Biofilm formation by asymptomatic and virulent urinary tract infectious Escherichia coli strains

Escherichia coli is the most common organism associated with asymptomatic bacteriuria (ABU) in humans. In contrast to uropathogenic E. coli (UPEC) that cause symptomatic urinary tract infection, very little is known about the mechanisms by which these strains colonize the urinary tract. Here, we have investigated the biofilm-forming capacity on abiotic surfaces of groups of ABU strains and UPEC strains in human urine. We found that there is a strong bias; ABU strains were significantly better biofilm formers than UPEC strains. Our data suggest that biofilm formation in urinary tract infectious E. coli seems to be associated with ABU strains and appears to be an important strategy used by these strains for persistence in this high-flow environment.     

Specific selection for virulent urinary tract infectious Escherichia coli strains during catheter-associated biofilm formation

Biofilm-associated bacterial infections have a major impact on artificial implants such as urinary catheters, often with devastating consequences. The capacity of a microorganism to form a biofilm on a surface depends on the nature of the surface and its conditioning. When a urinary catheter is exposed to urine, various components adsorb onto the surface and form a conditioning film, which becomes the real interface where microbial interaction takes place. It follows that the material constituting the catheter determines the composition of the conditioning film, which in turn influences which microorganisms can attach. Urinary tract infectious (UTI) Escherichia coli range in pathogenicity and the damage they cause--from benign asymptomatic bacteriuria (ABU) strains, which inflict no or few problems to the host, to uropathogenic E. coli (UPEC) strains, which are virulent and often cause severe symptoms and complications. We have found that whereas ABU strains produce better biofilms on polystyrene and glass, UPEC strains have a clear competitive advantage during biofilm growth on catheter surfaces. Our results indicate that some silicone and silicone-latex catheters actually select for and promote biofilm formation of the most virulent group of UTI E. coli strains, hardly a desirable situation for the catheterized patient.     

辽宁省2017年至2021年尿培养主要病原菌分布及临床意义

泌尿系统感染的临床发病率很高,仅次于呼吸系统感染。对分离的细菌进行鉴定以及药敏试验,有助于了解引起感染的各种细菌分布以及耐药情况。研究患者尿培养病原菌的分布以及临床常用抗生素耐药情况,从而为临床正确、合理使用药物提供参考。回顾分析了辽宁省2017年1月至2021年12月共4 865份尿标本感染菌鉴定结果和大肠埃希菌（Escherichia coli）的药物敏感试验结果,数据来自辽宁省各大医院。采用法国梅里埃VITEK MS全自动快速微生物质谱检测系统和/或VITEK 2 Compact全自动微生物鉴定仪进行菌种鉴定,对来自门诊和住院泌尿系统感染患者尿标本中分离的1 411株大肠埃希菌进行药敏试验分析。结果表明,尿培养的病原菌中主要以革兰阴性菌为主占66.2％,其次为革兰阳性菌。在革兰阴性菌当中大肠埃希菌占37.1%。大肠埃希菌对氨苄西林、环丙沙星、复方新诺明、头孢唑啉的耐药性比较高,每年的耐药率均超过50%,对哌拉西林的耐药率在2021年已经达到100%。而对于阿米卡星、呋喃妥英、美罗培南、哌拉西林/他唑巴坦、头孢替坦和亚胺培南则出现较低的耐药性,五年的耐药率均低于10%。对于临床治疗尿路感染选用的左氧氟沙星、头孢呋辛和头孢曲松三个一线药物,大肠埃希菌对左氧氟沙星的耐药率有逐年上升的趋势,但对头孢呋辛和头孢曲松的耐药率变化不大。上述结果表明,辽宁省近五年尿培养的主要致病菌是革兰阴性菌,其中大肠埃希菌占有的比例很高。大肠埃希菌易产生耐药性,需对其加强监测,通过向临床提供最新最快的耐药性分析资料,可以更好地控制大肠埃希菌导致的感染,为临床合理用药及治疗提供帮助。     

