南京地区1386株临床分离酵母的鉴定及药敏分析

本文旨在研究临床分离酵母的种类及药物敏感性。采用CHROMagar Candida显色培养基和API20CAUX对我院2008年1～12月分离自临床深部真菌感染患者的1386株酵母进行鉴定,并采用Rosco纸片扩散法分析其对两性霉素B、氟康唑、伊曲康唑、制霉菌素、伏立康唑、5-氟胞嘧啶、克霉唑的药物敏感性,数据用Whonet5.4软件分析。结果显示,分离出的1386株酵母中,白假丝酵母占58.95%,热带假丝酵母占15.95%,光滑假丝酵母占15.15%,克柔假丝酵母占2.74%,其他酵母占7.21%。葡萄牙假丝酵母、近平滑假丝酵母、白假丝酵母、热带假丝酵母、光滑假丝酵母和克柔假丝酵母对氟康唑的敏感率分别为95.45%、94.29%、82.99%、79.19%、68.57%和28.95%;白假丝酵母对5-氟胞嘧啶、两性霉素B、制霉菌素、伏立康唑、氟康唑、伊曲霉唑和克霉唑的敏感率分别为93.76%、93.15%、84.58%、84.09%、82.99%、80.05%和78.09%。结果提示,我院深部真菌感染仍以白假丝酵母为主,其次是热带假丝酵母、光滑假丝酵母;白假丝酵母对5-氟胞嘧啶、两性霉素B的敏感率最高;除克柔假丝酵母外的所有酵母对氟康唑的敏感率都很高。     

一株红酵母产类胡萝卜素的研究

对自然分离得到的产类胡萝卜素菌株Ｈｍ６８进行了菌种鉴定,色素成份分析,确定其产生的类胡萝卜素中含有β胡萝卜素。该菌株在１％麦芽糖为唯一碳源的培养基中生长良好,类胡萝卜素产量达６２５μｇ／ｇ。     

胶红酵母致真菌血症1例：临床及实验研究

目的报道1例由胶红酵母感染引起的真菌血症。方法通过对患者血培养分离致病菌,并作API 20C AUX及DNA序列测定鉴定菌种,采用抗真菌药敏纸片法对菌株进行体外药敏试验。结果患者,女性,38岁,因反复出现右乳肿块5个月行右乳肿块穿刺活检术,术后高热,发生于每日下午至夜间。2次查血真菌培养均为阳性,经菌落观察、API 20C AUX鉴定及基因测序,鉴定为胶红酵母。体外药敏试验显示对两性霉素B敏感,对伊曲康唑、氟康唑、伏立康唑耐药。未予治疗,24d后自愈。结论胶红酵母菌血症在国内罕见报道,其菌株毒力相对较低,在免疫功能正常患者中,部分病例可自愈。     

201例结核病患者分离株的药敏结果分析

本文旨在分析2008年12月～2009年5月就诊于上海市肺科医院的201例结核病患者结核分枝杆菌的药敏试验结果。结核分枝杆菌培养采用罗氏培养系统,药敏试验采用绝对浓度法。201例患者中,耐药率由高到低依次为异烟肼(INH,52.24%)、链霉素(SM,45.77%)、利福平(RFP,30.35%)、乙胺丁醇(EMB,28.86%)、阿米卡星(AK,28.18%)、利福喷汀(RIB,26.40%)、力克肺疾(Pa,25.56%)、对氨基水杨酸(PAS,23.60%)、丙硫异烟胺(Pt,23.03%)、卷曲霉素(CPM,20.56%)。其中,初治患者的耐药率为3.08%～26.15%,复治患者为27.50%～64.71%,耐多药患者为64.44%～100%。总体来看,与低浓度相比,高浓度SM、INH、EMB、RIB、Pt可明显降低结核分枝杆菌的耐药率(P0.05)。除INH、SM、RFP外,女性患者的耐药率均高于男性,耐多药率亦高于男性(P0.05)。结果提示,临床上应足量应用抗结核药物,对女性结核病患者要给予更多关注。     

红酵母产生类胡萝卜素的研究

本文对红酵母色素的形成,细菌破碎及色素提取的方法和色素性质的分析作了初步研究,通过生长曲线的测定,发现色素产生主要集中在对数期的后期。用薄层层析和吸收光谱分析,可以认为红酵母色素中β－胡萝卜素的含量很低,而大多是其它类胡萝卜素的组份,它们在极性和光吸收等方面同β－胡萝卜素相似。     

