细菌在含有游离胆红素的模拟胆汁体系中对胆固醇晶体形成的影响

目的探讨在含有游离胆红素(UCB)的模拟胆汁体系中细菌对胆固醇晶体形成的作用。方法大肠杆菌、铜绿假单胞菌和粪肠球菌分别加入含有不同浓度游离胆红素的模拟胆汁中,观察胆汁中胆固醇晶体形成时间(NT)的变化。结果游离胆红素缩短模拟胆汁中胆固醇晶体形成时间。铜绿假单胞菌和粪肠球菌缩短胆固醇晶体形成时间,但是同时加入游离胆红素后,NT未见进一步缩短。在CSI 0.6时单加铜绿假单胞菌的胆汁比单加UCB时的晶体形成时间更短。结论模拟胆汁体系中,细菌和游离胆红素对胆固醇晶体形成无协同作用。     

模拟胆汁体系中胆固醇结石内细菌对胆固醇晶体形成的作用

目的 探讨胆固醇结石中的细菌与结石形成的关系。方法 观察胆固醇结石中的细菌在模拟胆汁中的生长活性及其对胆固醇晶体成核时间(NT)的影响。结果 (1)模拟胆汁中大肠杆菌、铜绿假单胞菌、金黄色葡萄球菌、粪肠球菌、产孢梭菌和艰难梭菌生长旺盛;痤疮丙酸杆菌长势偏弱;脆弱类杆菌生长受抑制。(2)仅铜绿假单胞菌和粪肠球菌能缩短胆固醇晶体成核时间。(3)加入铜绿假单胞菌或粪肠球菌的胆汁,晶体形成呈现缓慢的阶段性演变过程。结论 铜绿假单胞菌和粪肠球菌在模拟胆汁中具有促成核活性,而痤疮丙酸杆菌无促成核作用。     

细菌促胆固醇晶体成核的机制研究

目的 定位铜绿假单胞茼、粪肠球菌促胆固醇晶体成棱活性来源,并探讨其作用途径.方法 分离细菌的外分泌物、细胞破坏后的上清和沉淀裂解组分.观察其在模拟胆汁体系中对胆固醇晶体形成的时间的影响,并对活性组分进行蛋白质提纯及促成核活性现察.结果 ①粪肠球菌和铜绿假单胞菌的外分泌组分和破壁上清组分能缩短胆固醇晶体成核时间(nucleation time,NT),破壁后沉淀物的裂解成分未见此活性.②大肠杆菌的外分泌组分不能缩短胆固醇晶体成核时间,但是其破壁上清组分能缩短胆固醇晶体成核时间.③从外分泌组分和破壁上清组分中提纯的蛋白质仍具有缩短胆固醇晶体成核时间的能力.结论 粪肠球菌和铜绿假单胞菌的外分泌组分和破壁上清组分,大肠杆菌的破壁上清组分具有促进胆固醇晶体形成的能力.蛋白质是重要的活性成分.     

胆固醇结石中细菌对人胆汁胆固醇晶体形成的作用

目的探讨胆固醇结石中的细菌与结石形成的关系。方法观察胆固醇结石中的细菌在人胆汁中的生长情况及其对胆固醇晶体形成的影响。结果(1)人胆汁中大肠杆菌、铜绿假单胞菌、金黄色葡萄球菌、无乳链球菌和脆弱类杆菌生长旺盛；痤疮丙酸杆菌、产孢梭菌和艰难梭菌生长缓慢；粪肠球菌生长受抑制。(2)在未离心的人胆汁中，大肠杆菌、铜绿假单胞菌、金黄色葡萄球菌、无乳链球菌、粪肠球菌和脆弱类杆菌明显缩短胆固醇晶体成核时间(NT)，产生的最大晶体量高于无菌的对照胆汁，在离心后的胆汁中该作用消失；痤疮丙酸杆菌、产孢梭菌和艰难梭菌在离心或未离心的胆汁中均不能显著降低NT，但是后两者在未离心的人胆汁中产生的最大晶体量高于对照胆汁。(3)人胆汁离心后的沉淀中含有蛋白质。结论(1)不同细菌在人胆汁中的生存能力有差异。(2)大肠杆菌、铜绿假单胞菌、金黄色葡萄球菌、无乳链球菌、粪肠球菌和脆弱类杆菌在未离心的人胆汁中有促成核作用。(3)离心后人胆汁中某些蛋白质的丢失可能与细菌促成核能力的丧失有关。(4)痤疮丙酸杆菌无促成核作用。     

