scholarly journals Results Obtained with Various Antifungal Susceptibility Testing Methods Do Not Predict Early Clinical Outcome in Patients with Cryptococcosis

2006 ◽  
Vol 50 (7) ◽  
pp. 2464-2470 ◽  
Author(s):  
E. Dannaoui ◽  
M. Abdul ◽  
M. Arpin ◽  
A. Michel-Nguyen ◽  
M. A. Piens ◽  
...  
Keyword(s):  
Clinical Outcome ◽  
Amphotericin B ◽  
Antifungal Susceptibility ◽  
Yeast Nitrogen Base ◽  
Broth Microdilution ◽  
Nitrogen Base ◽  
First Line Therapy ◽  
Multicenter Prospective Study ◽  
In Vitro Antifungal Susceptibility

ABSTRACT The in vitro susceptibilities of Cryptococcus neoformans isolates from consecutive human immunodeficiency virus-positive and -negative patients to the antifungal agents fluconazole, amphotericin B, and flucytosine were determined by different techniques, including the CLSI method, Etest, and broth microdilution in yeast nitrogen base (YNB) medium, during a multicenter prospective study in France. The relationship between the in vitro data and the clinical outcome 2 weeks after the initiation of antifungal therapy was assessed. In addition, the correlation between the strain serotype and the in vitro activities of the antifungals was determined, and the susceptibility results obtained with the different techniques were also compared. Thirty-seven patients received a combination of amphotericin B with flucytosine as first-line therapy, 22 were treated with amphotericin B alone, and 15 received fluconazole alone. Whatever the antifungal tested, there was no trend toward higher MICs for strains isolated from patients who failed to respond to a given therapy compared to those from patients who did not with either the CLSI method, Etest, or broth microdilution in YNB medium. The MICs obtained by the CLSI or Etest method were significantly lower for serotype D strains than for serotype A strains for both fluconazole and amphotericin B, while flucytosine MICs were not different according to serotype. These findings suggest that the in vitro antifungal susceptibility of C. neoformans, as determined with the techniques used, is not able to predict the early clinical outcome in patients with cryptococcosis.

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 Comparison of MIC Test Strip and Sensititre YeastOne with the CLSI and EUCAST Broth Microdilution Reference Methods for In Vitro Antifungal Susceptibility Testing of Cryptococcus neoformans

2020 ◽  
Vol 64 (4) ◽  
Author(s):  
Fatima Zohra Delma ◽  
Abdullah M. S. Al-Hatmi ◽  
Jochem B. Buil ◽  
Hein van der Lee ◽  
Marlou Tehupeiory-Kooreman ◽  
...  
Keyword(s):  
Cryptococcus Neoformans ◽  
Amphotericin B ◽  
Susceptibility Testing ◽  
Antifungal Susceptibility ◽  
Test Strip ◽  
Error Rates ◽  
Broth Microdilution ◽  
Content Type ◽  
In Vitro Antifungal Susceptibility

ABSTRACT We compared MIC test strip (MTS) and Sensititre YeastOne (SYO) methods with EUCAST and CLSI methods for amphotericin B, 5-fluocytosine, fluconazole, voriconazole, and isavuconazole against 106 Cryptococcus neoformans isolates. The overall essential agreement between the EUCAST and CLSI methods was >72% and >94% at ±1 and ±2 dilutions, respectively. The essential agreements between SYO and EUCAST/CLSI for amphotericin B, 5-flucytosine, fluconazole, and voriconazole were >89/>93% and between MTS and EUCAST/CLSI were >57/>75%. Very major error rates were low for amphotericin B and fluconazole (<3%) and a bit higher for the other drugs (<8%).

scholarly journals Flow Cytometry Antifungal Susceptibility Testing of Pathogenic Yeasts other than Candida albicans and Comparison with the NCCLS Broth Microdilution Test

2000 ◽  
Vol 44 (10) ◽  
pp. 2752-2758 ◽  
Author(s):  
Rama Ramani ◽  
Vishnu Chaturvedi
Keyword(s):  
Flow Cytometry ◽  
Candida Albicans ◽  
Amphotericin B ◽  
Susceptibility Testing ◽  
Antifungal Susceptibility ◽  
Antifungal Susceptibility Testing ◽  
Broth Microdilution ◽  
Nitrogen Base ◽  
Microdilution Method ◽  
Broth Microdilution Method

