂解法可通过空化作用的驱动, 在不破坏病原体活性的情况下破裂和剥离假体周围的生物膜释放出微生物, 极大地提高了培养检出率。本文就近年来假体周围感染、生物膜和超声裂解法相关文献进行综述, 旨在指导临床医生将超声裂解法用于假体周围感染的诊断。     

超声裂解在人工关节置换术后假体周围感染诊断中的作用

 目的 探讨超声裂解在人工关节置换术后假体周围感染诊断中的作用。方法 2012年1至12月对关节置换术后感染或无菌性松动的35例患者行翻修术,全髋关节27例、全膝关节8例。术前行关节腔穿刺,术中采集5个不同部位的假体周围组织标本,取出可疑感染的关节假体并应用超声裂解法处理,将处理液、术前关节液、术中假体周围组织分别进行血平板和BacT/Alert FN瓶培养。结果 各种标本的血平板培养细菌阳性率均低于BacT/Alert培养法,两种培养方法间的差异有统计学意义。超声裂解后BacT/Alert培养法细菌培养阳性率由处理前的37.1%（13/35）上升至57.1%（20/35）,血平板培养法由14.3%（5/35）上升至37.1%（13/35）,超声裂解前后细菌阳性率的差异有统计学意义。超声裂解后处理液细菌阳性率高于术前关节液、术中假体周围组织及超声裂解前处理液。确诊为假体周围感染的23例中细菌培养结果为金黄色葡萄球菌7例,表皮葡萄球菌11例,肺炎克雷伯杆菌、粪肠球菌、阴沟肠杆菌各1例;假体松动的12例中,表皮葡萄球菌、大肠杆菌、阴沟肠杆菌各1例。结论 对可疑关节感染的假体行超声裂解处理可以提高关节感染病原学检出率,应用BacT/Alert培养法较血平板培养细菌检出率高,引起假体周围感染的细菌以耐甲氧西林金黄色葡萄球菌及表皮葡萄球菌为主。     

兔关节内植物植入术后金黄色葡萄球菌感染模型的建立

目的探索人工关节置换术后金黄色葡萄球菌假体周围感染感染,可靠动物模型的建立方法,比较细菌数量与模型的关系,观察模型建立后实验动物的生存率,以及后期细菌毒力和基因变异情况。方法60只新西兰大白兔使用定制非骨水泥假体行膝关节置换后,随机分入对照组和实验组（共5组,给予金葡菌液1ml,浓度分别为1×10^4,1×10^5,1×10^6,1×10^7,1×10^8CFU／ml）。采用大体评分、组织学、细菌生化检验、金葡菌遗传学和毒理学分析、扩增片段长度多态性（AFLP）细菌遗传物质分析的方法,验证模型构建的效率、安全性和稳定性,基线齐性检验、动物模型大体评分,浓度梯度分析采用多组间卡方分析,细菌致病基因分析采用和AFLP分析采用组间聚类分析一平均联结法方法。结果动物生存率、感染率不完全相同,组问方差分析显示,各组间存在统计学差异（F=3．695,P〈0．01）;组织学、细菌培养、生化检验和23SrRNA基因、nile基因检测支持金葡菌感染,使用1ml,1×10^5CFU／ml金葡菌膝关节直接接种能够成功构建模型。致病基因分析和AFLP检测显示,细菌在自然繁殖过程中出现变异,但各基因变异率和基因组总体变异率低于10％。结论本研究成功构建了稳定的关节置换术后金葡菌感染动物模型,发现细菌感染初期的基因变异和毒理学改变。该模型可用于关节置换术后假体周围急性感染的相关研究。更远期的变异情况可能导致感染模型的不稳定,需进一步研究。     

表皮葡萄球菌生物膜蛋白在假体周围感染诊断中的应用

目的探讨表皮葡萄球菌生物膜蛋白作为抗原诊断假体周围感染的临床价值。方法制作表皮葡萄球菌感染的假体周围感染动物模型，并收集临床假体周围感染患者的血清。以从表皮葡萄球菌444生物膜中提取的蛋白为抗原，用ELISA方法检测感染动物和临床假体周围感染患者的血清中IgG水平。蛋白印迹杂交寻找特异性抗原蛋白。结果感染动物和感染患者血清中的IgG水平明显高于各自对照组，Western—blot结果显示，表皮葡萄球菌生物膜蛋白大小在15KD-37KD之间具有良好的抗原性。结论表皮葡萄球菌生物膜蛋白成份具有良好的抗原性，是引起机体免疫的重要成份。进一步纯化这些蛋白组分并作为诊断假体周围表皮葡萄球菌感染的抗原，具有重要的临床价值。     

