Sensitivity of scopulariopsis brevicaulis to some antimicrobial agents

Sensitivity tests were done against two isolates of Scopulariopsis brevicaulis, using amphotericin B in combination with chloramphenicol, Chloramphenicol alone, amphotericin B in combination with 5-fluorocytosine, and 5-fluorocytosine, myxin and clotrimazole alone. Results indicated that the effectiveness of amphotericin B was improved in the presence of chloramphenicol or 5-fluorocytosine. Growth inhibitory values recorded for chloramphenicol alone and combined with amphotericin B did not show much variation. Resistance of the fungus has been noticed to 5-fluorocytosine; but the organism's response was much better when tested against 5-fluorocytosine in the presence of amphotericin B. Both myxin and clotrimazole proved very effective and their ED50 was 50 and 2.5 ug/ml of the medium, respectively. Thus, clotrimazole may be the drug of choice in the cases of deep scopulariopsis.     

In vitro susceptibility of dematiaceous fungi to ten antifungal drugs using an agar diffusion test

We assessed the usefulness of an agar diffusion method, NeoSensitabs, to determine in vitro sensitivity of 52 isolates of dematiaceous filamentous fungi against ten antifungal agents: amphotericin B, 5-fluorocytosine, ketoconazole, fluconazole, itraconazole, terbinafine, bifonazole, miconazole, clotrimazole, and griseofulvin. For the preparation of the inoculum, a spectrophotometric method including both Shadomy and Casitone agar (CAS) culture media was used. Dematiaceous filamentous fungi were sensitive to itraconazole, terbinafine and bifonazole. Ketoconazole (90.4%), miconazole (71%), and clotrimazole (46%) showed a variable susceptibility pattern. Most species were resistant to griseofulvin and fluconazole (96%). All isolates were resistant to 5-fluorocytosine. Sixty-three percent of strains were susceptible to amphotericin B and 28.8% resistant. Inhibition zones in the antifungal susceptibility testing did not vary according to culture medium, although fungal growth was better in CAS. Variations in antifungal sensitivity in Exophiala spinifera and Fonsecaea pedrosoi spp. would justify an in vitro susceptibility study when indicating antifungal therapy. These results show that NeoSensitabs agar diffusion method is simple, rapid, and low-cost and can be available to many clinical laboratories for the study of in vitro sensitivity of dematiceous moulds.     

Broth dilution and disc diffusion methods in the susceptibility testing of pathogenic Candida albicans against four antimycotics

Susceptibility of Candida albicans isolated from mouthrinse specimens during episodes of acute pseudomembranous candidiasis in patients with haematological malignancies was tested by the broth dilution and disc diffusion methods using 24 and 48 h of incubation. The time factor did not significantly affect the results with 5-fluorocytosine. With amphotericin B, prolonged incubation doubled the geometric mean MIC of C. albicans as well as the number of isolates with intermediate sensitivity. With the shorter incubation in the disc diffusion assay, few isolates showed lowered sensitivity to clotrimazole; at 48 h, however, this figure was as high as 54%. The yeasts were highly sensitive to ketoconazole at 24 h, whereas at 48 h the results were bizarre. At 24 h, correlations between disc diffusion and broth dilution methods were satisfactory, with clotrimazole and ketoconazole accounting for most of the discordancies. Accordingly, the disc diffusion results should be recorded at 24 h.     

Systemic Candida infection in University Hospital 1997–1999: the distribution of Candida biotypes and antifungal susceptibility patterns

A total of 102 Candida species were isolated from blood cultures from January 1997 to October 1999. Using assimilation of carbohydrate test, 52 (51.0%) of the Candida sp. were identified as C. parapsilosis, 25.5% (26) were C. tropicalis. C. albicans made up 11.8% (12), 6.9% (7) were C. rugosa, 3.8% (4) C. glabrata and 1% (1) C. guilliermondii. No C. dubliniensis was found in the study. In vitro antifungal susceptibility tests showed that all Candida species were sensitive to nystatin, amphotericin B and ketoconazole. Although all isolates remained sensitive to fluconazole, intermediate susceptibility was found in 3 C. rugosa isolates. Antifungal agents with high frequency of resistance were econazole, clotrimazole, miconazole and 5-fluorocytosine. Candida species found to have resistance to these antifungal agents were non-C. albicans. This revised version was published online in June 2006 with corrections to the Cover Date.     