特比萘芬对24株黑酵母样真菌的体外药敏试验研究

目的 评价特比萘芬对7个属24株刺盾霉目（Chaetothyriales）黑酵母样真菌体外敏感性.方法 应用美国国家临床和实验室标准研究所（CLSI）的M38-A2方案.菌悬液终浓度为（0.4 ～5）＆#215;104 CFU/mL,30℃孵育5～7d,测定最低有效浓度（MEC）和最低抑菌浓度（MIC）.结果 特比萘芬对24株黑酵母样真菌MEC范围：0.125 ～4μg/mL,MEC90∶2μg/mL,MEC50∶0.25 μg/mL,GM∶0.392 9 μg/mL,特比萘芬对5株暗色真菌100％生长抑制,MIC范围：1～4 μg/mL,MIC50∶2μg/mL,MIC90∶4μg/mL.结论 特比萘芬对刺盾霉目（Chaetothyriales）中的黑酵母样真菌有较强的抑制作用,50％抑菌作用明显.     

临床分离161株念珠菌菌种鉴定及氟康唑药敏试验分析

目的调查临床分离的念珠菌种类及其对氟康唑的敏感性。方法采用科玛嘉念珠菌显色培养基和YBC平板对山东大学齐鲁医院细菌室分离到的161株念珠菌进行鉴定,并对分离出的白念珠菌分别采用NCCLS推荐的微量稀释法和ROSCO药敏纸片法对氟康唑进行药物敏感性试验。结果在161株念珠菌中白念珠菌为69．57％,热带念珠菌为19．88％,近平滑念珠菌为4．97％,克柔念珠菌为2．48％,光滑念珠菌为1．86％,其他念珠菌为1．24％。两种方法药敏结果显示：112株白念珠菌对氟康唑的敏感率分别为96．43％和97．32％,仅有2株耐药。结论白念珠菌仍然是我院分离率最高的念珠菌,其次是热带念珠菌和近平滑念珠菌。白念珠菌对氟康唑仍敏感,耐药菌株极少。     

糠秕马拉色菌药敏试验新方法的探讨

目的 建立一种新的糠秕马拉色菌药敏试验方法.方法 在ATBF2半固体培养基中添加不同种类和含量的脂质,用ATB Fungus 3药敏板条对ATCC14521和临床分离的糠秕马拉色菌进行了MIC测试.结果 孵育时间为72 h时对照孔中糠秕马拉色菌生长充分,吐温40浓度为1％时糠秕马拉色菌生长充分,且对药敏结果的影响最小.脂质的种类和含量对实验结果有影响.结论 用改良ATB Fungus 3药敏试验方法对糠秕马拉色菌进行抗真菌药敏试验,方法操作简便、结果易观察、试验结果重复性好.临床分离菌株与糠秕马拉色菌ATCC14521在ATB Fungus 3对照孔中的生长状况相同,结果易于判断.     

斑马鱼肠道中一株红酵母(Rhodotorula)的分离与鉴定

目的:分离及鉴定来自于斑马鱼肠道中的酵母菌.方法:采用马铃薯葡萄糖培养基( PDA),从斑马鱼肠道中分离到1株酵母菌,编号为ZF -2,进行形态学观察、生理特征、PCR扩增26S rDNA D1/D2区以及基因测序分析,并构建系统发育进化树.结果:ZF -2分离株为粉红色菌落、菌体呈椭圆形,芽殖;可以同化利用葡萄糖、乳糖、蔗糖等糖类;PCR扩增获得26S rDNA D1/D2区序列长度为642bp( HQ323251),序列比对分析表明与斯鲁菲亚红酵母(Rhodotorula slooffiae)相似性在99％-100％之间,构建的系统发育进化树显示菌株ZF-2与R.slooffiae( EU583485)关系最近,且位于同一分支.结论:首次从斑马鱼肠道中分离到斯鲁菲亚红酵母.     

提高红酵母胡萝卜素发酵产率的研究

以红酵母RY-998为实验菌株,采用液体摇瓶发酵方式,在培养基中加入氟化铵等6种添加物,研究它们对红酵母和长及胡萝卜素合成的影响。结果表明;除植酸和二甲基亚砜外,氟化铵,醋酸铵,L-亮氨酸和L-缬氨酸对红酵母胡萝卜素产率均有明显的提高作用;当同时添加氟化铵15mg/L,醋酸铵20mg/L,L-亮氨酸40mg/L和L-缬氨酸30mg/L时,细胞生物量,胡萝卜素含量和产率可分别比对照组提高42.2%,55.4%和121.2%。     

