Effect of antifungals on itraconazole resistant Candida glabrata

2010 ◽  
Vol 5 (3) ◽  
pp. 318-323 ◽  
Author(s):  
Soňa Kucharíková ◽  
Patrick Dijck ◽  
Magdaléna Lisalová ◽  
Helena Bujdáková
Keyword(s):  
Amphotericin B ◽  
Biofilm Formation ◽  
Candida Glabrata ◽  
Antifungal Agents ◽  
Inhibitory Concentration ◽  
Clinical Isolates ◽  
Azole Resistance ◽  
Low Concentrations ◽  
Reduction Assay ◽  
Very High

AbstractIn the last decade, infections caused by Candida glabrata have become more serious, particularly due to its decreased susceptibility to azole derivatives and its ability to form biofilm. Here we studied the resistance profile of 42 C. glabrata clinical isolates to different azoles, amphotericin B and echinocandins. This work was also focused on the ability to form biofilm which plays a role in the development of antifungal resistance. The minimal inhibitory concentration testing to antifungal agents was performed according to the CLSI (Clinical and Laboratory Standards Institute) M27-A3 protocol. Quantification of biofilm was done by XTT reduction assay. All C. glabrata clinical isolates were resistant to itraconazole and sixteen also showed resistance to fluconazole. All isolates remained susceptible to voriconazole. Amphotericin B was efficient in a concentration range of 0.125–1 mg/L. The most effective antifungal agents were micafungin and caspofungin with the MIC100 values of ≤0.0313–0.125 mg/L. Low concentrations of these agents reduced biofilm formation as well. Our results show that resistance of different C. glabrata strains is azole specific and therefore a single azole resistance cannot be assumed to indicate general azole resistance. Echinocandins proved to have very high efficacy against clinical C. glabrata strains including those with ability to form biofilm.

scholarly journals Role of ATP-Binding-Cassette Transporter Genes in High-Frequency Acquisition of Resistance to Azole Antifungals in Candida glabrata

2001 ◽  
Vol 45 (4) ◽  
pp. 1174-1183 ◽  
Author(s):  
Dominique Sanglard ◽  
Francoise Ischer ◽  
Jacques Bille
Keyword(s):  
Abc Transporter ◽  
High Frequency ◽  
Candida Glabrata ◽  
Antifungal Agents ◽  
Clinical Isolates ◽  
Azole Resistance ◽  
Atp Binding ◽  
Transporter Gene ◽  
Atp Binding Cassette

ABSTRACT Candida glabrata has been often isolated from AIDS patients with oropharyngeal candidiasis treated with azole antifungal agents, especially fluconazole. We recently showed that the ATP-binding-cassette (ABC) transporter gene CgCDR1 was upregulated in C. glabrata clinical isolates resistant to azole antifungal agents (D. Sanglard, F. Ischer, D. Calabrese, P. A. Majcherczyk, and J. Bille, Antimicrob. Agents Chemother. 43:2753–2765, 1999). Deletion of CgCDR1 in C. glabrata rendered the null mutant hypersusceptible to azole derivatives and showed the importance of this gene in mediating azole resistance. We observed that wild-type C. glabrata exposed to fluconazole in a medium containing the drug at 50 μg/ml developed resistance to this agent and other azoles at a surprisingly high frequency (2 × 10−4 to 4 × 10−4). We show here that this high-frequency azole resistance (HFAR) acquired in vitro was due, at least in part, to the upregulation ofCgCDR1. The CgCDR1 deletion mutant DSY1041 could still develop HFAR but in a medium containing fluconazole at 5 μg/ml. In the HFAR strain derived from DSY1041, a distinct ABC transporter gene similar to CgCDR1, calledCgCDR2, was upregulated. This gene was slightly expressed in clinical isolates but was upregulated in strains with the HFAR phenotype. Deletion of both CgCDR1 and CgCDR2suppressed the development of HFAR in a medium containing fluconazole at 5 μg/ml, showing that both genes are important mediators of resistance to azole derivatives in C. glabrata. We also show here that the HFAR phenomenon was linked to the loss of mitochondria in C. glabrata. Mitochondrial loss could be obtained by treatment with ethidium bromide and resulted in acquisition of resistance to azole derivatives without previous exposure to these agents. Azole resistance obtained in vitro by HFAR or by agents stimulating mitochondrial loss was at least linked to the upregulation of both CgCDR1 and CgCDR2.