糖尿病合并尿路感染患者尿液降钙素原水平及其临床意义

目的:探讨糖尿病合并尿路感染患者尿液降钙素原(PCT)水平及其临床意义。方法:选取2017年8月至2018年12月中山大学附属第五医院内分泌与代谢病科收治的糖尿病患者78例,以其中合并真性细菌尿者39例作为观察组,未合并尿路感染39例作为对照组,比较两组患者的临床资料以及相关实验室检查结果,同时留取尿液标本,观察组分别留取使用抗生素治疗前、后的尿液标本。采用酶联免疫吸附测定(ELISA)法检测尿液PCT浓度。分别比较观察组与对照组以及观察组治疗前后的尿液PCT水平,分析尿液PCT水平对于诊断糖尿病合并尿路感染的临床价值。结果:观察组尿液PCT水平为0.030 (0.025,0.039) ng/m L,明显高于对照组0.017 (0.011,0.021) ng/m L(P0.05);观察组有症状尿路感染与无症状细菌尿(ABU)的尿液PCT水平比较差异无统计学意义(P0.05),但其均显著高于对照组(P0.05);观察组使用抗生素治疗后的尿液PCT水平为0.031 (0.025,0.040) ng/mL,与治疗前相比较差异无统计学意义(P0.05)。尿液PCT对糖尿病合并尿路感染诊断的敏感度为82.05%,特异度为79.49%,阳性预测值为80.00%,阴性预测值81.58%,ROC曲线下面积为0.81 (95%CI为0.71-0.89, P0.0001)。结论:尿液PCT水平对糖尿病合并尿路感染有一定的诊断参考价值,但对于抗生素疗效的评估价值还需进一步深入研究。     

Rapid immunodetection of Escherichia coli

A filtration flow-through design was used to develop the rapid immunodetection of Escherichia coli. Polyclonal anti-E. coli IgG was conjugated to small, 0.8 Blue latex beads. Cells were mixed with conjugated beads in the presence of anti-E. coli monoclonal IgM. The suspension was then filtered through a 5 nitrocellulose membrane. The cell-containing complexes were effectively collected on the filter, forming a blue spot. The method produced reliable detection of E. coli at a concentration of 10⁵ cells ml^–1, which is a current benchmark figure for urinary tract infection (UTI) diagnosis.     

Ammonia enhanced dark respiration in Chlorella vulgaris is related to collapse of a transmembrane pH gradient

Abstract We obtained, by different methods, isogenic lipopolysaccharide (O antigen) and capsular polysaccharide (K antigen) mutants from Klebsiella pneumoniae strains able to induce experimental infections (cytitis and pyelonephritis) in rats. We compared the induction of experimental infections in rats by wild-type strains and the lipopolysaccharide and capsular polysaccharide mutants. The high-molecular mass lipopolysaccharide of K. pneumoniae is clearly implicated in the infection process of the rat urinary tract, whilst the capsular polysaccharide seems not to be involved to the same extent.     

泌尿外科住院患者泌尿系感染病原菌分布及其耐药性分析

了解泌尿外科住院患者泌尿系感染病原菌的分布及其对常用抗菌药物的耐药情况。对泌尿外科泌尿系感染住院患者的消毒中段尿培养结果进行回顾性分析,尿培养菌株的鉴定、药敏分析和统计分析采用VITEK2全自动微生物仪。3 a中泌尿外科泌尿系感染住院患者共分离到细菌1 233株,其中革兰阴性杆菌772株,占62.61%,革兰阳性球菌353株,占28.63%,真菌82株,占6.65%。菌株数居前5位的细菌依次为:大肠埃希菌、肠球菌属、洋葱伯克霍尔德菌、假丝酵母菌属和变形杆菌。分离大肠埃希菌产ESBLs率为66.18%,粪肠球菌中未发现VRE菌株,屎肠球菌VRE为0.8%。未发现对美洛培南耐药的大肠埃希菌,对肠埃希菌耐药率在10%以下的有亚胺培南、阿米卡星、哌拉西林/他唑巴坦和呋喃妥因。洋葱伯克霍尔德菌和铜绿假单胞菌对所监测的抗菌药物均有不同程度的耐药。未发现对万古霉素、替考拉宁及氨苄西林耐药的粪肠球菌。泌尿系感染的病原菌以大肠埃希菌和肠球菌为主,非发酵革兰阴性杆菌及假丝酵母菌所占比例超过20%,不容忽视,病原菌的耐药率较高,临床医生应根据尿培养和药敏试验结果合理使用抗菌药物。     

Antimicrobial resistance among urinary tract infection (UTI) isolates in Europe: results from the SENTRY Antimicrobial Surveillance Program 1997

