Influence of different susceptibility testing methods and media on determination of the relevant fluconazole minimum inhibitory concentrations for heavy trailing Candida isolates with low-high phenotype.

We investigated the incidence of trailing growth with fluconazole in 101 clinical Candida isolates (49 C. albicans and 52 C. tropicalis) and tried to establish the convenient susceptibility testing method and medium for fluconazole minimum inhibitory concentration (MIC) determination. MICs were determined by CLSI M27-A2 broth microdilution (BMD) and Etest methods on RPMI-1640 agar supplemented with 2% glucose (RPG) and on Mueller-Hinton agar supplemented with 2% glucose and 0.5 µg ml(-1) methylene blue (GMB). BMD and Etest MICs were read at 24 and 48 h, and susceptibility categories were compared. All isolates were determined as susceptible with BMD, Etest-RPG and Etest-GMB at 24 h. While all isolates were interpreted as susceptible at 48 h on Etest-RPG and Etest-GMB, one C. albicans isolate was interpreted as susceptible-dose dependent (S-DD) and two C. tropicalis isolates were interpreted as resistant with BMD. On Etest-RPG, trailing growth caused widespread microcolonies within the inhibition zone and resulted in confusion in MIC determination. On Etest-GMB, because of the nearly absence of microcolonies within the zone of inhibition, MICs were evaluated more easily. We conclude that, for the determination of fluconazole MICs of trailing Candida isolates, the Etest method has an advantage over BMD and can be used along with this reference method. Moreover, GMB appears more beneficial than RPG for the fluconazole Etest.

Molecular identification, genotyping, and drug susceptibility of the basidiomycetous yeast pathogen Trichosporon isolated from Turkish patients.

Deep-seated infections due to Trichosporon species are emerging mycoses that have a very poor prognosis in patients with persistent neutropenia. This study elucidated the mycological characteristics of Trichosporon strains obtained from deep-seated infections in Turkish patients and identified by DNA sequence analysis of intergenic spacer (IGS) region 1 of the rDNA locus. In addition, we genotyped the major causative agent, T. asahii, and evaluated the in vitro drug susceptibility of the isolates. While 87 (81.3%) of the 107 isolates were T. asahii, the remaining 20 were T. faecale (14.0%), T. asteroids (0.9%), T. coremiiforme (0.9%), T. japonicum, (0.9%), T. lactis (0.9%), and a new species (0.9%). In addition to the eight known T. asahii genotypes, one novel genotype was identified. The distribution of the T. asahii genotypes in this study were genotype 1 (79.3%), followed by 5 (8.0%), 3 (6.9%), 6 (3.4%), 4 (1.1%), and 9 (1.1%). Turkish isolates showed low susceptibility to amphotericin B, 5-flucytosine, and fluconazole. Although relatively low minimum inhibitory concentrations (MICs) were found with all drugs, voriconazole appeared to be the most active. The MICs of the non-Trichosporon asahiiTrichosporon species were similar to those of the T. asahii strains. Our findings suggest that Trichosporon species isolated from Turkish patients are more diverse than those reported from other countries.

[Investigation of in vitro activities of fluconazole, itraconazole and voriconazole against clinical isolates of Blastoschizomyces capitatus (Geotrichum capitatum) by two different methods]. / Flukonazol, itrakonazol ve vorikonazolün klinik Blastoschizomyces capitatus (Geotrichum capitatum) izolatlarina karsi in vitro aktivitesinin iki farkli yöntemle arastirilmasi.