ABSTRACT Candida species other than Candida albicansfrequently cause nosocomial infections in immunocompromised patients. Some of these pathogens have either variable susceptibility patterns or intrinsic resistance against common azoles. The availability of a rapid and reproducible susceptibility-testing method is likely to help in the selection of an appropriate regimen for therapy. A flow cytometry (FC) method was used in the present study for susceptibility testing ofCandida glabrata, Candida guilliermondii,Candida krusei, Candida lusitaniae,Candida parapsilosis, Candida tropicalis, andCryptococcus neoformans based on accumulation of the DNA binding dye propidium iodide (PI). The results were compared with MIC results obtained for amphotericin B and fluconazole using the NCCLS broth microdilution method (M27-A). For FC, the yeast inoculum was prepared spectrophotometrically, the drugs were diluted in either RPMI 1640 or yeast nitrogen base containing 1% dextrose, and yeast samples and drug dilutions were incubated with amphotericin B and fluconazole, respectively, for 4 to 6 h. Sodium deoxycholate and PI were added at the end of incubation, and fluorescence was measured with a FACScan flow cytometer (Becton Dickinson). The lowest drug concentration that showed a 50% increase in mean channel fluorescence compared to that of the growth control was designated the MIC. All tests were repeated once. The MICs obtained by FC for all yeast isolates except C. lusitaniae were in very good agreement (within 1 dilution) of the results of the NCCLS broth microdilution method. Paired ttest values were not statistically significant (P = 0.377 for amphotericin B; P = 0.383 for fluconazole). Exceptionally, C. lusitaniae isolates showed higher MICs (2 dilutions or more) than in the corresponding NCCLS broth microdilution method for amphotericin B. Overall, FC antifungal susceptibility testing provided rapid, reproducible results that were statistically comparable to those obtained with the NCCLS method.

scholarly journals Correlation of Fluconazole MICs with Clinical Outcome in Cryptococcal Infection

2000 ◽  
Vol 44 (6) ◽  
pp. 1544-1548 ◽  
Author(s):  
A. I. Aller ◽  
E. Martin-Mazuelos ◽  
F. Lozano ◽  
J. Gomez-Mateos ◽  
L. Steele-Moore ◽  
...  
Keyword(s):  
Clinical Outcome ◽  
Maintenance Therapy ◽  
National Committee ◽  
Yeast Nitrogen Base ◽  
Nitrogen Base ◽  
Cryptococcal Infection ◽  
Microdilution Method ◽  
Cryptococcal Disease ◽  
Fluconazole Therapy

ABSTRACT 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 104 CFU/ml. The fluconazole MIC at which 50% of isolates are inhibited (MIC50) and MIC90, obtained spectrophotometrically after 48 h of incubation, were 4 and 16 μg/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 μg/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 μg/ml) than when the patients are infected with strains that require higher fluconazole concentrations (MICs, ≥16 μg/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.

scholarly journals In Vitro Azole and Amphotericin B Susceptibilities of Malassezia furfur from Bloodstream Infections Using E-Test and CLSI Broth Microdilution Methods

Antibiotics ◽  
2020 ◽  
Vol 9 (6) ◽  
pp. 361 ◽  
Author(s):  
Wafa Rhimi ◽  
Chioma Inyang Aneke ◽  
Adriana Mosca ◽  
Domenico Otranto ◽  
Claudia Cafarchia
Keyword(s):  
Amphotericin B ◽  
Reading Time ◽  
Antifungal Susceptibility ◽  
Bloodstream Infections ◽  
Hospitalized Patients ◽  
Malassezia Furfur ◽  
Broth Microdilution ◽  
Test Procedures ◽  
The Media

The number of reports of Malassezia furfur bloodstream infections is constantly increasing and there is a need for more simple antifungal susceptibility methods for their management. In this study, a total of 39 M. furfur isolates collected from hospitalized patients with fungemia were screened for antifungal susceptibility to azole and amphotericin B (AmB) using Clinical and Laboratory Standards Institute broth microdilution (CLSI BMD) and E-test in Sabouraud dextrose agar + 1% Tween80 (SDAt) and mDixon agar (DIX). Essential agreement (EA) and discrepancies between the two methods were evaluated after 48 h and 72 h reading times. Itraconazole (ITZ) and posaconazole (POS) displayed the lowest MIC values whereas fluconazole (FLZ) and AmB the highest, regardless of the methods and the reading time. The EA between BMD was >95% for FLZ and voriconazole (VOR) regardless of the media in the E-tests and reading time. The EA between BMD with E-test for AmB was >97% only when E-test in SDAt was used. The EA between BMD and E-test for ITZ and POS varied according to the media in E-test procedures and the reading time and was higher than 66.6% (POS) or 72% (ITZ) only when SABt was used. Substantial discrepancies for ITZ and POS were >5.1% regardless of the media and the reading time. This study suggests that the E-test in SABt represents an alternative method to CLSI BMD to evaluate the susceptibility of M. furfur to FLZ, VOR and AmB and not for ITZ and POS.

