阿司匹林对白念珠菌生物膜的抑制作用

目的 研究阿司匹林对白念珠菌生物膜的抑制作用.方法 采用微量平板法制备白念珠菌生物膜,控温37℃,加同浓度阿司匹林,不同时期以活菌数判断其对白念珠菌生物膜的抑制作用;加不同浓度阿司匹林,同时期以活菌数判断其对白念珠菌生物膜的抑制作用.结果 1 mmol/L阿司匹林对白念珠菌芽管生成无抑制作用;阿司匹林对白念珠菌游离菌MIC为0.81-1.59 mmol/L;1mmol/L阿司匹林在不同时期对白念珠菌生物膜均有抑制作用;0.4～0.8 mmol/L阿司匹林对24 h白念珠菌生物膜均有抑制作用.结论 阿司匹林对白念珠菌芽管无抑制作用,对白念珠菌游离菌和生物膜均有抑制作用.     

国产伏立康唑对临床分离病原真菌体外抗菌活性研究

目的了解国产伏立康唑对北京和我国其他地区临床分离的常见病原真菌体外抗菌活性。方法分别参照CLSIM27-A2和M38-A方案测定伏立康唑对144株酵母和82株产孢丝状真菌的抗菌活性。受试菌株包括念珠菌114株（含氟康唑获得性耐药白念珠菌）、新型隐球菌20株、阿萨希毛孢子菌10株、曲霉62株（含伊曲康唑耐药曲霉及两性霉素B不敏感曲霉）、镰刀菌10株、尖端赛多孢菌10株。结果伏立康唑对念珠菌（不包括氟康唑耐药和剂量依赖敏感白念珠菌）、新型隐球菌、阿萨希毛孢子菌的MIC50≤0．5mg／L、MIC90≤1mg／L；而对氟康唑获得性耐药白念珠菌MIC50和MIC90均〉16mg／L。对曲霉、尖端赛多孢菌的MIC50≤1mg／L、MIC90≤2mg／L，对镰刀菌的MIC50和MIC90分别为4mg／L和〉16mg／L。结论伏立康唑对多数酵母有较强的体外抗菌活性，尤其是对克柔念珠菌和光滑念珠菌等氟康唑天然耐药菌株。该药对多数产孢丝状真菌也有较好的体外抗菌作用，包括伊曲康唑耐药及两性霉素B不敏感的曲霉以及对多种抗真菌药物耐药的尖端赛多孢菌；但其对氟康唑获得性耐药白念珠菌有一定交叉耐药。     

米诺环素对白念珠菌的抑制作用分析

目的初步探讨米诺环素对白念珠菌的抑制作用及其机制,为临床抗真菌治疗提供依据。方法收集分离的46株酵母菌临床标本,使用纸片扩散法对临床菌株进行药物敏感试验;采用电镜观察米诺环素对白念珠菌作用后菌株形态学的变化;采用XTT法检测白念珠菌生物膜代谢活性;检测半胱氨酸蛋白酶(Caspase)3的活化程度,对比分析各组之间差异。结果 46株酵母菌临床菌株中,米诺环素对白念珠菌表现出抑制作用;与对照组比较,米诺环素处理后的白念珠菌菌丝增长明显受抑制,生物膜代谢活性明显降低(P0.05),Caspase 3活性明显升高(P0.05)。结论米诺环素可抑制白念珠菌菌丝生长,通过诱导白念珠菌细胞凋亡而发挥抑制活性作用,这可能与生物膜和Caspase 3活性相关。     

芍药苷对白色念珠菌生物膜的作用

背景：研究证实中药赤芍有效成分对白色念珠菌有较好的抑制作用,但其单体芍药苷对白色念珠菌生物膜是否有抑制作用未见报道。目的：观察芍药苷对体外白色念珠菌生物膜的影响。方法：用RPMI-1640分别按2倍稀释法制备5个浓度梯度（4,2,1,0.5,0.25 g/L）的芍药苷溶液。用RPMI-1640稀释洗必泰为5个浓度梯度（2%,1%,0.5%,0.25%,0.125%）。采用琼脂扩散法检测不同浓度梯度芍药苷或洗必泰对白色念珠菌的抑菌直径。MTT法检测不同浓度洗必泰或芍药苷对白色念珠菌细胞黏附的作用,以及对白色念珠菌生物膜的抑制作用,并且利用激光共聚焦扫描显微镜和死菌活菌荧光染色技术相结合方法观察常态及药物作用下的白色念珠菌生物膜。结果与结论：洗必泰与芍药苷均有抑菌能力,抑菌环直径与药物浓度呈正相关;除2 g/L芍药苷组与1%,2%洗必泰组抑菌环直径无差异外,其余组间两两比较差异均有显著性意义。不同质量浓度芍药苷对白色念珠菌的细胞黏附都具有抑制作用,对白色念珠菌生物膜也具有抑制作用,且抑制率与药物质量浓度呈正相关。观察48 h时常态生物膜结构中大部分是活菌,有少量死菌存在;随芍药苷质量浓度改变白色念珠菌生物膜中死菌比例不断增高,其抑菌活性相对弱于洗必泰。表明芍药苷对体外白色念珠菌生物膜有较明显的抑制作用。     