Blastoschizomyces capitatus is an emerging opportunistic pathogen that may lead to invasive infections particularly in neutropenic patients. In this study, the in vitro activities of fluconazole, itraconazole and voriconazole against 15 clinical B. copitatus isolates were determined by microdilution method (MD) and Etest. The isolation and identification of the isolates were done by standard mycological methods. MD tests were done in accordance with CLSI microdilution method (M27A-2). Etest was performed according to the instructions of the manufacturer (AB Biodisk, Sweden) by using RPMI-2% glucose. Since susceptibility breakpoints were not yet established for B. copitatus, only the distribution of the MIC values obtained for the tested antifungals were given. MIC values were determined after 48 h incubation and by using MIC-2 value for all the drugs tested. At 48 h, MIC90 values obtained by MD and Etest were 16 and 32 microg/ml, 0.5 and 1 microg/ml, 0.5 and 1 microg/ml for fluconazole, itraconazole and voriconazole, respectively. These results suggested that voriconazole and itraconazole had favorable activity against B. capitatus isolates. However, the activity of fluconazole remained poor and limited at least for a significant number of isolates. Percent agreement of Etest with MD method within +/-1 dilution range and at 48 hour for fluconazole, itraconazole and voriconazole were 86.7%, 80% and 73.3%, respectively, suggesting a higher agreement of the two methods for fluconazole as compared to itraconazole and voriconazole. Etest tended to generate 1-2 fold higher MICs as compared to MD MICs for most of the isolates of this particular fungus. In conclusion, further studies are required for determination of the optimal susceptibility testing method and the MIC breakpoints for B. capitatus.

Systemic phaeohyphomycosis due to Exophiala (Wangiella) in an immunocompetent child.

We report a rare case of systemic lymphadenitis and hepatic involvement due to Exophiala (Wangiella) dermatitidis in a pediatric patient. An 8-year-old immunocompetent boy with chronic fever was examined through the use of sonography and CT scan which demonstrated cervical and mesenteric lymph node enlargement and numerous small hepatic lesions. The etiologic agent was isolated by means of lymph node aspiration. The fungus was identified by its morphological characteristics and through DNA sequencing of the internal transcribed spacer region of rDNA. Despite initial amphotericin B and voriconazole therapy, the child's jaundice subsided and he died 7 months later. In addition to pathogenic aspects of Exophiala dermatitidis, the diagnostic approaches and relevant therapeutic strategies are discussed.

Investigation of extracellular elastase, acid proteinase and phospholipase activities as putative virulence factors in clinical isolates of Aspergillus species.

We investigated the production of extracellular elastase, acid proteinase and phospholipase enzyme activities in clinical isolates of Aspergillus fumigatus, Aspergillus flavus and Aspergillus niger and any possible correlation between the existence of these enzymes and development of invasive aspergillosis. A total of 73 strains (45 A. fumigatus, 23 A. flavus, 5 A. niger) isolated from patients with invasive aspergillosis (n = 55), superficial aspergillosis (n = 5), allergic bronchopulmonary aspergillosis (n = 1), and from those colonized with Aspergillus (n = 12) were included in the study. The enzymatic activities were tested on solid media supplemented with the corresponding substrates. Elastase activity was detected in 95.6, 82.6, and 0% of A. fumigatus, A. flavus, and A. niger isolates, respectively. Acid proteinase activity was detected only for A. fumigatus and in 20 of 45 isolates belonging to this species. Phospholipase activity was present in all strains of A. fumigatus and A. niger but in none of the isolates of A. flavus. No statistical correlation could be established between the existence of elastase or acid proteinase activity and development of invasive disease (p > 0.05). While high phospholipase production was found to be associated with development of invasive aspergillosis (p < 0.01), not all isolates that caused invasive diseases showed high phospholipase activities.

[Determination of in vitro susceptibility of Candida species to amphotericin B by E-test and previously proposed MIC breakpoints on two different media]. / Candida türlerinin amfoterisin B'ye duyarliliginin E-test ve iki farkli besiyeri ile önerilmis olan direnç sinir degerlerine göre arastirilmasi.