The ATP Binding Cassette Transporter GeneCgCDR1 from Candida glabrata Is Involved in the Resistance of Clinical Isolates to Azole Antifungal Agents

1999 ◽  
Vol 43 (11) ◽  
pp. 2753-2765 ◽  
Author(s):  
Dominique Sanglard ◽  
Françoise Ischer ◽  
David Calabrese ◽  
Paul A. Majcherczyk ◽  
Jacques Bille
Keyword(s):  
Clinical Isolate ◽  
Abc Transporter ◽  
Candida Glabrata ◽  
Antifungal Agents ◽  
Clinical Isolates ◽  
Azole Resistance ◽  
Atp Binding ◽  
Transporter Gene ◽  
Azole Antifungals ◽  
Susceptible Isolate

ABSTRACT The resistance mechanisms to azole antifungal agents were investigated in this study with two pairs of Candida glabrata clinical isolates recovered from two separate AIDS patients. The two pairs each contained a fluconazole-susceptible isolate and a fluconazole-resistant isolate, the latter with cross-resistance to itraconazole and ketoconazole. Since the accumulation of fluconazole and of another unrelated substance, rhodamine 6G, was reduced in the azole-resistant isolates, enhanced drug efflux was considered as a possible resistance mechanism. The expression of multidrug efflux transporter genes was therefore examined in the azole-susceptible and azole-resistant yeast isolates. For this purpose, C. glabrata genes conferring resistance to azole antifungals were cloned in a Saccharomyces cerevisiaestrain in which the ATP binding cassette (ABC) transporter genePDR5 was deleted. Three different genes were recovered, and among them, only C. glabrata CDR1 (CgCDR1), a gene similar to the Candida albicans ABC transporterCDR genes, was upregulated by a factor of 5 to 8 in the azole-resistant isolates. A correlation between upregulation of this gene and azole resistance was thus established. The deletion ofCgCDR1 in an azole-resistant C. glabrataclinical isolate rendered the resulting mutant (DSY1041) susceptible to azole derivatives as the azole-susceptible clinical parent, thus providing genetic evidence that a specific mechanism was involved in the azole resistance of a clinical isolate. When CgCDR1obtained from an azole-susceptible isolate was reintroduced with the help of a centromeric vector in DSY1041, azole resistance was restored and thus suggested that a trans-acting mutation(s) could be made responsible for the increased expression of this ABC transporter gene in the azole-resistant strain. This study demonstrates for the first time the determinant role of an ABC transporter gene in the acquisition of resistance to azole antifungals by C. glabrata clinical isolates.

scholarly journals In Vitro Interaction of Posaconazole and Caspofungin against Clinical Isolates of Candida glabrata

2005 ◽  
Vol 49 (8) ◽  
pp. 3544-3545 ◽  
Author(s):  
E. R. Oliveira ◽  
A. W. Fothergill ◽  
W. R. Kirkpatrick ◽  
B. J. Coco ◽  
T. F. Patterson ◽  
...  
Keyword(s):  
Candida Glabrata ◽  
Concentration Index ◽  
Inhibitory Concentration ◽  
Clinical Isolates ◽  
Fractional Inhibitory Concentration ◽  
Fractional Inhibitory Concentration Index ◽  
Fluconazole Resistant ◽  
In Vitro Interaction

ABSTRACT Combinations of caspofungin and posaconazole were evaluated by fractional inhibitory concentration index against 119 Candida glabrata isolates. Synergy was seen in 18% of all isolates and in 4% of fluconazole-resistant isolates at 48 h without evidence of antagonism. This antifungal combination may have utility against this organism.