阿司匹林对骨髓间充质干细胞生长的影响及可能的作用途径

目的：观察阿司匹林对骨髓间充质干细胞生长和参与细胞信号传导的β-连环素表达的影响。方法：实验于2003—08／2005-01在阜外心血管病医院再生医学中心完成。选用体质量80g左右SD大鼠24只。体外分离培养SD大鼠的骨髓间充质干细胞，应用^3H-胸腺嘧啶核苷掺入法观察不同浓度(1，5，10mmol／L)的阿司匹林作用24h后对骨髓间充质干细胞DNA合成的影响。以免疫印迹法观察上述浓度的阿司匹林作用24h后骨髓间充质干细胞表达总β-连环素的情况和β-连环素的磷酸化水平。结果：①不同浓度(1，5，10mmol／L)的阿司匹林作用于骨髓间充质干细胞24h后，其^3H-胸腺嘧啶核苷掺入值明显降低。1，5和10mmol／L的阿司匹林作用后的细胞^3H-胸腺嘧啶核苷掺入的每分钟脉冲数明显低于对照组[(11061．83&;#177;1004．37)，(6609．33&;#177;1432．60)，(133．33&;#177;51．56)，(13080．83&;#177;1869．96)min^-1，P&;lt;0．05～0．01]。说明阿司匹林抑制了骨髓间充质干细胞的DNA合成。②^3H-胸腺嘧啶核苷掺入能力与阿司匹林浓度(1—10mmol／L)呈显著负相关(r=-0．95，P&;lt;0．05)。在10mmol／L浓度下，骨髓间充质干细胞的^3H-胸腺嘧啶核苷掺入几乎全部被抑制。③免疫印迹法结果表示，阿司匹林浓度与骨髓间充质干细胞33位丝氨酸磷酸化的β-连环素表达呈正相关(r=0．89，P&;lt;0．05)。说明阿司匹林的作用使β-连环素的磷酸化水平增高，即促进其降解。④3个浓度的阿司匹林作用24h后骨髓间充质干细胞总β-连环素的表达水平与对照组比较，无明显差异(P&;gt;0．05)。因此结合③可知阿司匹林使胞浆内未磷酸化的β-连环素降低。结论：阿司匹林对骨髓间充质干细胞的生长有明显抑制作用，这种作用可能是通过提高骨髓间充质干细胞中β-连环素磷酸化，促进其降解，进而抑制β-连环素参与的Wnt／β-连环素信号通路所致，其抑制作用的发生与阿司匹林的药物浓度相关。     

改良纸片扩散法检测172株酵母菌对氟康唑的敏感性

目的 研究氟康唑对172株酵母菌的体外抗菌活性。方法 酵母菌收集自2004年4月至2004年10月从住院患者采集的标本。采用NCCLS建议的改良纸片扩散法敏感试验，并以标准菌株做质量控制。结果 白念珠菌最常见，有110株，占64．0％；光滑念珠菌31株，占18．0％；热带念珠菌20株，占11．6％；克柔念珠菌3株，占1．8％；其他8株，占4．6％。白念珠菌、光滑念珠菌、热带念珠菌和克柔念珠菌对氟康唑的敏感率为92．3％～100％。结论 氟康唑对白念珠菌、光滑念珠菌、热带念珠菌和克柔念珠菌有较好的抗菌活性。     