人工关节置换术后感染的临床及预后分析

目的分析人工关节置换术后假体周围感染的病原学、临床特征,以及治疗方法对患者预后的影响。方法采用回顾性分析,查阅自2003年1月至2012年1月成渝某两家三甲医院收治行人工关节（髋、膝和肘关节）置换术后发生假体周围感染的病例,了解患者感染的微生物特征,患者的相关临床指标和预后,并利用医院电话随访平台了解出院患者的感染再发生情况。用多因素回归方法了解对患者预后有影响的的危险因素,Kaplan-Meier生存分析二期翻修对再发感染的影响。结果 10年中共获得资料完整病例72例,髋、膝、肘关节手术分别为26例、44例和2例。其中Ⅰ期置换56例,Ⅱ期置换16例。52.8%（38/72）患者出现了晚期感染。膝关节是感染最常见的部位。金黄色葡萄球菌（金葡菌）是最常见的感染病原菌（30.6%）,其次是凝固酶阴性葡萄球菌（19.4%）和鲍曼不动杆菌（8.7%）。对置换术后感染的治疗总痊愈率为41.7%,其中二期翻修的患者治愈率为（83.3%）,其它治疗方式的治愈率（36.7%）。两者相比,有统计学差异（P〈0.01）。多因素回归分析显示,二期翻修是对患者预后有统计学意义的有益因素,Kaplan-Meier生存分析也显示二期翻修发生感染复发几率显著低于非二期翻修组。结论金葡菌是引起人工关节置换术后感染最常见病原菌,二期翻修是治疗置换术后感染的适宜选择。     

Preoperative waiting time increased the risk of periprosthetic infection in patients with femoral neck fracture

Background and purpose Prosthetic joint infection (PJI) remains a devastating complication of arthroplasty. Today, most displaced femoral neck fractures in the elderly are treated with arthroplasty. We estimated the incidence of and risk factors for PJI in primary arthroplasty after femoral neck fracture.

Patients and methods Patients admitted for a femoral neck fracture in 2008 and 2009 were registered prospectively. We studied clinical, operative, and infection data in 184 consecutive patients.

Results 9% of the patients developed a PJI. Coagulase-negative staphylococci and Staphylococcus aureus were the most frequently isolated organisms. We found that preoperative waiting time was associated with PJI and also with urinary tract infection. The median preoperative waiting time was 37 (11–136) h in the infection group as opposed to 26 (4–133) h in the group with no infection (p = 0.04). The difference remained statistically significant after adjusted analysis. The success of treatment with debridement and retention of the prosthesis was limited, and 5 of the 17 patients with PJI ended up with a resection arthroplasty. The 1-year mortality rate was 21% in the patients with no infection, and it was 47% in the infection group (p = 0.03).

Interpretation We found a high incidence of PJI in this elderly population treated with arthroplasty after hip fracture, with possibly devastating outcome. The length of stay preoperatively increased the risk of developing PJI.     

红色荧光金葡菌假体感染临床株的构建

目的建立红色荧光标记金黄色葡萄球菌(金葡菌)假体感染(PJI)临床株，探究工具菌的生物学特性及和初步应用可行性。 方法通过分子克隆手段构建mCherry红色荧光表达质粒，通过电转化和噬菌体转导构建红色荧光标记金葡菌PJI临床株。通过生长曲线检测，体外成膜和生物量分析和荧光强度测量鉴定工具菌生物学特性。采用RAW264.7细胞株、工具菌建立共培养模型。采用该模型示踪不同锌离子浓度处理的巨噬细胞对于荧光PJI金葡菌吞噬能力。使用独立样本t检验、重复测量方差分析对定量数据进行统计。 结果使用Gibson系统成功构建了荧光表达质粒pRMC2-pts-mCherry，并且使用噬菌体Phage11将该质粒成功导入金葡菌假体感染临床株ST1792。较之于野生株ST1792，荧光金葡菌ST1792-pRMC2-pts-mCherry两者的生长曲线没有统计学差异(F＝0.012，P>0.05)。在0.5%葡萄糖胰蛋白胨大豆肉汤培养基(TSBG)内，两者的生物膜光密度(OD)值分别为(3.700±0.003)和(3.715±0.042)(t＝0.6056，P>0.05)；10%滑液中生物膜OD值为(3.682±0.084)和(3.648±0.095)(t＝0.474，P >0.05)。使用动物活体成像系统(IVIS)检测荧光强度，24 h荧光强度为(1.95± 0.04)、48 h荧光为(1.94±0.13)、72 h荧光强度为(1.95±0.04)，荧光强度72 h稳定(F＝2.944，P>0.05)。通过荧光显微镜观察以及菌落形成单位(CFU)计数评价发现，使用锌离子浓度30～60 μmol/L不含抗生素的培养基处理RAW264.7 24 h，可以促进其吞噬金葡菌，其中30 μmol/L吞噬率为(44±4)%(t ＝4.75，P<0.01)、45 μmol/L吞噬率为(45±6)%(t＝4.086，P<0.05)、60 μmol/L离子处理的巨噬细胞，其吞噬率为(38±4)%(t ＝4.786，P <0.01)。 结论本研究成功构建红色荧光临床PJI金葡菌，并验证其用于PJI相关体外吞噬研究的可行性。     

