Strategies for the control of catheter encrustation

Two general strategies have been adopted to develop catheter materials that resist encrustation by bacterial biofilms: (a) the incorporation of antimicrobial agents into the polymers and (b) the production of materials with surface properties which prevent the adherence of bacterial cells. Our experience to develop non-adherent surfaces which abstracts design from nature is reported. Compounds based on 2-methacryloloxyethylphosphorylcholine co-polymerised with long-chain alkyl methacrylates have been produced which have structural and surface properties similar to those of the outer membranes of erythrocytes. These PC-coatings have been applied onto catheter base materials where they produce polar surfaces that are extremely hydrophilic. In experiments using a laboratory model of the catheterised bladder we found that the PC-coatings did not reduce colonisation of latex or silicone catheters by crystalline Proteus mirabilis biofilm. There were no significant difference between the amounts of calcium and magnesium salts deposited on coated and non-coated catheters. In a further set of experiments the PC-coatings did not significantly increase the mean times for which catheters drained freely. In a parallel clinical study, the performance of PC-coated ureteral stents was investigated. Scanning electron microscopy and bacteriological analysis on 44 PC-coated stents that had been implanted in patients for 12-week periods and 28 control stents suggested that the PC-coated devices were less vulnerable to encrustation and colonisation by bacterial biofilm than normal stents. It was of interest that in contrast to encrusted catheters, urease producing species such as P. mirabilis were rarely isolated from the stents. The main organisms colonising the stents were enterococci and coagulase-negative staphylococci. These results suggest that the mechanisms of catheter and stent encrustation may be different and require different strategies for control.     

An in vitro study of the efficacy of rifampicin and minocycline coated umbilical venous catheters

The use of antibiotic coated catheters has been proposed as a means of reducing catheter related sepsis. In this study, an in vitro comparison of bacterial colonisation rates was made between uncoated umbilical venous catheters and catheters coated with rifampicin and minocycline. The following parameters were determined; the direct antimicrobial effect of coated and uncoated catheter segments against a range of organisms associated with line sepsis, the assessment of the decline in antimicrobial activity in coated catheters immersed in plasma and the inhibitory efficacy of the catheters to colonisation over a 28-day period. Minocycline and rifampicin coated umbilical catheters showed a superior inhibitory effect and prevented colonisation with the commoner line-related organisms, when compared with uncoated catheters. The inhibitory effect declined after 14 days in the human plasma. Resistance to colonisation in vitro may not extend beyond 21 days.     

Catheter-related urinary tract infection

Indwelling urinary catheters are used frequently in older populations. For either short- or long-term catheters, the infection rate is about 5% per day. Escherichia coli remains the most common infecting organism, but a wide variety of other organisms may be isolated, including yeast species. Bacteria tend to show increased resistance because of the repeated antimicrobial courses. Urinary tract infection (UTI) usually follows formation of biofilm on both the internal and external catheter surface. The biofilm protects organisms from both antimicrobials and the host immune response. Morbidity from UTI with short-term catheter use is limited if appropriate catheter care is practised. In patients with long-term catheters, fever from a urinary source is common with a frequency varying from 1 per 100 to 1 per 1000 catheter days. Long-term care facility residents with chronic indwelling catheters have a much greater risk for bacteraemia and other urinary complications than residents without catheters. Asymptomatic catheter-acquired UTI should not be treated with antimicrobials. Antimicrobial treatment does not decrease symptomatic episodes but will lead to emergence of more resistant organisms. For treatment of symptomatic infection, many antimicrobials are effective. Wherever possible, antimicrobial selection should be delayed until culture results are available. Whether to administer initial treatment by an oral or parenteral route is determined by clinical presentation. If empirical therapy is required, antimicrobial selection is based on variables such as route of administration, anticipated infecting organism and susceptibility, and patient tolerance. Renal function, concomitant medications, local formulary and cost may also be considered in selection of the antimicrobial agent. The duration of therapy is usually 10-14 days, but patients who respond promptly and in whom the catheter must remain in situ may be treated with a shorter 7-day course to reduce antimicrobial pressure. Relevant clinical trials are necessary to define optimal antimicrobial regimens for the management of catheter-acquired UTI. Prevention of catheter-acquired UTI and its complications is a major goal. With short-term catheters, avoiding their use or limiting the duration of use to as short a time as possible are the most effective prevention strategies. Maintaining a closed drainage system and adhering to appropriate catheter care techniques will also limit infection and complications. As the duration of catheterisation is the principal determinant of infection with long-term indwelling catheters, it is not clear that any interventions can decrease the prevalence of bacteriuria in this setting. Catheter flushing or daily perineal care do not prevent infection and may, in fact, increase the risk of infection. Complications of infection may be prevented by giving antibacterials for bacteriuria immediately prior to any invasive urological procedure, and by avoiding catheter blockage, twisting or trauma. The major focus of future advances in prevention of catheter-acquired UTI is the development of biomaterials resistant to biofilm formation. There is substantial current research addressing this issue, but current catheter materials all remain susceptible to biofilm formation.     

