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Stover KR, Hawkins BK, Keck JM, Barber KE, Cretella DA. Antifungal resistance, combinations and pipeline: oh my! Drugs Context 2023; 12:2023-7-1. [PMID: 38021410 PMCID: PMC10653594 DOI: 10.7573/dic.2023-7-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2023] [Accepted: 09/26/2023] [Indexed: 12/01/2023] Open
Abstract
Invasive fungal infections are a strong contributor to healthcare costs, morbidity and mortality, especially amongst hospitalized patients. Historically, Candida was responsible for approximately 15% of all nosocomial bloodstream infections. In the past 10 years, the epidemiology of Candida species has altered, with increasing prevalence of resistant species. With rising fungal resistance, especially in Candida spp., the demand for novel antifungal therapies has exponentially increased over the last decade. Newer antifungal agents have become an attractive option for patients needing long-term therapy for infections or those requiring antifungal prophylaxis. Despite advances in coverage of non-Candida pathogens with newer agents, clinical scenarios involving multidrug-resistant fungal pathogens continue to arise in practice. Combination antifungal therapy can lead to a host of side-effects, some of which can be drug limiting. Additional antifungal therapies with enhanced fungal spectrum of activity and decreased rates of adverse effects are warranted. Fosmanogepix, ibrexafungerp, olorofim and rezafungin may help fill some of these gaps in the antifungal armamentarium. This article is part of the Challenges and strategies in the management of invasive fungal infections Special Issue: https://www.drugsincontext.com/special_issues/challenges-and-strategies-in-the-management-of-invasive-fungal-infections.
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Affiliation(s)
- Kayla R Stover
- Department of Pharmacy Practice, University of Mississippi School of Pharmacy, Jackson, MS, USA
| | - Brandon K Hawkins
- Department of Clinical Pharmacy and Translational Science, The University of Tennessee Health Science Center, Knoxville, TN, USA
| | - J Myles Keck
- Department of Pharmacy, University of Arkansas for Medical Sciences, Little Rock, AR, USA
| | - Katie E Barber
- Department of Pharmacy Practice, University of Mississippi School of Pharmacy, Jackson, MS, USA
| | - David A Cretella
- Division of Infectious Diseases, University of Mississippi Medical Center, Jackson, MS, USA
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Meletiadis J, Beredaki MI, Elefanti A, Pournaras S, Muller A. In Vitro–In Vivo Correlation of Posaconazole–Amphotericin B Combination against Candida albicans: In Vitro Interacting Concentrations Are Associated with In Vivo Free Drug Levels. J Fungi (Basel) 2023; 9:jof9040434. [PMID: 37108889 PMCID: PMC10146624 DOI: 10.3390/jof9040434] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2023] [Revised: 03/27/2023] [Accepted: 03/29/2023] [Indexed: 04/05/2023] Open
Abstract
The in vitro/in vivo correlation of antifungal combination testing is necessary in order to assess the efficacy of combination regimens. We, therefore, attempted to correlate in vitro chequerboard testing of posaconazole (POS) and amphotericin B (AMB) with the in vivo outcome of combination therapy against experimental candidiasis in a neutropenic murine model. The AMB + POS combination was tested against a Candida albicans isolate. In vitro, a broth microdilution 8 × 12 chequerboard method with serial two-fold drug dilutions was used. In vivo, CD1 female neutropenic mice with experimental disseminated candidiasis were treated with i.p. AMB and p.o. POS alone and in combination at three effective doses (ED20, ED50 and ED80 corresponding to 20%, 50% and 80% of maximal effect, respectively). CFU/kidneys after 2 days were determined. The pharmacodynamic interactions were assessed based on Bliss independence interaction analysis. In vitro, a Bliss antagonism of −23% (−23% to −22%) was observed at 0.03–0.125 mg/L of AMB with 0.004–0.015 mg/L of POS, while a Bliss synergy of 27% (14%–58%) was observed at 0.008–0.03 mg/L of AMB with 0.000015–0.001 mg/L of POS. In vivo, Bliss synergy (13 ± 4%) was found when an AMB ED20 of 1 mg/kg was combined with all POS ED 0.2–0.9 mg/kg, while Bliss antagonism (35–83%) was found for the combinations of AMB ED50 2 mg/kg and ED80 3.2 mg/kg with POS ED80 of 0.9 mg/kg. Free drug serum levels of POS and AMB in in vivo synergistic and antagonistic combinations were correlated with the in vitro synergistic and antagonistic concentrations, respectively. Both synergistic and antagonistic interactions were found for the AMB + POS combination. POS compromised the efficacy of high effective AMB doses and enhanced low ineffective AMB doses. In vitro concentration-dependent interactions were correlated with in vivo dose-dependent interactions of the AMB + POS combination. In vivo interactions occurred at free drug serum levels close to in vitro interacting concentrations.