Antibiofilm activity of antifungal drugs, including the novel drug olorofim, against Lomentospora prolificans

2020 ◽  
Author(s):  
Lisa Kirchhoff ◽  
Silke Dittmer ◽  
Ann-Kathrin Weisner ◽  
Jan Buer ◽  
Peter-Michael Rath ◽  
...  
Keyword(s):  
Amphotericin B ◽  
Biofilm Formation ◽  
Laser Scanning ◽  
Antifungal Agents ◽  
Fungal Infections ◽  
Pathogenic Fungus ◽  
Antifungal Drugs ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Antibiofilm Activity

Abstract Objectives Patients with immunodeficiency or cystic fibrosis frequently suffer from respiratory fungal infections. In particular, biofilm-associated fungi cause refractory infection manifestations, linked to increased resistance to anti-infective agents. One emerging filamentous fungus is Lomentospora prolificans. Here, the biofilm-formation capabilities of L. prolificans isolates were investigated and the susceptibility of biofilms to various antifungal agents was analysed. Methods Biofilm formation of L. prolificans (n = 11) was estimated by crystal violet stain and antibiofilm activity was additionally determined via detection of metabolically active biofilm using an XTT assay. Amphotericin B, micafungin, voriconazole and olorofim were compared with regard to their antibiofilm effects when added prior to adhesion, after adhesion and on mature and preformed fungal biofilms. Imaging via confocal laser scanning microscopy was carried out to demonstrate the effect of drug treatment on the fungal biofilm. Results Antibiofilm activities of the tested antifungal agents were shown to be most effective on adherent cells whilst mature biofilm was the most resistant. The most promising antibiofilm effects were detected with voriconazole and olorofim. Olorofim showed an average minimum biofilm eradication concentration (MBEC) of 0.06 mg/L, when added prior to and after adhesion. The MBECs of voriconazole were ≤4 mg/L. On mature biofilm the MBECs of olorofim and voriconazole were higher than the previously determined MICs against planktonic cultures. In contrast, amphotericin B and especially micafungin did not exhibit sufficient antibiofilm activity against L. prolificans. Conclusions To our knowledge, this is the first study demonstrating the antibiofilm potential of olorofim against the human pathogenic fungus L. prolificans.

scholarly journals Effect of pH onIn VitroSusceptibility of Candida glabrata and Candida albicans to 11 Antifungal Agents and Implications for Clinical Use

2012 ◽  
Vol 56 (3) ◽  
pp. 1403-1406 ◽  
Author(s):  
Claire S. Danby ◽  
Dina Boikov ◽  
Rina Rautemaa-Richardson ◽  
Jack D. Sobel
Keyword(s):  
Amphotericin B ◽  
Candida Glabrata ◽  
Antifungal Agents ◽  
Susceptibility Testing ◽  
Low Ph ◽  
Clinical Use ◽  
Effect Of Ph ◽  
Content Type ◽  
Clinical Observations

ABSTRACTThe treatment of vulvovaginal candidiasis (VVC) due toCandida glabratais challenging, with limited therapeutic options. Unexplained disappointing clinical efficacy has been reported with systemic and topical azole antifungal agents in spite ofin vitrosusceptibility. Given that the vaginal pH of patients with VVC is unchanged at 4 to 4.5, we studied the effect of pH on thein vitroactivity of 11 antifungal agents against 40C. glabrataisolates and compared activity against 15 fluconazole-sensitive and 10 reduced-fluconazole-susceptibilityC. albicansstrains.In vitrosusceptibility to flucytosine, fluconazole, voriconazole, posaconazole, itraconazole, ketoconazole, clotrimazole, miconazole, ciclopirox olamine, amphotericin B, and caspofungin was determined using the CLSI method for yeast susceptibility testing. Test media were buffered to pHs of 7, 6, 5, and 4. Under conditions of reduced pH,C. glabrataisolates remained susceptible to caspofungin and flucytosine; however, there was a dramatic increase in the MIC90for amphotericin B and every azole drug tested. Although susceptible to other azole drugs tested at pH 7,C. albicansstrains with reduced fluconazole susceptibility also demonstrated reduced susceptibility to amphotericin B and all azoles at pH 4. In contrast, fluconazole-sensitiveC. albicansisolates remained susceptible at low pH to azoles, in keeping with clinical observations. In selecting agents for treatment of recurrentC. glabratavaginitis, clinicians should recognize the limitations ofin vitrosusceptibility testing utilizing pH 7.0.

scholarly journals Features of antifungal therapy during long-lasting infectious process: a clinical case of fungal keratitis and profile of antifungal sensitivity based on assessing biofilm formation