Spray coating of foley urinary catheter by chlorhexidine-loadedpoly(ε-caprolactone) nanospheres: effect of lyoprotectants,characteristics, and antibacterial activity evaluation

In this study, chlorhexidine-loaded poly(ε-caprolactone) nanospheres (CHX-NS) were prepared and successfully coated on the urinary catheters. Properties of CHX-NS were evaluated including drug loading content and the nanosphere size. Effects of different lyoprotectants for long-term storage of CHX-NS were also investigated. In vitro release study and antibacterial activity were also conducted using 20 cycles coated-urinary catheters. Results showed that the high-pressure emulsification-solvent evaporation technique provided the drug loading content at 1.14?±?0.16% and the size of nanospheres was 152?±?37?nm. The suitable lyoprotectant for long-term storage of CHX-NS was sucrose which provided noticeably no aggregation at the degree of reconstitution at 89.95%. The amount of CHX loading on coated catheters was at 4.55?±?0.31?mg. Drug release from the coated catheters in artificial urine could be prolonged up to 2 weeks and bacteria proliferation was inhibited up to 14?days. These results suggest that the antimicrobial activity of CHX-NS reduces the adherence of the uropathogens to the catheter surface. Chlorhexidine-loaded polymeric nanospheres were fabricated which can be successfully coated on urinary catheters. These systems have potential use for prolonged antimicrobial applications.     

Bacterial biofilm formation on urologic devices and heparin coating as preventive strategy

In the process of endourological development a variety of foreign bodies have been invented besides urinary catheters, on which biofilm can be formed. Bacteria in the biofilm are less susceptible to antibiotics. An additional problem of medical biomaterials in the urinary tract environment is the development of encrustation and consecutive obstruction. The most promising prevention strategy for bacterial biofilms is the production of materials with anti-adhesive surfaces such as heparin. Although heparin-coated ureteral stents are expensive, they justify their cost. Our studies show that such devices are protected against incrustation and biofilm formation for a longer period of time: 6-12 months, both in vitro and in vivo.     

碳青霉烯类耐药大肠杆菌尿路感染的危险因素探讨

目的 探讨碳青霉烯类耐药大肠埃希菌（CREco）的耐药性及患者发生CREco尿路感染的危险因素。方法 收集2015年1月—2017年12月在天津医科大学第二医院住院期间发生尿路感染,且尿培养结果为大肠埃希菌的患者资料共120例。采用病例对照研究方法分2组,病例组为感染CREco的患者24例,在出现CREco尿路感染的科室内按照性别及年龄（±5岁范围内）匹配的原则选取同时期发生碳青霉烯类敏感大肠埃希菌（CSEco）尿路感染患者作为对照,病例组与对照组按照1∶4比例匹配。比较2组的致病菌对18种抗菌药物的耐药性。探讨住院患者发生CREco尿路感染的危险因素。结果 本院住院患者感染的CREco对氨苄西林等12种抗菌药物均表现出很强的耐药性,耐药率均高于70%;对除氨苄西林、庆大霉素、复方新诺明及替加环素外,其他14种抗菌药物的耐药率明显高于CSEco组（均P＜0.05）。多因素分析结果显示,留置导尿管（OR=5.719,95%CI：2.084~15.697,P＜0.01）和检出前住院时间长（OR=9.325,95%CI：1.962~44.330,P＜0.01）是住院患者发生CREco尿路感染的独立危险因素。结论 住院患者尿路感染的CREco耐药形势严峻,患者留置导尿管时应严格遵守标准化操作及临床指征,尽量缩短其住院时间, 减少医院环境下的暴露,降低CREco所致尿路感染的风险。     