Vancomycin Powder and Dilute Povidone-Iodine Lavage for Infection Prophylaxis in High-Risk Total Joint Arthroplasty

BackgroundDilute povidone-iodine lavage has been shown to be safe and effective in decreasing acute periprosthetic joint infection (PJI) following total joint arthroplasty (TJA). Vancomycin powder is reported to be effective in preventing infection in spine surgery. We hypothesize that a “vanco-povidone protocol” (VIP) for TJA patients at high risk for infection is safe and will decrease the rate of PJI.MethodsHigh-risk TJA patients (body mass index >40, active smokers, American Society of Anesthesiologists ≥3, immunosuppression/diabetes, methicillin-resistant Staphylococcus aureus colonization, revision surgery) utilizing VIP were compared to a high-risk historical cohort not treated with VIP, at a single institution. VIP consisted of dilute povidone-iodine lavage followed by application of vancomycin powder prior to wound closure. Primary endpoint was PJI within 3 months postoperatively.ResultsThe historical, high-risk control cohort consisted of 3251 patients with a PJI incidence of 1.8%. A total of 1413 subjects received the VIP protocol with a PJI incidence of 1.3%. There was a 27.8% risk reduction when compared to the control group of high-risk subjects not treated with the VIP. There were no medical complications secondary to the use of VIP, no increase in vancomycin-resistant enterococcus or vancomycin-resistant Staph aureus, and no cases of acute renal impairment secondary to application of the local vancomycin.ConclusionsPJI remains a common complication of TJA, especially in high-risk populations. This study indicates that a protocol of dilute povidone-iodine lavage combined with topical vancomycin powder is safe and may reduce PJI incidence in high-risk TJA patients. Due to low, current PJI rates, a multi-institutional randomized controlled trial is necessary to assess interventions that minimize the risk of PJI.Level of EvidenceRetrospective Observational Cohort.     

Immune Response to Persistent Staphyloccocus Aureus Periprosthetic Joint Infection in a Mouse Tibial Implant Model

Staphyloccocus aureus is one of the major pathogens in orthopedic periprosthetic joint infection (PJI), a devastating complication of total joint arthroplasty that often results in chronic and persistent infections that are refractory to antibiotics and require surgical interventions. Biofilm formation has been extensively investigated as a reason for persistent infection. The cellular composition, activation status, cytokine profile, and role of the immune response during persistent S. aureus PJI are incompletely understood. In this study, we used histology, multiparametric flow cytometry, and gene expression analysis to characterize the immune response in a clinically relevant orthopedic PJI model. We tested the hypothesis that persistent S. aureus infection induces feedback mechanisms that suppress immune cell activation, thereby affecting the course of infection. Surprisingly, persistent infection was characterized by strikingly high cytokine gene expression indicative of robust activation of multiple components of innate and adaptive immunity, along with ongoing severe neutrophil-dominated inflammation, in infected joint and bone tissues. Activation and expansion of draining lymph nodes and a bone marrow stress granulopoiesis reaction were also maintained during late phase infection. In parallel, feedback mechanisms involving T-cell inhibitory receptors and exhaustion markers, suppressive cytokines, and regulatory T cells were activated and associated with decreased T-cell proliferation and tissue infiltration during the persistent phase of infection. These results identify the cellular and molecular components of the mouse immune response to persistent S. aureus PJI and indicate that neutrophil infiltration, inflammatory cytokine responses, and ongoing lymph node and bone marrow reactions are insufficient to clear infection and that immune effector mechanisms are suppressed by feedback inhibitory pathways. These immune-suppressive mechanisms are associated with diminished T-cell proliferation and tissue infiltration and can be targeted as part of adjuvant immunotherapeutic strategies in combination with debridement of biofilm, antibiotics, and other therapeutic modalities to promote eradication of infection. © 2021 American Society for Bone and Mineral Research (ASBMR).     

Common bacteria and treatment options for the acute and chronic infection of the total ankle arthroplasty

BackgroundThere is little valid data available on managing infected total ankle arthroplasty (TAA).MethodsA single-center, retrospective evaluation from 20 patients with PJI (periprosthetic joint infection) of the ankle compared the bacteria isolated by preoperative arthrocentesis and intraoperative cultures to the pathogens of knee PJI. Long-term failure rates of irrigation and debridement (I&D) and polyethylene exchange, revision arthroplasty, and arthrodesis were analyzed.ResultsThe most common bacteria were Staphylococcus aureus and Coagulase-negative staphylococci. There was no significant difference when comparing the causing pathogens of PJI of the ankle with the knee. After a follow-up of 50,4 months, the long-term failure rate after I&D and polyethylene exchange was 40%, and of revision was 9%.ConclusionsWe concluded that the pathogenesis of PJI of the ankle and knee seems to be comparable. Regarding treatment options, we found that standardized techniques for PJIs of the knee have their limitations regarding infected TAA.     

