In vitro susceptibility of yeasts for fluconazole and itraconazole. Evaluation of a microdilution test

In vitro susceptibilities were determined for a total of 159 clinical isolates and 12 reference strains of yeasts belonging to different Candida species including 94 Candida albicans strains, and further genera such as Cryptococcus, Trichosporon, Geotrichum and Saccharomyces. Minimum inhibitory concentration (MIC) values for fluconazole and itraconazole were assessed using a microdilution technique with the semisynthetic high resolution (HR) medium supplemented with glucose and asparagine but without sodium hydrogen carbonate (pH 7.0), according to a proposal of the working group 'Clinical Mycology' of the German Speaking Mycological Society. Fluconazole MIC values for C. albicans were between 0.125 and > or = 128 micrograms ml-1. Thus, the median of 1 microgram ml-1 showed that the overall fluconazole susceptibility was good. As expected, Candida krusei (seven strains) exhibited diminished in vitro susceptibility with MIC values for fluconazole of 8 to 128 micrograms ml-1 with a median of 64 micrograms ml-1. Some Candida kefyr strains seemed to be less susceptible against fluconazole which was indicated by a MIC90 of 64 micrograms ml-1. Surprisingly, no Candida glabrata isolate exhibited a MIC value greater than 16 micrograms ml-1. Other Candida species, Trichosporon cutaneum, Geotrichum candidum and Saccharomyces cerevisiae showed low MICs to fluconazole. In vitro susceptibility testing of itraconazole revealed that all Candida species except C. albicans, but also Trichosporon cutaneum, Geotrichum candidum, and Saccharomyces cerevisiae exhibited acceptable low MIC values against itraconazole (0.03-2 micrograms ml-1). Their MIC90 values for itraconazole were in the close range between 0.125 and 2 micrograms ml-1. MIC values between 0.125 and 2 micrograms ml-1 were obtained, even for C. krusei strains. On the other hand, the range of C. albicans MICs was between 0.0125 and > or = 16 micrograms ml-1 with MIC50 and MIC90 values of 0.125 and > or = 16 micrograms ml-1, respectively, indicating that a considerable number of yeast strains have high MICs. The comparative evaluation of different experimental conditions revealed that there exists a marked influence both of inoculum size and incubation time on the results of susceptibility testing. Therefore, for routine usage 10(2) CFU ml-1 and 18-24 h incubation time for this microdilution method with HR medium are recommended.     

In vitro activity of rilopirox against fluconazole-susceptible and fluconazole-resistant Candida isolates from patients with HIV infection

The in vitro antifungal activity of the new hydroxypyridone antimycotic rilopirox has been evaluated against 38 fluconazole-susceptible and -resistant clinical isolates of Candida albicans together with other Candida species isolated from patients with human immunodeficiency virus (HIV) infection and oropharyngeal candidosis. Minimum inhibitory concentrations (MICs) of both rilopirox and fluconazole were measured by a microdilution method using high-resolution medium supplemented with asparagine and glucose at pH 7.0. In comparison, an agar dilution technique was carried out for susceptibility testing of the antifungal agents. Rilopirox was found to be able to inhibit growth of all clinical yeast isolates. The rilopirox MICs at which 50% and 90% of strains were inhibited (MIC50 and MIC90 respectively), as determined by the microdilution method, were 4 and 8 micrograms ml-1 respectively. The highest MIC values for rilopirox using microdilution and the agar dilution method were 32 or 25 micrograms ml-1 respectively. On the other hand, for fluconazole, the MIC50 and MIC90 achieved were 0.5 and 128 micrograms ml-1, respectively, which means that the MIC90 value of fluconazole was 16-fold higher than that of rilopirox. Using the agar dilution technique, the MIC values of rilopirox were in the range 0.006-25 micrograms ml-1 with a median of 3.12 micrograms ml-1. For fluconazole, the MIC90 value was four-fold higher than that for rilopirox, indicating a considerable proportion of yeast strains with high MICs of 100 micrograms ml-1, suggesting in vitro resistance to this azole antifungal. All strains with diminished fluconazole susceptibility were susceptible to rilopirox. Even Candida krusei and Candida glabrata exhibited good in vitro susceptibility to rilopirox. Therefore, this new antifungal agent may be used as an alternative not only in the treatment of vaginal candidosis, but also in oropharyngeal Candida infections, e.g. in AIDS patients.     

