We have correlated the in vitro results of testing the susceptibility of Cryptococcus neoformans to fluconazole with the clinical outcome after fluconazole maintenance therapy in patients with AIDS-associated cryptococcal disease. A total of 28 isolates of C. neoformans from 25 patients (24 AIDS patients) were tested. The MICs were determined by the broth microdilution technique by following the modified guidelines described in National Committee for Clinical Standards (NCCLS) document M27-A, e.g., use of yeast nitrogen base medium and a final inoculum of 10 4 CFU/ml. The fluconazole MIC at which 50% of isolates are inhibited (MIC 50 ) and MIC 90 , obtained spectrophotometrically after 48 h of incubation, were 4 and 16 g/ml, respectively. Of the 25 patients studied, 4 died of active cryptococcal disease and 2 died of other causes. Therapeutic failure was observed in five patients who were infected with isolates for which fluconazole MICs were >16 g/ml. Four of these patients had previously had oropharyngeal candidiasis (OPC); three had previously had episodes of cryptococcal infection, and all five treatment failure patients had high cryptococcal antigen titers in either serum or cerebrospinal fluid (titers, >1:4,000). Although 14 of the 18 patients who responded to fluconazole therapy had previously had OPC infections, they each had only a single episode of cryptococcal infection. It appears that the clinical outcome after fluconazole maintenance therapy may be better when the infecting C. neoformans strain is inhibited by lower concentrations of fluconazole for eradication (MICs, <16 g/ml) than when the patients are infected with strains that require higher fluconazole concentrations (MICs, >16 g/ml). These findings also suggest that the MICs determined by the modified NCCLS microdilution method can be potential predictors of the clinical response to fluconazole therapy and may aid in the identification of patients who will not respond to fluconazole therapy.Cryptococcosis is an infection caused by the ubiquitous fungus Cryptococcus neoformans, an encapsulated yeast-like fungus. The most frequent clinical presentation of the disease is meningoencephalitis (5, 6, 12, 18, 19; M. S. Saag, Editorial Response, Clin. Infect. Dis. 21:35-36, 1995); 75 to 90% of AIDS patients infected with C. neoformans will develop meningitis (5). Cryptococcosis in AIDS patients is seldom cured, and fluconazole is the drug of choice for the necessary lifelong suppressive (maintenance) therapy (17). Use of fluconazole for long-term suppressive therapy may be associated with the development of azole resistance in cryptococcal infections in AIDS patients (21).Methods for testing the antifungal susceptibility of C. neoformans could become important tools in the selection and monitoring of an appropriate antifungal drug for the treatment and prophylaxis of cryptococcal infections. Ghannoum et al. (9) developed a broth microdilution method for measuring the susceptibility of cryptococci to fluconazole, which is described as an alternative a...

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BackgroundTo assess the performance of Candida albicans germ tube antibody (CAGTA), (1 → 3)-ß-D-glucan (BDG), mannan antigen (mannan-Ag), anti-mannan antibodies (mannan-Ab), and Candida DNA for diagnosing invasive candidiasis (IC) in ICU patients with severe abdominal conditions (SAC).MethodsA prospective study of 233 non-neutropenic patients with SAC on ICU admission and expected stay ≥ 7 days. CAGTA (cutoff positivity ≥ 1/160), BDG (≥80, 100 and 200 pg/mL), mannan-Ag (≥60 pg/mL), mannan-Ab (≥10 UA/mL) were measured twice a week, and Candida DNA only in patients treated with systemic antifungals. IC diagnosis required positivities of two biomarkers in a single sample or positivities of any biomarker in two consecutive samples. Patients were classified as neither colonized nor infected (n = 48), Candida spp. colonization (n = 154) (low-grade, n = 130; high-grade, n = 24), and IC (n = 31) (intra-abdominal candidiasis, n = 20; candidemia, n = 11).ResultsThe combination of CAGTA and BDG positivities in a single sample or at least one of the two biomarkers positive in two consecutive samples showed 90.3 % (95 % CI 74.2–98.0) sensitivity, 42.1 % (95 % CI 35.2–98.8) specificity, and 96.6 % (95 % CI 90.5–98.8) negative predictive value. BDG positivities in two consecutive samples had 76.7 % (95 % CI 57.7–90.1) sensitivity and 57.2 % (95 % CI 49.9–64.3) specificity. Mannan-Ag, mannan-Ab, and Candida DNA individually or combined showed a low discriminating capacity.ConclusionsPositive Candida albicans germ tube antibody and (1 → 3)-ß-D-glucan in a single blood sample or (1 → 3)-ß-D-glucan positivity in two consecutive blood samples allowed discriminating invasive candidiasis from Candida spp. colonization in critically ill patients with severe abdominal conditions. These findings may be helpful to tailor empirical antifungal therapy in this patient population.