Although much work has concentrated on defining a reliable and reproducible method for determining in vitro susceptibility of Candida species to amphotericin B, there still has been limitations of the proposed techniques. In this study, amphotericin B minimal inhibitory concentrations (MIC) and susceptibility categories of 212 Candida strains (57 C. glabrata, 53 C. lusitaniae, 51 C. krusei and 51 C. tropicalis) were determined by E-test on RPMI agar (RPG) and antibiotic medium 3 agar (AM3) both supplemented with 2% glucose. The results were interpreted according to the proposed MIC breakpoints (> or = 0.38 microg/ml on RPG, >1 microg/ml on AM3) and discrepancies between susceptibility categories were investigated. While all Candida strains included in the study were determined to be susceptible on AM3 by amphotericin B E-test at 48h, 36.3% of the isolates were classified as resistant on RPG at 48 hours. On RPG, C. krusei strains showed the highest resistance rate (94.1% at 48 h), followed by C. tropicalis (35.3% at 48 h) and C. glabrata (17.5% at 48h). At 48h of incubation, 98.1% of C. lusitaniae isolates were found to be susceptible on RPG. The categorical agreement rates between the results obtained on two media and for C. lusitaniae and C. glabrata were 98.1% and 82.5% at 48 hours. For C. tropicalis and C. krusei, the rates of agreement were 64.7% and 5.9% at 48 hours. Conclusively, according to the previously proposed MIC breakpoints for amphotericin B E-test on RPG and AM3, discrepancies between susceptibility categories of Candida species were of remarkable significance.

Comparative in vitro activities of posaconazole, voriconazole, itraconazole, and amphotericin B against Aspergillus and Rhizopus, and synergy testing for Rhizopus.

We compared the in vitro activities of posaconazole, voriconazole, itraconazole, and amphotericin B against clinical isolates of Aspergillus spp. and Rhizopus spp., and explored the in vitro interaction between posaconazole and amphotericin B against Rhizopus spp. Clinical strains of 82 Aspergillus spp. (43 Aspergillus fumigatus, 29 A. flavus, 7 A. niger, 2 A. terreus, 1 A. nidulans) and 11 Rhizopus oryzae isolates were tested in accordance with CLSI M38-A microdilution guidelines. In vitro activity of posaconazole against Aspergillus spp. was also investigated with the Etest. The combination of posaconazole and amphotericin B against R. oryzae isolates was investigated by the checkerboard methodology. Voriconazole was the most active drug in vitro against Aspergillus spp., followed by posaconazole, itraconazole, and amphotericin B, in order of decreasing activity. In studies with R. oryzae isolates, posaconazole was found to be the most potent drug followed by itraconazole and amphotericin B. Voriconazole had no meaningful activity against Rhizopus. Posaconazole Etest MICs (microg/ml) with Aspergillus spp. were found to be considerably lower than those obtained with the CLSI microdilution method (4-9 and 3-7 two-fold lower than CLSI MICs at 24 and 48 h, respectively). The interaction between posaconazole and amphotericin B was indifferent for all R. oryzae isolates tested; importantly no antagonism was observed.

[Molecular typing of clinical Candida krusei isolates by using restriction endonuclease analysis of genomic DNA and polymerase chain reaction]. / Candida krusei klinik izolatlarinin genomik DNA restriksiyon enzim analizi ve polimeraz zincir reaksiyonu ile tiplendirilmesi.

Candida krusei is inherently resistant to fluconazole and is an important pathogen responsible for nosocomial candidiasis especially in patients with hematological malignancy. Despite the growing clinical importance of C. krusei infections, little is known of its genetic diversity and molecular epidemiology. Therefore, differentiating between C. krusei isolates is of importance for a better understanding of the epidemiology, mode of transmission and pathogenesis of the organism. We investigated the use of two different methods (restriction endonuclease analysis of genomic DNA (REAG) with Hinfl and polymerase chain reaction by using Arno1 and Arno2 primers) for molecular typing of 56 C. krusei isolates from 56 patients. Ten different types (A-J) were determined by REAG. Depending on the patterns of isolates, the number of the bands varied from 12 to 15 and the size of the fragments varied from 2.0 kb to 6.2 kb. Of the isolates 71.4% were gathered under three major patterns (D, F, H). In the second method, PCR amplified different sizes of fragments varied approximately from 1 kb to 2 kb, which yielded 13 types (a-m) from 56 patients. Four major patterns (d, f, h, k) were observed for 58.9% of the isolates. The genotypes detected by REAG and PCR methods were found to be same in 43 isolates out of 56. As the banding patterns of the isolates were found to be similar in this study, it was thought that an exogenous origin could be the source of infections caused by C. krusei isolates. Both REA of genomic DNA and PCR analysis seem to be useful for the typing of C. krusei, however PCR assay can be preferred as it is a simple and rapid method. As a result, further studies are required for the validation of reproducibility and discriminatory power of these methods.

