临床相关毛孢子菌的鉴定及体外药物敏感性研究

目的探讨临床相关毛孢子菌的鉴定方法及对常见抗真菌药物的体外敏感性。方法对48株临床分离的毛孢子菌分别通过形态学、API20C AUX、Vitek 2 Compact及核糖体rDNA ITS序列分析等方法鉴定到种;采用浓度梯度法（E-test）测定氟康唑、伏立康唑、伊曲康唑、两性霉素B及卡泊芬净对48株毛孢子菌的最低抑菌浓度。结果形态学和API20C AUX、Vitek 2 Compact不能准确区分不同种的毛孢子菌,以核糖体rDNA ITS序列分析将48株毛孢子菌鉴定为8个种：阿萨希毛孢子菌,星型毛孢子菌,皮瘤毛孢子菌,真皮毛孢子菌,皮肤毛孢子菌,赖巴克毛孢子菌,T.domesticum,T.jirovecii。体外药敏结果显示：卡泊芬净对毛孢子菌无体外活性,MIC〉32μg/mL;氟康唑和两性霉素B对毛孢子菌活性差,体外活性最好的药物是伏立康唑和伊曲康唑。结论常规方法不易将毛孢子菌准确鉴定到种的水平,ITS序列分析准确快速,可以辅助临床区分难鉴定毛孢子菌。毛孢子菌药敏谱不同于临床常见其他酵母菌,氟康唑和两性霉素B对其活性差,伏立康唑具有良好的体外抗菌活性。     

Genotyping and Antifungal Drug Susceptibility of Trichosporon asahii Isolated from Chinese Patients

As a major pathogenic agent of trichosporonosis, Trichosporon asahii can cause life-threatening infection in immunocompromised patients. In this study, we analyzed the genotypes of the intergenic spacer (IGS) 1 region of the rRNA gene and the antifungal drug susceptibility of eight T. asahii isolates obtained from Chinese patients. Five genotypes were identified from the eight isolates, including three novel genotypes, three genotype 1, and two genotype 4. The eight T. asahii isolates were resistant to amphotericin B, 5-flucytosine, and terbinafine, but were highly sensitive to fluconazole (FLC), itraconazole (ITC), and voriconazole (VRC). The mean minimum inhibitory concentrations (MICs) of FLC and VRC were significantly lower than those reported in most other countries, while that of ITC was slightly higher. Our results suggest that genotypes of the T. asahii isolated from China are different from those of other countries, and azole drugs appeared to be more effective on the Chinese isolates. These results provide new insights into the epidemiology and antifungal treatment for T. asahii.     

Antifungal pharmacodynamic characteristics of amphotericin B against Trichosporon asahii, using time-kill methodology

We determined the MIC of amphotericin B against 45 Trichosporon asahii isolates from various clinical and environmental sources, and used in vitro time-kill methods to characterize the relationship between amphotericin B concentrations and MIC for four representative T. asahii isolates. Amphotericin B had concentration-dependent antifungal activity. MICs ranged from 0.5 to 16 microg/ml, and most T. asahii isolates (76%, 34/45) were inhibited at safely achievable amphotericin B serum concentrations (< or = 2 microg/ml). However, 40% (18/45) of isolates were not killed at these concentrations (MFCs from 1.0 to 32 microg/ml). At concentrations > or = 2 x MIC, amphotericin B exhibited fungicidal activity (< 99.9% reduction in CFU) over a 12-hr time-period; the maximal effect was achieved at > or =4 x MIC. Susceptibility testing confirmed the resistance of T. asahii to amphotericin B, and in vitro pharmacodynamic results also suggest that amphotericin B is not suitable therapy for T. asahii infection.     

In vitro activities of voriconazole, fluconazole, itraconazole and amphotericin B against non Candida albicans yeast isolates

Antifungal susceptibility testing was performed on 197 yeast isolates from the BCCM/IHEM biomedical fungi and yeasts collection (Belgian Co-ordinated Collections of Micro-organisms / IPH-Mycology) to study the in vitro activity of voriconazole against fluconazole, itraconazole and amphotericin B. MICs of the four antifungal agents were determined by an adapted NCCLS M27-A microdilution reference method. MIC readings were visually and spectrophotometrically determined. Optical density data were used for calculation of the MIC endpoints. For amphotericin B, the MIC endpoint was defined as the minimal antifungal concentration that exerts 90% inhibition, compared to the control growth. The azoles endpoints were determined at 50% inhibition of growth. The MIC distribution of voriconazole susceptibilities showed that 193 isolates had a MIC < or = 2 microg/ml and 185 a MIC < or = 1 microg/ml. Cross-tabulation of voriconazole, fluconazole, and itraconazole MICs indicated that voriconazole MICs raised with fluconazole and itraconazole MICs. The in vitro data obtained in this study suggest that voriconazole may also be effective treating yeast infection in patients infected with fluconazole or itraconazole resistant isolates.     