胆囊结石患者主要感染病原菌谱分析

目的:研究胆囊结石主要感染病原菌的分布及特征。方法:对胆囊结石60例,非胆囊结石66例患者手术切除的胆囊、结石和胆汁样本分别行细菌学培养,对主要检出菌做脉冲场凝胶电泳,分析菌株同源性。结果:126例患者共检出88株病原菌,排在前3位的是铜绿假单胞菌,肺炎克雷白杆菌和大肠杆菌,其中铜绿假单胞菌和肺炎克雷白杆菌在结石组和非结石组的检出率差异有统计学意义,经脉冲场凝胶电泳它们分属不同的型别。结论:胆囊结石患者感染病原菌以革兰阴性菌为主,细菌感染可能参与了胆囊结石的形成。     

胆固醇结石患者胆囊细菌感染的研究

目的 比较胆固醇类结石患者和非胆石症患者胆道细菌感染情况.方法 用不依赖细菌培养的半定量PCR和16SrRNA序列对照法,检测76例胆固醇类结石患者胆囊黏膜、胆汁和胆石中细菌DNA,与34例非胆石患者对照.结果 胆石组和非胆石组胆汁细菌DNA阳性率分别为77%和67%,胆囊黏膜细菌DNA阳性率分别为64%和69%,两组间差异均无统计学意义(P＞0.05).胆石组细菌种类主要为大肠杆菌、铜绿假单胞菌、金黄色葡萄球菌、不动杆菌、链球菌、鞘氨醇单胞菌、脆弱类杆菌和痤疮丙酸杆菌,胆石组菌种比非胆石组丰富,非胆石组菌种基本上均能在胆石组中找到.结论 胆固醇结石与非胆石症患者胆道细菌感染率相似,胆固醇结石中存在细菌不足以证明细菌参与胆固醇结石的形成.     

综合模拟胆汁体系中未结合胆红素与胆固醇的溶解方式

目的:在含有未结合胆红素(UCB)、胆固醇、磷脂和胆盐的综合模拟胆汁体系中,探讨UCB与胆固醇的溶解方式及相互关系.方法:检测UCB在Small模拟胆汁、胆汁泡(胆固醇-磷脂泡)溶液、泡对照组和本底对照组中的饱和溶解度,并分析比较Small模拟胆汁在加入过量UCB保存、过滤前后胆固醇含量的变化;同时观察UCB对胆固醇过饱和胆汁成核时间(NT)的影响.结果:微胶粒、泡能结合UCB而使其溶解,UCB能促进胆固醇结晶形成、NT缩短,且其差异显著.结论:UCB溶解依赖胆固醇的溶解方式,同时又可能作为促成核因子参与胆固醇结石形成.     

应用噬菌体预防铜绿假单胞菌所致的移植皮片坏死

铜绿假单胞菌常寄生于烧伤创面,可引起移植皮片的坏死、创面扩大甚至全身感染,局部用药作用有限,抗生素常因耐药而无效。Smith已证实噬菌体能有效治疗埃希大肠杆菌感染。现研究铜绿假单胞菌感染对豚鼠皮肤移植存活的影响和噬菌体的控制作用。伯明翰医院烧伤科临床分离铜绿假单胞菌3719菌株,对小鼠有很强的毒性。用Adams的方法从污水中分离获得铜绿假单胞菌噬菌体。本实验所用的是从169份噬菌体标本中筛选出最有效的噬     

铜绿假单胞菌对胰腺癌细胞的抑癌效应及分子机制研究

目的 :主要探讨铜绿假单胞菌抗胰腺癌细胞的效果及其主要机制。方法:采用CCK8法检测胰腺癌细胞经铜绿假单胞菌作用后细胞增殖率变化,并应用透射电镜观察药物处理后细胞超微结构的改变。通过AnnexinⅤ/PI流式细胞术检测细胞经不同浓度铜绿假单胞菌处理后细胞凋亡的变化,分析胰腺癌细胞周期改变。Western印迹检测胰腺癌细胞表皮生长因子受体(EGFR)信号通路相关蛋白质的表达。结果:铜绿假单胞菌可明显抑制胰腺癌细胞增殖,并可观察到形态学的明显凋亡改变。铜绿假单胞菌处理后肿瘤细胞凋亡明显增加,并诱导肿瘤细胞的细胞周期阻滞,肿瘤细胞EGFR信号通路磷酸化蛋白表达量明显下降。结论:铜绿假单胞菌可诱导胰腺癌细胞凋亡,抑制肿瘤生长,阻滞细胞周期,EGFR通路抑制是铜绿假单胞菌诱导胰腺癌细胞凋亡的重要机制之一。     

