In Vitro Interaction and Killing-Kinetics of Amphotericin B Combined with Anidulafungin or Caspofungin against Candida auris

Treatment of invasive infections caused by Candida auris is challenging due to the limited therapeutic options. The combination of antifungal drugs may be an interesting and feasible approach to be investigated. The aim of this study was to examine the in vitro activity of amphotericin B in combination with anidulafungin or caspofungin against C. auris. In vitro static time–kill curve experiments were conducted for 48 h with different combinations of amphotericin B with anidulafungin or caspofungin against six blood isolates of C. auris. The antifungal activity of 0.5 mg/L of amphotericin B was limited against the six isolates of C. auris. Similarly, echinocandins alone had a negligible effect, even at the highest tested concentrations. By contrast, 1 mg/L of amphotericin B showed fungistatic activity. Synergy was rapidly achieved (8 h) with 0.5 mg/L of amphotericin B plus 2 mg/L of anidulafungin or caspofungin. These combinations lead to a sustained fungistatic effect, and the fungicidal endpoint was reached against some C. auris isolates. Additionally, ≥0.5 mg/L of either of the two echinocandins with 1 mg/L of amphotericin B resulted in fungicidal effect against all C. auris isolates. In conclusion, combinations of amphotericin B with anidulafungin or caspofungin provided greater killing with a lower dose requirement for amphotericin B compared to monotherapy, with synergistic and/or fungicidal outcomes.

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Assessment of Candida auris Response to Antifungal Drugs Using Time–Kill Assays and an Animal Model

Open Forum Infectious Diseases ◽

10.1093/ofid/ofx163.003 ◽

2017 ◽

Vol 4 (suppl_1) ◽

pp. S73-S73 ◽

Cited By ~ 1

Author(s):

Ronen Ben-Ami ◽

Liat Ashkenazi ◽

Judith Berman ◽

Nuphar Korolker ◽

Anna Novikov

Keyword(s):

Amphotericin B ◽

Fungicidal Activity ◽

Antifungal Drugs ◽

Rank Test ◽

Infection Model ◽

Candida Auris ◽

Fungistatic Activity ◽

Kill Curve ◽

Time Kill

Abstract Background Candida auris is an emerging nosocomial pathogen that is resistant to Fluconazole and variably susceptible to other systemic drug classes. Treatment with echinocandins has been recommended based on MICs in the susceptible range, but supporting in vivo data is lacking. Methods We tested the MIC of C. auris strains (n = 12) to fluconazole, voriconazole, posaconazole. anidulafungin, amphotericin B and flucytosine. Representative C. auris strains from Israel and South Africa, and a reference C. albicans strain were analysed using time–kill curve assays. Fungicidal activity was defined as reduction of ≥3 log from baseline CFU/ml. Response to caspofungin treatment was assessed in BALB/c mice immunosuppressed with cyclophosphamide and inoculated with 7 × 107C. auris cells by tail vein injection. Mice were treated from day +1 to day +7 with caspofungin (IP) at doses of 1 or 5 mg/kg and compared with sham-treated controls. Survival was assessed daily. Kaplan-Meier survival analyses were performed and treatment arms were compared using the log-rank test. Results Drug susceptibility results (MIC50 and MIC90) were: fluconazole, 64 and 128 mg/l; voriconazole, 0.5 and 24 mg/l; posaconazole, 0.5 and 27 mg/l; anidulafungin, 0.03 and 0.06 mg/l; amphotericin B, 2 and 8 mg/l; flucytosine, 0.3 and 1 mg/l. Time–kill curve analyses showed log reduction from baseline CFU concentration of −3.0 to −2.8 for fluconazole (MIC ×1), 5.6–6.1 for amphotericin B (MIC ×4) and −0.4 to −0.9 for caspofungin (MIC ×16), consistent with fungicidal activity of amphotericin B and weak fungistatic activity of caspofungin. In the mouse model, survival rate was similar with sham treatment (33%) and treatment with caspofungin 1 mg/kg/day (44%) and 5 mg/kg/day (22%), P = 0.7. Conclusion Despite generally low MIC, caspofungin has only mild fungistatic activity on C. auris and no effect on survival in a mouse infection model. Amphotericin B has fungicidal activity against C. auris. Disclosures All authors: No reported disclosures.

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In Vitro Synergistic Interactions of Isavuconazole and Echinocandins against Candida auris

Antibiotics ◽

10.3390/antibiotics10040355 ◽

2021 ◽

Vol 10 (4) ◽

pp. 355

Author(s):

Unai Caballero ◽

Sarah Kim ◽

Elena Eraso ◽

Guillermo Quindós ◽

Valvanera Vozmediano ◽

...