In Vitro Antifungal Susceptibility of <Emphasis Type="Italic">Neoscytalidium dimidiatum</Emphasis> Clinical Isolates from Malaysia

Neoscytalidium dimidiatum is an opportunistic fungus causing cutaneous infections mostly, which are difficult to treat due to antifungal resistance. In Malaysia, N. dimidiatum is associated with skin and nail infections, especially in the elderly. These infections may be mistaken for dermatophyte infections due to similar clinical appearance. In this study, Neoscytalidium isolates from cutaneous specimens, identified using morphological and molecular methods (28 Neoscytalidium dimidiatum and 1 Neoscytalidium sp.), were evaluated for susceptibility towards antifungal agents using the CLSI broth microdilution (M38-A2) and Etest methods. Amphotericin B, voriconazole, miconazole and clotrimazole showed high in vitro activity against all isolates with MIC ranging from 0.0313 to 1 µg/mL. Susceptibility towards fluconazole and itraconazole was noted in up to 10% of isolates, while ketoconazole was inactive against all isolates. Clinical breakpoints for antifungal drugs are not yet available for most filamentous fungi, including Neoscytalidium species. However, the results indicate that clinical isolates of N. dimidiatum in Malaysia were sensitive towards miconazole, clotrimazole, voriconazole and amphotericin B, in vitro.     

Cutaneous phaeohyphomycosis of the sole caused by Exophiala jeanselmei and its susceptibility to amphotericin B, 5-FC and ketaoconazole

Cutaneous phaeohyphomycosis due to E. jeanselmei developed on the sole of a 61 years old Japanese female who was receiving the corticoids therapy for nephrotic syndrome. Although the causative fungus was resistant to 5-fluorocytosine, amphotericin B and ketoconazole, the lesion was successfully treated by surgical excision.     

Cryptococcus neoformans: Comparisons of in vitro antifungal susceptibilities of serotypes AD and BC

Thirty-nine isolates of Cryptococcus neoformans, nineteen serotype AD and twenty serotype BC, were assayed for susceptibility to eight antifungal agents using an in vitro agar dilution assay. Media employed were Kimmig agar and yeast nitrogen base supplemented with 10% glucose. The antifungal agents used were ketoconazole, amphotericin B, 5-fluorocytosine, nystatin, miconazole, BAY N 7133, ICI 153,066, and itraconazole. No clinically significant differences in in vitro minimum inhibitory concentrations were detected between serotypes AD and BC against any of the compounds tested. An adverse medium effect was observed in two of the assays, but the outcome of the AD/BC comparison was not affected. This is the first report in which the in vitro antifungal susceptibilities of Cryptococcus neoformans serotypes are analyzed.     

Effects of imidazole- and triazole-derivative antifungal compounds on the growth and morphological development of Candida albicans hyphae

Six azole-derivative antifungal compounds affected several aspects of Candida albicans hyphal development with only a relatively small degree of inhibition of growth rate, measured in terms of ATP concentration, whereas amphotericin B and 5-fluorocytosine affected morphology only when they also substantially inhibited fungal growth rate. At 10(-8) M, all the azoles tested inhibited branch formation by C. albicans hyphae. At 10(-7) M and higher concentrations, clotrimazole and miconazole strongly suppressed emergence of new hyphal outgrowths from parent yeast cells, whereas ICI 153066 and itraconazole had little effect on this phenomenon and ketoconazole and tioconazole had intermediate effects. At the highest concentrations tested (10(-5) M) hyphal development was ultimately arrested by the azole compounds and the fungus grew predominantly in the form of budding yeast cells; however, none of the azole antifungals prevented initial emergence of an apparently normal germ tube. The antifungals only exerted their morphological effects when they were present in the culture medium: removal of the compounds after exposure of C. albicans to them led to reversion to normal growth.     

