Broth Microdilution and Time–Kill Testing of Caspofungin, Voriconazole, Amphotericin B and their Combinations Against Clinical Isolates of Candida krusei

2011 ◽  
Vol 173 (1) ◽  
pp. 27-34 ◽  
Author(s):  
Yasemin Oz ◽  
Ilknur Dag ◽  
Nuri Kiraz
Keyword(s):  
Amphotericin B ◽  
Candida Krusei ◽  
Clinical Isolates ◽  
Broth Microdilution ◽  
Time Kill

scholarly journals Categorizing susceptibility of clinical isolates of Candida auris to amphotericin B, caspofungin, and fluconazole utilizing the CLSI M44-A2 disk diffusion method

2021 ◽  
Author(s):  
Natalie S. Nunnally ◽  
Tajah Damm ◽  
Shawn R. Lockhart ◽  
Elizabeth L. Berkow
Keyword(s):  
Amphotericin B ◽  
Accurate Method ◽  
Clinical Isolates ◽  
Disk Diffusion ◽  
Diffusion Method ◽  
Broth Microdilution ◽  
Candida Auris ◽  
Disk Diffusion Method ◽  
Microdilution Method ◽  
Broth Microdilution Method

We evaluated the CLSI M44ed3E disk diffusion method in comparison with the CLSI M27ed4 broth microdilution method for caspofungin and fluconazole and the Etest method for amphotericin B to categorize susceptibility of 347 clinical isolates of Candida auris. Utilizing the zone diameter cutoffs established here we observed the overall categorial agreement between the two methods. For caspofungin, concordant results were observed for 98% of isolates with <1% very major and 1% major errors. For fluconazole, concordant results were observed for 91% of isolates with 1% very major and 8% major errors. For amphotericin B, concordant results were observed for 74% of isolates with <1% very major errors and 25% major errors. The disk diffusion approach provides an accurate method for determining the susceptibility of C. auris for caspofungin and fluconazole, and for identification of at least 75% of amphotericin B-susceptible isolates.

scholarly journals Increased Antifungal Drug Resistance in Clinical Isolates of Cryptococcus neoformans in Uganda

2015 ◽  
Vol 59 (12) ◽  
pp. 7197-7204 ◽  
Author(s):  
Kyle D. Smith ◽  
Beatrice Achan ◽  
Kathy Huppler Hullsiek ◽  
Tami R. McDonald ◽  
Laura H. Okagaki ◽  
...  
Keyword(s):  
Amphotericin B ◽  
Low Income ◽  
Low Cost ◽  
Drug Susceptibility ◽  
Antifungal Drug ◽  
Clinical Isolates ◽  
Hiv Care ◽  
Low Income Countries ◽  
Broth Microdilution ◽  
Content Type

ABSTRACTCryptococcal antigen screening is recommended among people living with AIDS when entering HIV care with a CD4 count of <100 cells/μl, and preemptive fluconazole monotherapy treatment is recommended for those with subclinical cryptococcal antigenemia. Yet, knowledge is limited of current antimicrobial resistance in Africa. We examined antifungal drug susceptibility in 198 clinical isolates collected from Kampala, Uganda, between 2010 and 2014 using the CLSI broth microdilution assay. In comparison with two previous studies from 1998 to 1999 that reported an MIC50of 4 μg/ml and an MIC90of 8 μg/ml prior to widespread human fluconazole and agricultural azole fungicide usage, we report an upward shift in the fluconazole MIC50to 8 μg/ml and an MIC90value of 32 μg/ml, with 31% of isolates with a fluconazole MIC of ≥16 μg/ml. We observed an amphotericin B MIC50of 0.5 μg/ml and an MIC90of 1 μg/ml, of which 99.5% of isolates (197 of 198 isolates) were still susceptible. No correlation between MIC and clinical outcome was observed in the context of amphotericin B and fluconazole combination induction therapy. We also analyzedCryptococcussusceptibility to sertraline, with an MIC50of 4 μg/ml, suggesting that sertraline is a promising oral, low-cost, available, novel medication and a possible alternative to fluconazole. Although the CLSI broth microdilution assay is ideal to standardize results, limit human bias, and increase assay capacity, such assays are often inaccessible in low-income countries. Thus, we also developed and validated an assay that could easily be implemented in a resource-limited setting, with similar susceptibility results (P= 0.52).

scholarly journals In vitro kill curves of a new semisynthetic echinocandin, LY-303366, against fluconazole-sensitive and -resistant Candida species.

