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。     

Comparison of various surgical methods in the treatment of implant-related infection

The treatment of implant-related infections is troublesome. This study was conducted to compare the effectiveness of three different surgical modalities in the treatment of implant-related infection. A total of 32 Wistar albino rats were randomised into four groups after the establishment of implant-related infection: no treatment, surgical débridement, antibiotic-loaded bone cement and antibiotic-loaded autogenous bone. Microbiological colony counts were made at the sixth week in order to evaluate the effectiveness of of the treatments. The antibiotic-loaded bone cement group revealed superior results compared with the other groups in terms of reduction of microbiological colonies. Three animals in the bone cement group revealed extensive infection. Although antibiotic-loaded bone cement showed superiority over other treatment modalities, it should be employed after an unsuccessful trial of débridement because of the risk of extensive infection.     

骨科金属置入物并发感染的动物模型构建方法及效果评价

[目的]构建一种基于钛合金置人物的兔胫骨金黄色葡萄球菌感染模型,并探讨不同菌液浓度在模型制备中的作用.[方法]48只新西兰大白兔随机分成5组,4个实验组每组10只,对照组8只.在胫骨结节内侧钻孔后,向各实验组动物胫骨髓腔内注入浓度分别为1.0 ×105、1.0×106、1.0×107、1.0×108 CFU/ml的ATCC25923金黄色葡萄球菌悬液.然后在髓腔内置入长4.0 cm,直径0.25 cm钛合金棒.对照组注入等量生理盐水后置入相同规格的钛合金棒.术后4周通过肢体外观、体温测量、影像检查、微生物学检测和组织学分析,评价感染模型建立情况,筛选最佳细菌浓度.[结果]术后动物患肢早期局部软组织肿胀,出现跛行,体温呈现2周内明显升高、之后逐渐下降的趋势.术后4周实验组动物放射学显示不同程度骨膜反应,皮质溶解,死骨形成及软组织肿胀等表现.细菌培养结果显示注入的细菌浓度越高,感染越严重,其中C、D组感染率均为100％,高于A、B组;D组死亡率最高.4周组织切片出现骨髓纤维化、坏死骨片等感染表现.[结论]适当浓度的金黄色葡萄球菌菌液髓腔注射联合钛合金棒置入可以构建稳定的兔长骨感染模型,此为骨科金属置人物并发感染的防治研究奠定了基础.     

Remission rate of implant-related infections following revision surgery after fractures

Purpose

In contrast to a large amount of epidemiological data regarding the incidence of implant infections after fracture management, surprisingly few have been published concerning the success of their treatment.

Methods

This was a single-centre cohort study at Geneva University Hospitals from 2000 to 2012 investigating the remission rates of orthopaedic implant infections after fracture repair and associated variables.

Results

A total of 139 episodes were included: There were 51 women (37 %) and 28 immunosuppressed (20 %) patients with a median age and American Society of Anaesthesiologists (ASA) score of 51 years and 2 points, respectively. The infected implants were plates (n?=?75, 54 %), nails (24, 17 %), wires (20), screws (10), cerclage cables or wires (3), hip screws (4) or material for spondylodesis (3). A pathogen was identified in 135 (97 %) cases, including Staphylococcus aureus (73, 52 %), coagulase-negative staphylococci (20), streptococci (7) and 19 Gram-negative rods. All patients underwent antibiotic treatment, and 128 (92 %) remained in remission at a median follow-up time of 2.6 years (range one to 13 years). In multivariate logistic regression analysis, the plate infections were significantly associated with lower remission rates [65/75, 87 %, odds ratio (OR) 0.1, 95 % confidence interval (CI) 0.01–0.90]. No associations were found for gender, age, immune status, ASA score, additional surgical interventions (OR 0.4, 95 % CI 0.1–4.1) or duration of antibiotic treatment (OR 1.0, 95 % CI 0.98–1.01).

Conclusions

Among all infected and removed orthopaedic implants, plates were associated with slightly lower remission rates, while the overall treatment success exceeded 90 %. The duration of antibiotic therapy did not alter the outcome.     