Clinical and experimental keratitis caused by the Colletotrichum state of Glomerella cingulata and Acrophialophora fusispora

Two cases of mycotic keratitis caused by the Colletotrichum state of Glomerella cingulata and Acrophialophora fusispora are reported for the first time. Both the isolates produced experimental corneal lesions in rabbit eyes but A. fusispora was more pathogenic. The experimental infection was more severe, with both the fungi, in rabbits pretreated with cortisone as compared with untreated animals. In vitro A. fusispora was most sensitive to miconazole and tolciclate followed by clotrimazole, amphotericin B and lactones while clotrimazole exerted maximum inhibitory effect on Colletotrichum followed by miconazole, lactones, amphotericin B and arnebins. Arnebins and tolciclate were inactive respectively against A. fusispora and Colletotrichum. Of the 3 drugs tested in vivo, against A. fusispora keratitis in rabbit, amphotericin B showed better results than tolciclate and miconazole.     

Effect of antifungal azoles on the heme detoxification system of malarial parasite

The antimalarial activities of some antifungal azole agents (ketoconazole, miconazole, and clotrimazole) have been known for several years, however, their antimalarial mechanism remains equivocal. Our recent study showed that clotrimazole has a relative high affinity for heme, inhibits reduced glutathione-dependent heme catabolism, and enhances heme-induced hemolysis. In the present study, we have found that clotrimazole can remove heme from histidine rich peptide-heme complex, which initiates heme-polymerization in malaria. In addition, we show that two other azoles (ketoconazole and miconazole) behave similarly to clotrimazole in binding to heme: they bind to heme with similar affinities, remove heme from the histidine rich peptide-heme complex and from the reduced glutathione-heme complex to form stable heme-azole complexes with two nitrogenous ligands derived from the imidazole moieties of two azole molecules. We have also revealed that clotrimazole and miconazole have stronger promoting activities for heme-induced hemolysis than ketoconazole, implying that the stronger antimalarial activities of clotrimazole and miconazole might arise from their stronger ability to promote heme-induced hemolysis of clotrimazole and clotrimazole than that of ketoconazole. These results also suggest that ketoconazole and miconazole, like clotrimazole, might possess an antimalarial mechanism relating to their inhibition of heme polymerization and the degradation of reduced glutathione-dependent heme.     

重症监护病房白念珠菌耐药性8年变化趋势

目的调查上海长征医院重症监护室(ICU)近8 a中临床分离白念珠菌的耐药性变化,为临床治疗提供参考。方法上海长征医院ICU 2002～2009年从414例患者中首次分离出414株白念珠菌,对其中277株进行药敏试验。采用Cox-Stuart趋势检验回顾性分析临床分离真菌中白念珠菌所占比例变化趋势和白念珠菌对常用抗真菌药物耐药率的变化趋势。结果 2002～2009年间,上海长征医院ICU白念珠菌分离株数从2002年的34株增加至2009年的92株,但白念珠菌占总真菌分离株数的百分比维持在34.6%～55.7%,P=0.03。白念珠菌对于5-氟胞嘧啶和两性霉素B平均耐药率分别为4.0%和0.7%,对其他常用抗真菌药的耐药率依次为咪康唑47.0%、酮康唑10.8%、伊曲康唑19.9%、特比萘芬42.6%、氟康唑14.6%及伏立康唑13.0%。白念珠菌对5-氟胞嘧啶和两性霉素B和伊曲康唑耐药率的8年变化无统计学差异。结论上海长征医院ICU近8 a来白念珠菌仍然为临床较为常见的真菌分离株,但白念珠菌占总分离株数的百分比有逐渐减少的趋势。白念珠菌对常用抗真菌药物耐药性均无明显变化趋势。     

Susceptibilities of Candida albicans Mouth Isolates to Antifungal Agents, Essentials Oils and Mouth Rinses