Catheter-associated urinary tract infections: impact of catheter materials on their management

Infection associated with an indwelling catheter is a representative type of biofilm infection occurring in the urinary tract. Since the most effective way to control this intractable infection is the prevention of bacterial attachment and subsequent biofilm formation on the catheter, the importance of catheter materials and anti-bacterial coating cannot be underestimated. The difference in the degree of bacterial attachment among standard catheter materials, the efficacy of silver-coating of catheters in preventing infection and the potency and effectiveness of a new lecithin/silver coating are discussed.     

泌尿系统感染患者抗菌药物使用状况调查和细菌耐药监测研究

目的对泌尿系统感染患者抗菌药物的使用状况进行调查,并监测主要病原菌对常用抗菌药物的耐药率。方法收集泌尿系统感染患者的临床治疗资料,进行抗菌药物使用状况的调查。取患者中段尿液进行药敏试验,并研究主要泌尿系统感染病原菌对常用抗菌药物的耐药率。结果本组患者治疗期间所使用的抗菌药物例次南高到低依次为：头孢呋辛钠、阿米卡星、头孢唑肟、头孢他啶、头孢曲松以及其他。泌尿系统感染的病原菌主要有：大肠埃希菌、肺炎克雷伯菌、粪肠球菌、屎肠球菌、变形杆菌等。结论对泌尿系统感染患者抗菌药物使用状况和细菌耐药状况进行临测研究对提高抗菌药物的合理使用水平具有乖要的意义。     

欧美导尿管产品监管技术要求的比较研究及对策

目的比较研究欧美导尿管产品有关技术法规的具体要求,以合理制定并提高我国的导尿管产品的安全性。方法对美国、欧盟等国家和地区的一次性使用导尿管产品安全性和有效性技术要求进行标准和法规的具体比较,并与我国的现有要求进行对比分析。结果与结论我国尚缺乏对导尿管产品的材料及涂层的监管,而材料和涂层是引发留置导尿感染的重要因素之一,故应加强对导尿管的材料化学性能要求和生物学评价,增加对导尿管涂层的技术要求。     

Catheter-associated urinary tract infections: diagnosis and prophylaxis

Catheter-associated urinary tract infections (CAUTI) are the commonest nosocomial infections worldwide. While they are often asymptomatic and frequently cost less than nosocomial surgical site infections or nosocomial pneumonia, they are major reservoirs of antimicrobial resistant pathogens. Numerous strategies have been devised in an attempt to reduce the incidence of CAUTI but few have proven effective. Novel technologies such as the potential use of antiseptic or antimicrobial coatings on catheters hold promise for possibly reducing these infections in the fight against antimicrobial resistance.     