Accurate and early diagnosis of orthopedic device‐related infection by microbial heat production and sonication

Proper and rapid diagnosis of orthopedic device‐related infection is important for successful treatment. Sonication has been shown to improve the diagnostic performance. We hypothesized that the combination of sonication with a novel method called microcalorimetry will further improve and accelerate the diagnosis of implant infection. We prospectively included 39 consecutive patients (mean age 59 years, 62% males) at our institution from whom 29 orthopedic prostheses and 10 osteosynthesis material were explanted. The explanted device was sonicated. The resulting sonication fluid was analyzed using microcalorimetry. Using standardized criteria to define orthopedic device‐related infection, 12 cases (31%) were defined as infected. In all, positive periprosthetic tissue cultures were found. The sensitivity and specificity of microcalorimetry of sonication fluid were 100% and 97%, respectively. Mean time to detection, defined as time to reach a rising heat flow signal of 20 µW measured after equilibiration needed to get accurate measurement, was 10.9 h. In summary, microcalorimetry of sonication fluid is a reliable and a fast method in detecting the presence of microorganisms in orthopedic device‐related infection. © 2013 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 31:1700–1703, 2013     

The effect of proteolytic enzyme serratiopeptidase in the treatment of experimental implant-related infection

BACKGROUND: Infection around an implanted orthopaedic device is a devastating complication, and the treatment of infections involving slime-forming bacteria is especially difficult. The purpose of the present study was to evaluate the effectiveness of a proteolytic enzyme, serratiopeptidase, in the eradication of a periprosthetic infection in an in vivo animal model. METHODS: In sixty Sprague-Dawley rats, the medullary canal of the right femur was drilled through the intercondylar notch and was inoculated with a Staphylococcus epidermidis strain (ATCC 35984) with a high slime-producing capacity. The cavity was filled with polymethylmethacrylate cement, and a Kirschner wire that had contact with the knee joint was inserted. None of the animals received any treatment for two weeks. Twenty rats were killed at two weeks after the inoculation in order to determine if the infection had become established. The remaining forty rats were randomized into two groups. One group received serratiopeptidase enzyme injections into the knee joint in addition to antibiotic therapy for four weeks, and the other group received intra-articular saline solution injections together with the same antibiotic therapy. The animals from both groups were killed two weeks after the end of therapy (on Day 56). The knee specimens were evaluated bacteriologically and histologically to determine the prevalence of persistent infection and the effects of the enzyme on local tissue. RESULTS: At two weeks, inoculated bacteria grew on culture of specimens from twelve (63.2%) of nineteen animals in the no-treatment group. Microbiological testing suggested that infection persisted in only one (5.6%) of eighteen animals in the serratiopeptidase-and-antibiotic group, whereas it was present in six (37.5%) of sixteen animals in the antibiotic-only group (p = 0.001). Histological evaluation showed similar results (kappa = 0.92). CONCLUSIONS: Serratiopeptidase was effective for eradicating infection caused by biofilm-forming bacteria in this experimental animal model. The antibiofilm property of the enzyme may enhance antibiotic efficacy in the treatment of staphylococcal infections.     

脊柱手术后切口深部感染的早期判断

目的 :观察脊柱术后早期各项感染相关指标的变化情况,为尽早判断切口深部感染的存在提供更为可靠的依据。方法:2001年1月~2012年12月在复旦大学附属华山医院脊柱外科中心行脊柱手术的患者中,术后发生切口深部感染24例(感染组),男20例,女4例;年龄55.0±15.0岁(14~75岁);急性感染14例(术后3个月内发生),迟发性感染10例(术后3个月后发生)。以同时间段行脊柱手术、术后未出现感染的51例患者(男29例,女22例;年龄19~81岁)作为对照组。回顾性分析两组患者术后第3天及术后第5/6天外周血中白细胞总数、中性粒细胞总数、红细胞沉降率(ESR)及C-反应蛋白(CRP)等参数,同时回顾相应时间点患者体温与局部伤口情况。以白细胞总数、中性粒细胞总数、CRP、ESR及体温等参数超过对照组患者相应时间点该参数值的均数+2倍标准差(+2s)作为上述参数异常的标准;局部伤口以出现红肿热痛、伴或不伴渗出作为异常的标准。结果:与对照组比较,切口深部感染组患者术后3d的CRP显著性升高(P=0.005);术后5/6d,CRP(P=0.000)、中性粒细胞总数(P=0.020)及体温(P=0.001)均显著性增高。在术后3d或5/6d时,24例患者中共有8例(33.3%)体温增高;2例(8.3%)白细胞总数升高,11例(45.8%)中性粒细胞总数升高;18例(75%)ESR升高,21例(87.5%)CRP升高;3例(12.5%)在术后短期内(1周)出现手术伤口部位红肿热痛,伴或不伴渗出。CRP及ESR等参数对于切口深部感染诊断的敏感性明显高于体温、伤口局部体征及白细胞总数与中性粒细胞总数等感染相关指标(P0.05)。迟发性切口深部感染患者外周血各项炎症指标与急性切口深部感染患者比较无统计学差异(P0.05)。结论:术后早期定时检测周围血中CRP和ESR有利于早期判断切口深部感染,CRP升高可在早期有效判断切口深部感染。     

