scholarly journals In Vitro Susceptibility Testing of Geotrichum capitatum: Comparison of the E-Test, Disk Diffusion, and Sensititre Colorimetric Methods with the NCCLS M27-A2 Broth Microdilution Reference Method

2003 ◽  
Vol 47 (12) ◽  
pp. 3985-3988 ◽  
Author(s):  
C. Girmenia ◽  
G. Pizzarelli ◽  
D. D'Antonio ◽  
F. Cristini ◽  
P. Martino
Keyword(s):  
Amphotericin B ◽  
Clinical Laboratory ◽  
Reference Method ◽  
National Committee ◽  
In Vitro Susceptibility ◽  
Microdilution Method ◽  
Geotrichum Capitatum ◽  
In Vitro Susceptibility Testing ◽  
Test Disk

ABSTRACT The in vitro activities of amphotericin B, flucytosine, fluconazole, itraconazole, and voriconazole against 23 isolates of Geotrichum capitatum were determined by the National Committee for Clinical Laboratory Standards (NCCLS) M27-A2 microdilution method and the Sensititre and agar diffusion methods. Amphotericin B and voriconazole appeared to be the more active drugs. Sensititre showed the highest rates of agreement with the NCCLS M27-A2 method.

scholarly journals Evaluation of Amphotericin B Interpretive Breakpoints for Candida Bloodstream Isolates by Correlation with Therapeutic Outcome

2006 ◽  
Vol 50 (4) ◽  
pp. 1287-1292 ◽  
Author(s):  
Benjamin J. Park ◽  
Beth A. Arthington-Skaggs ◽  
Rana A. Hajjeh ◽  
Naureen Iqbal ◽  
Meral A. Ciblak ◽  
...  
Keyword(s):  
Amphotericin B ◽  
Susceptibility Testing ◽  
Clinical Laboratory ◽  
National Committee ◽  
Restricted Range ◽  
Broth Microdilution ◽  
Therapeutic Success ◽  
In Vitro Susceptibility ◽  
In Vitro Susceptibility Testing

ABSTRACT One hundred seven Candida bloodstream isolates (51 C. albicans, 24 C. glabrata, 13 C. parapsilosis, 13 C. tropicalis, 2 C. dubliniensis, 2 C. krusei, and 2 C. lusitaniae strains) from patients treated with amphotericin B alone underwent in vitro susceptibility testing against amphotericin B using five different methods. Fifty-four isolates were from patients who failed treatment, defined as death 7 to 14 days after the incident candidemia episode, having persistent fever of ≥5 days' duration after the date of the incident candidemia, or the recurrence of fever after two consecutive afebrile days while on antifungal treatment. MICs were determined by using the Clinical Laboratory Standards Institute (formally National Committee for Clinical Laboratory Standards) broth microdilution procedure with two media and by using Etest. Minimum fungicidal concentrations (MFCs) were also measured in two media. Broth microdilution tests with RPMI 1640 medium generated a restricted range of MICs (0.125 to 1 μg/ml); the corresponding MFC values ranged from 0.5 to 4 μg/ml. Broth microdilution tests with antibiotic medium 3 produced a broader distribution of MIC and MFC results (0.015 to 0.25 μg/ml and 0.06 to 2 μg/ml, respectively). Etest produced the widest distribution of MICs (0.094 to 2 μg/ml). However, none of the test formats studied generated results that significantly correlated with therapeutic success or failure.

scholarly journals In Vitro Susceptibility Testing of Filamentous Fungi: Comparison of Etest and Reference Microdilution Methods for Determining Itraconazole MICs

2000 ◽  
Vol 38 (9) ◽  
pp. 3359-3361 ◽  
Author(s):  
M. A. Pfaller ◽  
S. A. Messer ◽  
K. Mills ◽  
A. Bolmström
Keyword(s):  
Filamentous Fungi ◽  
Susceptibility Testing ◽  
Clinical Laboratory ◽  
Reference Method ◽  
National Committee ◽  
Pseudallescheria Boydii ◽  
In Vitro Susceptibility ◽  
In Vitro Susceptibility Testing ◽  
Microdilution Broth