Emergence of resistance to amphotericin B and triazoles in Candida glabrata vaginal isolates in a case of recurrent vaginitis

Emergence of resistance to triazoles and amphotericin B in Candida glabrata vaginal isolates is documented by Etest. During the 18-month follow-up of a case of vaginitis, 14 consecutive isolates of C. glabrata were examined. The isolates exhibited development of in vitro resistance beginning with itraconazole (>32 microg/ml), followed by fluconazole (>256 microg/ml), amphotericin B (>32 microg/ml), and voriconazole (>32 microg/ml). The DNA sequence analyses and finger printing of the isolates strongly suggest that our patient remained colonized with a single strain. The report underscores the propensity of C. glabrata to acquire resistance during antifungal therapy and the importance of susceptibility testing in the management of infections caused by this species.     

Effect of culture media on in vitro susceptibility testing of fluconazole against some yeasts

Thirty clinical isolates, comprising six strains of Candida albicans, and four strains each of C. lusitaniae, C. parapsilosis, C. tropicalis, Cryptococcus neoformans, Torulopsis glabrata and Trichosporon beigelii were tested against fluconazole, using Sabouraud's dextrose (SD) broth and a high resolution (HR) medium (Pfizer Central Research, Inc.). The procedure was a standard tube (1 ml/tube) dilution, and C. albicans Y01 09 was included as a reference strain to monitor quality and reproducibility. Results indicated that the minimum inhibitory concentrations (MICs) for all isolates of C. albicans, C. lusitaniae, C. tropicalis, and Tr. beigelii were 100 micrograms ml-1 or greater in the SD medium. In the HR medium, however, the MICs for two isolates of C. albicans were 1.56 micrograms ml-1, in other four gave higher values (greater than 100 micrograms ml-1), and the results for C. lusitaniae and Tr. beigelii were in the range 1.56-3.12 micrograms ml-1. The MICs for C. tropicalis were unaffected (100 micrograms ml-1) by the medium used. All Cr. neoformans isolates yielded a uniform value (1.56 micrograms ml-1) in HR medium as compared to somewhat more variable results (MICs 0.39-1.56 micrograms ml-1) in SD broth. The MICs for T. glabrata in the SD and HR media were 3.12-12.5 and 6.25 micrograms ml-1, respectively. The data indicated that the HR medium is preferable for the in vitro susceptibility testing of C. albicans, C. lusitaniae and Tr. beigelii to fluconazole. The MICs for other yeasts were not affected by the culture medium. The reference C. albicans isolate yielded an MIC of 1.56 micrograms ml-1 throughout.     

Phenotypic variation and antifungal susceptibility patterns of Candida albicans strains isolated from neutropenic patients

The aim of this study was to investigate the relationship between phenotypes of Candida albicans strains isolated from clinical specimens and the susceptibility of the strains to three antifungal agents, fluconazole, amphotericin B and flucytosine. Oropharyngeal, gastrointestinal and urogenital tract specimens were collected from 122 neutropenic patients who had received no previous prophylactic treatment. Each of 122 C. albicans strains recovered was found to express one of the six phenotypes: smooth, fuzzy, irregular, star, ring and stipple. The mean minimum inhibitory concentrations (MICs) of fluconazole was consistently higher for C. albicans strains expressing the stipple phenotype. The mean MICs for the six phenotypes of C. albicans strains ranged between 1.22 and 7.94 micrograms ml-1 for fluconazole, 0.99 and 2.55 micrograms ml-1 for amphotericin B and 1.23 and 1.83 micrograms ml-1 for flucytosine. The antifungal susceptibility of the stipple phenotype requires attention, especially in patients who are clinically unresponsive to fluconazole chemotherapy or in cases of life-threatening C. albicans infections of immunocompromised hosts. Long-term use of fluconazole may explain the outcome of the resistant stipple phenotype.     

Changes of virulence factors accompanying the phenomenon of induced fluconazole resistance in Candida albicans

We investigated a fluconazole-sensitive (MICflu = 5 micrograms ml-1) clinical isolate and a fluconazole-resistant (MICflu > 80 micrograms ml-1) laboratory mutant Candida albicans strain developed from the sensitive one. We studied putative virulence factors including germination, adherence ability to either buccal epithelial cells or acrylate surface, the secreted aspartic proteinase, and the extracellular phospholipase activity of the two strains as well as their growth. The fluconazole-resistant strain proved to be superior to the original strain in all the virulence traits tested. The higher virulence of the fluconazole-resistant strain was also supported by a mouse model. These results suggest that the development of fluconazole resistance can be accompanied by serious morphological and physiological changes: several putative virulence traits, moreover the in vivo virulence can increase simultaneously.     

