scholarly journals In vitro susceptibility of Paracoccidioides brasiliensis yeast form to antifungal agents

1984 ◽  
Vol 26 (6) ◽  
pp. 322-328 ◽  
Author(s):  
Angela Restrepo ◽  
Catalina de Bedoutand Angela M. Tabares
Keyword(s):  
Amphotericin B ◽  
Antifungal Agents ◽  
Inhibitory Concentration ◽  
Paracoccidioides Brasiliensis ◽  
Fractional Inhibitory Concentration ◽  
In Vitro Susceptibility ◽  
Yeast Form ◽  
Minimal Inhibitory Concentrations ◽  
Combined Use

A study was conducted to determine the susceptibility of P. brasiliensis yeast form to amphotericin B (A), ketoconazole (K), 5-fluorocytosine (5-FC) and rifampin (R). The three isolates tested produced minimal inhibitory concentrations (MICs) (mcg/ml) in the following range: A: 0.09-0.18; K: 0.001-0.007; 5-FC: 62.5-250 and R: 40-80. The minimal fungicidal concentrations (MFC) were several times higher than the corresponding MICs. Precise MFC for 5-FC were not obtained (> 500 mcg/ml). Combination of K plus A proved synergic, with the fractional inhibitory concentration (FIC) indices revealing synergy when the drugs were combined at the 1 to 1 and 1 to 5 MIC ratios. R (40 mcg/ml) appeared to antagonize K. These results indicate promise for the combined use of K plus A as a therapeutical regimen.

scholarly journals In vitro susceptibility to antifungal agents of clinical and environmental Cryptococcus neoformans isolated in Southern of Brazil

2001 ◽  
Vol 43 (5) ◽  
pp. 267-270 ◽  
Author(s):  
Sydney Hartz ALVES ◽  
Loiva T. OLIVEIRA ◽  
Jane M. COSTA ◽  
Irina LUBECK ◽  
Agnes Kiesling CASALI ◽  
...  
Keyword(s):  
Cryptococcus Neoformans ◽  
Amphotericin B ◽  
Antifungal Agents ◽  
Susceptibility Testing ◽  
Clinical Isolates ◽  
Environmental Isolates ◽  
Aids Patients ◽  
In Vitro Susceptibility ◽  
Minimal Inhibitory Concentrations

The purpose of the present study was to compare the susceptibility to four antifungal agents of 69 Cryptococcus neoformans strains isolated from AIDS patients with that of 13 C. neoformans strains isolated from the environment. Based on the NCCLS M27-A methodology the Minimal Inhibitory Concentrations (MICs) obtained for amphotericin B, itraconazole and ketoconazole were very similar for clinical and environmental isolates. Clinical isolates were less susceptible to fluconazole than environmental isolates. The significance of these findings and aspects concerning the importance, role and difficulties of C. neoformans susceptibility testing are also discussed.

scholarly journals Effect of pH on the In Vitro Activities of Amphotericin B, Itraconazole, and Flucytosine against Aspergillus Isolates

2004 ◽  
Vol 48 (8) ◽  
pp. 3147-3150 ◽  
Author(s):  
D. T. A. Te Dorsthorst ◽  
J. W. Mouton ◽  
C. J. P. van den Beukel ◽  
H. A. L. van der Lee ◽  
J. F. G. M. Meis ◽  
...  
Keyword(s):  
Clinical Outcome ◽  
Amphotericin B ◽  
Antifungal Agents ◽  
Poor Correlation ◽  
Yeast Nitrogen Base ◽  
Broth Microdilution ◽  
In Vitro Susceptibility ◽  
Nitrogen Base ◽  
The Poor

ABSTRACT The in vitro susceptibilities of 21 Aspergillus isolates were tested against three antifungal agents in RPMI 1640 and yeast nitrogen base at pH 5.0 and 7.0 by a broth microdilution format of the NCCLS method. The MICs of amphotericin B and itraconazole were higher, while those of flucytosine were lower, at pH 5.0 than at pH 7.0. The poor correlation between in vitro results and clinical outcome could be due to a difference in pH between the in vitro susceptibility test and at the site of infection.