Efficacy of clarithromycin plus vancomycin in mice with implant-related infection caused by biofilm-forming Staphylococcus aureus

Background  

Staphylococcal biofilms pose an important problem, especially after orthopedic surgery using foreign implants. Clarithromycin (CAM) eliminates the biofilms formed by a wide variety of aerobic and anaerobic bacteria. In a previous in vitro study, we showed that treatment with CAM and vancomycin (VCM) eradicated staphylococcal biofilms from surgical implants. To investigate the efficacy of this eradication therapy, we assessed its effects against Staphylococcus aureus on titanium plates implanted in mice.     

急性坏死性胰腺炎继发感染的早期诊断

目的 探讨急性坏死性胰腺炎继发感染的早期诊断方法。方法 对１３例急性坏死性胰腺炎的临床、ＣＴ影像学、ＣＴ引导下细地穿针（ＦＮＡ）结合ＰＣＲ微生物学检查，诊断胰腺感染的敏感性、特异性进行前瞻性比较研究。结果 ９例最终诊断为胰腺感染，４例为胰腺未感染。根据临床症状体征及常规实验室检查，诊断胰腺感染的敏感性为１００％（９／９），特异性为２５％（１／４）；ＣＴ 泡征诊断胰腺感染的敏感性为５５．６％（５／９     

全膝关节置换术后感染诊断研究进展

全膝关节置换术(TKA)后感染的诊断仍然是一个挑战。完整的诊断流程十分重要,术中组织培养是目前检测TKA后感染的金标准。采用~(111)铟-同位素标记白细胞(~(111)In-WBC)的单光子发射断层扫描(SPECT)/CT结合~(99m)锝-亚甲基二膦酸盐(~(99m)Tc-MDP)或~(99m)Tc-硫胶体骨髓图像检查,能有效提高检出率;正电子发射断层扫描(PET)的检出敏感性较高,花费时间较短;基于rRNA的逆转录定量PCR(RT-qPCR)的特异性与敏感性均较高,信号维持可探测水平时间较长;关节穿刺检查与术中冰冻组织切片检查虽尚无统一标准,但对于明确致病菌种的作用仍巨大。     

Low sensitivity of implant sonication when screening for infection in revision surgery

Background and purpose — Prosthetic-joint infection (PJI) is the most serious complication of arthroplasty, and accurate identification of a potentially responsible microorganism is essential for successful antibiotic treatment. We therefore determined the diagnostic accuracy of sonication and compared it with tissue culture as a screening tool in detecting prosthetic joint infection in revision arthroplasty.

Patients and methods — 252 consecutive revision arthroplasty cases were enrolled. These cases were determined as being suspected or unsuspected of having infection according to standard criteria. Perioperatively, 6 periprosthetic interface tissue biopsies were obtained from each patient and the implants removed were sonicated. The sensitivity and specificity of periprosthetic tissue culture and sonication fluid cultures were determined.

Results — Preoperatively, 75 revision cases were classified as having PJI (33 early and 42 late) and 177 were unsuspected of having infection. Compared with tissue culture, the sensitivity of the sonication fluid analysis was low: 0.47 (95% CI: 0.35–0.59) for sonication as compared to 0.68 (95% CI: 0.56–0.78) for tissue culture. The specificity of the sonication fluid analysis was higher than that for tissue culture: 0.99 (95% CI: 0.96–1.0) as compared to 0.80 (95% CI: 0.74–0.86).

Interpretation — Sonication is a highly specific test for diagnosis of PJI. However, due to the low sensitivity, a negative sonication result does not rule out the presence of PJI. Thus, sonication is not of value for screening of microorganisms during revision surgery.     

A new animal model for implant-related infected non-unions after intramedullary fixation of the tibia in rats with fluorescent in situ hybridization of bacteria in bone infection