临床分离白色念珠菌的生物膜形成与耐药关系研究

目的分析临床标本分离的白色念珠菌生物膜形成情况，探讨其与耐药的关系，为临床诊疗白色念殊菌感染提供可靠依据。方法用黑马鉴定板和全自动细菌鉴定仪鉴别白色念珠菌120株，电镜下观察白色念珠菌生物膜形成，用M—H琼脂培养基进行药敏试验。结果白色念珠菌生物膜的阳性率为75．0％（90／120）。白色念珠菌有生物膜者对抗真菌伊曲康唑、氟康唑、酮康唑、伏立康唑、制霉菌素和两性霉素B药物的耐药率分别为83．3％，77．8％，61．1％，84．4％，44．4％和38．9％。而无生物膜者对抗真菌药物的耐药率分别为33．3％，26．7％，20．0％，36．7％，16．7％和10．0％。白色念珠菌有生物膜者对抗真菌药物的耐药率明显高于无生物膜者，两者比较差异有统计学意义（χ^2=7．41～27．23，P均〈0．01）。有生物膜的白色念珠菌对制霉菌素和两性霉素的耐药率均明显低于其它唑类抗真菌药物（χ^2=8．21～26．37，7．49～26．87，P均〈0．01）。对酮康唑的耐药率明显低于其它唑类（χ^2=3．48～5．24，P均〈0．05）。结论白色念珠菌的生物膜形成率较高，致使其对抗真菌药物的耐药性增加，可首选两性霉素B治疗。     

阿坝州1231例藏族人群血脂参考值调查

目的建立阿坝州藏族健康成人血脂4项参考值，促进临床对血脂指标的科学运用。方法总胆固醇（TC）、三酰甘油（TG）采用氧化酶-终点法，高密度脂蛋白胆固醇（HDL-C）、低密度脂蛋白胆目醇（LDL-C）采用直接一步法，均在日立7080型全自动生化分析仪上进行测定。结果TC：男性（4．97±0．90）mmol／L，女性（4．59±0．80）mmol／L；TG：男性（1．70±0．29）mmol／L，女性（1．65±0．31）mmol／L；HDL-C：男性（1．31±0．24）mmol／L，女性（1．30±0．24）mmol／L；LDL-C：男性（2．88±0．75）mmol／L，女性（2．79±0．71）mmol／L。结论阿坝州藏族人群血脂水平明显高于其他地区，且不同年龄、性别，不同地区和民族的血脂参考值也有差异。     

孕妇阴道念珠菌感染与糖代谢异常程度的关系

目的探讨孕妇阴道念珠菌感染与糖代谢异常程度的关系。方法选择2002年1月至2007年6月在重庆市九龙坡区第二人民医院行产前检查并分娩的213例妊娠期糖代谢异常孕妇为观察对象,其中妊娠期糖尿病（GDM）132例,妊娠期糖耐量受损（GIGT）81例。213例患者中,27例妊娠期合并阴道念珠菌感染,其中16例妊娠期有阴道念珠菌感染再次发作;186例未合并阴道念珠菌感染。比较3组孕妇的50g葡萄糖筛查试验（GCT）,75g葡萄糖耐量试验（OGTT）结果。结果GDM患者阴道念珠菌感染的发病率（15％,21／132）高于妊娠期GIGT的发病率（7．4％,6／81）,二者比较,差异有统计学意义（P〈0．05）;阴道念珠菌感染组及未合并阴道念珠菌感染组的GCT分别为（9．6±1．8）、（9．2±1．5）mmol／L;OGTT空腹血糖分别为（5．4±0．9）、（5．3±0．8）mmol／L,1h血糖分别为（11．1±1．8）、（11．0±1．6）mmol／L,2h血糖分别为（9．3±1．7）、（9．2±1．5）mmol／L;分别比较,差异均无统计学意义（P〉0．05）。反复阴道念珠菌感染组GCT为（10．5士1．1）mmol／L;OGTT空腹血糖为（5．4±1．1）mmol／L,1h血糖为（11．5±0．9）mmol／L,2h血糖为（9．4±1．4）mmol／L,与未合并阴道念珠菌感染组比较,差异均无统计学意义（P〉0．05）。结论妊娠合并糖代谢异常伴阴道念珠菌感染时,GCT、OGTT各点血糖水平无明显升高,但GDM与GIGT孕妇比较,阴道念珠菌感染发病率呈现上升趋势。     