scholarly journals In Vitro Interaction of Flucytosine Combined with Amphotericin B or Fluconazole against Thirty-Five Yeast Isolates Determined by both the Fractional Inhibitory Concentration Index and the Response Surface Approach

2002 ◽  
Vol 46 (9) ◽  
pp. 2982-2989 ◽  
Author(s):  
D. T. A. Te Dorsthorst ◽  
P. E. Verweij ◽  
J. Meletiadis ◽  
M. Bergervoet ◽  
N. C. Punt ◽  
...  
Keyword(s):  
Response Surface ◽  
Amphotericin B ◽  
Inhibitory Concentration ◽  
Interaction Model ◽  
Interaction Coefficient ◽  
Fractional Inhibitory Concentration ◽  
Surface Approach ◽  
Additional Advantage ◽  
In Vitro Interaction

ABSTRACT Combination therapy could be of benefit for the treatment of invasive yeast infections. However, in vitro interaction studies are relatively scarce and the interpretation of the fractional inhibitory concentration (FIC) index can be contradictory due to various definitions used; not all information on the interaction study is used in the index, and different MIC end points exist for different classes of drugs. Fitting an interaction model to the whole response surface and estimation of an interaction coefficient alpha (ICα) would overcome these objections and has the additional advantage that confidence intervals of the interaction are obtained. The efficacy of flucytosine (5FC) in combination with amphotericin B (AB) and fluconazole (FCZ) was studied against 35 yeast isolates in triplicate (Candida albicans [n = 9], Candida glabrata [n = 9], Candida krusei [n = 9], and Cryptococcus neoformans [n = 8]) using a broth microdilution checkerboard method and measuring growth after 48 h by a spectrophotometer. The FIC index and ICα were determined, the latter by estimation from the response surface approach described by Greco et al. (W. R. Greco, G. Bravo, and J. C. Parsons, Pharmacol. Rev. 47:331-385, 1995) by using a computer program developed for that purpose. For the 5FC-FCZ combination, the interactions determined by the ICα generally were in concordance with the interactions determined by the FIC index, but large discrepancies were found between both methods for the 5FC-AB combination. These could mainly be explained by shortcomings in the FIC approach. The in vitro interaction of 5FC-AB demonstrated variable results depending on the tested Candida isolate. In general, the 5FC-FCZ combination was antagonistic against Candida species, but for some Candida isolates synergism was found. For C. neoformans the interaction for both combinations was highly dependent on the tested isolate and the method used. Response surface approach is an alternative method for determining the interaction between antifungal agents. By using this approach, some of the problems encountered with the FIC were overcome.

scholarly journals In VitroEvaluation of the Type of Interaction Obtained by the Combination of Terbinafine and Itraconazole, Voriconazole, or Amphotericin B against Dematiaceous Molds

2011 ◽  
Vol 55 (9) ◽  
pp. 4485-4487 ◽  
Author(s):  
Fernanda Simas Corrêa Biancalana ◽  
Luzia Lyra ◽  
Angélica Zaninelli Schreiber
Keyword(s):  
Amphotericin B ◽  
Alternative Treatment ◽  
Concentration Index ◽  
Inhibitory Concentration ◽  
Drug Combinations ◽  
Fractional Inhibitory Concentration ◽  
Fractional Inhibitory Concentration Index ◽  
Single Drug ◽  
Microdilution Method

ABSTRACTIn vitroassociations using the checkerboard microdilution method indicated lower MIC ranges and MIC median values for each drug (terbinafine, itraconazole, voriconazole, and amphotericin B) in association than those obtained for each single drug. Fractional inhibitory concentration index (FIC) results showed 100% synergism in the association of terbinafine with voriconazole, 96.5% in the association of terbinafine with amphotericin B, and 75.9% in the association of terbinafine with itraconazole. Drug combinations may be useful for treatment of dematiaceous mold infections as an alternative treatment to enhance the effectiveness of each drug.

scholarly journals Antifungal Activities of Posaconazole, Ravuconazole, and Voriconazole Compared to Those of Itraconazole and Amphotericin B against 239 Clinical Isolates of Aspergillus spp. and Other Filamentous Fungi: Report from SENTRY Antimicrobial Surveillance Program, 2000