There is no adequate animal model to mimic the difficult clinical situation of infected non-union of the tibia after intramedullary stabilization. The purpose was to establish an animal model of implant-related infected non-unions of the tibia in rats. Furthermore, it was evaluated if detection of bacteria by fluorescent in situ hybridisation (FISH) technique is possible in bone infection. 17 rats were used in which osteotomy of the midshaft tibia was performed and stabilized with an intramedullary device. Two groups were tested: group 1: contamination of the osteotomy site with 10(4) colony forming units (CFUs) of Staphylococcus aureus (11 animals), group 2: no bacterial contamination (6 animals). The animals were sacrificed after 42 days and bone healing and infection were assessed clinically, by X-ray, micro-CT, and microbiological methods including FISH technique using EUB and STAPHY probes. Histology and scanning electron microscopy (SEM) for biofilm formation were performed. All animals of the control group showed uneventful bone healing after 6 weeks without any signs of local infections. 10 of 11 (90.9%) animals of group 1 with bacterial contamination exhibited infected non-union formation with positive clinical, radiological and microbiological infection signs of the tibia but without any systemic infection signs. FISH technique was able to identify bacteria in the infected bone. All intramedullary implants from the infected animals showed positive biofilm formation in SEM. This work presents the first animal model for the induction of intramedullary device-related infected non-union in the tibia and detection of bacteria by FISH technique in infected bone.     

A new small animal model for simulating a two-stage-revision procedure in implant-related methicillin-resistant Staphylococcus aureus bone infection

BackgroundImplant-related bone infections with methicillin-resistant Staphylococcus aureus (MRSA) remain a challenge for orthopedic surgeons. This devasting complication may lead to functional impairment and loss of the affected limbs. High failure rates in treatment make improvement of surgical treatment necessary. Beside an already established demanding and costly large animal model, a small animal model of a two-stage revision does not exist, yet. Thus, the purpose of this study was to establish a preclinical small animal model to simulate a two-stage revision in implant-related MRSA infection.Materials and MethodsIn twelve rabbits Steel K-wires were implanted into the intramedullary canal of the left tibia, followed by inoculation with MRSA. Two different clinical isolates of MRSA-strains were used in two different concentrations (CFUs; 10⁵ and 10⁷ colony forming units (CFUs). This led to four groups of three rabbits each. Eleven rabbits survived the whole study period. After four weeks the inoculated K-wires were removed and replaced with vancomycin loaded PMMA-spacers (stage 1). Twenty-eight days later new K-wire implants were placed intramedullary (stage 2). After 84 days all animals were sacrificed. Tibiae were analyzed microbiologically, radiologically and histologically.ResultsIn every rabbit K-wire associated infection could be established within the first four weeks. After irrigation and debridement at revision one (stage 1), infection could be eradicated in 67% of group I, in 50% of group II and in 33% of group III and IV. Recurrence of the infection could be determined in all animals of group I and IV at day 84. X-ray analysis and histology both demonstrated clear signs of osteomyelitis after twelve weeks. Survival, clinical observations and weight assessment confirmed the ethical justifiable stress of the animals during the experiment.ConclusionThe presented small animal model of a two-stage revision in implant-related infection is a promising preclinical set-up for assessment of new treatment strategies of implant-related infections. Both high survival as well as reinfection rates were possible by simulating the clinical gold standard of two-stage revision surgery in an MRSA implant-related infection model. Therefore, the model can be deemed suitable for further preclinical in vivo testing.     

CMV infection, diagnosis and antiviral strategies after liver transplantation

Cytomegalovirus (CMV) is a significant pathogen complicating the post-transplant course of organ recipients. In liver transplant patients, the febrile clinical illness caused by CMV may be associated with end-organ disease, such as hepatitis or infection of the gastrointestinal tract. In addition to direct effects, CMV may have indirect effects including the risk of other infections or graft rejection. Recently, major advances in the management of CMV infection have been achieved through the development of new diagnostic techniques and antiviral strategies to prevent CMV disease. Quantitative nucleic acid testing to monitor viral load is now commonly used to diagnose and guide the treatment of CMV infections. The standardization of the testing, however, needs to be improved. There are two main strategies to prevent CMV disease after liver transplantation: prophylaxis and pre-emptive therapy. Both strategies are effective, but also have disadvantages. The disadvantages of prophylaxis include prolonged drug exposure, the development of resistance and, most of all, the development of delayed and late-onset CMV disease. On the other hand, the pre-emptive strategy is based on frequent laboratory monitoring of viral loads, and some patients may develop symptomatic infection before the diagnosis of CMV. This overview summarizes the current status of CMV in liver transplantation.     

腰椎间盘术后椎间隙感染的早期诊断治疗

目的: 探讨椎间盘术后椎间隙感染的发病特点及防治方法。方法: 对本院 641例椎间盘摘除术中的 7例腰椎间隙感染的病例分析回顾总结。结果: 感染与病人基础条件差、术前抗炎准备不足、术中组织损伤多等因素有关, 7例病人均有腰腿痛加剧, 血沉加快。结论: 严格的术前准备, 术中减少副损伤, 术后早诊断, 严格制动, 足量抗生素长期应用有效。