Keyword(s):

Interaction Model ◽

Antifungal Drugs ◽

Health Concern ◽

Candida Auris ◽

Fungistatic Activity ◽

Drug Concentrations ◽

Low Concentrations ◽

Wide Range ◽

Time Kill

Candida auris is an emergent fungal pathogen that causes severe infectious outbreaks globally. The public health concern when dealing with this pathogen is mainly due to reduced susceptibility to current antifungal drugs. A valuable alternative to overcome this problem is to investigate the efficacy of combination therapy. The aim of this study was to determine the in vitro interactions of isavuconazole with echinocandins against C. auris. Interactions were determined using a checkerboard method, and absorbance data were analyzed with different approaches: the fractional inhibitory concentration index (FICI), Greco universal response surface approach, and Bliss interaction model. All models were in accordance and showed that combinations of isavuconazole with echinocandins resulted in an overall synergistic interaction. A wide range of concentrations within the therapeutic range were selected to perform time-kill curves. These confirmed that isavuconazole–echinocandin combinations were more effective than monotherapy regimens. Synergism and fungistatic activity were achieved with combinations that included isavuconazole in low concentrations (≥0.125 mg/L) and ≥1 mg/L of echinocandin. Time-kill curves revealed that once synergy was achieved, combinations of higher drug concentrations did not improve the antifungal activity. This work launches promising results regarding the combination of isavuconazole with echinocandins for the treatment of C. auris infections.

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In VitroInteraction between Alginate Lyase and Amphotericin B against Aspergillus fumigatus Biofilm Determined by Different Methods

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.01875-12 ◽

2012 ◽

Vol 57 (3) ◽

pp. 1275-1282 ◽

Cited By ~ 32

Author(s):

Francesca Bugli ◽

Brunella Posteraro ◽

Massimiliano Papi ◽

Riccardo Torelli ◽

Alessandro Maiorana ◽

...

Keyword(s):

Invasive Aspergillosis ◽

Aspergillus Fumigatus ◽

Amphotericin B ◽

Extracellular Polymeric Substances ◽

Alginate Lyase ◽

Antifungal Drugs ◽

Antibiofilm Activity ◽

Content Type ◽

Time Kill

ABSTRACTAspergillus fumigatusbiofilms represent a problematic clinical entity, especially because of their recalcitrance to antifungal drugs, which poses a number of therapeutic implications for invasive aspergillosis, the most difficult-to-treatAspergillus-related disease. While the antibiofilm activities of amphotericin B (AMB) deoxycholate and its lipid formulations (e.g., liposomal AMB [LAMB]) are well documented, the effectiveness of these drugs in combination with nonantifungal agents is poorly understood. In the present study,in vitrointeractions between polyene antifungals (AMB and LAMB) and alginate lyase (AlgL), an enzyme degrading the polysaccharides produced as extracellular polymeric substances (EPSs) within the biofilm matrix, againstA. fumigatusbiofilms were evaluated by using the checkerboard microdilution and the time-kill assays. Furthermore, atomic force microscopy (AFM) was used to image and quantify the effects of AlgL-antifungal combinations on biofilm-growing hyphal cells. On the basis of fractional inhibitory concentration index values, synergy was found between both AMB formulations and AlgL, and this finding was also confirmed by the time-kill test. Finally, AFM analysis showed that whenA. fumigatusbiofilms were treated with AlgL or polyene alone, as well as with their combination, both a reduction of hyphal thicknesses and an increase of adhesive forces were observed compared to the findings for untreated controls, probably owing to the different action by the enzyme or the antifungal compounds. Interestingly, marked physical changes were noticed inA. fumigatusbiofilms exposed to the AlgL-antifungal combinations compared with the physical characteristics detected after exposure to the antifungals alone, indicating that AlgL may enhance the antibiofilm activity of both AMB and LAMB, perhaps by disrupting the hypha-embedding EPSs and thus facilitating the drugs to reach biofilm cells. Taken together, our results suggest that a combination of AlgL and a polyene antifungal may prove to be a new therapeutic strategy for invasive aspergillosis, while reinforcing the EPS as a valuable antibiofilm drug target.

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Potent In Vitro Synergism of Fluconazole and Berberine Chloride against Clinical Isolates of Candida albicans Resistant to Fluconazole

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.50.3.1096-1099.2006 ◽

2006 ◽

Vol 50 (3) ◽

pp. 1096-1099 ◽

Cited By ~ 93

Author(s):

Hua Quan ◽

Ying-Ying Cao ◽

Zheng Xu ◽

Jing-Xia Zhao ◽

Ping-Hui Gao ◽

...