2002 ◽  
Vol 46 (4) ◽  
pp. 1032-1037 ◽  
Author(s):  
M. A. Pfaller ◽  
S. A. Messer ◽  
R. J. Hollis ◽  
R. N. Jones
Keyword(s):  
Amphotericin B ◽  
Filamentous Fungi ◽  
Antifungal Agents ◽  
Clinical Laboratory ◽  
The United States ◽  
Clinical Isolates ◽  
National Committee ◽  
Surveillance Program ◽  
In Vitro Susceptibility

ABSTRACT Posaconazole, ravuconazole, and voriconazole are new triazole derivatives that possess potent, broad-spectrum antifungal activity. We evaluated the in vitro activity of these investigational triazoles compared with that of itraconazole and amphotericin B against 239 clinical isolates of filamentous fungi from the SENTRY Program, including Aspergillus spp. (198 isolates), Fusarium spp. (7 isolates), Penicillium spp. (19 isolates), Rhizopus spp. (4 isolates), Mucor spp. (2 isolates), and miscellaneous species (9 isolates). The isolates were obtained from 16 different medical centers in the United States and Canada between January and December 2000. In vitro susceptibility testing was performed using the microdilution broth method outlined in the National Committee for Clinical Laboratory Standards M38-P document. Overall, posaconazole was the most active compound, inhibiting 94% of isolates at a MIC of ≤1 μg/ml, followed by voriconazole (91%), amphotericin B (89%), ravuconazole (88%), and itraconazole (70%). All three new triazoles demonstrated excellent activity (MIC, ≤1 μg/ml) against Aspergillus spp. (114 Aspergillus fumigatus, 22 Aspergillus niger, 13 Aspergillus flavus, 9 Aspergillus versicolor, 8 Aspergillus terreus, and 32 Aspergillus spp.): posaconazole (98%), voriconazole (98%), ravuconazole (92%), amphotericin B (89%), and itraconazole (72%). None of the triazoles were active against Fusarium spp. (MIC at which 50% of the isolates tested were inhibited [MIC50], >8 μg/ml) or Mucor spp. (MIC50, >8 μg/ml). Posaconazole and ravuconazole were more active than voriconazole against Rhizopus spp. (MIC50, 1 to 2 μg/ml versus >8 μg/ml, respectively). Based on these results, all three new triazoles exhibited promising activity against Aspergillus spp. and other less commonly encountered isolates of filamentous fungi. The clinical value of these in vitro data remains to be seen, and in vitro-in vivo correlation is needed for both new and established antifungal agents. Surveillance efforts should be expanded in order to monitor the spectrum of filamentous fungal pathogens and their in vitro susceptibility as these new antifungal agents are introduced into clinical use.

In Vitro Susceptibility of Berberine Combined with Antifungal Agents Against the Yeast Form of Talaromyces marneffei

2019 ◽  
Vol 184 (2) ◽  
pp. 295-301 ◽  
Author(s):  
Hong Luo ◽  
Kai-su Pan ◽  
Xiao-lu Luo ◽  
Dong-yan Zheng ◽  
Alex Andrianopoulos ◽  
...  
Keyword(s):  
Antifungal Agents ◽  
In Vitro Susceptibility ◽  
Yeast Form ◽  
Talaromyces Marneffei

scholarly journals In Vitro Susceptibility ofCandidaSpecies to Four Antifungal Agents Assessed by the Reference Broth Microdilution Method

2013 ◽  
Vol 2013 ◽  
pp. 1-6 ◽  
Author(s):  
Fahriye Eksi ◽  
Efgan Dogan Gayyurhan ◽  
Iclal Balci
Keyword(s):  
Amphotericin B ◽  
Antifungal Agents ◽  
Antifungal Susceptibility ◽  
Resistance Rate ◽  
Broth Microdilution ◽  
In Vitro Susceptibility ◽  
Microdilution Method ◽  
Broth Microdilution Method ◽  
Dose Dependent