2021 ◽  
Vol 11 (4) ◽  
pp. 789-797
Author(s):  
R. I. Valieva ◽  
S. A. Lisovskaya ◽  
K. A. Mayanskaya ◽  
D. V. Samigullin ◽  
G. Sh. Isaeva
Keyword(s):  
Amphotericin B ◽  
Biofilm Formation ◽  
Clinical Case ◽  
Antifungal Agents ◽  
Fungal Keratitis ◽  
Laser Scanning Microscopy ◽  
Clinical Strain ◽  
Mycelial Fungi ◽  
Infectious Process ◽  
Test Culture

Among infectious diseases, opportunistic mycoses hold a special place. There has been accumulating a lot of evidence regarding the clinical and epidemiological aspects of infection caused by Fusarium spp., which global incidence rate among microbial keratitis ranges from 2 to 40% depending on the geographical location of the country. Colonizing mucous membranes, fungi can exist not only in the form of plankton, but form biofilms after surface attachment, which leads to elevated resistance to multiple antifungal agents. Here we describe a clinical case of fungal keratitis due to Fusarium solani by determining profile of the antifungal sensitivity for isolated fungal strains, by taking into account their potential for biofilm formation. We used an F. solani culture isolated from the patient as well as F. solani test culture obtained from the Russian National Collection of Microorganisms. While determining the sensitivity of fungal planktonic cultures to antifungal agents from the azole group (fluconazole, voriconazole), amphotericin B and terbinafine, it was revealed that antimycotics amphotericin B and voriconazole exerted a marked antifungal activity against clinical isolate, whereas the plankton F. solani test culture was more sensitive to all groups of antifungal agents. Due to a long-lasting progressive course of the infectious process and the high biofilm-forming ability of the clinical strain F. solani, the activity of antifungal agents on biofilm cells was modeled and examined in vitro. It was shown that regarding to the fungal biofilms, value of the minimally inhibitory concentration exceeded those for planktonic cultures by 100-fold. The mechanisms of action for antifungal agents on vital parameters of fungal cell structures were analyzed by using confocal laser scanning microscopy after staining samples with propidium iodide and acridine orange for 15 min to detect changes between intact and damaged cell surface. It was found that within the biofilm fungal cells preserved viability even after exposure to high concentrations of antifungals. In addition, despite the fungicidal drug activity at substantial concentrations acting on the biofilm cell membrane, the cell nuclei remained viable. Owing to the presence ot the mechanism of resistance in mycelial fungi shown in the study, it is necessary to take into account and investigate characteristics of biofilms in terms of drug sensitivity that will allow to optimize a choice of antimicrobial therapy.

scholarly journals Antifungal agents in non-neonatologic pediatrics

2013 ◽  
Vol 4 (1S) ◽  
pp. 45-50
Author(s):  
Elio Castagnola
Keyword(s):  
Minimal Inhibitory Concentration ◽  
Amphotericin B ◽  
Antifungal Agent ◽  
Antifungal Agents ◽  
Inhibitory Concentration ◽  
Time Dependent ◽  
Combination Therapies ◽  
Agent Interactions

The spectrum of action of antifungal agents helps driving the choice of the treatment, basing on the activity against the fungus of interest. Pharmacokinetics should also be taken into account, considering the time-dependent and the concentration-dependent drugs. Triazoles belong to the first group, while amphotericin B and echinocandins belong to the second one. The effectiveness of time-dependent drugs hangs on the time spent above the Minimal Inhibitory Concentration (MIC), whereas that of concentration-dependent drugs is related to the peak of concentration achieved. Thetissue penetration is another important factor that should be taken into account while prescribing an antifungal agent. Interactions with other drugs, above all with those used to treat underlying pathologies, should also be considered. Fungicidal drugs are generally preferred to fungistatic agents, therefore echinocandins and amphotericin B are more prescribed than azoles. Combination therapies are not recommended.

scholarly journals Combination of antifungal drugs and protease inhibitors prevent Candida albicans biofilm formation and disrupt mature biofilms