The SENTRY Antimicrobial Surveillance Program was established to monitor the occurrence and antimicrobial susceptibility of bacterial pathogens via an international network of sentinel hospitals. Twenty European hospitals referred a total of 887 urinary tract infection (UTI) isolates to the European SENTRY reference laboratory during the period October–December 1997. Ninety percent of the referred species were represented by Escherichia coli (52%), Enterococcus spp. (12%), Klebsiella spp. (7%), Proteus spp. (7%), Pseudomonas aeruginosa (7%), and Enterobacter spp. (5%). The susceptibility of E. coli isolates to penicillins was less than 60%, while almost all of the isolates were susceptible to piperacillin/tazobactam (98% susceptibility), cephalosporins (98%), and carbapenems (100%). Amikacin was the best aminoglycoside (99.8% susceptibility). The susceptibility to quinolones was only 88–89%, with highest levels of resistance observed for isolates from Portugal, Italy, England, The Netherlands, and some centers in France, Spain, and Poland. The susceptibility of Klebsiella spp. to the newer generations of cephalosporins was 82–95% and to the carbapenems 100%. Amikacin was again the best aminoglycoside (94% susceptibility). The susceptibility of Enterobacter spp. to any ß-lactam antibiotic was poor, except for the carbapenems (100% susceptibility) and cefepime (90% susceptibility), while the susceptibility to aminoglycosides was 80–89%. Proteus spp. showed complete susceptibility to cefepime, ceftriaxone, the carbapenems, and piperacillin/tazobactam, while the susceptibility of P. aeruginosa isolates was poor, with best results for the carbapenems (susceptibility 89%), piperacillin/tazobactam (susceptibility 84%), and amikacin and ticarcillin (susceptibility to both 80%). Enterococcus spp. showed the highest susceptibility to vancomycin (98%), teicoplanin (98%), and ampicillin (94%).     

Human epithelial cells cultured from urine: Growth properties and keratin staining

Summary Epithelial cells can be cultured from the urine of newborn infants, providing a simple, noninvasive biopsy method. We established such cultures by standard techniques from 44% of uncontaminated, specimens obtained from newborn infants up to 1 week of age. There was an average of three colonies per milliliter of urine. Many cultures accomplished 15 to 25 population doublings in as many as five subcultures and yielded total potential culture sizes of 10⁴ to 6×10⁸ cells. Plating efficiency was high at each passage. The cultures displayed two morphologically distinct epithelial cell types. Immunofluorescent staining of keratin fibers in most of these cells further, identified them as epithelial. This work was supported by NIH grants, CA16754 (J. S. F., J. W. L.) and EY02472, AM25140, AM21358, and a Research Career Development Award (EY00125) to T.-T. S.     

老年人单纯性尿路感染病原菌的分布及耐药性分析

目的 研究引起老年人单纯性尿路感染的病原菌的分布情况及其耐药性.方法 对新疆医科大学第一附属医院2009年至2012年期间患者尿培养分离出的1035株细菌进行鉴定,并采用K-B纸片扩散法进行耐药性分析.结果 致老年人单纯性尿路感染的病原菌以大肠埃希菌为主(54.0％),其次分别为粪肠球菌(15.1％)、肺炎克雷伯菌(8.7％)、金黄色葡萄球菌(7.2％);大肠埃希菌、肺炎克雷伯菌和变形杆菌除对亚胺培南保持100％敏感外,对其他抗生素的耐药率均呈上升的趋势;粪肠球菌、金黄色葡萄球菌和表皮葡萄球菌除同时对万古霉素保持100％敏感外,对其他抗生素的耐药率也较严重.结论 老年人单纯性尿路感染的病原菌耐药性严重,不能单凭经验选择抗生素,应该在细菌培养和药敏试验的指导下慎重选用敏感药物.     

绿脓杆菌MSHA菌毛株菌苗对反复发作性尿路感染的治疗及其机制研究

采用绿脓杆菌ＭＳＨＡ菌毛株菌苗（ＰＡ－ＭＳＨＡ菌苗）治疗了４０例使用抗生素无效的ＲＵＴＩ,取得了满意的疗效,有效率９５％（３８／４０）,治愈率９２．５％（３７／４０）。对其中１８例进行了治疗前后血清抗ＭＳＨＡ菌毛株抗体效价和外周血Ｔ淋巴细胞亚群测定。疗后患者血清中抗ＭＳＨＡ菌毛株抗体效价较疗前增高８～６４倍;同时外周血Ｔ淋巴细胞亚群的比例得到了改善,ＣＤ３＾＋和ＣＤ４＾＋Ｔ细胞的百分率显著提高（Ｐ〈０．０１）,而ＣＤ８＾＋Ｔ细胞的百分率则显著下降（Ｐ〈０．００１）。治疗过程未见明显的副作用。研究表明：ＰＡ－ＭＳＨＡ菌苗对反复发作性尿路感染治愈率高,安全可靠,患者的免疫低下状态得到改善,且对多种病原菌（包括革兰阴性杆菌及其Ｌ型、金黄色葡萄球菌及其Ｌ型）所致的ＲＵＴＩ效果都很好。