In vitro comparative evaluations of the postantifungal effect: synergistic interaction between flucytosine and fluconazole against Candida albicans

In vitro comparative evaluations were performed to study the efficacy of combinations of flucytosine and fluconazole in producing a postantifungal effect (PAFE) on Candida albicans. Initial studies were done to determine MIC, FIC (fractional inhibitory concentration) and optimal PAFE parameters. A turbidometric method was used to measure yeast cell growth following exposure to different concentrations of the two drugs for periods of 0.5, 1 or 2 h at temperatures of 30 degrees C and 37 degrees C. The PAFE was determined by the difference in time (h) required for growth of the control and test cultures to reach the 0.5 absorbance level following removal of the drug by dilution. Ten strains of C. albicans were then assayed (30 degrees C; 2 h exposure time) and a synergistic PAFE was evidenced with the two drugs at concentrations well below their individual MICs. PAFEs ranging from 3.8 to 10.5 h, which persisted for 1.2-2.5 h longer than those achieved with either agent separately, were evidenced when flucytosine and fluconazole were combined (flucytosine: fluconazole ratios of 1:16-1:32) at concentrations ranging from 0.024 to 0.098 micrograms ml-1 and 0.78 to 1.56 micrograms ml-1 respectively. The concentrations of each agent required to produce an optimal PAFE varied according to the C. albicans strain being assayed.     

Antifungal action of Hevea brasiliensis latex. Its effect in combination with fluconazole on Candida albicans growth.

Latex from Hevea brasiliensis and its subcellular fractions (L-serum and C-serum) were tested for antifungal activity alone or in combination with fluconazole. Candida albicans growth was inhibited with the same efficacy when yeasts were inoculated into culture medium supplemented over the total growth phase with latex as when latex was added during the exponential phase only: the minimum inhibitory concentration (MIC 80%) of H. brasiliensis latex was 123 micrograms protein ml-1. By means of a non-linear regression analysis of the experimental data, two distinct fixation sites for fluconazole (FCZ) could be determined: one of strong affinity (Kaff = 0.0162 microgram-1 protein ml) and another of low affinity (Kaff = 0.0071 microgram-1 protein ml). After addition of a mixture of FCZ and latex during the exponential phase, the affinity constant of yeasts for FCZ was calculated: when latex was in a final concentration of 21 micrograms protein ml-1 (Kaff = 1 microgram-1 protein ml) or 42 micrograms protein ml-1 (Kaff = 0.277 microgram-1 protein ml) and without latex (Kaff = 0.0502 microgram-1 protein ml). In two cases a synergistic effect between latex and FCZ was obtained. The highest efficacy was obtained with a latex concentration of 21 micrograms protein ml-1. The addition of subcellular fractions of latex, L-serum and C-serum, did not cause an antifungal effect. The indispensable role of rubber particles for raising an antifungal effect is demonstrated. Electron microscopy observations indicated a limited cell wall degradation and a high percentage of coagulated yeasts.     

Disseminated aspergillosis due to Aspergillus flavus in an experimental model: efficacy of azole therapy

The aim of this investigation was to create a reproducible experimental model of disseminated Aspergillus flavus aspergillosis, and to compare the relative therapeutic efficacies of itraconazole and fluconazole in this model. Temporarily immunosuppressed male Wistar rats received intravenous challenge by A. flavus conidia. Treatment was initiated 24 h later with oral itraconazole (1 mg kg-1 BW day-1), oral fluconazole (1 mg kg-1 BW day-1) or excipient only (infected-untreated rats); this was continued for 10 days. At this time, although 100% mortality had occurred among all infected-untreated rats, no mortality was noted among the control-uninfected, infected-itraconazole-treated or infected-fluconazole-treated rats. After killing, essential organs were processed for microbiological and histopathological studies. Aspergillus flavus was recovered in high colony counts from the organs of infected-untreated rats (lungs > liver > brain > kidneys), but in significantly lower colony counts, or not at all, from the organs of itraconazole-treated and fluconazole-treated rats. Histopathological alterations were pronounced in tissues of infected-untreated rats, but less so in treated rats. These data suggest that administration of itraconazole or fluconazole sufficiently early may prevent, or retard, progression of lesions in disseminated aspergillosis.     