卡泊芬净、米卡芬净对念珠菌体外药物敏感性的动态研究

目的 动态研究卡泊芬净、米卡芬净体外对念珠菌的药物敏感性.方法 参照CLSI公布的M-27A方案微量液体稀释法分别测定卡泊芬净、米卡芬净、氟康唑对85株念珠菌的体外敏感性,并连续7d观测结果.结果 48 h卡泊芬净对白念珠菌、光滑念珠菌及其他念珠菌MIC50、MIC90中位数分别为0.030μg/mL、0.030 μg/mL,0.060μg/mL、0.125 μg/mL,0.125 μg/mL、0.500 μg/mL.48 h米卡芬净对白念珠菌、光滑念珠菌及其他念珠菌MIC50、MIC90中位数分别为0.030 μg/mL、0.030 μg/mL,0.060 μg/mL、0.060 μg/mL,0.250 μg/mL、0.500 μg/mL.48 h氟康唑对白念珠菌、光滑念珠菌及其他念珠菌MIC80、MIC100中位数分别为2μg/mL、128 μg/mL,64 μg/mL、128 μg/mL,2μg/mL、32μg／mL.85株念珠菌中未见对3种药物同时耐药的菌株.卡泊芬净组白念珠菌MIC50、MIC90 24 h后不再升高;光滑念珠菌MIC50 72 h后不再升高,MIC90 120 h后不再升高;其他念珠菌组MIC50 168 h、MIC90 96 h后不再升高.米卡芬净组白念珠菌、光滑念珠菌MIC50、MIC90 24 h后不再升高;其他念珠菌MIC50、MIC90在72 h后不再升高.结论卡泊芬净、米卡芬净对念珠菌属有较好的抗菌作用,其中对白念珠菌、光滑念珠菌作用更强,且MICs随着作用时间延长而升高并存在药物特异性和念珠菌种属特异性.     

Nosocomial urinary infection due to Trichosporon asahii. First two cases in Chile

We present two cases of nosocomial urinary tract infection due to Trichosporon asahii in intensive care unit patients with bladder catheter from two hospitals in Santiago, Chile. Both patients had an several catheters and bacterial infections that required the use of antibiotic therapy. One strain showed in vitro resistance to amphotericin B. Both strains were susceptible to fluconazole, but presented MIC with dose-dependent susceptibility to ketoconazole and itraconazole. This is the first report showing T. asahii as urinary tract infection agent in Chile.     

阿萨希毛孢子菌生物膜构建及水杨酸干预策略研究

目的在医院内常用生物材料聚氯乙烯（PVC）表面构建阿萨希毛孢子菌的生物膜,评估该生物膜对几种临床抗真菌药物的耐药性,并观察水杨酸是否对阿萨希毛孢子菌生物膜的形成有干预作用。方法菌株鉴定采用API20CAUX并经PCR鉴定复核;使用PVC于RPM11640-MOPS中培养进行阿萨希毛孢子菌生物膜构建;MIC测定采用法国生物梅里埃公司ATB Fungus-3真菌药敏试剂条以及微量液体稀释法,并观察水杨酸对生物膜构建的影响。结果阿萨希毛孢子菌可以通过几个不连续阶段在聚氯乙烯表面形成生物膜,且已使用PVC块上附着的生物膜细胞比未使用PVC块上黏附的生物膜细胞明显密集;固着相即生物膜细胞的MIC比浮游相成倍提高;24h两性霉素B的MIC〉512μ/ml,且经两性霉素B的药物刺激后,阿萨希毛孢子明显可见芽管延长,菌丝交织;水杨酸作用后阿萨希毛孢子菌的菌丝明显变短,孢子短小。结论介入性器械可以作为阿萨希毛孢子菌生物膜构建的黏附基质,使微生物群体黏附于细胞外多聚材料表面而造成持续播散感染,因此生物膜干预对阿萨希毛孢子菌深部感染的治疗有很重要的意义。     