scholarly journals Relationship between the Antifungal Susceptibility Profile and the Production of Virulence-Related Hydrolytic Enzymes in Brazilian Clinical Strains ofCandida glabrata

2017 ◽  
Vol 2017 ◽  
pp. 1-10 ◽  
Author(s):  
Maria Helena Galdino Figueiredo-Carvalho ◽  
Lívia de Souza Ramos ◽  
Leonardo Silva Barbedo ◽  
Jean Carlos Almeida de Oliveira ◽  
André Luis Souza dos Santos ◽  
...  
Keyword(s):  
Amphotericin B ◽  
Antifungal Susceptibility ◽  
Hydrolytic Enzymes ◽  
Antifungal Drug ◽  
Clinical Strains ◽  
Antifungal Drug Resistance ◽  
Opportunistic Fungal Pathogen ◽  
Esterase Production ◽  
In Vitro Antifungal Susceptibility

Candida glabratais a facultative intracellular opportunistic fungal pathogen in human infections. Several virulence-associated attributes are involved in its pathogenesis, host-pathogen interactions, modulation of host immune defenses, and regulation of antifungal drug resistance. This study evaluated the in vitro antifungal susceptibility profile to five antifungal agents, the production of seven hydrolytic enzymes related to virulence, and the relationship between these phenotypes in 91 clinical strains ofC. glabrata. AllC. glabratastrains were susceptible to flucytosine. However, some of these strains showed resistance to amphotericin B (9.9%), fluconazole (15.4%), itraconazole (5.5%), or micafungin (15.4%). Overall,C. glabratastrains were good producers of catalase, aspartic protease, esterase, phytase, and hemolysin. However, caseinase and phospholipase in vitro activities were not detected. Statistically significant correlations were identified between micafungin minimum inhibitory concentration (MIC) and esterase production, between fluconazole and micafungin MIC and hemolytic activity, and between amphotericin B MIC and phytase production. These results contribute to clarify some of theC. glabratamechanisms of pathogenicity. Moreover, the association between some virulence attributes and the regulation of antifungal resistance encourage the development of new therapeutic strategies involving virulence mechanisms as potential targets for effective antifungal drug development for the treatment ofC. glabratainfections.

scholarly journals Etest Cannot Be Recommended forIn VitroSusceptibility Testing of Mucorales

2015 ◽  
Vol 59 (6) ◽  
pp. 3663-3665 ◽  
Author(s):  
Rita Caramalho ◽  
Elisabeth Maurer ◽  
Ulrike Binder ◽  
Ricardo Araújo ◽  
Somayeh Dolatabadi ◽  
...  
Keyword(s):  
Amphotericin B ◽  
Antimicrobial Susceptibility ◽  
Active Drug ◽  
Susceptibility Testing ◽  
Antifungal Susceptibility ◽  
Antifungal Susceptibility Testing ◽  
Broth Microdilution ◽  
European Committee ◽  
Susceptibility Patterns

ABSTRACTAmphotericin B and posaconazole susceptibility patterns were determined for the most prevalent Mucorales, following EUCAST (European Committee on Antimicrobial Susceptibility Testing) broth microdilution guidelines. In parallel, Etest was performed and evaluated against EUCAST. The overall agreement of MICs gained with Etest and EUCAST was 75.1%; therefore, Etest cannot be recommended for antifungal susceptibility testing of Mucorales. Amphotericin B was the most active drug against Mucorales speciesin vitro, while the activities of posaconazole were more restricted.

scholarly journals Molecular Identification and Antifungal Susceptibility Patterns of Candida Species Isolated from Candidemia Patients in Yasuj, Southwestern Iran

2021 ◽  
Vol 14 (7) ◽  
Author(s):  
Shaghayegh Rostami Yasuj ◽  
Maral Gharaghani ◽  
Seyed Sajjad Khoramrooz ◽  
Marjan Salahi ◽  
Ali Keshtkari ◽  
...  
Keyword(s):  
Mortality Rate ◽  
Amphotericin B ◽  
Molecular Identification ◽  
Candida Species ◽  
Antifungal Susceptibility ◽  
Hospitalized Patients ◽  
Susceptibility Tests ◽  
In Vitro Antifungal Susceptibility ◽  
Susceptibility Patterns