In vitro susceptibilities of Malaysian clinical isolates of Cryptococcus neoformans var. grubii and Cryptococcus gattii to five antifungal drugs

The in vitro susceptibilities of Malaysian clinical isolates of Cryptococcus neoformans var. grubii and C . gattii to five antifungal drugs (amphotericin B, flucytosine, fluconazole, itraconazole and ketoconazole) were determined using the Etest method. None of the Malaysian isolates was resistant to amphotericin B and ketoconazole. Isolates resistant to flucytosine, fluconazole and itraconazole were observed in this study. Minimum inhibition concentrations (MICs) of > or = 32 microg ml(-1) against flucytosine, > or = 64 microg ml(-1) against fluconazole and > or = 1 microg ml(-1) against itraconazole were noted in four (8.3%), two (4.2%) and one (2.1%) isolates respectively. There was no significant difference in the MICs for both Cryptococcus species (P > 0.05), indicating that C. gattii was as susceptible as var. grubii to all the antifungal drugs tested. No significant difference in the MICs for both Cryptococcus species collected from 1980 to 1990 and 2002 to 2004 were observed (P > 0.05).     

Breakthrough invasive fungal infections in neutropenic patients after prophylaxis with itraconazole.

This study analyses invasive fungal infections in neutropenic patients with haematological malignancies during antifungal prophylaxis with itraconazole. From September 1994 to December 1998 20 patients developed fungal infections. Two patients suffered from disseminated infections by yeasts and 18 patients suffered from pulmonary infections by moulds (eight proven, 10 highly probable in high-resolution CT scans). In these patients the itraconazole trough concentrations exceeded 500 ng ml-1 (measured by high performance liquid chromatography) significantly less often (median 48%, interquartile range 0-100%) than in another group of 150 leukaemia patients without invasive fungal infections who received 287 courses of prophylaxis with itraconazole at our institution (median 100%, interquartile range 38-100%, P = 0.039). Twelve patients died, six of these had refractory disease. Patients with fatal invasive fungal infections had lower median itraconazole concentrations immediately before occurrence of the infection than patients with non-fatal infections: 120 (0-478) ng ml-1 versus 690 (305-1908) ng ml-1 (P = 0.039). In conclusion, this analysis of breakthrough invasive fungal infections during prophylaxis with itraconazole demonstrates that patients with itraconazole trough concentrations below 500 ng ml-1 were significantly more likely to develop fungal infections and that the last itraconazole trough concentration before occurrence of the infection was significantly lower in patients with fatal invasive fungal infections.     

Emergence of Resistance to Amphotericin B and Triazoles in Candida glabrata Vaginal Isolates in a Case of Recurrent Vaginitis

Abstract

Emergence of resistance to triazoles and amphotericin B in Candida glabrata vaginal isolates is documented by Etest. During the 18-month follow-up of a case of vaginitis, 14 consecutive isolates of C. glabrata were examined. The isolates exhibited development of in vitro resistance beginning with itraconazole (>32 μg/ml), followed by fluconazole (>256 μg/ml), amphotericin B (>32 μg/ml), and voriconazole (>32 μg/ml). The DNA sequence analyses and finger printing of the isolates strongly suggest that our patient remained colonized with a single strain. The report underscores the propensity of C. glabrata to acquire resistance during antifungal therapy and the importance of susceptibility testing in the management of infections caused by this species.     

Fluconazole and itraconazole susceptibilities of Candida spp. isolated from oropharyngeal specimens and blood cultures of paediatric haematology/oncology patients

This study examined the in vitro susceptibilities to fluconazole and itraconazole of isolates of Candida spp. from surveillance oropharyngeal specimens and blood cultures from paediatric patients with malignancy. The species distribution of 100 isolates from oropharyngeal specimens was C. albicans 86%, C. glabrata 7%, C. lusitaniae 4%, C. parapsilosis 2% and C. tropicalis 1%. From a total of nine isolates from blood cultures the species distribution was C. albicans 33.3%, C. parapsilosis 33.3 % and C. guilliermondii 33.3%. Only three of the oropharyngeal isolates were resistant to fluconazole (MIC > or = 64 mg l(-1)) and only two were resistant to itraconazole (MIC > or = 1 mg l(-1)). None of the blood culture isolates was resistant to either agent. At this centre, C. albicans is the predominant species from oropharyngeal specimens, but non-albicans Candida species predominate in blood cultures. Although resistance to fluconazole and itraconazole is rare at present, continued surveillance is warranted to monitor trends in species distribution and antifungal susceptibility.     