男性尿道炎和包皮龟头炎致病真菌的分布与药敏分析

目的了解男性念珠菌性尿道炎和包皮龟头炎的菌群分布及体外抗真菌药敏试验情况。方法菌株分离均来自复旦大学附属华山医院皮肤性病门诊临床症状轻重不一、真菌直接镜检阳性的61例患者。用科玛嘉念珠菌显色培养基及API 20C AUX鉴定系统进行菌种鉴定;采用CLSIM27-A2肉汤微量稀释法对61株临床分离念珠菌作了氟康唑、两性霉素B、氟胞嘧啶、伊曲康唑、伏立康唑、特比萘芬6种抗真菌药物敏感性测定。结果对培养阳性的61例菌株,通过科玛嘉念珠菌显色培养基及API 20C AUX鉴定系统作菌种鉴定,白念珠菌52例（85.2%）,近平滑念珠菌3例,光滑念珠菌2例,热带念珠菌2例,季也蒙念珠菌1例,克柔念珠菌1例。对52株白念珠菌的药敏试验显示氟康唑98.1%敏感,1.9%剂量依赖性敏感;氟胞嘧啶96.2%敏感,3.8%耐药;伊曲康唑44.2%敏感,40.5%剂量依赖性敏感,15.3%耐药;伏立康唑84.6%敏感,15.4%耐药;两性霉素B全部敏感;特比萘芬的MIC范围为1-64μg/ml,MIC50和MIC90皆为64μg/ml。结论在男性念珠菌性尿道炎和包皮龟头炎中,白念珠菌仍是第一位致病菌,体外药敏试验显示氟康唑、伏立康唑、氟胞嘧啶、两性霉素B对男性念珠菌性尿道炎均有较好的敏感性。     

Identification and susceptibility against fluconazole and albaconazole of 100 yeasts' strains isolated from vaginal discharge

Vulvovaginal candidiasis is a condition that affects a great number of fertile women. It is considered the second cause of genital infection after vaginosis due to GAM complex. Candida albicans is the most frequent isolated species from vaginal discharge. However, sometimes more than one yeast species could be found in the same clinical sample that are more resistant to antifungal drugs. Nowadays, it is necessary to identify properly up to species level the isolated microorganism and to determine the antifungal susceptibility profile. One hundred strains obtained from vaginal discharge of 94 patients suffering acute vulvovaginal candidiasis were studied. The identification of the isolates showed: C. albicans 86%, Candida glabrata 6%, Candida inconspicua 3%, Candida krusei 2% and Candida intermedia, Candida holmii and Trichosporon asahii one case each. Minimal inhibitory concentrations (MIC) of all the yeasts against fluconazole and albaconazole were performed. C. glabrata, C. krusei and C. inconspicua were the most resistant against fluconazole, on the other hand albicans was susceptible to this drug. All the isolates presented MIC against albaconazole much lower than fluconazole.     

焦性没食子酸联合唑类药物对念珠菌的抑菌作用

目的了解光滑念珠菌临床菌株的药敏情况以及中药单体焦性没食子酸联合唑类药物对念珠菌的抑菌作用。方法收集临床分离的光滑念珠菌116株、白念珠菌49株、热带念珠菌42株、克柔念珠菌4株和近平滑念珠菌13株,采用ATB FUNGUS3药敏试条检测光滑念珠菌的药敏情况;同时采用棋盘肉汤稀释法检测焦性没食子酸联合唑类药物对念珠菌的抑菌情况。结果116株光滑念珠菌中,14.66%(17株)的菌株对氟康唑耐药,22.41%(26株)对伊曲康唑表现为非野生型和81.03%(94株)对伏立康唑表现为非野生型。焦性没食子酸对5种念珠菌的抑菌情况,46.55%光滑念珠菌的MIC值为64μg/mL;34.69%白念珠菌的MIC值为64μg/mL;59.52%热带念珠菌的MIC值为64μg/mL;25%克柔念珠菌的MIC值为128μg/mL;46.15%近平滑念珠菌的MIC值为128μg/mL。唑类药物与焦性没食子酸联合用药时,100%、99.14%、99.14%的光滑念珠菌分别对氟康唑、伊曲康唑和伏立康唑表现为协同作用或相加作用,差异无统计学意义(P>0.05);而白念珠菌、热带念珠菌、克柔念珠菌和近平滑念珠菌均表现为无关作用和拮抗作用。与单独用药相比,联合用药时81.03%、68.1%、77.59%的光滑念珠菌分别对氟康唑、伊曲康唑、伏立康唑的MIC值降低2~3个浓度梯度,且耐药组与非耐药组之间差异具有统计学意义(P<0.05)。结论光滑念珠菌对唑类药物具有耐药性,伏立康唑非野生型菌株所占比例最高。焦性没食子酸单独用药时,5组念珠菌中对光滑念珠菌的抑菌效果最好,且敏感组比耐药组的抑菌效果更加显著。焦性没食子酸联合唑类药物显著降低了光滑念珠菌唑类药物的MIC值,且耐药组比非耐药组的效果更加显著,为中西医结合治疗临床光滑念珠菌感染提供实验依据。     