氟康唑和伏立康唑对酵母菌抗菌活性的研究

目的 :研究氟康唑和伏立康唑对 2 14株酵母菌的体外抗菌活性。方法 :酵母菌收集自 2 0 0 0年 1月至 2 0 0 1年 12月住院患者提供的标本。采用酵母菌纸片扩散法敏感试验 ,Mueller Hinton琼脂中补充 2 %葡萄糖和 0 .5mg/L美蓝 ,其他类似于美国国家临床实验室标准委员会 (NCCLS)M2 A6细菌药敏试验法。采用BIOMIC仪自动读取平皿抑菌环直径、解释和记录试验结果及核对质控数据。结果 :白念珠菌最常见 ,占 5 4 .7% ,其次为热带念珠菌占 18.7% ,光滑念珠菌占 12 .1% ,近平滑念珠菌占 4 .7% ,克柔念珠菌占 3.7%和新型隐球菌占 3.7%。白念珠菌、热带念珠菌和近平滑念珠菌对氟康唑的敏感率为 92 .5 %～10 0 .0 % ,MIC90 均在敏感范围内 (<3～ 8mg/L) ,伏立康唑对白念珠菌、热带念珠菌、光滑念珠菌和近平滑念珠菌的MIC90 为 0 .0 6 4～ 1.5mg/L。结论 :氟康唑对白念珠菌、热带念珠菌和近平滑念珠菌有较好的抗菌活性 ,伏立康唑比氟康唑对白念珠菌、热带念珠菌、光滑念珠菌和近平滑念珠菌有更高的抗菌活性 ,有较低的MIC值     

Effects of aspirin and other nonsteroidal anti-inflammatory drugs on biofilms and planktonic cells of Candida albicans

Prostaglandins are now known to be produced by Candida albicans and may play an important role in fungal colonization. Their synthesis in mammalian cells is decreased by inhibitors of the cyclooxygenase isoenzymes required for prostaglandin formation. In the present study, a catheter disk model system was used to investigate the effects of nonsteroidal anti-inflammatory drugs (all cyclooxygenase inhibitors) on biofilm formation by three strains of C. albicans. Seven of nine drugs tested at a concentration of 1 mM inhibited biofilm formation. Aspirin, etodolac, and diclofenac produced the greatest effects, with aspirin causing up to 95% inhibition. Celecoxib, nimesulide, ibuprofen, and meloxicam also inhibited biofilm formation, but to a lesser extent. Aspirin was active against growing and fully mature (48-h) biofilms; its effect was dose related, and it produced significant inhibition (20 to 80%) at pharmacological concentrations. Simultaneous addition of prostaglandin E(2) abolished the inhibitory effect of 25 or 50 micro M aspirin. At 1 mM, aspirin reduced the viability of biofilm organisms to 1.9% of that of controls. Surviving cells had a wrinkled appearance, as judged by scanning electron microscopy, and consisted of both yeasts and hyphae. Treatment with other cyclooxygenase inhibitors, such as etodolac, resulted in biofilms that consisted almost entirely of yeast cells. In conventional assays for germ tube formation, these drugs produced significant inhibition, whereas aspirin had little effect. Our findings suggest that cyclooxygenase-dependent synthesis of fungal prostaglandin(s) is important for both biofilm development and morphogenesis in C. albicans and may act as a regulator in these physiological processes. Our results also demonstrate that aspirin possesses potent antibiofilm activity in vitro and could be useful in combined therapy with conventional antifungal agents in the management of some biofilm-associated Candida infections.     

山苍子精油对白色念珠菌生物被膜芽管形成的抑制作用研究

目的研究山苍子精油在体外对白色念珠菌生物被膜芽管形成初始阶段的抑制作用,为预防由白色念珠菌生物被膜引起的难治性感染提供新思路。方法通过血清芽管实验,观察不同浓度山苍子精油对白色念珠菌出芽生长现象的抑制作用。结果 2~5μL/mL的山苍子精油对白色念珠菌出芽生长的抑制率为100.0%,但不具有杀菌作用,0.25μL/mL的山苍子精油对白色念珠菌芽管生长的抑制率为85.0%。结论 2~5μL/mL的山苍子精油可完全抑制白色念珠菌初始阶段生物被膜的形成,但不能杀灭酵母细胞。0.25μL/mL几乎不能抑制芽管生长。     

Effect of amphotericin B, fluconazole and itraconazole on intracellular Candida albicans and germ tube development in macrophages