Current status of antifungal susceptibility testing methods.

Antifungal susceptibility testing is a very dynamic field of medical mycology. Standardization of in vitro susceptibility tests by the Clinical and Laboratory Standards Institute (CLSI) and the European Committee for Antimicrobial Susceptibility Testing (EUCAST), and current availability of reference methods constituted the major remarkable steps in the field. Based on the established minimum inhibitory concentration (MIC) breakpoints, it is now possible to determine the susceptibilities of Candida strains to fluconazole, itraconazole, voriconazole, and flucytosine. Moreover, utility of fluconazole antifungal susceptibility tests as an adjunct in optimizing treatment of candidiasis has now been validated. While the MIC breakpoints and clinical significance of susceptibility testing for the remaining fungi and antifungal drugs remain yet unclear, modifications of the available methods as well as other methodologies are being intensively studied to overcome the present drawbacks and limitations. Among the other methods under investigation are Etest, colorimetric microdilution, agar dilution, determination of fungicidal activity, flow cytometry, and ergosterol quantitation. Etest offers the advantage of practical application and favorable agreement rates with the reference methods that are frequently above acceptable limits. However, MIC breakpoints for Etest remain to be evaluated and established. Development of commercially available, standardized colorimetric panels that are based on CLSI method parameters has added more to the antifungal susceptibility testing armamentarium. Flow cytometry, on the other hand, appears to offer rapid susceptibility testing but requires specified equipment and further evaluation for reproducibility and standardization. Ergosterol quantitation is another novel approach, which appears potentially beneficial particularly in discrimination of azole-resistant isolates from heavy trailers. The method is yet investigational and requires to be further studied. Developments in methodology and applications of antifungal susceptibility testing will hopefully provide enhanced utility in clinical guidance of antifungal therapy. However, and particularly in immunosuppressed host, in vitro susceptibility is and will remain only one of several factors that influence clinical outcome.

Colonization of neonate skin by Malassezia species: relationship with neonatal cephalic pustulosis.

BACKGROUND: Colonization of neonate skin by Malassezia species and their causative role in neonatal cephalic pustulosis is unclear. OBJECTIVES: We sought to determine the skin colonization by Malassezia in healthy newborns, and to investigate its association with neonatal cephalic pustulosis. METHODS: Samples for Malassezia colonization were taken from cheeks and scalps of 104 neonates between 24 and 72 hours after birth, and again 2 or 4 weeks later. Pustules were sampled with concomitant nonlesional skin cultures if neonatal cephalic pustulosis was diagnosed. RESULTS: Malassezia colonization increased significantly with age of the neonate (5% at the first week, 30% at 2-4 weeks). In all, 26 patients were given the diagnosis of neonatal cephalic pustulosis during follow-up. No correlation was found between the severity of the disease and Malassezia isolation. Skin colonization of patients with neonatal cephalic pustulosis (20.8%) was not higher than colonization of healthy newborns (37%). LIMITATIONS: Not all of the neonates were examined by the authors at the second visit. CONCLUSIONS: Malassezia colonization increases after the first week of life. No correlation was found between neonatal cephalic pustulosis and Malassezia.

[In vitro activity of amphotericin B, fluconazole and itraconazole against Candida glabrata strains isolated from clinical samples]. / Klinik örneklerden izole edilen Candida glabrata suslarinin amfoterisin B, flukonazol ve itrakonazole in vitro duyarliliginin arastirilmasi.