The performance of the Etest for itraconazole susceptibility testing of 50 isolates of filamentous fungi was assessed in comparison with the National Committee for Clinical Laboratory Standards (NCCLS) proposed standard microdilution broth method. The NCCLS method employed RPMI 1640 broth medium, and MICs were read after incubation for 48 h at 35°C. Etest MICs were determined with RPMI agar containing 2% glucose and with Casitone agar and were read after incubation for 24 h (Aspergillus spp. and Rhizopus spp.) and 48 h (all species except Rhizopus spp.) at 35°C. The isolates included Aspergillus flavus, Aspergillus fumigatus, Aspergillus niger, Aspergillus terreus, Fusarium spp., Pseudallescheria boydii, Rhizopus spp., Paecilomyces variotii, and an Acremonium sp. Overall agreement between Etest and microdilution MICs was 96% with RPMI agar and 80% with Casitone agar. The agreement was 100% for all species exceptRhizopus spp. (83%) and Paecilomyces varioti(0%) with RPMI agar. When Casitone agar was used, the agreement ranged from 50% with Rhizopus spp. to 100% withFusarium spp., P. boydii, P. varioti, and an Acremonium sp. Notably, forAspergillus spp., the agreement between itraconazole Etest MICs read at 24 h and reference microdilution MICs read at 48 h was 100% with both RPMI and Casitone agar. Both media supported the growth of all filamentous fungi tested. Where a discrepancy was observed between Etest and the reference method, the Etest MIC was generally higher. The Etest method using RPMI agar appears to be a useful method for determining itraconazole susceptibilities ofAspergillus spp. and other filamentous fungi.

Use of spectrophotometric reading for in vitro antifungal susceptibility testing ofAspergillusspp.

1999 ◽  
Vol 45 (10) ◽  
pp. 871-874 ◽  
Author(s):  
Eric Dannaoui ◽  
Florence Persat ◽  
Marie-France Monier ◽  
Elisabeth Borel ◽  
Marie-Antoinette Piens ◽  
...  
Keyword(s):  
Amphotericin B ◽  
Susceptibility Testing ◽  
Clinical Laboratory ◽  
Antifungal Susceptibility ◽  
Reference Method ◽  
Antifungal Susceptibility Testing ◽  
Aspergillus Species ◽  
National Committee ◽  
Broth Microdilution Method

A comparative study of visual and spectrophotometric MIC endpoint determinations for antifungal susceptibility testing of Aspergillus species was performed. A broth microdilution method adapted from the National Committee for Clinical Laboratory Standards (NCCLS) was used for susceptibility testing of 180 clinical isolates of Aspergillus species against amphotericin B and itraconazole. MICs were determined visually and spectrophotometrically at 490 nm after 24, 48, and 72h of incubation, and MIC pairs were compared. The agreement between the two methods was 99% for amphotericin B and ranged from 95 to 98% for itraconazole. It is concluded that spectrophotometric MIC endpoint determination is a valuable alternative to the visual reference method for susceptibility testing of Aspergillus species.Key words: antifungal, susceptibility testing, Aspergillus, spectrophotometric reading.

scholarly journals In Vitro Activities of Free and Lipid Formulations of Amphotericin B and Nystatin against Clinical Isolates of Coccidioides immitis at Various Saprobic Stages

2002 ◽  
Vol 46 (5) ◽  
pp. 1583-1585 ◽  
Author(s):  
Gloria M. González ◽  
Rolando Tijerina ◽  
Deanna A. Sutton ◽  
John R. Graybill ◽  
Michael G. Rinaldi
Keyword(s):  
Amphotericin B ◽  
Clinical Laboratory ◽  
National Committee ◽  
Growth Stages ◽  
Coccidioides Immitis ◽  
In Vitro Susceptibility ◽  
Broth Macrodilution ◽  
Lipid Formulations ◽  
Different Growth Stages

ABSTRACT We investigated the susceptibilities of hyphal, mixed hyphal, ungerminated arthroconidial, and germinated arthroconidial populations of Coccidioides immitis to lipid formulations of amphotericin B and nystatin and their conventional preparations, utilizing the National Committee for Clinical Laboratory Standards M38-P broth macrodilution method. The differences in effects of the three different growth stages of the saprobic phase of C. immitis on the MIC/minimum lethal concentration (MLC) ratio were not statistically significant for any of the antifungal agents tested. These results suggest that either inocula could be used for in vitro susceptibility studies with C. immitis.

