Antibiotic Lock for Treatment of Tunneled Hemodialysis Catheter Bacteremia

Catheter‐related bacteremia is a major cause of morbidity and mortality among catheter‐dependent hemodialysis patients. Microorganism biofilm matrix formation in the catheter is the pathogenic process of this entity. Administration of systemic antibiotics and removal of the offending catheter is the most logical treatment. This article discusses an alternative option, instillation of an antibiotic‐lock solution into the lumen of the catheter plus systemic antibiotic therapy. Recent studies suggest that this strategy could treat the infection and salvage the catheter, thus avoiding the need for further interventional procedures including but not limited to the removal of the catheter, placement of a temporary catheter, and finally placement of a new permanent catheter. The implementation of this effective approach will reduce morbidity and possibly reduce the cost and interventions associated with it.     

Antibiotic prophylaxis in lower-extremity amputations due to ischemia

Summary The efficiency of prophylactic antibiotic therapy in amputation surgery was studied in a prospective, randomized trial of a first-generation cephalosporin (cephalothin) compared with a narrow-spectrum betalactam stable penicillin (methicillin). Eighty-eight patients received cephalothin 2 g x 4 on the day of operation, while 86 patients received methicillin 1 g x 4. The patients were followed up for 21 days. Infected wounds occurred in 14.8% of the patients in the cephalothin group, compared with 14% in the methicillin group. The frequency of deep infections was 10.2% versus 4.7% (P = 0.1611). The reamputation frequency was 18.2% in the cephalothin group compared with 12.8% in the methicillin group; the frequency of below-knee reamputation was 18.4% versus 7.7% (P = 0.1469). No clostridial infections were found. The study did not demonstrate any significant difference between cephalothin and methicillin in the prophylaxis for lower-extremity amputations, although the latter drug tended to be the best choice.     

Catheter Dysfunction: The Role of Lock Solutions

Vascular access dysfunction is a major cause of morbidity in hemodialysis (HD) patients. An upper extremity autogenous arteriovenous fistula (AVF) that preferentially involves the cephalic vein is the access of choice for HD patients, followed by autogenous AVF utilizing the basilic vein and the use of prosthetic arteriovenous grafts (AVGs). Despite these recommendations, central venous catheter (CVC) use is widespread among both incident and prevalent HD patients. Long‐term use of CVCs for HD is complicated by a high rate of infection and thrombus‐related dysfunction. Catheter locking solutions have been used both prophylactically and therapeutically for catheter thrombosis as well as catheter‐related infections, with varying degrees of success. This review aims to address the different catheter locking solutions, their advantages and disadvantages, and new directions in this field.     

Antibiotic treatment in pneumonia due to Q fever.

BACKGROUND: Whether Q fever responds better to doxycycline or erythromycin is unknown. METHODS: The efficacy of doxycycline and erythromycin in the treatment of pneumonia due to Q fever was assessed in a prospective, randomised, double blind study of 82 patients with a diagnosis of pneumonia and features suggestive of Q fever infection; 48 proved to have Q fever. Of the 48, 23 received doxycycline 100 mg twice a day and 25 patients received erythromycin 500 mg six hourly, both for 10 days. RESULTS: Both treatment groups had similar demographic characteristics. Fever showed a more rapid reduction in the doxycycline group (3(1.6) days versus 4.3(2) days). Side effects were observed in two patients receiving doxycycline compared with 11 patients receiving erythromycin (p less than 0.01). No differences were observed in other clinical or radiological measures. By day 40 the chest radiograph was normal in 47 of 48 patients. CONCLUSION: The results demonstrate the self limiting and benign nature of most cases of pneumonia due to Q fever. Doxycycline was more effective than erythromycin.     

Gastric Bypass for Insulin Resistance due to Lipodystrophy

We report a 41-year-old woman with severe insulin resistance due to partial lipodystrophy, who was successfully treated with gastric bypass surgery.     