In recent years, the incidence of Candida albicans infections tends to decrease, at least in some centers other Candida species have emerged as opportunistic pathogens. Among non-albicans Candida species, C. glabrata is one of the most frequently isolated species. In this study, the in vitro activities of amphotericin B, itraconazole and fluconazole were tested against 134 clinical C. glabrata strains. The isolation and identification of the isolates were done by standard mycological methods. Microbroth susceptibility tests were done in accordance with CLSI microdilution method (M27A-2). MICs were read at both 24 and 48 hours. At 24 h, MIC range, MIC50 and MIC90 values for amphotericin B were 0.5-4 micorg/ml, 2 microg/ml and 4 microg/ml, respectively. At 48 h, MIC range, MIC50 and MIC90 values for amphotericin B were 2-4 microg/ml, 4 microg/ml and 4 microg/ml respectively. At 24 h, 97% of the isolates were susceptible (S) and 3% were dose-dependent susceptible (S-DD) to fluconazole. None of the isolates were resistant (R) to fluconazole at this time point. At 48 h, 94% of the isolates were S, 5.2% were S-DD and 0.8% were R to fluconazole. At 24 h, 20.9% of the isolates were S, 73.1% were S-DD and 6% were R to itraconazole. At 48 h, 0.8% of the isolates were S, 62.7% were S-DD and 36.5% were R to itraconazole. These results suggest that although C.glabrata strains that were isolated in our hospital were rarely resistant to fluconazole, resistance rate to itraconazole is relatively high. Most of the isolates that are resistant to itraconazole remain susceptible to fluconazole.

[In vitro activity of ketoconazole, itraconazole and terbinafine against Malassezia strains isolated from neonates]. / Yenidoganlardan izole edilen Malassezia suslarinin ketokonazol, itrakonazol ve terbinafine in vitro duyarliligi.

Malassezia, a yeast-like fungus found in normal skin flora is known to be associated with various skin diseases and systemic infections. There is yet no standardized in vitro susceptibility testing method and minimum inhibitory concentration (MIC) breakpoints for Malassezia species. In this study, we investigated the in vitro activity of ketoconazole, itraconazole and terbinafine against 30 Malassezia strains (22 Malassezia furfur/dermatis, 8 M. japonica) isolated from cheek and/or scalp swabs and/or cephalic pustules of 21 neonates. The isolates were identified to species level on the basis of growth on Sabouraud dextrose agar, assimilation of Tween compounds and catalase reaction. The antifungal susceptibility tests were performed by agar dilution method using modified Dixon agar (MDA) and the agar dilution plates were incubated at 32 degrees C. For the isolates which exhibited sufficient growth, MICs were read at 48 hours, for the remaining slow-growing isolates, MIC readings were done on 7th day. For all drugs tested, the lowest concentration that provided complete inhibition of growth visually was interpreted as the MIC (microg/ml) value. Itraconazole was the most active drug in vitro against Malassezia species, followed by ketoconazole and terbinafine in rank order. In vitro activity of terbinafine was poor for half of the Malassezia strains tested. Variations in activity against individual Malassezia strains were detected for ketoconazole and terbinafine, while in vitro activity of itraconazole was similar for all strains tested. In order to validate the clinical significance of these results, further in vitro and in vivo correlation studies are needed.

Incubation at room temperature may be an independent factor that induces chlamydospore production in Candida dubliniensis.

Production of chlamydospores is one of the phenotypic features used to differentiate Candida albicans and Candida dubliniensis. C. albicans produces few chlamydospores on only cornmeal/rice-Tween agar at room temperature, whereas C. dubliniensis produces abundant chlamydospores at this temperature both on cornmeal agar and some other commonly used media. We tried to determine whether the room temperature is the main factor that induces chlamydospore production of C. dubliniensis, regardless of the medium used. For this purpose, 100 C. albicans and 24 C. dubliniensis isolates were tested for chlamydospore production at room temperature and at 37 degrees C on some routinely used media, including eosin-methylene blue agar (EMB), nutrient agar (NA), nutrient broth (NB), and also on an investigational medium, phenol red agar (PR). At 37 degrees C, none of the isolates produced chlamydospores on any of the tested media. At 26 degrees C, all C. dubliniensis isolates produced abundant chlamydospores and pseudohyphae after 24-48 h on all tested media. At this incubation temperature, all C. albicans isolates failed to produce chlamydospores and pseudohyphae on EMB, NA, and NB, whereas 2 of the C. albicans isolates produced a few chlamydospores on PR. We also observed that all C. dubliniensis isolates tested on EMB and PR produced rough colonies with a hyphal fringe around the colonies, whereas none of the C. albicans isolates showed this property. In conclusion, incubation at 26 degrees C may play the key role for production of abundant chlamydospores and pseudohyphae by C. dubliniensis. Comprehensive molecular studies are needed to clarify the genetic basis of this observation. Using EMB and PR may be an inexpensive, a time-saving, and a simple way of presumptive identification of C. dubliniensis based on chlamydospore formation and colony morphology.