Keyword(s):

Candida Albicans ◽

Clinical Isolates ◽

Antagonistic Action ◽

Berberine Chloride ◽

Agar Diffusion ◽

Fungistatic Activity ◽

Fluconazole Resistant ◽

Time Kill ◽

In Vitro Interaction

ABSTRACT In vitro interaction of fluconazole and berberine chloride was investigated against 40 fluconazole-resistant clinical isolates of Candida albicans. Synergism in fungistatic activity was found with the checkerboard microdilution assay. The findings of agar diffusion tests and time-kill curves confirmed the synergistic interaction, but no antagonistic action was observed.

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Dynamic Interaction between Fluconazole and Amphotericin B against Cryptococcus gattii

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.06098-11 ◽

2012 ◽

Vol 56 (5) ◽

pp. 2553-2558 ◽

Cited By ~ 29

Author(s):

Julliana Ribeiro Alves Santos ◽

Ludmila Ferreira Gouveia ◽

Erika Linzi Silva Taylor ◽

Maria Aparecida Resende-Stoianoff ◽

Gerson Antônio Pianetti ◽

...

Keyword(s):

Amphotericin B ◽

Cryptococcus Gattii ◽

Content Type ◽

Antagonistic Interaction ◽

Ergosterol Content ◽

Kill Curve ◽

Time Kill ◽

Postantifungal Effect

ABSTRACTCryptococcus gattiiis the main pathogen of cryptococcosis in healthy patients and is treated mainly with fluconazole and amphotericin B. The combination of these drugs has been questioned because the mechanisms of action could lead to a theoretical antagonistic interaction. We evaluated distinct parameters involved in thein vitrocombination of fluconazole and amphotericin B againstCryptococcus gattii. Fourteen strains ofC. gattiiwere used for the determination of MIC, fractional inhibitory concentration, time-kill curve, and postantifungal effect (PAFE). Ergosterol quantification was performed to evaluate the influence of ergosterol content on the interaction between these antifungals. Interaction between the drugs varied from synergistic to antagonistic depending on the strain and concentration tested. Increasing fluconazole levels were correlated with an antagonistic interaction. A total of 48 h was necessary for reducing the fungal viability in the presence of fluconazole, while 12 h were required for amphotericin B. When these antifungals were tested in combination, fluconazole impaired the amphotericin B activity. The ergosterol content decreased with the increase of fluconazole levels and it was correlated with the lower activity of amphotericin B. The PAFE found varied from 1 to 4 h for fluconazole and from 1 to 3 h for amphotericin B. The interaction of fluconazole and amphotericin B was concentration-dependent and special attention should be directed when these drugs are used in combination againstC. gattii.

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Synergistic Activity of Minocycline and Rifampin in Combination with Antifungal Drugs against Candida auris

10.1101/2021.02.23.432620 ◽

2021 ◽

Author(s):

Thea Brennan-Krohn ◽

Liam Friar ◽

Sarah Ditelberg ◽

James E. Kirby

Keyword(s):

Amphotericin B ◽

Antibacterial Agents ◽

Treatment Options ◽

Multidrug Resistant ◽

Antifungal Drugs ◽

Synergistic Activity ◽

Candida Auris ◽

Healthcare Settings ◽

Time Kill ◽

Synergy Testing

ABSTRACTCandida auris is an emerging multidrug-resistant fungal pathogen that spreads readily in healthcare settings and has caused numerous hospital outbreaks. Very few treatment options exist for C. auris infections. We evaluated the activity of all two-drug combinations of three antifungal agents (amphotericin B, caspofungin, and voriconazole) and two antibacterial agents (minocycline and rifampin) against a collection of 10 C. auris isolates using an automated, inkjet printer-assisted checkerboard array method. Three antibacterial-antifungal combinations (amphotericin B plus rifampin, amphotericin B plus minocycline, and caspofungin plus minocycline) demonstrated synergistic activity by checkerboard array against ≥90% of strains. The two amphotericin B-containing combinations were also synergistic using the time-kill synergy testing method. Our results suggest that combinations of antifungal and antibacterial agents may provide a promising avenue for treatment of this multidrug-resistant pathogen.

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Antifungal activity and killing kinetics of anidulafungin, caspofungin and amphotericin B against Candida auris

Journal of Antimicrobial Chemotherapy ◽

10.1093/jac/dkz178 ◽

2019 ◽

Vol 74 (8) ◽

pp. 2295-2302 ◽

Cited By ~ 11

Author(s):

Catiana Dudiuk ◽

Indira Berrio ◽

Florencia Leonardelli ◽

Soraya Morales-Lopez ◽

Laura Theill ◽

...