Cloning of the lanosterol 14-α-demethylase ( ERG11 ) gene in Trichosporon asahii: a possible association between G453R amino acid substitution and azole resistance in T. asahii

Lanosterol 14-α-demethylase ( Erg11 protein; Erg11p ), encoded by the ERG11 gene, is the primary target of azoles. Recently, a change in affinity of this enzyme for azoles has been reported as a resistance mechanism in several fungal species. Trichosporon asahii ( T.?asahii) is susceptible to fluconazole (FLC). This report identified the ERG11 gene of T.?asahii (NCBI accession; HQ176415). The Erg11p of T.?asahii, presumed from the DNA sequence, was closely related to the Erg11p of Cryptococcus neoformans. Furthermore, a FLC-susceptible strain was cultured in medium containing FLC at concentrations from 4.0 to 16?μg?mL(-1) in order to analyze the development of FLC resistance in T.?asahii. The degree of resistance was related to the FLC concentration of the growth medium. One highly resistant strain that was cultured in the medium containing 16?μg?mL(-1) FLC contained 1 point mutation (G1357C) that caused a single amino acid substitution at G453R. This amino acid is highly conserved among major fungal pathogens, and it is in a region very close to the heme-binding domain, which is characteristic of the cytochrome P450 superfamily, the primary target for the azole class of antifungal agents. This amino acid substitution may have caused the high resistance to azoles in T.?asahii.     

棘白菌素对氟康唑耐药的念珠菌体外药物敏感性的研究

目的评价3种棘白菌素类药物（卡泊芬净、米卡芬净、阿尼多芬净）体外对氟康唑耐药念珠菌的药物敏感性。方法采用微量液体稀释法和琼脂稀释法测定最小抑制浓度（MIC）。结果微量液体稀释法：59株耐药白念珠菌3种药物MIC50均为0.06μg/mL,米卡芬净、阿尼多芬净的MIC范围均为0.015～0.125μg/mL,卡泊芬净为0.015～0.25μg/mL;8株耐药光滑念珠菌MIC值均为0.063μg/mL。琼脂稀释法：59株耐药白念珠菌和8株耐药光滑念珠菌3种药物MIC值均为0.063μg/mL。结论3种棘白菌素类药物可能具有治疗氟康唑耐药的念珠菌感染的临床价值。     

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。     

Antifungal Susceptibility Profile of Candida Albicans Isolated from Vulvovaginal Candidiasis in Xinjiang Province of China

We investigated the antifungal susceptibility profiles of 207 independent Candida albicans strains isolated from patients with vulvovaginal candidiasis (VVC) in Xinjiang Province of China. Using CLSI M27-A3 and M27-S4 guidelines, anidulafungin and micafungin were the most active drugs against C. albicans showing an MIC₅₀/MIC₉₀ corresponding to 0.016/0.0313 µg/mL, followed by caspofungin (0.25/0.25 µg/mL), posaconazole (0.125/0.5 µg/mL), ravuconazole (0.063/1 µg/mL), itraconazole (0.125/1 µg/mL), amphotericine B (0.5/1 µg/mL), isavuconazole (0.063/2 µg/mL), 5-flucytosine (1/2 µg/mL), voriconazole (0.125/4 µg/mL), and fluconazole (0.5/4 µg/mL). 96.1% (199)–100.0% (207) isolates were sensitive to the three echinocandins tested, amphotericine B and 5-flucytosine. The in vitro activity of triazoles against all isolates tested was variable; itraconazole and voriconazole had reduced the activity to almost half of the isolates (55.1% (114) and 51.2% (106) susceptible, respectively). Fluconazole was active against 76.3% (158) isolates tested. The new triazoles ravuconazole, isavuconazole and posaconazole showed good in vitro potency against 89.9% (186)–95.2% (197) of isolates with the geometric mean MIC (µg/mL) of 0.10, 0.12 and 0.14 µg/mL, respectively. In conclusion, our study indicates that for effective management of systemic candidiasis in Xinjiang Province of China, it is important to determine the susceptibility profiles of isolated C. albicans from patients with VVC.