Forty Candida albicans strains isolated from patient's mouth with fixed orthodontic appliances were analyzed to their susceptibilities to antifungal agents, mouth rinses and essential oils. Susceptibility to fluconazole, econazole, miconazole and ketoconazole, amphotericin B and nystatin was assessed by the disk diffusion (DD) method based on the Clinical and Laboratory Standards Institute M44-A protocol, and by Etest (fluconazole and amphotericin B). The susceptibilities to mouth rinses and essential oils were also determined by the DD technique. All isolates tested were susceptible (S) to amphotericin B, nystatin and fluconazole. The overall concordance between the DD and the Etest was 100% for amphotericin and fluconazole. One isolate was resistant to econazole (2.5%) and the other to ketoconazole (2.5%). Econazole and ketoconazole had the highest percentages of susceptible dose dependent (SDD), 55 and 95%, respectively. Regarding to the susceptibility isolates profile, seven phenotypes were detected, and the 3 more represented (90% of the isolates) of them were SDD to one, two or three azoles. The study of mouth rinses showed a high variability of efficacy against C. albicans. The results showed that the isolates susceptibility to essential oils differed (P < 0.05). The profile activity was: cinnamon > laurel > mint > eucalyptus > rosemary > lemon > myrrh > tangerine. The main finding was that the susceptibility to cinnamon and laurel varied among the three more representative antifungal phenotypes (P < 0.05). The susceptibility of econazole-SDD isolates to cinnamon and lemon was higher than those of the econazole-S yeasts (P < 0.05). In contrast, econazole-SDD isolates were less affected by laurel than econazole-S counterparts (P < 0.05).     

Comparative efficacy of amphotericin B,clotrimazole and itraconazole againstAspergillus spp.

The susceptibilities of two isolates ofAspergillus flavus, one from a human case of recalcitrant mycotic keratitis, and an environmental isolate ofA. fumigatus, to itraconazole, clotrimazole and amphotericin B were measured. Observations of macroscopic growth and microscopic evaluations of conidia germination both indicated that the two isolates ofA. flavus were markedly more resistant to amphotericin B than to itraconazole and clotrimazole. Itraconazole was more effective than clotrimazole for all isolates. Ourin vitro susceptibility results suggest the use of itraconazole should be a primary consideration in the treatment ofAspergillus keratitis.     

Corneal transplant infection by Paecilomyces lilacinus

Paecilomyces lilacinus was cultured from an ulcerated corneal transplant, sections of which, following surgical removal, revealed dense mycelial growth throughout the corneal remnant and penetrating Descemet's membrane. PAS-stained sections showed, in addition to the hyphae, numerous small, ovoid elements consistent with conidia of P. lilacinus. Infection apparently had spread to the transplant from the recipient's cornea. The fungal isolate proved resistant, in vitro, to amphotericin B, 5-fluorocytosine, and pimaricin, but sensitive to ketoconazole and moderately sensitive to miconazole. Following a second transplant and intensive antifungal therapy, the infection appears to have been eliminated.     

Susceptibility of clinical isolates of yeasts to anti-fungal agents

The antimicrobial activity of amphotericin B, 5-fluorocytosine, nystatin, clotrimazole and miconazole were compared in vitro against 244 strains of yeasts that had been isolated from clinical specimens. The yeasts used in this study included 20 species of Candida, Cryptococcus, Saccharomyces Geotrichum, Rhodotorula, Torulopsis and Trichosporon. The majority of the strains (78%) had an MIC of 0.5 g/ml for amphotericin B, 81% an MIC of 1 g/ml for 5-fluorocytosine, 99% 8 g/ml for nystatin, 91%, 8.0 g/ml for clotrimazole and 98% had an MIC of 4.0 for miconazole. Of the anti-fungal agents tested, 5-fluorocytosine and nystatin were found to have the greatest antifungal activity.     

In Vitro Sensitivity of Torulopsis glabrata to Amphotericin B, 5-Fluorocytosine, and Clotrimazole (Bay 5097)

Thirty-five strains of Torulopsis glabrata were tested by a tube dilution method for their susceptibility to amphotericin B, 5-fluorocytosine, and clotrimazole (Bay 5097). Amphotericin B was the most active in vitro, inhibiting all strains at a concentration of 1 μg/ml and killing all strains at 2 μg/ml. 5-Fluorocytosine inhibited over 80% of strains at 0.24 μg/ml, but three strains required ≥7.8 μg/ml for killing. A concentration of 2 μg of clotrimazole per ml inhibited less than 50% of strains, and 8 μg/ml killed only 10% of strains. Most strains of T. glabrata were killed by therapeutically achievable concentrations of amphotericin B and 5-fluorocytosine, but not clotrimazole.     