Background: Candidemia is the most common systemic infection in hospitalized patients causing high mortality. Hence, the diagnosis of this infection in the early stage with appropriate antifungal therapy is paramount. Objectives: The study aimed at molecular identification of Candida species isolated from candidemia patients and evaluation of the in vitro antifungal susceptibility patterns of these strains to fluconazole, amphotericin B, and caspofungin. Methods: In the present study, 800 hospitalized patients who were suspected to have candidemia were sampled. Candida species were isolated and identified based on morphological characteristics and PCR-sequencing of the ITS1-5.8S-ITS2 region. Antifungal susceptibility tests for fluconazole, amphotericin B, and caspofungin were performed according to the Clinical and Laboratory Standards Institute protocol M27-A3. Also, clinical data were recorded from the patients' records. Results: Twenty-seven patients among the sample of hospitalized patients were found to have candidemia. A total of 33.3% of candidemia patients were treated with amphotericin B, in which case the mortality rate was 14.8%. The majority of patients (59%) were from the neonatal intensive care unit, and premature birth was the most common underlying condition. Candida albicans (n = 18; 66.6%) was the most common species isolated from blood cultures, followed by C. parapsilosis (n = 7; 25.9%), C. pelliculosa (n = 1; 3.7%), and C. tropicalis (n = 1; 3.7%). Only one C. albicans isolate resistant to fluconazole (minimum inhibitory concentration = 32 µg/mL). Conclusions: Generally, C. albicans has been the most frequent causative agent of candidemia. Resistance to antifungal drugs among candidemia agents was rare. Also, the identification of Candida isolates at the species level with in vitro antifungal susceptibility tests helps manage candidemia patients better and decrease the mortality rate among them.

Comparative antifungal susceptibility analyses of Cryptococcus neoformans VNI and Cryptococcus gattii VGII from the Brazilian Amazon Region by the Etest, Vitek 2, and the Clinical and Laboratory Standards Institute broth microdilution methods

2019 ◽  
Vol 57 (7) ◽  
pp. 864-873 ◽  
Author(s):  
Marília Martins Nishikawa ◽  
Rodrigo Almeida-Paes ◽  
Fabio Brito-Santos ◽  
Carlos Roberto Nascimento ◽  
Miguel Madi Fialho ◽  
...  
Keyword(s):  
Amphotericin B ◽  
Antifungal Susceptibility ◽  
Amazon Region ◽  
Antifungal Drugs ◽  
Epidemiological Surveillance ◽  
Broth Microdilution ◽  
Wild Type ◽  
Brazilian Amazon Region ◽  
Vitek 2

AbstractEarly diagnosis, efficient clinical support, and proper antifungal therapy are essential to reduce death and sequels caused by cryptococcosis. The emergence of resistance to the antifungal drugs commonly used for cryptococcosis treatment is an important issue of concern. Thus, the in vitro antifungal susceptibility of clinical strains from northern Brazil, including C. neoformans VNI (n = 62) and C. gattii VGII (n = 37), to amphotericin B (AMB), 5-flucytosine, fluconazole, voriconazole, and itraconazole was evaluated using the Etest and Vitek 2 systems and the standardized broth microdilution (CLSI-BMD) methodology. According to the CLSI-BMD, the most active in vitro azole was voriconazole (C. neoformans VNI modal MIC of 0.06 μg/ml and C. gattii VGII modal MIC of 0.25 μg/ml), and fluconazole was the least active (modal MIC of 4 μg/ml for both fungi). Modal MICs for amphotericin B were 1 μg/ml for both fungi. In general, good essential agreement (EA) values were observed between the methods. However, AMB presented the lowest EA between CLSI-BMD and Etest for C. neoformans VNI and C. gattii VGII (1.6% and 2.56%, respectively, P < .05 for both). Considering the proposed Cryptococcus spp. epidemiological cutoff values, more than 97% of the studied isolates were categorized as wild-type for the azoles. However, the high frequency of C. neoformans VNI isolates in the population described here that displayed non-wild-type susceptibility to AMB is noteworthy. Epidemiological surveillance of the antifungal resistance of cryptococcal strains is relevant due to the potential burden and the high lethality of cryptococcal meningitis in the Amazon region.

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