Candida albicans may resist intracellular killing by macrophages through the formation of germ tubes. Antifungal drugs that inhibit intracellular germ tube formation could therefore facilitate host defence against C. albicans. We assessed the effects of amphotericin B and the new triazole drugs fluconazole and itraconazole on the multiplication and intracellular germ tube formation of C. albicans phagocytosed by murine peritoneal macrophages, and compared the findings with the effects of these drugs on C. albicans in the absence of macrophages. The fungicidal effect of amphotericin B against C. albicans in macrophages was less prominent than that found for extracellular candida. However, amphotericin B completely blocked germ tube formation of C. albicans both in macrophages and extracellularly. Fluconazole and itraconazole had little effect on the number of candida but significantly, although incompletely, inhibited germ tube formation both inside macrophages and extracellularly. The inhibition of intracellular germ tube formation by the triazoles may facilitate host defences against C. albicans and contribute to the efficacies of these drugs in vivo.     

阴香植物精油对白色念珠菌生物膜的抑制研究

目的观察阴香精油对白色念珠菌生物膜(BF)的抑制作用。方法采用改良Brown平板连续培养法制备生物膜和应用悬液定量杀菌试验法,对阴香精油抑制白色念珠菌生物膜的效果进行了实验室检测。结果用体积分数2.5%阴香精油作用30 min,对培养3 d的白色念珠菌生物膜达到完全杀灭;作用90 min对培养7 d的白色念珠菌生物膜达到完全清除。用体积分数2.5%阴香精油作用10 min,可完全杀灭悬液内白色念珠菌浮游菌。结论阴香精油对白色念珠菌生物膜有清除效应,可抑制生物膜形成,对悬液内浮游菌杀灭效果更好。     

In vitro analyses of the effects of heparin and parabens on Candida albicans biofilms and planktonic cells

Infections and thromboses are the most common complications associated with central venous catheters. Suggested strategies for prevention and management of these complications include the use of heparin-coated catheters, heparin locks, and antimicrobial lock therapy. However, the effects of heparin on Candida albicans biofilms and planktonic cells have not been previously studied. Therefore, we sought to determine the in vitro effect of a heparin sodium preparation (HP) on biofilms and planktonic cells of C. albicans. Because HP contains two preservatives, methyl paraben (MP) and propyl paraben (PP), these compounds and heparin sodium without preservatives (Pure-H) were also tested individually. The metabolic activity of the mature biofilm after treatment was assessed using XTT [2,3-bis-(2-methoxy-4-nitro-5-sulfophenyl)-2H-tetrazolium-5-carboxanilide] reduction and microscopy. Pure-H, MP, and PP caused up to 75, 85, and 60% reductions of metabolic activity of the mature preformed C. albicans biofilms, respectively. Maximal efficacy against the mature biofilm was observed with HP (up to 90%) compared to the individual compounds (P < 0.0001). Pure-H, MP, and PP each inhibited C. albicans biofilm formation up to 90%. A complete inhibition of biofilm formation was observed with HP at 5,000 U/ml and higher. When tested against planktonic cells, each compound inhibited growth in a dose-dependent manner. These data indicated that HP, MP, PP, and Pure-H have in vitro antifungal activity against C. albicans mature biofilms, formation of biofilms, and planktonic cells. Investigation of high-dose heparin-based strategies (e.g., heparin locks) in combination with traditional antifungal agents for the treatment and/or prevention of C. albicans biofilms is warranted.     

In vitro interactions between aspirin and amphotericin B against planktonic cells and biofilm cells of Candida albicans and C. parapsilosis

The increase in drug resistance and invasion caused by biofilm formation brings enormous challenges to the management of Candida infection. Aspirin's antibiofilm activity in vitro was discovered recently. The spectrophotometric method and the XTT {2,3-bis(2-methoxy-4-nitro-5-sulfophenyl)-5-[(phenylamino)carbonyl]-2H-tetrazolium hydroxide} reduction assay used for data generation make it possible to evaluate fungal biofilm growth accurately. The combined use of the most commonly used methods, the fractional inhibitory concentration index (FICI) and a newly developed method, the ΔE model, which uses the concentration-effect relationship over the whole concentration range instead of using the MIC index alone, makes the interpretation of results more reliable. As an attractive tool for studying the pharmacodynamics of antimicrobial agents, time-kill curves can provide detailed information about antimicrobial efficacy as a function of both time and concentration. In the present study, in vitro interactions between aspirin (acetylsalicylic acid [ASA]) and amphotericin B (AMB) against planktonic cells and biofilm cells of Candida albicans and C. parapsilosis were evaluated by the checkerboard microdilution method and the time-kill test. Synergistic and indifferent effects were found for the combination of ASA and AMB against planktonic cells, while strong synergy was found against biofilm cells analyzed by FICI. The ΔE model gave more consistent results with FICI. The positive interactions in concentration were also confirmed by the time-kill test. Moreover, this approach also revealed the pharmacodynamics changes of ASA and synergistic action on time. Our findings suggest a potential clinical use for combination therapy with ASA and AMB to augment activity against biofilm-associated infections.     