铜绿假单胞菌的临床分布及耐药性分析

铜绿假单胞菌已是院内感染的重要病原菌之一。有报道铜绿假单胞菌的耐药率呈上升趋势,己报道本院铜绿假单胞菌的耐药率很高。为及时了解全院分离的铜绿假单胞菌耐药性与不同病房分离的铜绿假单胞菌耐药性是否相同,本研究对2012年10月至2012年12月间全院分离的142株铜绿假单胞菌和不同病区（ICU重症监护病房和神经外病房）分离的铜绿假单胞菌分别进行耐药性分析,现报道如下。     

Antimicrobial effects of two anaesthetic agents: dexmedetomidine and midazolam

Some anaesthetic agents are known to inhibit microbial growth. The aim of this in vitro study was to investigate possible antimicrobial effects of two frequently used agents in intensive care units, dexmedetomidine and midazolam. Antimicrobial effect was tested on Staphylococcus aureus, Enterococcus faecalis, Escherichia coli and Pseudomonas aeruginosa by broth microdilution method. Midazolam showed inhibitor and bactericidal effect on S. aureus at concentrations 256 mmicrog x ml(-1) and 512/microg x ml(-1) respectively and on E. faecalis at concentrations 128 microg x ml(-1) and 256 microg x ml(-1). Dexmedetomidine demonstrated inhibitor effect on S. aureus, E. coli and P aeruginosa at concentrations 32 microg x ml(-1), 16 microg x ml(-1) and 16 microg x ml(-1) respectively. Midazolam had inhibitor and bactericidal effects on S. aureus and E. faecalis. Dexmedetomidine had only inhibitor effects on S. aureus, E. coli and P aeruginosa. Further studies are needed to determine the antimicrobial mechanisms and clinical applications.     

Pre-inoculation of urinary catheters with Escherichia coli 83972 inhibits catheter colonization by Enterococcus faecalis.

PURPOSE: The capacity of a preexisting coating of Escherichia coli 83972 to reduce catheter colonization by Enterococcus faecalis 210 was investigated. Enterococcus was chosen for these trials since it is a common urinary pathogen in patients with an indwelling urinary catheter. MATERIALS AND METHODS: Each experiment tested 3 growth conditions. Group 1 or E. coli plus Enterococcus catheters were exposed to E. coli 83972 for 24 hours and then to Enterococcus for 30 minutes. Group 2 or E. coli alone catheters were incubated in E. coli for 24 hours and then in sterile broth for 30 minutes. Group 3 or Enterococcus alone catheters did not undergo the initial incubation with E. coli before the 30-minute incubation with Enterococcus: All catheters were then incubated in sterile human urine for 24 hours. Catheters were washed with saline and cut into 5, 1 cm. segments. Each segment was sonicated and the sonication fluid was diluted and plated. The results of each of the 5 segments were averaged and the set of experiments was repeated 7 times. RESULTS: A preexisting coating of E. coli 83972 reduced catheter colonization by E. faecalis 210 more than 10-fold. Enterococcus alone catheters had a median of 9.7 x 10(5) enterococci per cm., whereas E. coli plus Enterococcus catheters had a median of 0.38 x 10(5) enterococci per cm. (p = 0.016). CONCLUSIONS: Pre-inoculating urinary catheters with E. coli 83972 significantly impedes catheter colonization by Enterococcus: These promising in vitro results prompt the clinical investigation of this particular application of bacterial interference.     