重症脑卒中患者留置尿管漏尿相关因素分析

目的　分析重症脑卒中留置尿管患者漏尿的影响因素并提出处理对策。方法　通过查阅文献,筛查出留置尿管患者漏尿的原因主要包括尿管的型号、材质、是否感染、堵塞等。自制患者漏尿监测表,收集2018年1月至2020年12月广州医科大学附属第一医院神经重症病房110例（男71例,女39例,年龄19～86岁）留置尿管重症脑卒中患者的临床资料并进行统计学分析,探讨漏尿的影响因素。单因素分析两组间计量资料采用t检验,多组间计量资料采用方差分析。结果　110例重症脑卒中留置尿管患者中,有22例患者出现了漏尿,单因素分析中显示存在漏尿患者与非漏尿患者在年龄因素、文化程度因素、性别因素、尿管型号、气囊注水量、腹泻因素上差异无统计学意义（均P>0.05）,在住院天数、留置尿管天数、便秘、尿沉渣、发热、胃潴留、腹胀等差异有统计意义（均P<0.05）;logistics回归分析显示住院天数、留置尿管天数、便秘、腹胀、尿沉渣为留置尿管漏尿的因素。结论　重症脑卒中留置尿管患者漏尿发生率较高,应做好尿管管理,加强引起漏尿因素的控制和预防,可减少漏尿的发生。     

导尿管伴随性尿路感染患者感染生物被膜菌及药敏分析

目的：了解柳州地区近2年来导尿管伴随性尿路感染（UTIc）患者生物被膜菌的形成情况、构成比及耐药性,促进合理使用抗生素。方法：对92支（来自86位病人,平均插管56d（范围1-182d）拔除）导尿管进行生物被膜菌定量培养及耐药性检测。结果：92支导尿管有68支（占73．91％）分离出76株生物被膜菌;被膜菌以大肠埃希菌为主,占36．84％;其次为肠球菌属、铜绿假单胞菌、表皮葡萄球菌。定量研究显示其密度可高达4×10^8cfu／mL;大肠埃希菌和铜绿假单胞菌除对亚胺培南保持100％敏感外,对其他抗生素耐药率均呈上升趋势;革兰阳性球菌耐药率也相当严重,仅万古霉素对革兰阳性球菌敏感率为100％。结论：导尿管内的细菌寄殖和生物被膜形成是导尿管伴随性尿路感染发病机制中的1个重要因素及持续存在的1个病原来源。由于病原菌耐药性呈上升趋势,临床应根据尿培养结果合理使用抗菌药物。     

成人住院患者尿路感染及经验用药调查

目的：调查某院成人住院患者尿路感染及经验用药情况。方法：调取柳州市人民医院2015年1月-2016年12月住院尿培养阳性的成人尿路感染患者,分析不同年龄、性别及危险因素对尿路感染的影响及细菌耐药及经验用药情况。结果：505例住院尿路感染患者,女性（71.49%）、61~90岁（70.30%）所占比例高,其中77例为反复发作性尿路感染患者。糖尿病、尿路梗阻和留置导尿管患者分别占40.59%、35.05%和30.10%。致病菌以大肠埃希氏菌为主（57.28%）,ESBL （extended-spectrum β-lactamases,超广谱β-内酰胺酶）阳性率达42.57%,环丙沙星耐药率达56.77%;反复发作性尿路感染检出细菌耐药率更高;84例真菌感染,尿路梗阻和留置导尿管都占67.86%。经验用药中以喹诺酮类（51.68%）、β-内酰胺类/β-内酰胺酶抑制剂（28.12%）和头孢类（14.85%）为主;反复发作患者以喹诺酮类（44.16%）、β-内酰胺类/β-内酰胺酶抑制剂（42.86%）为主。结论：我院住院患者尿路感染以G^-菌为主,耐药率高;控制血糖、尽早拔除导尿管以减低尿路感染的危险因素;经验用药基本符合指南要求,但对反复发作的尿路感染患者,经验用药可减少喹诺酮类的使用。     

Urinary tract infections in patients with spinal cord lesions: treatment and prevention

