大蒜素对白色念珠菌生长的抑制作用

探讨大蒜素对白色念珠菌生长的抑制作用。以NCCLS方案检测了胡桃楸提取物和伊曲康唑(ICZ)、氟康唑(FCZ)、两性霉素B(AMB)和5-氟胞嘧啶(5-FC)对133株白念珠菌体外生长抑制作用。标准菌株JC1A的M IC结果表明大蒜素提取物对白念珠菌的抗菌作用相当于FCZ,略低于ICZ、AMB和5-FC;临床分离株对ICZ和FCZ的耐药率很高,对大蒜素提取物的耐药率较低。大蒜素提取物对白色念珠菌生长有强力抑制作用。     

外阴阴道念珠菌病的病原检测及体外药敏试验

目的了解STD门诊患者外阴阴道念珠菌病的菌种分布及对常用抗真菌药物的敏感状况,为临床治疗提供参考。方法取STD门诊疑似念珠菌感染患者的阴道分泌物标本,用沙氏琼脂培养基分离纯化菌株,然后用ATB ID 32C酵母菌鉴定系统和ATB Fungus3药敏系统进行菌种鉴定与药物敏感试验。结果950份标本中检出306株念珠菌,占32.21%,其中白色念珠菌226株,阳性率为73.86%;光滑念珠菌37株,阳性率为12.09%;热带念珠菌24株,阳性率为7.84%;近平滑念珠菌13株,占4.25%。药敏结果显示：念珠菌对5-氟胞嘧啶（5-FC）;两性霉素B（AMB）,伏立康唑（VRC）耐药率〈6%;近平滑念珠菌对5种抗真菌药物均敏感;白色念珠菌对氟康唑（FCZ）、伊曲康唑（ICZ）耐药率依次：9.29%、11.06%,光滑念珠菌药耐药率依次为37.84%,67.57%,热带念珠菌药耐药率依次为8.33%、12.5%。结论STD门诊患者阴道念珠菌检出率明显高于普通妇科门诊患者,检出菌种仍以白色念珠菌为主,但光滑念珠菌和热带念珠菌生殖道感染有明显上升趋势;念珠菌对两性霉素B、5-氟胞嘧啶敏感性较高,对唑类药物有耐药菌株。因此,念珠菌鉴定和药敏监测是非常必要的,临床医生应根据药敏结果合理使用抗真菌药物。     

胡桃楸提取物对体外白念珠菌生物膜形成的影响

目的研究胡桃楸提取物对白念珠菌生物膜形成的影响。方法采用甲基四氮盐（XTT）还原法评价胡桃楸提取物对白念珠菌的生物膜形成及黏附性的影响。镜下观察胡桃楸提取物对白念珠菌生物膜的形态学影响。结果胡桃楸提取物抑制白念珠菌生物膜50％及90％的最小抑制药物浓度（SMIC50、SMIC90）分别为15．2μg、23．4μg。胡桃楸提取物作用浓度大于20μg时对该菌细胞黏附有抑制作用。30μg胡桃楸提取物可完全抑制白念珠菌生物膜的形成。结论胡桃楸提取物对体外白念珠菌生物的膜形成有较强的抑制作用。     

妇科住院患者酵母样真菌感染的菌株分布与药敏研究

目的对妇科住院患者阴道分泌物酵母样真菌隐性感染的菌群分布与药敏结果进行回顾性分析,为临床围手术期合理使用抗真菌药物提供依据。方法妇科住院患者5813例阴道分泌物中分离到396株酵母样真菌,采用API-20Aux和ATBFUNGUS进行鉴定和药敏试验。结果396株酵母样真菌中,分离率最高的前3位是白色假丝酵母菌（59.6%）、光滑假丝酵母菌（21.2%）和接合假丝酵母菌（6.6%）。酵母样真菌对5-氟胞嘧啶（5-FC）、两性霉素B（AMB）和制霉菌素（NYS）敏感率最高,达90.7%、92.7%和96.2%,咪康唑（MIC）、益康唑（ECO）和酮康唑（KET）分别为74.2%、61.6%和69.4%。结论住院妇科患者阴道分泌物酵母样真菌隐性感染主要以白色念珠菌和光滑念珠菌为主,感染的酵母样真菌对5-FC、AMB和NYS的药物敏感性较高,对唑类抗真菌药则有不同程度的耐药率。     