This study was performed to determine the distribution ofCandidaspecies isolated from the blood cultures of the patients hospitalized in our hospital and to investigate their antifungal susceptibility.Candidastrains were identified at species level by using classical methods and API ID 32C (bioMerieux, France) identification kits. The susceptibility of the strains to amphotericin B, fluconazole, voriconazole, and caspofungin was evaluated by using the reference broth microdilution method in document M27-A3 of the Clinical and Laboratory Standards Institute. Of the 111Candidastrains isolated, 47.7% were identified asC. albicansand 52.3% as non-albicansCandidastrains. The MIC ranges were 0.03–1 μg/mL for amphotericin B, 0.125–≥64 μg/mL for fluconazole, 0.03–16 μg/mL for voriconazole, and 0.015–0.25 μg/mL for caspofungin. AllCandidastrains were susceptible to amphotericin B and caspofungin. 10.8% isolates were resistant to fluconazole and 8.1% isolates were dose-dependent susceptible. While 0.9% isolate was resistant to voriconazole, 0.9% isolate was dose-dependent susceptible. In our study,C. albicansandC. parapsilosiswere the most frequently encountered agents of candidemia and it was detected that voriconazole with a low resistance rate might also be used with confidence in the treatment of infections occurring with these agents, primarily besides amphotericin B and caspofungin.

scholarly journals In Vitro Interactions between Amphotericin B, Itraconazole, and Flucytosine against 21 Clinical Aspergillus Isolates Determined by Two Drug Interaction Models

2004 ◽  
Vol 48 (6) ◽  
pp. 2007-2013 ◽  
Author(s):  
D. T. A. Te Dorsthorst ◽  
P. E. Verweij ◽  
J. F. G. M. Meis ◽  
N. C. Punt ◽  
J. W. Mouton
Keyword(s):  
Drug Interaction ◽  
Response Surface ◽  
Amphotericin B ◽  
Antifungal Agents ◽  
Inhibitory Concentration ◽  
Interaction Coefficient ◽  
Surface Approach ◽  
In Vitro Interaction ◽  
In Vitro Interactions

ABSTRACT Combination therapy of flucytosine (5FC) with other antifungal agents could be of use for the treatment of invasive aspergillosis. However, interpretation of the results of in vitro interactions is problematic. The fractional inhibitory concentration (FIC) index is the most commonly used method, but it has several major drawbacks in characterizing antifungal drug interaction. Alternatively, a response surface approach using the concentration-effect relationship over the whole concentration range instead of just the MIC can be used. We determined the in vitro interactions between amphotericin B (AMB), itraconazole, and 5FC against 21 Aspergillus isolates with a broth microdilution checkerboard method that employs the dye MTT [3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide]. FIC indices based on three different MIC endpoints (MIC-0, MIC-1, and MIC-2) and the interaction coefficient alpha were determined, the latter by estimation from the response surface approach described by Greco et al. (W. R. Greco, G. Bravo, and J. C. Parsons, Pharmacol. Rev. 47:331-385, 1995). The value obtained for the FIC index was found to be dependent on the MIC endpoint used and could be either synergistic, indifferent, or antagonistic. The response surface approach gave more consistent results. Of the three combinations tested, the AMB-5FC combination was the most potent in vitro against Aspergillus spp. We conclude that the use of the response surface approach for the interpretation of in vitro interaction studies of antifungals may be helpful in order to predict the nature and intensity of the drug interaction. However, the correlation of these results with clinical outcome remains difficult and needs to be further investigated.

scholarly journals Susceptibility Testing and Molecular Classification of Paecilomyces spp.

2008 ◽  
Vol 52 (8) ◽  
pp. 2926-2928 ◽  
Author(s):  
Maria Victoria Castelli ◽  
Ana Alastruey-Izquierdo ◽  
Isabel Cuesta ◽  
Araceli Monzon ◽  
Emilia Mellado ◽  
...  
Keyword(s):  
Amphotericin B ◽  
Antifungal Agents ◽  
Susceptibility Testing ◽  
Molecular Classification ◽  
Susceptibility Pattern ◽  
Paecilomyces Variotii ◽  
In Vitro Susceptibility ◽  
Susceptibility Profiles

ABSTRACT In vitro susceptibility profiles of 58 Paecilomyces clinical isolates are reported. Amphotericin B, itraconazole, and echinocandins showed poor activity against Paecilomyces lilacinus, while the new triazoles were active against it. Paecilomyces variotii exhibited a different susceptibility pattern, being susceptible to most antifungal agents apart from voriconazole and ravuconazole.

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