耐氟康唑念珠菌和耐伊曲康唑烟曲霉对泊沙康唑的敏感性测定

目的：测定耐氟康唑念珠菌和耐伊曲康唑烟曲霉临床分离株对泊沙康唑的敏感性。方法参照美国临床实验室标准化研究所制定的 M27-A3和 M38-A2方案,测定从临床获得的11株耐氟康唑的念珠菌和3株耐伊曲康唑烟曲霉对泊沙康唑的 MIC 值。结果对于氟康唑耐药的念珠菌,泊沙康唑的 MIC 范围是0.125-1μg/ mL。对于伊曲康唑耐药烟曲霉,泊沙康唑的 MIC 范围是0.06-0.5μg/ mL。结论11株耐氟康唑的念珠菌和3株耐伊曲康唑烟曲霉均对泊沙康唑有效。     

Rhodotorula infection. A systematic review of 128 cases from literature

Rhodotorula is an emerging opportunistic pathogen, particularly in immunocompromised patients. Many cases of fungemia associated with catheters, endocarditis, peritonitis, meningitis, and endophthalmitis are infections incited by this yeast. The main purpose of this study was to review all cases of Rhodotorula infection reported in the literature and to describe risk factors, underlying conditions and outcome. From 128 cases, 79% were fungemia (103 cases), 7% eye infections (nine cases) and 5% (six cases) peritonitis associated with continuous ambulatory peritoneal dialysis. Eighty seven percent of Rhodotorula infections are associated with underlying immunosuppression or cancer. The most common isolated risk factor associated with Rhodotorula infection was the use of a central venous catheter, which was found in 83.4% of Rhodotorula fungemia (86 cases). Rhodotorula mucilaginosa was the most common species of fungemia (74% of cases), followed by Rhodotorula glutinis with 7.7%. The species was not identified in 17% of the cases of fungemias. Amphotericin was the drug of choice in the treatment of fungemia and most of the eye infections were treated with topical amphotericin, although all patients lost their vision. All peritonitis cases associated with continous ambulatory peritoneal dialysis needed to have the Tenckoff catheter changed. The overall mortality of Rhodotorula infection was 12.6%.     

Antifungal susceptibility of epigallocatechin 3-O-gallate (EGCg) on clinical isolates of pathogenic yeasts

This is the first report to investigate the antifungal susceptibility of 21 clinical isolates of seven Candida species to epigallocatechin 3-O-gallate (EGCg) and to compare with six antifungal agents, amphotericin B (AMPH), fluconazole (FLCZ), flucytosin (5FC), itraconazole (ITCZ), micafungin (MCFG), and miconazole (MCZ), using a method following the National Committee for Clinical Laboratory Standards (NCCLS) M27-A guidelines. Among the tested species, Candida glabrata exhibited the highest susceptibility to EGCg (MIC50, 0.5-1 microg/ml and MIC90, 1-2 microg/ml) compared favorably with FLCZ, although they were slightly less susceptible than to AMPH, 5FC, MCFG, ITCZ, and MCZ. Candida guilliemondii and Candida parapsilosis (MIC50, 1-4 microg/ml and MIC90, 2-16 microg/ml) were also susceptible to EGCg, although they appear to be slightly less susceptible to EGCg than C. glabrata and the other antifungal agents tested. Moreover, the susceptibility of Candida krusei strains (MIC50, 2 microg/ml and MIC90, 4-8 microg/ml) to EGCg was approximately 2- to 8-fold higher than those of 5FC and FLCZ. Our data indicate that EGCg can inhibit clinically pathogenic Candida species, although the concentrations of EGCg for antifungal susceptibility were slightly higher than those of tested antifungal agents on the whole. Based on these results, we suggest that EGCg may be effectively used as a possible agent or adjuvant for antifungal therapy in Candidiasis.     

Yersiniabactin and other siderophores produced by clinical isolates of Enterobacter spp. and Citrobacter spp

We analyzed the ability of extraintestinal strains of Enterobacter spp. and Citrobacter spp. to employ different siderophore-mediated strategies of iron acquisition. All strains produced iron-chelating compounds. Cross-feeding assays indicated that most isolates of both Enterobacter spp. and Citrobacter spp. excreted catecholate siderophore enterobactin, less produced aerobactin, and single strains excreted hydroxamates different from aerobactin. Besides, we analyzed if the strains had the ability to produce the siderophore yersiniabactin coded by the Yersinia high-pathogenicity island (HPI). The presence of HPI genes was observed in single isolates of three species: E. cloaceae, E. aerogenes and C. koseri. A detailed polymerase chain reaction analysis revealed differences in the genetic organization of the HPIs; however, in a cross-feeding test we proved that yersiniabactin was produced and the island was functional.     