Increasing the Osmolarity of Joint Irrigation Solutions May Avoid Injury to Cartilage: A Pilot Study

Saline (0.9%, 285 mOsm) and Hartmann’s solution (255 mOsm) are two commonly used joint irrigation solutions that alter the extracellular osmolarity of in situ chondrocytes during articular surgery. We asked whether varying the osmolarity of these solutions influences in situ chondrocyte death in mechanically injured articular cartilage. We initially exposed osteochondral tissue harvested from the metacarpophalangeal joints of 3-year-old cows to solutions of 0.9% saline and Hartmann’s solution of different osmolarity (100–600 mOsm) for 2 minutes to allow in situ chondrocytes to respond to the altered osmotic environment. The full thickness of articular cartilage then was “injured” with a fresh scalpel. Using confocal laser scanning microscopy, in situ chondrocyte death at the injured cartilage edge was quantified spatially as a function of osmolarity at 2.5 hours. Increasing the osmolarity of 0.9% saline and Hartmann’s solution to 600 mOsm decreased in situ chondrocyte death in the superficial zone of injured cartilage. Compared with 0.9% saline, Hartmann’s solution was associated with greater chondrocyte death in the superficial zone of injured cartilage, but not when the osmolarity of both solutions was increased to 600 mOsm. These experiments may have implications for the design of irrigation solutions used during arthroscopic and open articular surgery.     

上海地区细菌耐药性特点及其防治措施

上海地区细菌耐药性监测网由本市11家医院组成。1989年起每年按统一的监测方案采用统一的材料和Kirby-bauer方法对各医院细菌检验室从临床所取标本中培养分离所得菌株进行药物敏感试验。2000年4月1日—2001年3月31日,收集各     

Modular Augmentation in Varus-Valgus–Constrained Knee Arthroplasty—Do We Need Sleeves to Avoid Femoral Loosening After Excessive Distal Augmentation?

BackgroundIn revision total knee arthroplasty, zonal fixation methods with a combination of augments, press-fit stems, and sleeves are popular. We hypothesized that high distal femoral augmentation with diaphyseal press-fit stems leads to an increased rate of early aseptic loosening and that femoral metaphyseal sleeves improve implant survival. Therefore, we retrospectively investigated implant survival in relation to augment heights and sleeves.MethodsA total of 136 patients with mean clinical follow-up of 50 months (range, 28-85) who underwent modular total knee arthroplasty and revision total knee arthroplasty with semiconstrained implants between January 2012 and July 2018 were retrospectively evaluated. Implant survival with 4, 8, and 12 mm distal femoral augments was compared to no distal augmentation. Subsequently, a subgroup analysis was performed for femoral sleeve implantation.ResultsWe observed an implant survival rate of 97.0%, 87.5%, and 69.2% for 4, 8, and 12 mm distal femoral augmentation, respectively (P = .73; P = .19; P = .008). The implant survival rate with femoral sleeves was 95.8% for the 8 mm augments and 85.7% for the 12 mm augments (P = .42; P = .96). Without femoral sleeves, the implant survival rate was 78.3% with the 8 mm augments and 50.0% with the 12 mm augments (P = .02; P < .001).ConclusionHigher rates of aseptic femoral loosening were identified for distal femoral augmentation of 8 mm or more without metaphyseal sleeve fixation in semiconstrained implants. Thus, in cases with femoral metaphyseal bone damage requiring high distal femoral augmentation, metaphyseal sleeves should be used to avoid early aseptic femoral loosening.     

肺炎克雷伯菌医院感染现状及耐药性分析

目的:了解我院2010年肺炎克雷伯菌对常用抗菌药物的耐药现状及标本分布,为临床治疗提供依据.方法:采用回顾性方法纯计分析448株肺炎克雷伯菌的标本来源、忘染科室分布及耐药情况.结果:临床标本中肺炎克雷伯茼除对碳青霉烯类亚胺培南、美洛培南以及含有β-内酰胺酶抑制剂的复方制剂头孢哌酮/舒巴坦、哌拉西林/他唑巴坦高度敏惠外(敏感率高于96.0%),对其他各类常用抗菌药物均表现不同程度的耐药现象.如对青霉素类氨苄西林和1～3代头孢菌素头孢唑林、头孢吱辛、头孢曲松、头孢噻肟普遍存在较高的耐药性,其耐药率均在50.0%以上:氨基糖苷类阿米卡星、异帕米星和喹诺酮类左氧氟沙星、环丙沙星的耐药率稍低,大多在20.0%-30.0%之间,结论:该临床分离的肺炎克霄伯菌耐药严重,且至多重耐药,因此临床必须重视合理使用抗萄药物,以减少或廷缓多重耐药菌株的产生.     