Risk Factors for Periprosthetic Joint Infection Following Primary Total Hip Arthroplasty: A Case Control Study

The purpose of this study was to identify the specific comorbidities and demographic factors that are independently associated with an increased risk of periprosthetic joint infection (PJI) in total hip arthroplasty (THA) patients. A case–control study design was used to compare 88 patients who underwent unilateral primary THA and developed PJI with 499 unilateral primary THA patients who did not develop PJI. The impact of 18 comorbid conditions and other demographic factors on PJI was examined. Depression, obesity, cardiac arrhythmia, and male gender were found to be independently associated with an increased risk of PJI in THA patients. This information is important to consider when counseling patients on the risks associated with elective THA, and for risk-adjusting publicly reported THA outcomes.     

The Risk Factor and Outcome of Metachronous Periprosthetic Joint Infections: A Retrospective Analysis With a Minimum Ten-Year Follow-Up

BackgroundPatients with multiple prosthetic joints are at risk of developing periprosthetic joint infections (PJIs). We aimed to determine whether PJI development at one site may lead to infection at another prosthetic joint site and assess the risk factors leading to this subsequent infection.MethodsWe reviewed all cases (294 patients with first-time PJI [159 hips, 135 knees]) with PJI treated at our institute between January 1994 and December 2020. The average follow-up period was 11.2 years (range 10.1-23.2). Patients were included if they had at least one other prosthetic joint at the time of developing a single PJI (96 patients). Patients with synchronous PJI were excluded from the study. The incidence of metachronous PJI was assessed, and the risk factors were determined by comparing different characteristics between patients without metachronous PJI.ResultsOf the 96 patients, 19.79% developed metachronous PJI. The identified causative pathogen was the same in 63.16% of the patients. The time to developing a second PJI was 789.84 days (range 10-3386). The identified risk factors were PJI with systemic inflammatory response syndrome, ≥3 stages of resection arthroplasty, and PJI caused by methicillin-resistant Staphylococcus aureus.ConclusionPJI may predispose patients to subsequent PJI in another prosthesis with identified risks. Most causative organisms of metachronous PJI were the same species as those of the first PJI. We believe that bacteremia may be involved in pathogenesis, but further research is required.     

CSA-90 reduces periprosthetic joint infection in a novel rat model challenged with local and systemic Staphylococcus aureus

Infection of orthopedic implants is a growing clinical challenge to manage due to the proliferation of drug-resistant bacterial strains. In this study, we aimed to investigate whether the treatment of implants with ceragenin-90 (CSA-90), a synthetic compound based on endogenous antibacterial peptides, could prevent infection in a novel rat model of periprosthetic joint infection (PJI) challenged with either local or systemic Staphylococcus aureus. A novel preclinical model of PJI was created using press-fit porous titanium implants in the distal femur of male Wistar rats. Sterile implants were pre-treated with 500 μg CSA-90 in saline. S. aureus was applied either directly at the time of surgery or administered via tail vein injection immediately afterward. Animals were monitored daily for clinical and radiographic evidence of infection for a total of 6 weeks. Post-study microbiological, radiographic, and histological analysis were performed to determine the incidence of PJI and assess osseointegration. CSA-90 treated groups demonstrated a reduced rate of PJI as confirmed by deep tissue swab culture at the time of cull compared with untreated groups with both local (33% vs 100%; P = .009) and systemic (10% vs 90%; P < .0001) S. aureus inoculation. Median survival time also increased from 8 to 17 days and from 8 to 42 days, respectively. In conclusion, this study describes a novel preclinical model of local and hematogenous PJI using a porous metal implant. CSA-90 reduced the incidence of PJI in this model supporting its further development as an antimicrobial coating for orthopedic implants.     

人工关节置换术后感染的生物治疗方法及前景

人工关节假体术后感染是骨科临床治疗的难点、热点。目前假体周围感染(PJI)的治疗方法包括保守治疗和手术治疗,但总的治疗效果不理想。PJI生物治疗是指利用新型杀菌/抑菌剂、生物工程、组织工程等方法,通过破坏生物膜、靶向杀灭致病菌、被动免疫以及局部缓释杀菌剂等方式对PJI进行治疗的新方法。它的出现有望解决PJI治疗存在的一系列难题。本文就近年来PJI生物治疗的研究进展及应用前景进行综述。