Itraconazole trough concentrations in antifungal prophylaxis with six different dosing regimens using hydroxypropyl-beta-cyclodextrin oral solution or coated-pellet capsules

We have previously shown that a trough concentration of at least 500 ng ml-1 itraconazole is necessary for an effective antifungal prophylaxis in neutropenic patients. Since the bioavailability of itraconazole is reduced in these patients, a satisfactory dosing regimen remains to be defined. In this study, six dosing regimens with itraconazole capsules 400, 600 or 800 mg day-1, itraconazole solution 400 mg day-1 (additional loading dose: 400 mg day-1 solution for 2 days), 800 mg day-1 or 400 mg day-1 (additional loading dose: 800 mg day-1 capsules for 7 days, s/c1200) were compared during 160 courses of myelosuppressive chemotherapy in 123 patients with acute leukaemia. After the first week, patients taking 800 mg day-1 or 400 mg day-1 (s/c1200) itraconazole solution achieved significantly higher trough concentrations (high-performance liquid chromatography) than patients in other groups (P < 0.05) and 87 and 100%, respectively, of these had concentrations > 500 ng ml-1. Contrary to a dose of 400 mg day-1, a dose of 800 mg day-1 itraconazole solution induced severe nausea and vomiting in 46% of the patients. We conclude that 400 mg day-1 itraconazole solution with a loading dose of 800 mg day-1 capsules for 7 days resulted in sufficient trough concentrations from the first week onwards and appears to be suitable for antifungal prophylaxis in neutropenic patients.     

A phase I and pharmacokinetic study of didox administered by 36 hour infusion. The Cancer Research Campaign Phase I/II Clinical Trials Committee

Twelve patients were treated with didox, a new ribonucleotide reductase inhibitor, by 36 h infusion. The maximum tolerated dose was 6 g m-2, above which dose-limiting hepatic toxicity was observed. Patient tolerance was significantly better using the 36 h infusion compared to patients receiving the drug by a 30 min infusion; in particular, there were no reports of nausea or vomiting. No responses were seen in these patients. Detailed pharmacokinetics were performed at 6 g m-2 comparing the 36 h and 30 min infusions in four patients. Parent drug AUC values were lower for the 36 h infusion, 67.8 micrograms ml-1 h-1 compared to 232 micrograms ml-1 h-1 for the 30 min infusion. AUC values for the 3-hydroxy metabolite were much higher following the 36 h infusion: 55.4 compared to 18.6 micrograms ml-1 h-1. In contrast, the amide metabolite was not detected following the 36 h infusion, but AUC values of 23 micrograms ml-1 h-1 were seen after the 30 min infusion. The mean peak plasma level was 72 micrograms ml-1 following 6 g m-2 given by a 30 min infusion compared to 2.8 micrograms ml-1 following the prolonged infusion. Clearance was higher following the 36 h infusion: 97.6 versus 24.4 l h-1.     

A study of ethacrynic acid as a potential modifier of melphalan and cisplatin sensitivity in human lung cancer parental and drug-resistant cell lines.

We have studied alterations in glutathione (GSH) levels and glutathione-S-transferase (GST) activity in a series of in vitro derived multidrug resistant and cisplatin resistant sublines of the human lung cancer lines NCI-H69 (small cell), COR-L23 (large cell) and MOR (adenocarcinoma). We have also investigated the effects of ethacrynic acid, a putative inhibitor of GSTs, on levels of GSH and GST activity and on cellular sensitivity to melphalan and to cisplatin. Neither GSH content nor GST activity were significantly greater in the resistant sublines compared with their respective parental lines. The only effects of treating with ethacrynic acid at doses of 1 microgram ml-1 and 3 micrograms ml-1 for 2 h were a reduction in GSH content in the cisplatin resistant subline H69/CPR at the 3 micrograms ml-1 dose, and an increase to over 140% of control at 1 microgram ml-1 and 3 micrograms ml-1 in the MOR parental line (MOR/P) and at 1 microgram ml-1 in the multidrug resistant subline MOR/R. Exposure of parental line COR-L23/P to 3 micrograms ml-1 and 6 micrograms ml-1 of ethacrynic acid for 24 h, however, increased the GSH content to over 300% and 500% of control respectively. Variable effects of ethacrynic acid on GST activity were seen in these cell lines. Doses of 1 microgram ml-1 and 3 micrograms ml-1 reduced activity to 59% and 48% of control respectively in multidrug resistant subline H69/LX4. On the other hand, activity was increased in the cisplatin resistant subline H69/CPR (to 146% and 218% of control) and in MOR/P (to 117% and 137% of control) by 1 microgram ml-1 and 3 micrograms ml-1 respectively of ethacrynic acid. Addition of ethacrynic acid (3 micrograms ml-1) to treatment of the cell lines with melphalan or with cisplatin did not alter the dose-response curves to these agents.     