In vitro activity of caspofungin compared to amphotericin B, fluconazole, and itraconazole against Candida strains isolated in a Turkish University Hospital.

We investigated the in vitro activity of caspofungin compared to amphotericin B, fluconazole, and itraconazole against clinical strains of Candida spp. (n =239). Antifungal susceptibility tests were done in accordance with NCCLS M27-A2 microdilution method and the results were read after 24 and 48 h. In general, 24 h MIC readings were similar to those at 48 h for most isolates and all antifungal agents. Caspofungin was active against all species tested. Caspofungin MICs of Candida parapsilosis were slightly higher than those for other Candida spp. Caspofungin MIC (microg/ml) ranges at 24 h for C. albicans, C. glabrata, C tropicalis, C. parapsilosis, C kefyr, C krusei, C. lusitaniae, C. norvegensis, C. guilliermondii and C. lipolytica were 0.06-2, 0.125-2, 0.125-2, 1-4, 0.125-2, 1-2, 0.5-2, 0.5-1, 0.5-2 and 1-2, respectively. Eagle (paradoxical) effect was observed in 31 and 8% of the isolates at highest concentrations of caspofungin and itraconazole, respectively. The activity of caspofungin against fluconazole- and/or itraconazole-resistant isolates was similar to that detected for the susceptible ones. We conclude that caspofungin appears as a promising antifungal agent with enhanced activity against Candida, including the azole-resistant strains.

Deep dermatophytosis caused by Trichophyton rubrum with concomitant disseminated nocardiosis in a renal transplant recipient.

Deep dermatophytosis and nocardiosis are uncommon infections. This article describes a patient who was immunosuppressed with deep dermatophytosis caused by Trichophyton rubrum and concurrent disseminated nocardiosis. The infections occurred 16 years after the patient underwent renal transplantation, and may have been related to tacrolimus therapy.

[Evaluation of the Tween 80 opacity test for detection of the lipolytic activity of various Candida species and its utility in differentiation of C. albicans and C. dubliniensis]. / Cesitli Candida türlerinin lipolitik aktivitelerinin saptanmasinda Tween 80 opaklasma testinin degerlendirilmesi ve C. albicans ile C. dubliniensis ayirimindaki yeri.

In this study a total of 253 strains belonging to 10 different species of Candida were examined for their lipolytic activity by using the Tween-80 opacity test. Hundred and seventy-four of 182 C. albicans, all of 21 C. tropicalis, 1 C. rugosa and 2 of 5 C. famata strains produced halo on Tween 80 medium and around the inoculum after 10 days of incubation pointing out the positive lipolytic (esterase) activity. Seven of 8 negative C. albicans strains were isolated from hemocultures of patients with different malignancies. Remaining strains of Candida species; C. glabrata (12), C. dubliniensis (6), C. kefyr (8), C. guillermondii (5) and C. spherica (3) did not produce the halo. Tween 80 medium may be useful for the presumptive identification of some Candida species but regarding our results further large scale studies are necessary to establish the role of the medium in differentiating particularly the two similar species, C. albicans and C. dubliniensis.

[Identification of Candida dubliniensis strains using heat tolerance tests, morphological characteristics and molecular methods]. / Candida dubliniensis suslarinin sicaklik toleransi testi, morfolojik özellikler ve moleküler yöntemlerle tanimlanmasi.