Bacterial adherence to ofloxacin-blended polylactone-coated self-reinforced L-lactic acid polymer urological stents

OBJECTIVE: To determine whether ofloxacin coating has any effect on bacterial adherence to bioresorbable self-reinforced L-lactic acid polymer (SR-PLLA) urological stents. MATERIALS ANS METHODS: SR-PLLA stents were coated with epsilon-caprolactone/L-lactide copolymer blended with ofloxacin at three different concentrations of ofloxacin (0.5, 2 and 5% w/w). The adherence of five bacterial strains (Pseudomonas aeruginosa, Enterococcus faecalis, Proteus mirabilis and two strains of Escherichia coli) to the coated SR-PLLA stents was analysed. Uncoated stent pieces were used as controls. The effect of ofloxacin coating on bacterial growth in the microenvironment of the stent pieces was also analysed. RESULTS: Ofloxacin coating prevented bacterial adherence to SR-PLLA stent material; this effect correlated significantly with the ofloxacin concentration of the caprolactone coating. Ofloxacin coating reduced the amount of bacteria in the microenvironment of the stent, but because of natural resistance, ofloxacin coating had little effect on E. faecalis. CONCLUSION: Except for E. faecalis, ofloxacin coating may reduce stent-associated infections. However, further studies are needed to confirm its biocompatibility and efficacy in clinical use.     

In-vitro activity of triclosan-eluting ureteral stents against common bacterial uropathogens

BACKGROUND AND PURPOSE: Ureteral stents are commonly used in urology today, but the biofilms that form on them within hours of placement may harbor bacteria that can result in infection or encrustation. Triclosan is an antimicrobial commonly used in consumer and medical products that inhibits bacterial fatty-acid synthesis. The bactericidal and bacteriostatic effect of a triclosan-eluting ureteral stent was tested against clinical isolates of common bacterial uropathogens in an in-vitro setting. MATERIALS AND METHODS: Triclosan eluted from a drug-loaded ureteral stent was suspended in artificial urine with bacterial pathogens (Escherichia coli C1214, Proteus mirabilis 296, Enterococcus faecalis 1131, Klebsiella pneumoniae 280, Staphylococcus aureus Newman, Pseudomonas aeruginosa AK1) to assess growth, virulence-promoter activity, and bacterial adherence to the stent. Generic stents were utilized as controls. RESULTS: Triclosan inhibited the growth of E. faecalis, K. pneumoniae, S. aureus, and P. mirabilis in a dose-dependent manner. Pseudomonas aeruginosa demonstrated significant resistance. Lower concentrations of triclosan downregulated E. coli virulence-factor promoters of outer membrane protein X and p-fimbriae. Triclosan stents had significantly fewer adherent viable bacteria than control stents. CONCLUSIONS: Triclosan-eluting ureteral stents inhibit the growth of common bacterial uropathogens and thus may reduce the incidence of urinary-tract infections and, potentially, encrustation. This drug-eluting stent provides both mechanical drainage of the upper urinary tract and local antibiosis.     

Investigation and analysis of the characteristics and drug sensitivity of bacteria in skin ulcer infections

Purpose: Skin ulcer is a common type of disease affecting patients'' health and quality of life, and bacterial infection increases the difficulty of its management. Methods: The present study collected the results of bacterial culture sampled from the surface of 110 cases of skin ulcers at our hospital from January 2011 to December 2012. We analyzed the constituent ratios of ulcer surface bacteria, the change in the main infectious bacteria and the results of drugsensitivity testing for common bacteria. In addition, the characteristics of bacterial infection of skin ulcers were summarized. Result: Of the 110 samples, 90 isolated bacteria were cultured. Sixty-one were Gram-negative bacteria, mainly comprising Pseudomonas aeruginosa, Klebsiella pneumoniae, Enterobacter cloacae and Escherichia coli. In addition, 23 isolates were Gram-positive bacteria, mainly comprising Staphylococcus aureus and Enterococcus faecalis. The probability of a negative bacterial culture in 2012 was significantly lower than that in 2011 (16.7% vs. 40.0%, p < 0.01). Moreover, the probability of P. aeruginosa infection in 2012 was significantly higher than that in 2011 (31.7% vs. 14.0%, p < 0.01). P. aeruginosa was resistant to seven commonly used antibiotics. Both K. pneumoniae and E. coli had higher resistance to ampicillin. E. cloacae were not sensitive to piperacillin/tazobactam. Acinetobacter baumannii was resistant to all the tested drugs. S. aureus, E. faecalis and Staphylococcus epidermidis had high resistance to clindamycin. There was other drug resistance to reflect the higher rate of skin bacterial resistance. Conclusion: Skin bacterial resistance rate is high. Gram-negative bacteria gradually account for the majority, and P. aeruginosa becomes the most important skin infection pathogen. These characteristics of bacterial infections of skin ulcers provide a significant reference for guiding the selection of antibiotics, better controlling infections of skin ulcers and accelerating the healing of skin ulcers.     