Susceptibility of Candida spp. clinical isolates to antimycotics and disinfectants

The incidence of candidiasis among immunocompromised patients and emergence of antimycotics resistant strains has increased significantly. The aims of this study were: to examine the in vitro activity of antimycotics and biocides against Candida clinical isolates; to detect cross-resistance of fungi to these preparations and to estimate whether disinfectants applied in hospital areas are active against clinical Candida isolates. In vitro susceptibility of 102 Candida isolates to eight antimycotics was examined by Etest and ATB Fungus. Sensitivity of these strains to four disinfectants and an antiseptic agent was tested according to EN 1275:2005. Amphotericin B, caspofungin and 5-fluorocytosine were the most effective antimycotics against all Candida isolates. Resistance to itraconazole and fluconazole was observed among C. krusei and C. glabrata. The MICs (Minimal Inhibitory Concentrations) for ketoconazole, voriconazole and posaconazole against Candida albicans ranged: 0.003 - >32 μg/ml and one strain was resistant to three agents tested. All analysed Candida strains were sensitive to biocides containing either chlorine, aldehyde, alcohol mixtures, glucoprotamin or chlorhexidine gluconate with isopropanol. Sensitivity to these agents was observed at concentrations lower than those concentrations recommended by manufacturers to achieve proper biocidal activity to those preparations. Our data suggest that these disinfectants can be effectively applied in clinical wards to prevent nosocomial Candida infections.     

In vitro antifungal susceptibility of clinical isolates of Candida spp. obtained from patients with different predisposing factors to candidosis

The increase in the number of infections caused by Candida species and the consequent use of antifungal agents favours an increase of resistant isolates. The aim of this study was to evaluate the antifungal susceptibility of Candida spp. isolates from patients with different systemic predisposing factors to candidosis. Seventy-nine Candida spp. isolates were assayed for in vitro susceptibility to amphotericin B, fluconazole, 5-flucytosine and itraconazole using the technique proposed by the Clinical and Laboratory Standards Institute (CLSI). Four C. albicans, one C. guilliermondii, four C. parapsilosis and two C. tropicalis isolates were resistant to amphotericin B. Only two isolate was resistant to itraconazole. All the isolates tested were susceptible to fluconazole and flucytosine. It could be concluded that the most efficient drugs against the Candida isolates studied were fluconazole and flucytosine and that all of the antifungal agents used in this study were effective against the Candida spp. isolates tested.     

Aerotolerance of human clinical isolates of Prevotella spp

AIMS: To determine the influence of oxygen exposure and growth stages on oxygen tolerance for clinical and reference specimens of the genus Prevotella. METHODS AND RESULTS: Tolerance to oxygen exposure was evaluated along growth stages for a total of four Prevotella isolates constituted by two strains tested soon after isolation from periodontally compromised patients and two reference strains kept frozen (-86 degrees C) in our laboratory collection. Additionally, the recently recovered isolates were also assayed after 4 months exposed to oxygen during laboratory handling. On solid medium, recently recovered Prevotella specimens proved to be less tolerant to oxygen exposure soon after isolation than when exposed for 4 months to oxygen during laboratory handling. Oxygen resistance of reference strains maintained in the laboratory collection showed to be the highest when compared with the clinical isolates both before and after oxygen exposure. When oxygen tolerance was tested during growth, bacterial cells from the exponential phase were more tolerant. Differences were observed in protein patterns between clinical isolates soon after recovery and after laboratory handling as determined by SDS-PAGE of crude cell-free extracts. However, SOD activities were similar in all bacterial samples tested. CONCLUSIONS: The ability to adaptively change oxygen tolerance was observed for pathogenic specimens of Prevotella. This property may be considered a virulence factor. SIGNIFICANCE AND IMPACT OF THE STUDY: Adaptative aerotolerance of Prevotella as a factor for virulence and survival.     

Distribution of virulence genes in clinical and environmental isolates of Aeromonas spp.

The distribution and phenotypic activity of the genes encoding for serine protease, glycerophospholipid-cholesterol acyltransferase, lipases, aerolysin/hemolysin and DNases were investigated in 234 isolates identified by 16S rDNA-RFLP representing all the species of Aeromonas. The former three genes were found to be highly conserved among the genus. Aerolysin/hemolysin and DNase genes and β-hemolytic activity were significantly more frequent in clinical than in environmental isolates. Aerolysin/hemolysin and serine protease genes were present in all β-hemolytic strains supporting serine protease as possibly important for the activation of the former gene. The high prevalence of virulence factors in clinical isolates indicates that they may play a role in the mechanisms of pathogenesis of these microorganisms. This revised version was published online in June 2006 with corrections to the Cover Date.