scholarly journals In Vitro Activity of A-192411.29, a Novel Antifungal Lipopeptide

2000 ◽  
Vol 44 (5) ◽  
pp. 1242-1246 ◽  
Author(s):  
Angela M. Nilius ◽  
Patti M. Raney ◽  
Dena M. Hensey-Rudloff ◽  
Weibo Wang ◽  
Qun Li ◽  
...  
Keyword(s):  
Amphotericin B ◽  
Clinical Laboratory ◽  
Vitro Activity ◽  
National Committee ◽  
In Vitro Activity ◽  
Microdilution Method ◽  
Broth Microdilution Method ◽  
Structural Template ◽  
Better Than

ABSTRACT A-192411.29 is a novel antifungal agent derived from the structural template of the natural product echinocandin. The in vitro activity of A-192411.29 against common pathogenic yeasts was assessed by National Committee for Clinical Laboratory Standards method M27-A. It demonstrated broad-spectrum, fungicidal activity and was active against the most clinically relevant yeasts, such as Candida albicans, Candida tropicalis, and Candida glabrata, as well as less commonly encounteredCandida species; in general, its potency on a weight basis was comparable to that of amphotericin B. It maintained potent in vitro activity against Candida strains with reduced susceptibilities to fluconazole and amphotericin B. The in vitro activity of A-192411.29 against Cryptococcus neoformans was comparable to its activity against Candida spp. However, A-192411.29 did not demonstrate complete growth inhibition ofAspergillus fumigatus by the broth microdilution method used. A-192411.29 possesses an antifungal profile comparable to or better than those of fluconazole and amphotericin B against pathogenic yeasts, including strains resistant to fluconazole or amphotericin B, suggesting that it may be a therapeutically useful new antifungal drug.

scholarly journals Attenuation of Itraconazole Fungicidal Activity following Preexposure of Aspergillus fumigatus to Fluconazole

2003 ◽  
Vol 47 (11) ◽  
pp. 3592-3597 ◽  
Author(s):  
Wei Liu ◽  
Michail S. Lionakis ◽  
Russell E. Lewis ◽  
Nathan Wiederhold ◽  
Gregory S. May ◽  
...  
Keyword(s):  
Aspergillus Fumigatus ◽  
Fungicidal Activity ◽  
Clinical Laboratory ◽  
Marrow Transplant ◽  
National Committee ◽  
In Vitro Susceptibility ◽  
Fourfold Increase ◽  
Microdilution Method

ABSTRACT Fluconazole (FLC), a triazole with limited activity against Aspergillus species, is frequently used as prophylaxis in leukemia patients and bone marrow transplant recipients. Prior FLC use has been associated with an increasing incidence of invasive aspergillosis in these patients. We hypothesized that prior exposure of Aspergillus fumigatus to FLC could result in altered in vitro susceptibility of this fungus to other, more active triazoles. Thus, we performed serial passages of conidia of 10 clinical isolates of A. fumigatus (all itraconazole [ITC] susceptible) on FLC-containing yeast agar glucose plates. The MICs and minimal fungicidal concentrations (MFCs) of amphotericin B, FLC, ITC, and voriconazole (VRC) for A. fumigatus conidia were measured following four passages on FLC-containing medium according to the National Committee for Clinical Laboratory Standards microdilution method. Serial passages on FLC-containing plates resulted in a fourfold increase in the MFCs (but not the MICs) of ITC for nine isolates. The attenuated ITC fungicidal activity against A. fumigatus following FLC preexposure was medium independent and was also observed against FLC-preexposed A. fumigatus hyphae with the viability staining FUN-1 dye. Moreover, FLC preexposure of A. fumigatus conidia resulted in an analogous increase in the MFCs (but not the MICs) of VRC. Our findings suggest that preexposure of A. fumigatus to FLC attenuates the in vitro fungicidal activity of subsequent ITC use against it. This phenotypic adaptation is not captured by a routine MIC determination but requires MFC measurement. The in vivo significance of this in vitro phenomenon requires further investigation.

scholarly journals Comparison of a spectrophotometric microdilution method with RPMI-2% glucose with the National Committee for Clinical Laboratory Standards reference macrodilution method M27-P for in vitro susceptibility testing of amphotericin B, flucytosine, and fluconazole against Candida albicans.