Intrathecal baclofen does not inhibit the growth of different bacterial species and Candida albicans

BACKGROUND: The antimicrobial activity of intrathecal baclofen was investigated. Several different microorganisms were used: Staphylococcus aureus (beta-lactamase-positive and beta-lactamase-negative strains); S epidermidis; Enterococcus faecalis; Klebsiella pneumoniae; Escherichia coli; Pseudomonas aeruginosa; and Candida albicans. METHODS: Three experimental approaches were used to assess baclofen antimicrobial activity: (1) determination of the MIC; (2) determination of the MBC; and (3) kinetic time-kill assay. Experiments were performed according to current methods of the NCCLS. RESULTS: As compared with control organisms exposed to physiologic saline, organisms exposed to baclofen over a 10-day period failed to reduce the number of viable cells by at least 3 log(10), as requested by NCCLS criteria. CONCLUSIONS: Because the viability of the investigated organisms was not reduced over that of microbial suspensions exposed to physiologic saline, we conclude that intrathecal baclofen has no measurable activity against different bacterial species and C albicans.     

急性胆道感染患者胆汁病原菌分布及耐药率变迁

目的探讨急性胆道感染患者胆汁病原菌分布和耐药率的变化趋势。方法回顾性分析2009年7月至2019年7月于上海交通大学医学院附属新华医院普通外科行胆囊穿刺或内镜下逆行胰胆管造影引流的223例急性胆道感染患者的临床资料,男性141例,女性82例,年龄67.3岁(范围:28~93岁)。每例患者抽取胆汁3~5 ml,送至检验科细菌培养室,对胆汁进行细菌培养、鉴定和药物敏感性试验。按照患者就诊时间分为前、后两组,前组(n=124)的收治时间为2009年7月至2014年7月,后组(n=99)的收治时间为2014年8月至2019年7月,对比两组患者的病原菌分布及常见细菌的耐药率变化趋势。采用WHO细菌监测网提供的WHONET软件对药物敏感性试验结果进行分析。不同时间段耐药率的比较采用χ²检验。结果本研究包括急性胆管炎患者147例,急性胆囊炎患者76例,共培养出病原菌376株。其中革兰阳性菌98株(26.1%),革兰阴性菌269株(71.5%),真菌9株(2.4%)。革兰阳性菌中前3位为屎肠球菌(49.0%,48/98)、粪肠球菌(20.4%,20/98)、铅黄肠球菌(7.1%,7/98);革兰阴性菌中前5位为大肠埃希菌(33.5%,90/269)、肺炎克雷伯菌(13.8%,37/269)、铜绿假单胞菌(13.0%,35/269)、鲍曼不动杆菌(12.6%,34/269)、阴沟肠杆菌(4.8%,13/269)。2009年至2019年急性胆道感染患者胆汁中革兰阳性菌(前组∶后组为25.3%∶28.2%)与革兰阴性菌(前组∶后组为74.7%∶71.8%)的比例无明显变化。革兰阳性菌以肠球菌属(85.7%,84/98)为主,革兰阴性菌以大肠埃希菌(33.5%,90/269)为主。前组中鲍曼不动杆菌占革兰阴性菌比例为7.8%(11/142),后组为18.1%(23/127),比例较前5年上升10.3%;铜绿假单胞菌在前组中比例为16.9%(24/142),后组为8.7%(11/127),比例下降8.2%;其余菌株变化不显著。常见革兰阴性菌中,肺炎克雷伯菌对大部分抗菌药物的耐药率呈上升趋势(前组:0/15~4/13,后组:55.0%~70.0%;χ²=3.996~16.942,P=0.000~0.046);鲍曼不动杆菌的耐药率总体较高,但在前、后两组中的耐药率无较大变化;铜绿单胞菌属对抗菌药物的耐药率有升有降;大肠埃希菌的总体耐药率较平稳,呈轻度上升趋势。结论急性胆道感染患者胆汁病原菌中以革兰阴性菌为主,2009年至2019年各种革兰阴性菌的构成比无明显变化,但耐药率呈上升趋势;革兰阴性菌中,大肠埃希菌是最主要病原菌,感染比例无明显变化,鲍曼不动杆菌的感染比例大幅上升,铜绿假单胞菌的感染比例呈下降趋势。