Epidemiology and Antibiotic Resistance of Late Prosthetic Knee and Hip Infections

Background

Prosthetic joint infections (PJI) are still a major complication of hip and knee arthroplasties. Identification of the causative pathogens and knowledge of their antibiotic susceptibilities are essential for the management of these infections. The main purpose of the study was to identify and compare the causative bacteria of prosthetic knee and hip joint infections in a reference Italian orthopedic center and to characterize antibiotic resistance profiles of bacteria involved.

Selection of Pulmonary Resection Procedures to Avoid Postoperative Complications

Purpose We previously found a potential predictive value in a retrospective analysis of spirometry and an expired gas analysis during the exercise. We sought to reduce postoperative cardiopulmonary complications by selecting lung tumor resection procedures based on a combination of specific preoperative cardiopulmonary function test results. Methods Out of the 53 patients requiring a lung tumor resection, five preoperative parameters (forced expiratory volume in 1 s for intact-side, maximal oxygen uptake, ejection fraction, occluded pulmonary artery pressure, and occluded total pulmonary vascular resistant index) were used to assign patients to one of five risk categories in order to select the optimal pulmonary resection procedure. The patients were later grouped according to their postoperative course to test the value of this procedure selection method. Results No patient died or developed severe complications after surgery. Five patients had mild complications, while 46 had a good postoperative course; the 13 deaths, in the cancer cases, included 11 from primary or metastatic cancer and 2 from other causes. The overall five-year survival was 61.4%. Conclusion This method for determining a pulmonary resection procedure avoided postoperative deaths and severe cardiopulmonary complications, while achieving a good outcome.     

Tolerant Small-colony Variants Form Prior to Resistance Within a Staphylococcus aureus Biofilm Based on Antibiotic Selective Pressure

BackgroundThe treatment of periprosthetic joint infection (PJI) is focused on the surgical or chemical removal of biofilm. Antibiotics in isolation are typically ineffective against PJI. Bacteria survive after antibiotic administration because of antibiotic tolerance, resistance, and persistence that arise in the resident bacteria of a biofilm. Small-colony variants are typically slow-growing bacterial subpopulations that arise after antibiotic exposure and are associated with persistent and chronic infections such as PJI. The role of biofilm-mediated antibiotic tolerance in the emergence of antibiotic resistance remains poorly defined experimentally.Questions/purposesWe asked: (1) Does prior antibiotic exposure affect how Staphylococcus aureus survives within a developing biofilm when exposed to an antibiotic that penetrates biofilm, like rifampicin? (2) Does exposure to an antibiotic with poor biofilm penetration, such as vancomycin, affect how S. aureus survives within a developing biofilm? (3) Do small-colony variants emerge from antibiotic-tolerant or -resistant bacteria in a S. aureus biofilm?MethodsWe used a porous membrane as an in vitro implant model to grow luminescent S. aureus biofilms and simultaneously track microcolony expansion. We evaluated the impact of tolerance on the development of resistance by comparing rifampicin (an antibiotic that penetrates S. aureus biofilm) with vancomycin (an antibiotic that penetrates biofilm poorly). We performed viability counting after membrane dissociation to discriminate among tolerant, resistant, and persistent bacteria. Biofilm quantification and small-colony morphologies were confirmed using scanning electron microscopy. Because of experimental variability induced by the starting bacterial inoculum, relative changes were compared since absolute values may not have been statistically comparable.ResultsAntibiotic-naïve S. aureus placed under the selective pressure of rifampicin initially survived within an emerging biofilm by using tolerance given that biofilm resident cell viability revealed 1.0 x 10⁸ CFU, of which 7.5 x 10⁶ CFU were attributed to the emergence of resistance and 9.3 x 10⁷ CFU of which were attributed to the development of tolerance. Previous exposure of S. aureus to rifampicin obviated tolerance-mediate survival when rifampicin resistance was present, since the number of viable biofilm resident cells (9.5 x 10⁹ CFU) nearly equaled the number of rifampicin-resistant bacteria (1.1 x 10¹⁰ CFU). Bacteria exposed to an antibiotic with poor biofilm penetration, like vancomycin, survive within an emerging biofilm by using tolerance as well because the biofilm resident cell viability for vancomycin-naïve (1.6 x 10¹⁰ CFU) and vancomycin-resistant (1.0 x 10¹⁰ CFU) S. aureus could not be accounted for by emergence of resistance. Adding rifampicin to vancomycin resulted in a nearly 500-fold reduction in vancomycin-tolerant bacteria from 1.5 x 10¹⁰ CFU to 3.3 x 10⁷ CFU. Small-colony variant S. aureus emerged within the tolerant bacterial population within 24 hours of biofilm-penetrating antibiotic administration. Scanning electron microscopy before membrane dissociation confirmed the presence of small, uniform cells with biofilm-related microstructures when unexposed to rifampicin as well as large, misshapen, lysed cells with a small-colony variant morphology [29, 41, 42, 63] and a lack of biofilm-related microstructures when exposed to rifampicin. This visually confirmed the rapid emergence of small-colony variants within the sessile niche of a developing biofilm when exposed to an antibiotic that exerted selective pressure.ConclusionTolerance explains why surgical and nonsurgical modalities that rely on antibiotics to “treat” residual microscopic biofilm may fail over time. The differential emergence of resistance based on biofilm penetration may explain why some suppressive antibiotic therapies that do not penetrate biofilm well may rely on bacterial control while limiting the emergence of resistance. However, this strategy fails to address the tolerant bacterial niche that harbors persistent bacteria with a small-colony variant morphology.Clinical RelevanceOur work establishes biofilm-mediated antibiotic tolerance as a neglected feature of bacterial communities that prevents the effective treatment of PJI.     