1996 ◽  
Vol 40 (9) ◽  
pp. 1998-2003 ◽  
Author(s):  
J L Rodríguez-Tudela ◽  
J Berenguer ◽  
J V Martínez-Suárez ◽  
R Sanchez
Keyword(s):  
Quality Control ◽  
Candida Albicans ◽  
Amphotericin B ◽  
Susceptibility Testing ◽  
Clinical Laboratory ◽  
Antifungal Susceptibility ◽  
National Committee ◽  
Microdilution Method ◽  
Reference Strains

The National Committee for Clinical Laboratory Standards has proposed a reference broth macrodilution method for in vitro antifungal susceptibility testing of yeasts (the M27-P method). This method is cumbersome and time-consuming and includes MIC endpoint determination by visual and subjective inspection of growth inhibition after 48 h of incubation. An alternative microdilution procedure was compared with the M27-P method for determination of the amphotericin B, flucytosine, and fluconazole susceptibilities of 8 American Type Culture Collection strains (6 of them were quality control or reference strains) and 50 clinical isolates of candida albicans. This microdilution method uses as culture medium RPMI 1640 supplemented with 18 g of glucose per liter (RPMI-2% glucose). Preparation of drugs, basal medium, and inocula was done by following the recommendations of the National Committee for Clinical Laboratory Standards. The MIC endpoint was calculated objectively from the turbidimetric data read at 24 h. Increased growth of C. albicans in RPMI-2% glucose and its spectrophotometric reading allowed for the rapid (24 h) and objective calculation of MIC endpoints compared with previous microdilution methods with standard RPMI 1640. Nevertheless, good agreement was shown between the M27-P method and this microdilution test. The MICs obtained for the quality control or reference strains by the microdilution method were in the ranges published for those strains. For clinical isolates, the percentages of agreement were 100% for amphotericin B and fluconazole and 98.1% for flucytosine. These data suggest that this microdilution method may serve as a less subjective and more rapid alternative to the M27-P method for antifungal susceptibility testing of yeasts.

scholarly journals Activity of a new triazole, Sch 56592, compared with those of four other antifungal agents tested against clinical isolates of Candida spp. and Saccharomyces cerevisiae.

1997 ◽  
Vol 41 (2) ◽  
pp. 233-235 ◽  
Author(s):  
M A Pfaller ◽  
S Messer ◽  
R N Jones
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Antifungal Activity ◽  
Amphotericin B ◽  
Clinical Laboratory ◽  
Clinical Isolates ◽  
National Committee ◽  
Candida Spp ◽  
In Vitro Susceptibility ◽  
Broth Microdilution Method

Sch 56592 is a new triazole agent with potent, broad-spectrum antifungal activity. The in vitro activities of Sch 56592, itraconazole, fluconazole, amphotericin B, and flucytosine (5-FC) against 404 clinical isolates of Candida spp. (382 isolates) and Saccharomyces cerevisiae (22 isolates) were investigated. In vitro susceptibility testing was performed by a broth microdilution method performed according to National Committee for Clinical Laboratory Standards guidelines. Overall, Sch 56592 was very active (MIC at which 90% of isolates are inhibited [MIC90], 0.5 microgram/ml) against these yeast isolates. Sch 56592 was most active against Candida tropicalis, Candida parapsilosis, candida lusitaniae, and Candida stellatoidea (MIC90, < or = 0.12 microgram/ml) and was least active against Candida glabrata (MIC90, 2.0 micrograms/ml). Sch 56592 was 2- to 32-fold more active than amphotericin B and 5-FC against all species except C. glabrata. By comparison with the other triazoles, Sch 56592 was equivalent to itraconazole and greater than or equal to eightfold more active than fluconazole. On the basis of these results, Sch 56592 has promising antifungal activity, and further in vitro and in vivo investigations are warranted.

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