uAlthough epidemiological cutoff values (ECVs) have been established for Candida spp. and the triazoles, they are based on MIC data from a single laboratory. We have established ECVs for eight Candida species and fluconazole, posaconazole, and voriconazole based on wild-type (WT) MIC distributions for isolates of C. albicans (n ‫؍‬ 11,241 isolates), C. glabrata (7,538), C. parapsilosis (6,023), C. tropicalis (3,748), C. krusei (1,073), C. lusitaniae (574), C. guilliermondii (373), and C. dubliniensis (162). The 24-h CLSI broth microdilution MICs were collated from multiple laboratories (in Canada, Brazil, Europe, Mexico, Peru, and the United States). The ECVs for distributions originating from >6 laboratories, which included >95% of the modeled WT population, for fluconazole, posaconazole, and voriconazole were, respectively, 0.5, 0.06 and 0.03 g/ml for C. albicans, 0.5, 0.25, and 0.03 g/ml for C. dubliniensis, 8, 1, and 0.25 g/ml for C. glabrata, 8, 0.5, and 0.12 g/ml for C. guilliermondii, 32, 0.5, and 0.25 g/ml for C. krusei, 1, 0.06, and 0.06 g/ml for C. lusitaniae, 1, 0.25, and 0.03 g/ml for C. parapsilosis, and 1, 0.12, and 0.06 g/ml for C. tropicalis. The low number of MICs (<100) for other less prevalent species (C. famata, C. kefyr, C. orthopsilosis, C. rugosa) precluded ECV definition, but their MIC distributions are documented. Evaluation of our ECVs for some species/ agent combinations using published individual MICs for 136 isolates (harboring mutations in or upregulation of ERG11, MDR1, CDR1, or CDR2) and 64 WT isolates indicated that our ECVs may be useful in distinguishing WT from non-WT isolates.

Epidemiological cutoff values (ECVs) were established for the new triazole isavuconazole and Aspergillus species wild-type (WT) MIC distributions (organisms in a species-drug combination with no detectable acquired resistance mechanisms) that were defined with 855 Aspergillus fumigatus, 444 A. flavus, 106 A. nidulans, 207 A. niger, 384 A. terreus, and 75 A. versicolor species complex isolates; 22 Aspergillus section Usti isolates were also included. CLSI broth microdilution MIC data gathered in Europe, India, Mexico, and the United States were aggregated to statistically define ECVs. ECVs were 1 g/ml for the A. fumigatus species complex, 1 g/ml for the A. flavus species complex, 0.25 g/ml for the A. nidulans species complex, 4 g/ml for the A. niger species complex, 1 g/ml for the A. terreus species complex, and 1 g/ml for the A. versicolor species complex; due to the small number of isolates, an ECV was not proposed for Aspergillus section Usti. These ECVs may aid in detecting non-WT isolates with reduced susceptibility to isavuconazole due to cyp51A (an A. fumigatus species complex resistance mechanism among the triazoles) or other mutations.

Method-dependent Etest epidemiological cutoff values (ECVs) are not available for susceptibility testing of either Candida or Aspergillus species with amphotericin B or echinocandins. In addition, reference caspofungin MICs for Candida spp. are unreliable. Candida and Aspergillus species wild-type (WT) Etest MIC distributions (microorganisms in a species-drug combination with no detectable phenotypic resistance) were established for 4,341 Candida albicans, 113 C. dubliniensis, 1,683 C. glabrata species complex (SC), 709 C. krusei, 767 C. parapsilosis SC, 796 C. tropicalis, 1,637 Aspergillus fumigatus SC, 238 A. flavus SC, 321 A. niger SC, and 247 A. terreus SC isolates. Etest MICs from 15 laboratories (in Argentina, Europe, Mexico, South Africa, and the United States) were pooled to establish Etest ECVs. Anidulafungin, caspofungin, micafungin, and amphotericin B ECVs (in micrograms per milliliter) encompassing Ն97.5% of the statistically modeled population were 0.016, 0.5, 0.03, and 1 for C. albicans; 0.03, 1, 0.03, and 2 for C. glabrata SC; 0.06, 1, 0.25, and 4 for C. krusei; 8, 4, 2, and 2 for C. parapsilosis SC; and 0.03, 1, 0.12, and 2 for C. tropicalis. The amphotericin B ECV was 0.25 g/ml for C. dubliniensis and 2, 8, 2, and 16 g/ml for the complexes of A. fumigatus, A. flavus, A. niger, and A. terreus, respectively. While anidulafungin Etest ECVs classified 92% of the Candida fks mutants evaluated as non-WT, the performance was lower for caspofungin (75%) and micafungin (84%) cutoffs. Finally, although anidulafungin (as an echinocandin surrogate susceptibility

TE or PG are widely expressed among Candida spp., although they do not seem to influence clinical outcome.

Background: Candida dubliniensis is a recently described Candida species closely related to Candida albicans, which has been associated with oral candidiasis in HIV-infected patients. Fluconazole-resistant strains of C. dubliniensis are easily obtained in vitro and this fact could be a complication if this resistance develops during treatment with this drug. Methods: In the present study, the in vitro antifungal susceptibilities of 36 C. dubliniensis clinical isolates and culture strains to current and new antifungal agents, such as amphotericin B (AMB), amphotericin B lipid complex (ABLC), amphotericin B colloidal dispersion (ABCD), 5-fluorocytosine (5FC), fluconazole (FLC), itraconazole (ITC), ketoconazole (KTC), liposomal amphoteri- cin B (LAMB), liposomal nystatin (LNYT), LY303366 (LY), SCH56592 (SCH), and voriconazole (VRC), were determined according to the National Committee for Clinical Laboratory Standards M27-A broth microdilution method for yeasts. Results: Most isolates of C. dubliniensis were susceptible to both new and current antifungal drugs, with 75.9% isolates susceptible to KTC, 86.2% to FLC and to ITC, and ∼100% to the other antifungal agents tested. The cross-resistance phenotypes are detailed. Four isolates were resistant (MIC ≥64 μg/ml) to FLC. These 4 isolates were also resistant to KTC, and 3 of them were also resistant to ITC (MIC ≥1 μg/ml for both agents). However, these isolates were highly susceptible to 5FC and all polyene formulations (AMB, ABLC, ABCD, LAMB, and LNYT), triazole (SCH and VRC) and echinocandin (LY) antifungal agents. Conclusion: The new liposomal and lipidic formulations of AMB, LNYT, and the new triazoles and echinocandins may provide new alternatives to FLC for the treatment of infections by C. dubliniensis.