     

Candida dubliniensis: an appraisal of its clinical significance as a bloodstream pathogen

A nine-year prospective study (2002-2010) on the prevalence of Candida dubliniensis among Candida bloodstream isolates is presented. The germ tube positive isolates were provisionally identified as C. dubliniensis by presence of fringed and rough colonies on sunflower seed agar. Subsequently, their identity was confirmed by Vitek2 Yeast identification system and/or by amplification and sequencing of the ITS region of rDNA. In all, 368 isolates were identified as C. dubliniensis; 67.1% came from respiratory specimens, 11.7% from oral swabs, 9.2% from urine, 3.8% from blood, 2.7% from vaginal swabs and 5.4% from other sources. All C. dubliniensis isolates tested by Etest were susceptible to voriconazole and amphotericin B. Resistance to fluconazole (≥8 μg/ml) was observed in 2.5% of C. dubliniensis isolates, 7 of which occurred between 2008-2010. Of note was the diagnosis of C. dubliniensis candidemia in 14 patients, 11 of them occurring between 2008-2010. None of the bloodstream isolate was resistant to fluconazole, while a solitary isolate showed increased MIC to 5-flucytosine (>32 μg/ml) and belonged to genotype 4. A review of literature since 1999 revealed 28 additional cases of C. dubliniensis candidemia, and 167 isolates identified from blood cultures since 1982. In conclusion, this study highlights a greater role of C. dubliniensis in bloodstream infections than hitherto recognized.     

Comparative evaluation of standard dilution method and commercial kit for frozen plate antifungal susceptibility testing of yeasts using 200 clinical isolates

A comparative evaluation of standard microdilution methods and a commercial kit for frozen plate antifungal susceptibility testing of yeasts was performed using amphotericin B, flucytosine, fluconazole, miconazole, and itraconazole on 200 yeast isolates. The isolates included 100 strains of Candida albicans, eight of C. tropicalis, twelve of C. parapsilosis, eight of C. glabrata, five of Cryptococcus neoformans, thirteen of Trichosporon asahii, and 54 other strains of seven other species of ascomycotic yeasts. Microdilution testing was performed according to the standard method for antifungal susceptibility testing published by the Japanese Society for Medical Mycology (JSMM), which are a modification of the method developed by the National Committee for Clinical Laboratory Standards (NCCLS) M27-P. The commercial kit was prepared according to the manufacturer's instructions. The degree of agreement within +/-1 dilution for 200 clinical isolates against five antifungal agents was excellent with values for amphotericin B, flucytosine, fluconazole, miconazole, and itraconazole of 100%, 99.0%, 97.5%, 97.0%, and 97.0%, respectively. Overall, the frozen plate antifungal susceptibility testing kit provided convenient and reproducible results comparable to those obtained with the JSMM standard method.     

Antifungal Activity of Chitosan-Coated Poly(lactic-co-glycolic) Acid Nanoparticles Containing Amphotericin B