1997 ◽  
Vol 41 (11) ◽  
pp. 2576-2578 ◽  
Author(s):  
J A Karlowsky ◽  
G A Harding ◽  
S A Zelenitsky ◽  
D J Hoban ◽  
A Kabani ◽  
...  
Keyword(s):  
Candida Albicans ◽  
Amphotericin B ◽  
Candida Species ◽  
Candida Glabrata ◽  
Candida Krusei ◽  
Clinical Isolates

In vitro killing by a new semisynthetic echinocandin, LY-303366, was characterized using clinical isolates of fluconazole-sensitive (Y58) and -resistant (Y180) Candida albicans as well as Candida glabrata (Y7) and Candida krusei (Y171). The 24-h kill curves for Y58 and Y180 demonstrated dose-independent killing of between 1 and 2 log10 with LY-303366 at concentrations of 0.1, 1, 10, 50, 100, and 1,000 times the MIC. Regrowth did not occur at 24 h with either C. albicans isolate at the aforementioned LY-303366 concentrations. At their MICs, LY-303366 and amphotericin B produced similar killing kinetics in cultures of Y58, Y180, Y7, and Y171, while all cultures exposed to fluconazole at its MIC demonstrated stasis or growth over 24 h.

Time-Kill Curves Studies with Amphotericin B Against Cryptococcus neoformans/C. gattii Species Complex Clinical Isolates

2017 ◽  
Vol 11 (4) ◽  
pp. 158-162 ◽  
Author(s):  
Lidiane de Oliveira ◽  
Dayane Cristina Silva Santos ◽  
Marilena dos Anjos Martins ◽  
Maria Walderez Szeszs ◽  
Marcia Souza Carvalho Melhem
Keyword(s):  
Cryptococcus Neoformans ◽  
Amphotericin B ◽  
Species Complex ◽  
Clinical Isolates ◽  
Time Kill

Susceptibility of clinical isolates of Cryptococcus neoformans to amphotericin B using time–kill methodology

2009 ◽  
Vol 64 (2) ◽  
pp. 146-151 ◽  
Author(s):  
Mara C.S.M. Pappalardo ◽  
Maria Walderez Szeszs ◽  
Marilena A. Martins ◽  
Liliana B. Baceti ◽  
Lucas X. Bonfietti ◽  
...  
Keyword(s):  
Cryptococcus Neoformans ◽  
Amphotericin B ◽  
Clinical Isolates ◽  
Time Kill

Slow response of invasive Candida krusei infection to amphotericin B in a clinical time-kill study

2006 ◽  
Vol 25 (12) ◽  
pp. 803-806 ◽  
Author(s):  
L. Majoros ◽  
I. Szegedi ◽  
G. Kardos ◽  
C. Erdész ◽  
J. Kónya ◽  
...  
Keyword(s):  
Amphotericin B ◽  
Candida Krusei ◽  
Slow Response ◽  
Time Kill

scholarly journals Antifungal susceptibilities of clinical and environmental isolates of Cryptococcus neoformans in goiânia city, Goiás, Brasil