念珠菌分离鉴定及耐药性分析

目的 了解念珠菌在临床标本中的分布情况及常用抗真菌药物的敏感性,为临床使用抗真菌药提供依据.方法 对2003年至2005年各种临床标本中分离的244株念珠菌进行鉴定,用真菌药敏卡做念珠菌对8种抗真菌药物的药敏试验,结合临床资料综合分析.结果 痰液标本念珠菌检出率最高达60.7%,其次是分泌物为19.3%.共分离白色念珠菌142株,占58.2%,热带念珠菌54株,占22.1%,敏感性较高的药物是5-FC、NYS、AMB,灰黄霉素耐药率最高,达到70%以上.结论 肿瘤,免疫功能低下,病情严重,意识障碍,长期卧床的患者念珠菌感染以白色念珠菌为主,长期使用抗生素是患者真菌感染的主要原因,真菌药敏试验可为临床治疗提供依据.     

胡桃楸提取液对肿瘤细胞细胞周期的影响

目的考察胡桃楸提取液对Hela和K562细胞周期的影响。方法用流式细胞仪分析胡桃楸提取液对Hela、K562细胞细胞周期的影响。结果胡桃楸提取物体外作用于Hela细胞可引起细胞周期在S期的停滞,这种效果随药物浓度和作用时间的增加而增加,胡桃楸提取物体外作用于K562细胞,可引起细胞周期在G1期的停滞,随药物浓度的增加而增加。结论胡桃楸提取液对Hela细胞的生长抑制作用可能通过S期阻滞实现,对K562细胞抑制作用可能通过G1期阻滞实现。     

球形孢子丝菌黑素抵御抗真菌药物杀伤作用的研究

目的探讨球形孢子丝菌黑素对抗真菌药特比萘芬(TRB)、氟康唑(FCZ)、伊曲康唑(ICZ)和两性霉素B(AMB)的作用。方法利用琼脂平板涂布法比较球形孢子丝菌黑素野生株(MEL+)与白化突变株(MEL-)对抗真菌药物的敏感性;利用紫外分光光度法,检测黑素对抗真菌药浓度的影响;利用HPLC法,分析黑素对抗真菌药的作用机制。结果药敏结果显示,在AMB的(4~16)μg/mL和ICZ的(0.06~0.25)μg/mL浓度间,MEL-生存率显著低于MEL+;紫外分光光度法检测显示,黑素可以显著降低AMB的浓度(P0.01);HPLC图谱显示,黑素加入后AMB出现新峰。结论球形孢子丝菌黑素能够抵御AMB和ICZ对菌株的杀伤,并提示黑素可能对AMB进行转化,从而降低药物浓度。     

胡桃楸个体有性生殖过程研究

胡桃楸是东北东部山地阔叶红松林的重要组成树种。以胡桃楸个体有性生殖过程为研究对象,通过定株定枝调查,研究了胡桃楸芽种群分化、物候及散粉规律、颗粒生长发育过程及环境影响因子。结果表明：１．胡桃楸壮龄树芽种群分化简单。２．胡桃楸个体间花期物候差异很大,并具有典型的雌雄异熟现象。３．胡桃幼果期生长速度快,生长分化现象严重,疏果率高;进入果实生长后期之后,生长速度及疏果率均显著降低。     

肝移植患者真菌感染的流行病学特点及耐药性分析

目的了解肝移植术后真菌感染的种类及耐药特性,为临床治疗提供依据。方法分析2003年6月至2006年6月,我院67例肝移植患者术后感染的标本,鉴定真菌种类,分析其耐药性。结果67例肝移植患者有21例发生真菌感染,占肝移植患者的31.3%;共检出73株真菌,以酵母菌感染为主,占98.6%,其中近平滑念珠菌、白色念珠菌、热带念珠菌、季也蒙念珠菌、克柔念珠菌的检出率分别是53.4%、21.9%、9.6%、8.2%、2.7%。曲霉菌感染1例。药敏试验显示73株真菌对两性霉素B(AMB)、5-氟胞嘧啶(5-FC)、制霉菌素(MYS)、酮康唑(KTC)、益康唑(ECO)和咪康唑(MIC)的平均敏感率分别为98.6%、95.7%、87.1%、70.0%、65.7%和64.3%。结论加强肝移植术后真菌的鉴定和耐药性监测,对指导临床治疗具有重要意义。     