Described in 1995, Candida dubliniensis is a novel Candida species closely related to Candida albicans due primarily to its ability to produce germ tube and chlamydospores. Given these phenotypic similarities between the two species, C. dubliniensis cannot be readily distinguished from Candida albicans by routine laboratory work-up. We explored the frequency of isolation of C. dubliniensis among 213 strains previously defined as C. albicans based on their ability to produce germ tube. The test isolates were initially examined for their morphological features on cornmeal tween 80 agar, inability to grow at 45 degrees C, and the biochemical assimilation profile (ID 32C system, bioMerieux, France). Among all, 2 (0.9%) of the isolates were identified as C. dubliniensis based on the production of numerous chlamydospores in chains on cornmeal tween 80 agar and the lack of growth at 45 degrees C. The assimilation profile of these isolates was found to be in accordance with this identification. In an effort to confirm the identification, polymerase chain reaction (PCR) studies were carried out by using the C. dubliniensis specific primer set, DUBF and DUBR. Both of the isolates yielded C. dubliniensis-specific 288 base pair amplification products, confirming the previous identification obtained with the initial screening tests. The isolates were found to be susceptible to fluconazole and itraconazole, and generated amphotericin B minimal inhibitory concentrations of 0.5-1 microgram/ml by NCCLS M27-A2 microdilution method. These data suggest that the isolation rate of C. dubliniensis among our clinical isolates is low. The morphological features on cornmeal tween 80 agar and the lack of ability to grow at 45 degrees C appear as reliable, cheap, and practical screening tests in initial identification of C. dubliniensis among germ tube-producing Candida strains.

Comparison of two methods and three end points in determination of in vitro activity of micafungin against Aspergillus spp.

We investigated the in vitro activity of micafungin against clinical Aspergillus isolates (n = 37) (Aspergillusfumigatus [n = 21], Aspergillusflavus [n = 14], and Aspergillus niger [n = 2]) by using NCCLS M38A microdilution and an investigational disk diffusion assay. Microdilution assay results were evaluated by using the end points of a MIC-2 (measured in micrograms per milliliter) and minimum effective concentration (MEC, measured in micrograms per milliliter; the lowest concentration of micafungin that produces short and aberrant hyphal branchings microscopically). Disk diffusion results were interpreted by measuring the zone(s) of inhibition (ZOI, measured in millimeters). Micafungin proved to be similarly active against all Aspergillus species tested. At 24 h, MIC-2s and MECs were identical. At 48 h, however, MIC-2s increased unpredictably, leading to the loss of a consistent correlation between the two end points. MECs and ZOI remained consistent and correlated at both reading times, suggesting their use as relevant end points in susceptibility testing of micafungin against Aspergillus: All Aspergillus isolates yielded intrazonal growth on disk diffusion agar plates. The intrazonal colonies contained short, aberrant hyphal branchings microscopically. The in vivo significance of these findings remains to be further investigated.

Prevalence of dermatomycoses in Mal de Meleda patients: a field study.

Mal de Meleda is a rare autosomal recessive form of palmoplantar keratoderma characterized by hyperkeratosis of the palms and soles. The presence of yeast and dermatophytes was investigated in 29 mal de Meleda patients from Koprucay canyon, Turkey, a newer geographical focus, and was found in 62.0% and 20.7% of cases, respectively. Antifungal resistance of isolates was not detected.

Lipid-based antifungal agents: a concise overview.

The development of lipid formulations of antifungal drugs has been a remarkable progress in the systemic antifungal arena. The lipid-based amphotericin B formulations; amphotericin B lipid complex (ABLC), amphotericin B colloidal dispersion (ABCD), and liposomal amphotericin B (L-AMB) have been in clinical use since the 1990s. They are significantly less nephrotoxic than the parent compound and can be safely used at higher doses. The primary cost of these formulations is significantly high and the extent of data related to their head-to-head comparison remains limited. The lipid formulation of nystatin, liposomal nystatin, is another lipid-based polyene under development. Available data concerning the in vitro activity, pharmacokinetic profile, in vivo efficacy, and safety of these formulations are summarized in this overview.