胃镜下黏膜活检行幽门螺杆菌培养的耐药性与多因素分析

目的探讨北京地区胃镜下黏膜活检培养得到的幽门螺杆菌菌株耐药性情况以及影响耐药率的因素。方法对2013年4月~2014年3月820例胃镜检查快速尿素酶检测结果阳性的患者,采集胃窦及胃体部黏膜进行幽门螺杆菌培养,并对获得的幽门螺杆菌菌株进行阿莫西林、克拉霉素、甲硝唑、左氧氟沙星、四环素、利福平药物敏感性试验。结果820例黏膜标本中,700例培养阳性,阳性率为85.4%(700/820)。总体耐药率方面,甲硝唑、左氧氟沙星、克拉霉素、利福平、四环素、阿莫西林的耐药率分别为63.9%(447/700)、54.4%(381/700)、50.1%(351/700)、18.0%(126/700)、7.3%(51/700)、3.7%(26/700)。多重耐药率方面,对全部6种抗生素敏感的菌株仅占9.9%(69/700),对单一抗生素耐药的菌株占27.1%(190/700),二重、三重、四重、五重、六重耐药率分别为29.6%(207/700)、24.3%(170/700)、7.4%(52/700)、1.6%(11/700)、0.1%(1/700)。单因素分析及多因素分析显示,克拉霉素在非溃疡性消化不良的患者中耐药率明显高于消化性溃疡的患者(χ2=11.619,P=0.001;OR=1.834,95%CI:1.366~2.424);甲硝唑耐药率在女性患者中明显高于男性患者(χ2=5.674,P=0.017;OR=1.486,95%CI:1.176~1.824);左氧氟沙星耐药率在中老年患者中明显高于青年患者(χ2=6.731,P=0.035;OR=1.204,95%CI:1.076~1.385),在女性患者中亦明显高于男性患者(χ2=6.693,P=0.010;OR=1.502,95%CI:1.181~1.786)。结论在北京地区,幽门螺杆菌对甲硝唑、克拉霉素及左氧氟沙星的耐药水平很高,对利福平的耐药率较高,对阿莫西林、四环素的耐药率较低,多重耐药情况也很严重。