胡桃楸活性成分时空动态及抗肿瘤活性初步研究

采用超声波辅助提取方法,以胡桃楸为原料,在单因素实验的基础上研究一年内不同月份胡桃楸不同部位总黄酮、总酚的含量变化,同时对胡桃楸提取物体外抗肿瘤活性进行初步评价。结果显示,乙醇浓度60%,超声时间40 min,料液比1：20,提取温度30℃为最佳提取参数。在此条件下,不同采摘时期胡桃楸不同部位的总黄酮、总酚含量存在显著差异。5~7月份叶和小枝的总黄酮及总酚含量明显高于8~10月份,其中7月份叶的总黄酮总酚含量最高,分别为12.56±0.33和76.98±3.73 mg·g^-1,然而茎皮总黄酮、总酚含量随月份增加呈持续下降趋势。体外抗肿瘤研究表明胡桃楸叶提取物对人肝癌细胞SMMC-7721、人乳腺癌细胞MCF-7和人口腔表皮样癌细胞KB的增殖抑制作用,其中7月份胡桃楸叶提取物对人乳腺癌MCF-7细胞增殖抑制作用更明显,其IC₅₀值为0.24 mg·mL^-1。本研究为胡桃楸资源的合理开发及利用提供一定的理论基础。     

吸毒人群口腔念珠菌的药物敏感性分析

目的了解吸毒人群口腔念珠菌对常用抗真菌药物的敏感性,为临床治疗念珠菌病提供参考资料。方法采用美国CLSI推荐的微量稀释法测定75株念珠菌对4种常用抗真菌药物两性霉素B、5-氟胞嘧啶、氟康唑和酮康唑的药物敏感性。结果 75株吸毒人群口腔念珠菌对两性霉素B、5-氟胞嘧啶、氟康唑和酮康唑的耐药率分别为0%、4%、8%和13.3%(P0.01),对氟康唑和酮康唑的交叉耐药率为8%;非白念珠菌对氟康唑和酮康唑的耐药率高于白念珠菌(P0.05)。结论吸毒人群口腔念珠菌对两性霉素B和5-氟胞嘧啶的敏感性高于对氟康唑和酮康唑的敏感性。吸毒人群口腔念珠菌存在着对氟康唑、酮康唑和5-氟胞嘧啶的天然耐药株和对唑类药物的天然交叉耐药株,且非白念珠菌对氟康唑和酮康唑的耐药率及交叉耐药率高于白念珠菌。     

6038例儿科临床标本深部真菌检出率及其药敏分析

目的了解儿童常见深部真菌的种类及耐药状况,指导临床合理用药。方法对785株深部真菌用YBC鉴定卡鉴定到种,用ATB-FUNGS试剂盒进行药物敏感试验。结果785株真菌中自色念珠菌占72．2％,其次是光滑念珠菌、热带念珠菌、克柔念珠菌,分别占17．2％、8．7％、1．3％。呼吸科、心内科、新生儿科、血液科真菌的检出率分别为：30．1％、13．5％、13．1％、12．1％;785株真菌对5-氟胞嘧啶、两性霉素B、制霉菌素、咪康唑、益康唑、酮康唑总的敏感率分别为93．2％、85．2％、87．4％、30．5％、61．8％、45．4％。结论儿童深部真菌以白色念珠菌最多。785株真菌对5-氟胞嘧啶、两性霉素B、制霉菌素的敏感性较高,它们仍然是治疗深部真菌感染的有效药物,而咪康唑、益康唑、酮康唑的敏感性较低,应引起临床医生的重视。     

Increase in the in vitro susceptibility of Staphylococcus aureus to antimicrobial agents in the presence of Candida albicans.

In experiments with mixed cultures of Staphylococcus aureus and Candida albicans both in the absence and in the presence of 5-fluorocytosine (5-FC), we have observed that (1) there is an inhibition of S. aureus growth in mixed cultures with C. albicans in media supplemented with 1 microgram/mL of 5-fc and that 5-FC has no effect on staphylococci in pure cultures; (2) this inhibition occurred with clinically isolated and laboratory strains and could be reversed by specific metabolites; (3) Staphylococcus aureus was inhibited by filtrates of C. albicans cultures treated with 5-FC and this seemed to be favored by some C. albicans filterable product which can affect the cell wall and the permeability of the staphylococcal cells since they become sensitive to 5-FC; (4) nine other commonly used antimicrobials showed an increased inhibitory activity against S. aureus in mixed cultures with C. albicans; and (5) there is a decrease in the number of precipitating antigens of S. aureus and of the activity of alpha toxin when this species was grown with both C. albicans and 5-FC. Our results indicate that the susceptibility of some species to antimicrobials could be significantly modified in the presence of other species. One cannot exclude that a similar phenomenon could happen in hosts under treatment with antibiotics against infection.     