2020 ◽  
Author(s):  
Matthew B. Lohse ◽  
Megha Gulati ◽  
Charles S. Craik ◽  
Alexander D. Johnson ◽  
Clarissa J. Nobile
Keyword(s):  
Candida Albicans ◽  
Protease Inhibitors ◽  
Amphotericin B ◽  
Biofilm Formation ◽  
Antifungal Agents ◽  
Antifungal Drugs ◽  
Aspartyl Protease ◽  
Abiotic Surfaces ◽  
Drug Concentrations ◽  
Aspartyl Protease Inhibitors

AbstractBiofilms formed by the fungal pathogen Candida albicans are resistant to many of the antifungal agents commonly used in the clinic. Previous reports suggest that protease inhibitors, specifically inhibitors of aspartyl proteases, could be effective antibiofilm agents. We screened three protease inhibitor libraries, containing a total of 80 compounds for the abilities to prevent C. albicans biofilm formation and to disrupt mature biofilms. The compounds were screened individually and in the presence of subinhibitory concentrations of the most commonly prescribed antifungal agents for Candida infections: fluconazole, amphotericin B, or caspofungin. Although few of the compounds affected biofilms on their own, seven aspartyl protease inhibitors inhibited biofilm formation when combined with amphotericin B or caspofungin. Furthermore, nine aspartyl protease inhibitors disrupted mature biofilms when combined with caspofungin. These results suggest that the combination of standard antifungal agents together with specific protease inhibitors may be useful in the prevention and treatment of C. albicans biofilm infections.ImportanceCandida albicans is one of the most common pathogens of humans. C. albicans forms biofilms, structured communities of cells several hundred microns thick, on both biotic and abiotic surfaces. These biofilms are typically resistant to antifungal drugs at the concentrations that are normally effective against free-floating cells, thus requiring treatment with higher drug concentrations that often have significant side effects. Here, we show that certain combinations of existing antifungal agents with protease inhibitors, including several drugs already commonly used to treat HIV patients, are effective at inhibiting biofilm formation by C. albicans and/or at disrupting mature C. albicans biofilms.

Impact of calmodulin inhibition by fluphenazine on susceptibility, biofilm formation and pathogenicity of caspofungin-resistant Candida glabrata

2020 ◽  
Vol 75 (5) ◽  
pp. 1187-1193 ◽  
Author(s):  
Andrés Ceballos Garzon ◽  
Daniela Amado ◽  
Estelle Robert ◽  
Claudia M Parra Giraldo ◽  
Patrice Le Pape
Keyword(s):  
Biofilm Formation ◽  
Candida Glabrata ◽  
Galleria Mellonella ◽  
Larval Survival ◽  
Clinical Isolates ◽  
Dilution Method ◽  
Life Threatening ◽  
Polyurethane Catheter ◽  
The Impact

Abstract Background In recent decades, Candida glabrata has emerged as a frequent cause of life-threatening fungal infection. In C. glabrata, echinocandin resistance is associated with mutations in FKS1/FKS2 (β-1,3-glucan synthase). The calmodulin/calcineurin pathway is implicated in response to antifungal stress and calcineurin gene disruption specifically reverses Fks2-mediated resistance of clinical isolates. Objectives We evaluated the impact of calmodulin inhibition by fluphenazine in two caspofungin-resistant C. glabrata isolates. Methods C. glabrata isolates were identified by ITS1/ITS4 (where ITS stands for internal transcribed spacer) sequencing and the echinocandin target FKS1/FKS2 genes were sequenced. Susceptibility testing of caspofungin in the presence of fluphenazine was performed by a modified CLSI microbroth dilution method. The effect of the fluphenazine/caspofungin combination on heat stress (37°C or 40°C), oxidative stress (0.2 and 0.4 mM menadione) and biofilm formation (polyurethane catheter) was analysed. A Galleria mellonella model using blastospores (1 × 109 cfu/mL) was developed to evaluate the impact of this combination on larval survival. Results F659del was found in the FKS2 gene of both resistant strains. In these clinical isolates, fluphenazine increased susceptibility to caspofungin and reduced their thermotolerance. Furthermore, the fluphenazine/caspofungin combination significantly impaired biofilm formation in an in vitro polyurethane catheter model. All these features participated in the increasing survival of infected G. mellonella after combination treatment in comparison with caspofungin alone. Conclusions In a repurposing strategy, our findings confirm that calmodulin could provide a relevant target in life-threatening fungal infectious diseases.

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