Keyword(s):

Amphotericin B ◽

Fungicidal Activity ◽

Geometric Mean ◽

Candida Auris ◽

Initial Inoculum ◽

Concentration Maximum ◽

High Concentrations ◽

Time Kill ◽

Kinetics Of

AbstractBackgroundCandida auris is an emerging MDR pathogen. It shows reduced susceptibility to azole drugs and, in some strains, high amphotericin B MICs have been described. For these reasons, echinocandins were proposed as first-line treatment for C. auris infections. However, information on how echinocandins and amphotericin B act against this species is lacking.ObjectivesOur aim was to establish the killing kinetics of anidulafungin, caspofungin and amphotericin B against C. auris by time–kill methodology and to determine if these antifungals behave as fungicidal or fungistatic agents against this species.MethodsThe susceptibility of 50 C. auris strains was studied. Nine strains were selected (based on echinocandin MICs) to be further studied. Minimal fungicidal concentrations, in vitro dose–response and time–kill patterns were determined.ResultsEchinocandins showed lower MIC values than amphotericin B (geometric mean of 0.12 and 0.94 mg/L, respectively). Anidulafungin and caspofungin showed no fungicidal activity at any concentration (maximum log decreases in cfu/mL between 1.34 and 2.22). On the other hand, amphotericin B showed fungicidal activity, but at high concentrations (≥2.00 mg/L). In addition, the tested polyene was faster than echinocandins at killing 50% of the initial inoculum (0.92 versus >8.00 h, respectively).ConclusionsAmphotericin B was the only agent regarded as fungicidal against C. auris. Moreover, C. auris should be considered tolerant to caspofungin and anidulafungin considering that their MFC:MIC ratios were mostly ≥32 and that after 6 h of incubation the starting inoculum was not reduced in >90%.

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A novel use for an old drug: resistance reversal in Candida albicans by combining dihydroartemisinin with fluconazole

Future Microbiology ◽

10.2217/fmb-2020-0148 ◽

2021 ◽

Author(s):

Hui Li ◽

Haisheng Chen ◽

Wenna Shi ◽

Jing Shi ◽

Jupeng Yuan ◽

...

Keyword(s):

Drug Combination ◽

Fungistatic Activity ◽

Resistance Reversal ◽

Antifungal Effects ◽

Curve Method ◽

Fluconazole Resistant ◽

Kill Curve ◽

Underlying Mechanisms ◽

Time Kill

Aim: To investigate the effects of dihydroartemisinin combined with fluconazole against C. albicans in vitro and to explore the underlying mechanisms. Materials & methods: Checkerboard microdilution assay and time–kill curve method were employed to evaluate the static and dynamic antifungal effects against C. albicans. Reactive oxygen species (ROS) was measured by a fluorescent probe. Results: Combination of dihydroartemisinin and fluconazole exerted potent synergy against planktonic cells and biofilms of fluconazole-resistant C. albicans, with the fractional inhibitory concentration index values less than 0.07. A potent fungistatic activity of this drug combination could still be observed after 18 h. The accumulation of ROS induced by the drug combination might contribute to the synergy. Conclusion: Dihydroartemisinin reversed the resistance of C. albicans to fluconazole.

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In Vitro Pharmacodynamic Characteristics of Amphotericin B, Caspofungin, Fluconazole, and Voriconazole against Bloodstream Isolates of Infrequent Candida Species from Patients with Hematologic Malignancies

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.48.11.4453-4456.2004 ◽

2004 ◽

Vol 48 (11) ◽

pp. 4453-4456 ◽

Cited By ~ 32

Author(s):

Giovanni Di Bonaventura ◽

Ilaria Spedicato ◽

Carla Picciani ◽

Domenico D'Antonio ◽

Raffaele Piccolomini

Keyword(s):

Amphotericin B ◽

Hematologic Malignancies ◽

Candida Guilliermondii ◽

Fungistatic Activity ◽

Candida Kefyr ◽

Candida Lusitaniae ◽

Time Kill ◽

Postantifungal Effect ◽

Dose Dependent

ABSTRACT Time-kill and postantifungal effect (PAFE) of amphotericin B, caspofungin, fluconazole, and voriconazole were determined against clinical isolates of Candida guilliermondii, Candida kefyr, and Candida lusitaniae. Azoles displayed fungistatic activity and no measurable PAFE, regardless of the concentration tested. Amphotericin B and caspofungin demonstrated concentration-dependent fungicidal activity, although amphotericin B only produced a significant dose-dependent PAFE against all isolates tested.

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