In Vitro Interaction of Itraconazole with Amphotericin B,Caspofungin, and Terbinafine Against Clinical Isolates of <Emphasis Type="Italic">Trichosporon asahii</Emphasis>

Treatment of disseminated trichosporosis is still challenging. Itraconazole is a widely used broad-spectrum antifungal drug. In vitro interactions of itraconazole (ICZ) with amphotericin B (AMB), caspofungin (CAS), and terbinafine (TBF) against 18 clinical isolates of Trichosporon asahii were assessed by chequerboard microdilution method. ICZ combined with CAS showed the highest percentage of synergistic effect (72.2%), followed by ICZ/AMB (11%) and ICZ/TBF (11%) combination. Antagonistic effect was not observed. This study demonstrates that itraconazole can enhance the antifungal activity of CAS against T. asahii, suggesting that this combination may be a potential strategy for treating disseminated trichosporosis.     

Biofilm formation by and antifungal susceptibility of Candida isolates from urine

Biofilm formation (BF) in the setting of candiduria has not been well studied. We determined BF and MIC to antifungals in Candida spp. isolates grown from urine samples of patients and performed a retrospective chart review to examine the correlation with risk factors. A total of 67 Candida spp. isolates were grown from urine samples from 55 patients. The species distribution was C. albicans (54%), C. glabrata (36%), and C. tropicalis (10%). BF varied greatly among individual Candida isolates but was stable in sequential isolates during chronic infection. BF also depended on the growth medium and especially in C. albicans was significantly enhanced in artificial urine (AU) compared to RPMI medium. In nine of the C. albicans strains BF was 4- to 10-fold higher in AU, whereas in three of the C. albicans strains and two of the C. glabrata strains higher BF was measured in RPMI medium than in AU. Determination of the MICs showed that planktonic cells of all strains were susceptible to amphotericin B (AMB) and caspofungin (CASPO) and that three of the C. glabrata strains and two of the C. albicans strains were resistant to fluconazole (FLU). In contrast, all biofilm-associated adherent cells were resistant to CASPO and FLU. The biofilms of 14 strains (28%) were sensitive to AMB (MIC(50) of <1 mug/ml). Correlation between degree of BF and MIC of AMB was not seen in RPMI grown biofilms but was present when grown in AU. A retrospective chart review demonstrated no correlation of known risk factors of candiduria with BF in AU or RPMI. We conclude that BF is a stable characteristic of Candida strains that varies greatly among clinical strains and is dependent on the growth medium. Resistance to AMB is associated with higher BF in AU, which may represent the more physiologic medium to test BF. Future studies should address whether in vitro BF can predict treatment failure in vivo.     

Yeasts acquire resistance secondary to antifungal drug treatment by adaptive mutagenesis

Acquisition of resistance secondary to treatment both by microorganisms and by tumor cells is a major public health concern. Several species of bacteria acquire resistance to various antibiotics through stress-induced responses that have an adaptive mutagenesis effect. So far, adaptive mutagenesis in yeast has only been described when the stress is nutrient deprivation. Here, we hypothesized that adaptive mutagenesis in yeast (Saccharomyces cerevisiae and Candida albicans as model organisms) would also take place in response to antifungal agents (5-fluorocytosine or flucytosine, 5-FC, and caspofungin, CSP), giving rise to resistance secondary to treatment with these agents. We have developed a clinically relevant model where both yeasts acquire resistance when exposed to these agents. Stressful lifestyle associated mutation (SLAM) experiments show that the adaptive mutation frequencies are 20 (S. cerevisiae -5-FC), 600 (C. albicans -5-FC) or 1000 (S. cerevisiae - CSP) fold higher than the spontaneous mutation frequency, the experimental data for C. albicans -5-FC being in agreement with the clinical data of acquisition of resistance secondary to treatment. The spectrum of mutations in the S. cerevisiae -5-FC model differs between spontaneous and acquired, indicating that the molecular mechanisms that generate them are different. Remarkably, in the acquired mutations, an ectopic intrachromosomal recombination with an 87% homologous gene takes place with a high frequency. In conclusion, we present here a clinically relevant adaptive mutation model that fulfils the conditions reported previously.