In vivo pharmacokinetics/pharmacodynamics of colistin and imipenem in Pseudomonas aeruginosa biofilm infection

Many Pseudomonas aeruginosa isolates from the airways of patients with cystic fibrosis (CF) are sensitive to antibiotics in susceptibility testing, but eradication of the infection is difficult. The main reason is the biofilm formation in the airways of patients with CF. The pharmacokinetics (PKs) and pharmacodynamics (PDs) of antimicrobials can reliably be used to predict whether antimicrobial regimens will achieve the maximum bactericidal effect against infections. Unfortunately, however, most PK/PD studies of antimicrobials have been done on planktonic cells and very few PK/PD studies have been done on biofilms, partly due to the lack of suitable models in vivo. In the present study, a biofilm lung infection model was developed to provide an objective and quantitative evaluation of the PK/PD profile of antimicrobials. Killing curves were set up to detect the antimicrobial kinetics on planktonic and biofilm P. aeruginosa cells in vivo. Colistin showed concentration-dependent killing, while imipenem showed time-dependent killing on both planktonic and biofilm P. aeruginosa cells in vivo. The parameter best correlated to the elimination of bacteria in lung by colistin was the area under the curve (AUC) versus MIC (AUC/MIC) for planktonic cells or the AUC versus minimal biofilm inhibitory concentration (MBIC; AUC/MBIC) for biofilm cells. The best-correlated parameter for imipenem was the time that the drug concentration was above the MIC for planktonic cells (T(MIC)) or time that the drug concentration was above the MBIC (T(MBIC)) for biofilm cells. However, the AUC/MIC of imipenem showed a better correlation with the efficacy of imipenem for biofilm infections (R(2) = 0.89) than planktonic cell infections (R(2) = 0.38). The postantibiotic effect (PAE) of colistin and imipenem was shorter in biofilm infections than planktonic cell infections in this model.     

Investigation of multidrug efflux pumps in relation to fluconazole resistance in Candida albicans biofilms

A main characteristic associated with microbial biofilms is their increased resistance to antimicrobial chemotherapies. However, at present very little is known about the phenotypic changes that occur during the transition from the planktonic to the biofilm mode of growth. Candida albicans biofilms displayed an organized three-dimensional structure, and consisted of a dense network of yeasts and filamentous cells deeply embedded in exopolymeric matrix. These biofilms were intrinsically resistant to fluconazole. Moreover, the resistance phenotype was maintained by sessile cells when resuspended as free-floating cells, thus demonstrating that biofilm integrity and the presence of exopolymeric material are not the sole determinants of biofilm resistance. Under planktonic conditions, one of the main mechanisms of azole resistance in C. albicans is through active efflux of these drugs mediated by ATP-binding cassette (ABC) transporters and major facilitators. In this study we used northern hybridization to monitor expression of genes belonging to two different types of efflux pump, the ABC transporters and major facilitators (encoded by CDR and MDR genes, respectively), in C. albicans populations under both planktonic and biofilm growth. It was demonstrated that expression of genes encoding both types of efflux pump were up-regulated during the course of biofilm formation and development. Moreover, antifungal susceptibilities of biofilms formed by a set of C. albicans mutant strains deficient in efflux pumps were investigated to determine their contribution to biofilm resistance. Remarkably, mutants carrying single and double deletion mutations in Delta(cdr)1, Delta(cdr)2, Delta(mdr)1, Delta(cdr)1/Delta(cdr)2 and Delta(mdr)1/Delta(cdr)1 were hypersusceptible to fluconazole when planktonic, but still retained the resistant phenotype during biofilm growth. These analyses demonstrate that C. albicans biofilm resistance is a complex phenomenon that cannot be explained by one mechanism alone, instead it is multifactorial and may involve different molecular mechanisms of resistance compared with those displayed by planktonic cells.