Even though the mortality due to urinary tract complications has decreased dramatically during the last decades in individuals with spinal cord lesions (SCL), urinary tract infections (UTI) still cause significant morbidity in this population. Complicated UTI are caused by a much wider variety of organisms in individuals with SCL than in the general population and are often polymicrobial. Escherichia coli, Pseudomonas spp., Klebsiella spp., Proteus spp., Serratia spp., Providencia spp., enterococci, and staphylococci are the most frequently isolated bacteria in urine specimens taken from individuals with SCL. There is no doubt that the greatest risk for complicated UTI in these individuals is the use of an indwelling catheter. Intermittent catheterisation during the rehabilitation phase has been shown to lower the rate of UTI, and virtually eliminate many of the complications associated with indwelling catheters. Persons with SCL should only be treated for bacteriuria if they have symptoms. Generally, it is advisable to use antibacterial agents with little or no impact on the normal flora. Single agent therapy - in accordance with antimicrobial susceptibility test - is preferred. We advise extending treatment to at least 5 days, and in those with reinfection or relapsing UTI, at least 7 to 14 days, depending on the severity of the infection. The diagnosis of structural and/or functional risk factors is essential in order to plan an optimal treatment for UTI in individuals with SCL, which should include treatment of simultaneously occurring predisposing factors. The treatment of structural risk factors follows general urological principles, aiming for sufficient outlet from the bladder with minimal residual urine and low pressure voiding. For prevention of UTI, general cleanliness and local hygiene should be encouraged. If the patient has a reinfection or relapsing symptomatic UTI, it is important to check for inadequately treated infection and complications, which need special attention, in particular residual urine and urinary stones. No reliable evidence exists of the effectiveness of cranberry juice and other cranberry products. Prophylactic antibacterials should only be used in patients with recurrent UTI where no underlying cause can be found and managed, and in particular if the upper urinary tract is dilated. Antibacterials should not be used for the prevention of UTI in individuals with SCL and indwelling catheters. However, the use of prophylactic antibacterials for individuals with SCL using intermittent catheterisation or other methods of bladder emptying is controversial.     

Combination of paclitaxel and nitric oxide as a novel treatment for the reduction of restenosis

The combination of a nitric oxide (NO) donor and a paclitaxel-NO donor conjugate coated on a vascular stent was tested in a rabbit iliac artery model of stenosis as a potential therapy for restenosis. Paclitaxel was conjugated with a NO donor at the 7-position to give compound 7. An adamantane-based NO donor 14 was synthesized and combined with 7 to provide a burst of NO in the first few critical hours following injury to the vessel wall. Both 7 and 14 demonstrated antiproliferative activity (IC(50) = 20 nM and 15 microM, respectively) and antiplatelet activity (IC(50) = 10 and 1 microM, respectively). Stents were coated with a layer of a polymer containing test compounds. The total amount of NO eluted from the stents after a 6 h implantation in the rabbit iliac artery was 35%, 95%, and 69% of the original content for the stents coated with 7, 14, and the combination of 7 and 14, respectively. The antistenotic activity of 7 and 14 was determined in a 28-day rabbit model with two control groups (uncoated stents and polymer-coated stents) and two study groups (paclitaxel-coated stents and stents coated with the combination of 7 and 14). Polymer-coated stents caused inflammation and increased stenosis by 39% when compared to the uncoated stents. The stents coated with 7 plus 14 were as good as the uncoated stents, 41% better than the polymer-coated stents and 34% better than the paclitaxel-coated stents. These data indicate a beneficial effect of adding NO to an antiproliferative agent (paclitaxel) and suggest a potential therapeutic combination for the treatment of stenotic vessel disease.     

Urinary infections in the elderly: symptomatic or asymptomatic?

Asymptomatic bacteriuria is common in the elderly, occurring in as many as 25–50% of elderly nursing home residents. Asymptomatic bacteriuria itself should not be treated with antimicrobial therapy. Difficulties in communication, chronic genitourinary symptoms, and the high frequency of positive urine cultures, make ascertainment of symptomatic infection problematic for the functionally impaired elderly. Chronic genitourinary symptoms are not a manifestation of acute urinary infection, although acute deterioration in symptoms may be consistent with infection. Fever in an institutionalized elderly subject with a positive urine culture and without an indwelling catheter is due to urinary infection in less than 10% of episodes. However, there are no criteria to differentiate urinary infection from other sites in this clinical scenario. Thus, neither urine culture nor clinical presentation allows a diagnosis of symptomatic urinary infection to be made with a high level of certainty. Decisions with respect to antimicrobial therapy must be made on an individual basis and with an understanding of these diagnostic limitations. It is not realistic to expect to optimize antimicrobial usage in this population until issues of diagnostic uncertainty are addressed.     