2005 ◽  
Vol 47 (5) ◽  
pp. 253-256 ◽  
Author(s):  
Lúcia Kioko Hasimoto Souza ◽  
Orionalda de Fátima Lisboa Fernandes ◽  
Cláudia Castelo Branco Artiaga Kobayashi ◽  
Xisto Sena Passos ◽  
Carolina Rodrigues Costa ◽  
...  
Keyword(s):  
Cerebrospinal Fluid ◽  
Cryptococcus Neoformans ◽  
Amphotericin B ◽  
Similar Pattern ◽  
Clinical Isolates ◽  
Broth Microdilution ◽  
Environmental Isolates ◽  
Minimal Inhibitory Concentrations ◽  
Microdilution Method ◽  
Broth Microdilution Method

We evaluated the antifungal activities of amphotericin B, fluconazole, itraconazole and voriconazole in 70 Cryptococcus neoformans strains obtained from cerebrospinal fluid from AIDS patients and 40 C. neoformans strains isolated from the environment. Four clinical isolates were identified as C. neoformans var. gattii. The susceptibility test was done using a broth microdilution method according to NCCLS M27-A2. Range minimal inhibitory concentrations (MICs) for C. neoformans clinical isolates were 0.06-1.0 µg/mL for amphotericin B, 0.125-8 µg/mL for fluconazole, 0.03-0.5 µg/mL for itraconazole and 0.03-0.25 µg/mL for voriconazole. C. neoformans environmental isolates showed range MICs 0.015-0.125 µg/mL, 0.25-2.0 µg/mL, 0.007-0.125 µg/mL and 0.03-0.25 µg/mL for amphotericin B, fluconazole, itraconazole and voriconazole respectively. The MICs results obtained from clinical and environmental isolates showed similar pattern of susceptibility and no resistance has been found in our isolates.

scholarly journals Rates and Extents of Antifungal Activities of Amphotericin B, Flucytosine, Fluconazole, and Voriconazole against Candida lusitaniae Determined by Microdilution, Etest, and Time-Kill Methods

2002 ◽  
Vol 46 (2) ◽  
pp. 578-581 ◽  
Author(s):  
Erika J. Ernst ◽  
Keiko Yodoi ◽  
Ellen E. Roling ◽  
Michael E. Klepser
Keyword(s):  
Amphotericin B ◽  
Fungicidal Activity ◽  
Broth Microdilution ◽  
Antifungal Activities ◽  
Candida Lusitaniae ◽  
Time Kill

ABSTRACT Amphotericin B, flucytosine, fluconazole, and voriconazole alone and in combination were evaluated against isolates of Candida lusitaniae. MICs were determined by broth microdilution and Etest, and time-kill studies were conducted. Amphotericin B resulted in fungicidal activity against most isolates, whereas fluconazole, voriconazole, and flucytosine produced primarily fungistatic activities. The addition of flucytosine to amphotericin B resulted in a faster rate and greater extent of kill for isolates for which the MICs of amphotericin B were elevated.

Killing rates exerted by caspofungin in 50 % serum and its correlation with in vivo efficacy in a neutropenic murine model against Candida krusei and Candida inconspicua

2014 ◽  
Vol 63 (2) ◽  
pp. 186-194 ◽  
Author(s):  
Renátó Kovács ◽  
Rudolf Gesztelyi ◽  
Réka Berényi ◽  
Marianna Domán ◽  
Gábor Kardos ◽  
...  
Keyword(s):  
Murine Model ◽  
Candida Krusei ◽  
Clinical Isolates ◽  
Killing Rate ◽  
Serum Killing ◽  
Effective Doses ◽  
Fungal Tissue ◽  
Time Kill