Amphotericin B (AmB) is one of the most used drugs for the treatment of systemic fungal infections; however, the treatment causes several toxic manifestations, including nephrotoxicity and hemolytic anemia. Chitosan-coated poly(lactide-co-glycolide) (PLGA) nanoparticles containing AmB were developed with the aim to decrease AmB toxicity and propose the oral route for AmB delivery. In this work, the antifungal efficacy of chitosan-coated PLGA nanoparticles containing AmB was evaluated in 20 strains of fungus isolates from patients with vulvovaginal candidiasis (01 Candida glabrata and 03 Candida albicans), bloodstream infections (04 C. albicans and 01 C. tropicalis) and patients with urinary tract infection (04 Candida albicans, 02 Trichosporon asahii, 01 C. guilhermondii, 03 C. glabrata) and 01 Candida albicans ATCC 90028. Moreover, the cytotoxicity over erythrocytes was evaluated. The single-emulsion solvent evaporation method was suitable for obtaining chitosan-coated PGLA nanoparticles containing AmB. Nanoparticles were spherical in shape, presented mean particle size about 460 nm, positive zeta potential and encapsulation efficiency of 42%. Moreover, nanoparticles prolonged the AmB release. All the strains were susceptible to plain AmB and nanostructured AmB, according to EUCAST breakpoint version 8.1 (resistant > 1 μg/mL), using broth microdilution method. In C. albicans (urine, blood, and vulvovaginal secretion isolates, and 1 ATCC), the MIC value of AmB-loaded nanoparticles varied from 0.25 to 0.5 μg/mL and EUCAST varied from 0.03 to 0.5 μg/mL. In urine and vulvovaginal secretion isolates of C. glabrata, the MIC value of AmB-loaded nanoparticles varied from 0.25 to 0.5 μg/mL and EUCAST varied from 0.03 to 0.015 μg/mL. In urine isolates of C. guilhermondii, the MIC value of AmB-loaded nanoparticles was 0.12 μg/mL and EUCAST was 0.06 μg/mL. In blood isolates of C. tropicalis, the MIC value of AmB-loaded nanoparticles was 0.5 μg/mL and EUCAST was 0.25 μg/mL. Finally, in urine isolates of T asahii, the MIC value of AmB-loaded nanoparticles was 1 μg/mL and EUCAST varied from 0.5 to 1 μg/mL. In the cytotoxicity assay, plain AmB was highly hemolytic (100% in 24 h) while AmB-loaded chitosan/PLGA nanoparticles presented negligible hemolysis.     

Comparsion ofin vitro activities of antifungal drugs and propolis against yeasts isolated from patients with superficial mycoses

Thein vitro susceptibilities of propolis and antifungal drugs were determined against some yeasts isolated from patients with superficial mycoses. The agents tested included fluconazole, itraconazole, ketoconazole, terbinafine and propolis. MICs were determined by the broth microdilution technique following National Committee for Clinical Laboratory Standards document M27-P. For allCandida albicans isolates from the patients with superficial mycoses, ketoconazole presented higher (P<0.05) efficiency than that of the other antifungal agents tested. The geometric mean MIC values of antifungal drugs and propolis against the yeasts tested ranged from 0.087 to 12.69 μg/mL and 0.4–0.6 μg/mL, respectively. Propolis also showed an important antifungal activity against the yeasts tested, MIC ranges of the propolis were between 0.01–1.65 μg/mL. Based on these results, propolis requires further investigation as a potential agent for the treatment of superficial mycoses.     

Interlaboratory evaluation of VITEK2 system and Sensititre YeastOne® for antifungal susceptibility testing of yeasts isolated from blood cultures against four antifungal agents

An interlaboratory evaluation (seven centers) of VITEK2 System and Sensititre YeastOne? was conducted to test the antifungal susceptibilities of yeasts. The MICs of amphotericin B, fluconazole, flucytosine, and voriconazole were determined for 70 isolates of Candida spp. Our results demonstrated a higher interlaboratory agreement of VITEK 2 System than Sensititre YeastOne?. A good concordance between the two methods was observed for amphotericin B, fluconazole, voriconazole and 5-fluorocytosine (from 81.4% to 88.6%). The study suggests the potential value of the VITEK2 System as a convenient alternative method for testing the susceptibility of yeasts. It also indicates the need for further optimization of MIC endpoint criteria to improve interlaboratory agreement.     

Comparison between efficacy of allicin and fluconazole against Candida albicans in vitro and in a systemic candidiasis mouse model

The efficacy of allicin compared with fluconazole in alleviating systemic Candida albicans infections was evaluated both in vitro and in vivo through a systemic candidiasis mouse model. Determination of in vitro minimum inhibitory concentrations (MICs) for different C. albicans isolates revealed that both allicin and fluconazole showed different MICs that ranged from 0.05 to 12.5 μg mL(-1) and 0.25 to 16 μg mL(-1) , respectively. A time-kill study showed a significant effect of allicin (P<0.01) against C. albicans, comparable to that of fluconazole. Scanning electron microscopy observation revealed that, similar to fluconazole, allicin produced structural destruction of C. albicans cell surface at low MIC and lysis or puncture at high MIC concentrations. Treatment of BALB/c mice systemically infected with C. albicans showed that although the allicin treatment (at 5 mg kg(-1) day(-1) ) was slightly less efficacious than fluconazole treatment in terms of the fungal load reduction and host survival time, it was still effective against C. albicans in terms of mean survival time, which increased from 8.4 to 15.8 days. These results demonstrate the efficacy of anticandidal effects of allicin both in vitro and in an animal model of candidiasis and affirm the potential of allicin as an adjuvant therapy to fluconazole.