Antifungal drug resistance pattern of Candida. spp isolated from vaginitis in Ilam-Iran during 2013-2014

Vaginal Candidiasis is the most common and important opportunistic fungal infection in women. By increasing use of antifungal drugs in recent years, it has caused drug resistance. This study aims to evaluate antifungal drugs susceptibility of Candida. spp isolated of women with vaginitis from Ilam-Iran during 2013-2014. samples were collected and cultured from 385 women with vaginitis, then Candida.spp was diagnosed by standard method. Antifungal drug susceptibility test for nystatin 100 unit/disk, fluconazole 10µg/disk, itraconazole 10µg/disk, ketoconazole 10µg/disk, amphotericinB 20µg/disk, clotrimazole 10µg/disk, posaconazole 5µg/disk, and voriconazole 1µg/disk were carried out by M44-A method(CLSI). From all culture positive samples, 150 isolates were Candida albicans and 89 isolates were non-albicans. The resistance to fluconazole, itraconazole, ketoconazole, clotrimazole, voriconazole, posaconazole, nystatin and amphotericin B was 76%, 62%, 72%, 55%, 6%, 7%, 1% and 0%. The highest resistance was seen for fluconazole , itraconazole, and the highest susceptible was seen for nystatin and amphotericin B. These results indicate nystatin and amphotericin B can be used as the first line for empirical therapy of vaginal candidiasis in the district.     

用聚类法分析受抗真菌物质处理后的酵母细胞全基因表达谱

微阵列DNA芯片技术可以并行分析成千上万个基因的表达情况,它为研究药物的作用机制提供了一个新的高效技术平台.用9种已知和未知作用机理的抗真菌化合物处理酵母细胞,并得到酵母细胞的全基因表达谱,然后对其进行聚类分析.结果表明作用机制类似的化合物具有相近的聚类关系.两性霉素B和制霉菌素、酮康唑和克霉唑都是已知的作用机制类似的抗真菌药物.通过对基因表达谱进行聚类分析,发现前一组和后一组分别被聚类在一起.另外已知澳洲茄胺抑制的是细胞膜上麦角固醇的合成,聚类分析表明它与酮康唑,克霉唑的聚类很靠近.对微阵列DNA芯片产生的基因表达谱进行聚类分析,由于作用机制相似的药物会被聚类在一起,因此根据未知药物和已知药物的聚类关系,可以了解未知药物的作用机制,这对于加速新药开发的步伐具有十分重要的意义.     

Effect of synthetic antifungal drugs on the adherence of Candida albicans to the mouth mucosa epithelium in vitro

Ten Candida albicans strains were tested for their adherence to buccal epithelial cells in vitro in the presence of synthetic antimycotic drugs as 5-fluorocytosine, clotrimazole and ketoconazole. The drugs when applied in therapeutic concentrations inhibited adherence stronger than when applied in subinhibitory concentrations although in both situations the inhibition was statistically significant in comparison to control experiments without these drugs (p less than 0.01). The highest inhibition of adherence was seen with 5-fluorocytosine and the weakest with clotrimazole. Out of imidazole derived drugs strong inhibition of adherence was achieved with ketoconazole.     

Occurrence and the sensitivity to drugs of fungi other than Candida albicans isolated from the vagina

Frequency of occurrence of fungal species distinct from C. albicans isolated from vaginal mucosa and their sensitivity to antimycotic chemotherapeutics was determined. Material consisted of 452 fungal strains isolated from vagina from patients suffering from afflictions within genital area. Fungal strains isolated belonged to 13 genera. Fungi distinct from C. albicans constituted 27.1% of all the strains. Fungi the most frequently isolated from vagina belonged to following genera: T. glabrata 35.2% C. krusei 18.4% C. pseudotropicalis 15.2% S. cerevisiae 10.4%. In the majority of cases of vaginal infections caused by fungi distinct from C. albicans, Lactobacillus sp. was present and normal pH values of vaginal content 3/4 with variable number of leucocytes were observed. Evaluation of sensitivity to antimycotic drugs of fungal strains was performed by agar dilution technique. In this study the following chemotherapeutics were assayed: nystatin, pimaricin, amphotericin B, flucytosine, clotrimazole, miconazole and ketoconazole. It is worth to underline resistance of T. glabrata and S. cerevisiae to clotrimazole and ketoconazole. Moreover, resistance of strains belonging to genera C. krusei and C. pseudotropicalis to amphotericin B and C. krusei strains to nystatin and flucytosine was noted.