In vitro activity of terbinafine and itraconazole against Aspergillus species isolated from otomycosis

The minimum inhibitory concentrations (MIC, microg ml-1) of itraconazole and terbinafine against overall 34 Aspergillus isolates from the external ear canals with otomycosis have been determined with M38-P microdilution method suggested by National Committee for Clinical Laboratory Standards (NCCLS). MIC intervals in 48 h determined by taking MIC-2 value of itraconazole (the lowest drug concentration causing 50% inhibition of visible fungal growth) and MIC-0 value of terbinafine (the lowest drug concentration causing 100% inhibition of visible fungal growth) as a basis have been found as follows: 0.125-1 and 0.06-0.5 microg ml-1 for A. niger (22 strains), 0.06-0.25 and 0.06-0.125 microg ml-1 for A. flavus (10 strains), 0.125 and 0.125-0.5 microg ml-1 for A. terreus (two strains). It has been observed that both of the antifungal agents showed an in vitro activity against all Aspergillus species tested.     

Detection of Ca antigen in sera from normal individuals and patients with benign and malignant breast disease

Two assay procedures, an inhibition radioimmunoassay (Inhibition-RIA) and an immunoradiometric assay (IRMA), were established for the detection of circulating tumour-associated Ca antigen. There was a good correlation between results (r = 0.987) but the Inhibition-RIA was selected for extended tests on human sera from patients with breast disease because of its greater ease and economy in use. Circulating Ca antigen was not exclusive to malignancy and the level failed to discriminate between patients with primary carcinoma and those with benign disease. Ca antigen was present in sera of 100 healthy individuals (median 7.1 micrograms ml-1, range 1.8-24.4 micrograms ml)-1, 39 patients with benign disease (median 9.9 micrograms ml-1, range 2.5- greater than 100 micrograms ml-1) and in 67 patients with primary carcinoma (median 11.0 micrograms ml-1, range 3.8- greater than 100 micrograms ml-1). Elevated Ca antigen levels were found in 50% of patients with metastatic spread (median 30.7 micrograms ml-1, range 8.2- greater than 100 micrograms ml-1) and in some patients with primary disease but further studies are needed to determine the prognostic significance. Immunochemical studies confirmed that Ca antigen is a normal serum product but its function is unclear.     

Azole Resistance in Neonatal Intensive Care Units in Argentina

Abstract

The aim of this study was to determine the antifungal susceptibility profile and to detect resistant strains of yeast species isolated from neonates in Intensive Care Units. 92 strains isolated from 25 bloodstream cultures, 20 venous catheters, 23 suprapubic aspirations and 24 rectal swabs were studied. A Candida glabrata strain resistant to fluconazole was detected. Candida krusei appeared with its inherent resistance to fluconazole and showed cross-resistance to itraconazole. Two Candida albicans strains were resistant to azoles, one to itraconazole and the other to fluconazole with a high minimum inhibitory concentration (MIC) for itraconazole. All Candida tropicalis strains were susceptible to fluconazole but two of them showed resistance to itraconazole. The detection of resistant strains in neonates whom had not received previous antifungal therapy is noteworthy. The variations in the epidemiology of fungal infections observed and the antifungal resistance detected emphasize the importance of performing a regular surveillance to observe and to assess them.     

Colorimetric method for susceptibility testing of voriconazole and other triazoles against Candida species

A microdilution assay using Alamar Blue, a colorimetric indicator, was compared with the NCCLS macrodilution broth assay for voriconazole, fluconazole, and itraconazole against Candida albicans, Candida glabrata, and Candida krusei. Concordance (+/- 2 dilutions) between the two methods was highest for voriconazole (98.3%), and for fluconazole and itraconazole it was 94.3 and 95.4%, respectively. Twenty-six of 32 (81.2%) discordant readings (> or = 3 dilutions different) were noted in C. glabrata isolates, and all but two isolates showing discordance had higher minimum inhibitory concentration readings with the colorimetric method.