Killing rates (K) of 1–32 µg ml−1 caspofungin were determined in RPMI-1640 and in 50 % serum using time–kill methodology against three Candida krusei (MICs of all three isolates 0.25 µg ml−1 in RPMI-1640 and 2 µg ml−1 in serum) and three Candida inconspicua clinical isolates (MIC ranges 0.06–0.12 µg ml−1 in RPMI-1640 and 0.25–0.5 µg ml−1 in serum), against C. krusei ATCC 6258 and against one C. krusei isolate that was resistant to echinocandins (MIC 8 µg ml−1 in RPMI-1640 and 32 µg ml−1 in serum). In RPMI-1640, the highest mean K values were observed at 4 (−1.05 h−1) and 16 (−0.27 h−1) μg ml−1 caspofungin for C. krusei and C. inconspicua clinical isolates, respectively. In 50 % serum, mean K value ranges at 1–32 and 4–32 µg ml−1 concentrations for C. inconspicua and C. krusei were −1.12 to −1.44 and −0.42 to −0.57 h−1, respectively. While K values against C. krusei in RPMI-1640 and 50 % serum were comparable, serum significantly increased the killing rate against C. inconspicua (P<0.0003 for all tested concentrations). In a neutropenic murine model, daily caspofungin at 1, 2, 3, 5 and 15 mg kg−1 significantly decreased the fungal tissue burden of C. inconspicua in the kidneys (P<0.05–0.001). Against C. krusei, doses of 3, 5 and 15 mg kg−1 caspofungin were effective (P<0.05–0.01). All effective doses were comparably efficacious for both species. Only the highest 15 mg kg−1 caspofungin dose was effective even against the echinocandin-resistant C. krusei isolate. In 50 % serum, killing was concentration independent at effective concentrations (≥4 and ≥1 µg ml−1 for C. krusei and C. inconspicua, respectively), suggesting that the efficacy of dose escalation is questionable. These in vitro results were also supported by the murine model.

scholarly journals Comparison of the MICs Obtained by Gradient Concentration Strip and EUCAST Methods for Four Azole Drugs and Amphotericin B against Azole-Susceptible and -Resistant Aspergillus Section Fumigati Clinical Isolates

2019 ◽  
Vol 64 (3) ◽  
Author(s):  
S. Dellière ◽  
L. Verdurme ◽  
J. Bigot ◽  
E. Dannaoui ◽  
Y. Senghor ◽  
...  
Keyword(s):  
Amphotericin B ◽  
Sensu Stricto ◽  
Clinical Isolates ◽  
Broth Microdilution ◽  
Routine Testing ◽  
Content Type ◽  
Valuable Method ◽  
Resistant Strains ◽  
Potential Impact

ABSTRACT Reference methods used to assess the drug susceptibilities of Aspergillus fumigatus isolates consisted of EUCAST and CLSI standardized broth microdilution techniques. Considering the increasing rate and the potential impact on the clinical outcome of azole resistance in A. fumigatus, more suitable techniques for routine testing are needed. The gradient concentration strip (GCS) method has been favorably evaluated for yeast testing. The aim of this study was to compare the CGS test with EUCAST broth microdilution for amphotericin B (AMB), posaconazole (PCZ), itraconazole (ITZ), voriconazole (VRZ), and isavuconazole (ISA). A total of 121 Aspergillus section Fumigati strains were collected, including 24 A. fumigatus sensu stricto strains that were resistant to at least one azole drug. MICs were determined using GCS and EUCAST methods. Essential agreement between the 2 methods was considered when MICs fell within ±1 dilution or ±2 dilutions of the 2-fold dilution scale. Categorical agreement was defined as the percentage of strains classified in the same category (susceptible, intermediate, or resistant) with both methods. Essential agreements with ±1 dilution and ±2 dilutions were 96.7, 93.4, 90.0, 89.3, and 95% and 100, 99.2, 100, 97.5, and 100% for AMB, PCZ, ITZ, VRZ, and ISA, respectively. Categorical agreements were 94.3, 86.1, 89.3, and 88.5% for AMB, PCZ, ITZ, and VRZ, respectively. Detection of resistance was missed with the GCS for one strain (4.1%) for PCZ and for 2 strains (8.3%) for ISA. Determination of ITZ MICs using the GCS allowed the detection of 91.7% of azole-resistant strains. The GCS test appears to be a valuable method for screening azole-resistant A. fumigatus clinical isolates.

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