某院复杂性尿路感染致病菌分布及抗菌药物应用情况

目的:了解某院复杂尿路感染常见致病菌的分布及抗菌药物应用情况,为临床抗菌药物的合理使用提供依据。方法:回顾性抽取2009年1月-2010年12月某院泌尿外科住院病历复杂性尿路感染,对中段尿培养及药敏试验结果进行统计,结合现阶段泌尿外科复杂性尿路感染抗菌药物的使用情况进行分析。结果:156株复杂性尿路感染致病菌中革兰阴性杆菌占69.9%革兰阳性球菌占24.3%,真菌占5.8%。革兰阴性菌以大肠杆菌最常见,占40.4%。从药敏试验得出,大肠埃希菌耐药率最低的是亚胺培南、美罗培南,其次为阿米卡星、头孢哌酮舒巴坦。产超广谱β-内酰胺酶(ESBLs)的大肠埃希菌、肺炎克雷伯菌的检出率分别为23.80%、38.4%。革兰阳性球菌对利奈唑胺、万古霉素、替考拉宁敏感性好。β-内酰胺类抗菌药物使用占抗菌药物的首位。结论:临床在治疗复杂性尿路感染时应根据药敏试验结果正确选择抗菌药物。     

A comparative multicentre study on the incidence of catheter-associated urinary tract infection between nitrofurazone-coated and silicone catheters

The efficacy of nitrofurazone-coated urinary catheter in inhibitory activity of catheter-associated urinary tract infection (CAUTI) was evaluated. The incidence rate and onset of CAUTI after catheterisation of standard silicone urinary catheters and nitrofurazone-coated catheters was compared. There was no statistical significance between the two groups in the incidence rate of CAUTI. However, in patients who had indwelling urinary catheters for 5-7 days, the incidence rate of CAUTI was significantly lower in the experimental group. Logistic regression analysis showed that the two variables, including age and period of insertion, affected the incidence rate of CAUTI significantly. Nitrofurazone-coated catheters can be useful for inhibition of CAUTI in patients who have indwelling urinary catheter for 5-7 days and in old-age patients.     

Clinical and economic effect of ciprofloxacin as an alternative to injectable antimicrobial therapy

The effect of the use of oral ciprofloxacin on patient outcome and the cost of antimicrobial therapy was investigated. In 1988 ciprofloxacin was placed on the antimicrobial formulary at a Veterans Affairs medical center. Patients with urinary tract infections, soft tissue infections, osteomyelitis, or pneumonia due to organisms that were documented as being susceptible to ciprofloxacin and either resistant to other oral antimicrobials or susceptible to other oral antimicrobials in patients allergic to such agents were monitored in a prospective open study over 12 months. When a patient was enrolled, the physician was asked to select the i.v. antimicrobial regimen that would have been used if ciprofloxacin were not available. Patient outcome was determined from medical records, and the difference in the costs of the oral and i.v. regimens was calculated. Clinical cure occurred in 96/100 (96%) of patients with urinary tract infection, 19/22 (86%) with soft tissue infection, 14/16 (88%) with osteomyelitis, and 10/12 (83%) with pneumonia. The overall cure rate was 139/150 (93%). The 11 clinical failures occurred in patients infected with methicillin-resistant Staphylococcus aureus (MRSA) alone, group D enterococcus alone, MRSA and Pseudomonas sp., and Pseudomonas sp. alone. The total cost avoidance achieved by using oral ciprofloxacin instead of i.v. antimicrobials was $77,158. Oral ciprofloxacin was an effective and cost-efficient alternative to traditional i.v. antimicrobial therapy in the patients studied.