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Affiliation(s)
- Joseph Meletiadis
- Clinical Microbiology Laboratory, Attikon University Hospital, Medical School, National and Kapodistrian University of Athens, 12462 Athens, Greece
- Department of Medical Microbiology and Infectious Diseases, Erasmus MC, 3015 CN Rotterdam, The Netherlands
| | - Maria-Ioanna Beredaki
- Clinical Microbiology Laboratory, Attikon University Hospital, Medical School, National and Kapodistrian University of Athens, 12462 Athens, Greece
| | - Antigoni Elefanti
- Clinical Microbiology Laboratory, Attikon University Hospital, Medical School, National and Kapodistrian University of Athens, 12462 Athens, Greece
| | - Spyros Pournaras
- Clinical Microbiology Laboratory, Attikon University Hospital, Medical School, National and Kapodistrian University of Athens, 12462 Athens, Greece
| | - Anouk Muller
- Department of Medical Microbiology and Infectious Diseases, Erasmus MC, 3015 CN Rotterdam, The Netherlands
- Department of Medical Microbiology, Haaglanden Medisch Centrum, 2512 VA The Hague, The Netherlands
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Ambati S, Pham T, Lewis ZA, Lin X, Meagher RB. DectiSomes: Glycan Targeting of Liposomal Drugs Improves the Treatment of Disseminated Candidiasis. Antimicrob Agents Chemother 2022; 66:e0146721. [PMID: 34633846 PMCID: PMC8765427 DOI: 10.1128/aac.01467-21] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2021] [Accepted: 09/22/2021] [Indexed: 11/24/2022] Open
Abstract
Candida albicans causes life-threatening disseminated candidiasis. Individuals at greatest risk have weakened immune systems. An outer cell wall, exopolysaccharide matrix, and biofilm rich in oligoglucans and oligomannans help Candida spp. evade host defenses. Even after antifungal treatment, the 1-year mortality rate exceeds 25%. Undoubtedly, there is room to improve drug performance. The mammalian C-type lectin pathogen receptors Dectin-1 and Dectin-2 bind to fungal oligoglucans and oligomannans, respectively. We previously coated amphotericin B-loaded liposomes, AmB-LLs, pegylated analogs of AmBisome, with the ligand binding domains of these two Dectins. DectiSomes, DEC1-AmB-LLs and DEC2-AmB-LLs, showed two distinct patterns of binding to the exopolysaccharide matrix surrounding C. albicans hyphae grown in vitro. Here we showed that DectiSomes were preferentially associated with fungal colonies in the kidneys. In a neutropenic mouse model of candidiasis, DEC1-AmB-LLs and DEC2-AmB-LLs delivering only one dose of 0.2 mg/kg AmB reduced the kidney fungal burden several fold relative to AmB-LLs. DEC1-AmB-LLs and DEC2-AmB-LLs increased the percent of surviving mice 2.5-fold and 8.3-fold, respectively, relative to AmB-LLs. Dectin-2 targeting of anidulafungin loaded liposomes, DEC2-AFG-LLs, and of commercial AmBisome, DEC2-AmBisome, reduced fungal burden in the kidneys several fold over their untargeted counterparts. The data herein suggest that targeting of a variety of antifungal drugs to fungal glycans may achieve lower safer effective doses and improve drug efficacy against a variety of invasive fungal infections.
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Affiliation(s)
- Suresh Ambati
- Department of Genetics, University of Georgia, Athens, Georgia, USA
| | - Tuyetnhu Pham
- Department of Microbiology, University of Georgia, Athens, Georgia, USA
| | - Zachary A. Lewis
- Department of Microbiology, University of Georgia, Athens, Georgia, USA
| | - Xiaorong Lin
- Department of Microbiology, University of Georgia, Athens, Georgia, USA
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Bidaud AL, Schwarz P, Herbreteau G, Dannaoui E. Techniques for the Assessment of In Vitro and In Vivo Antifungal Combinations. J Fungi (Basel) 2021; 7:jof7020113. [PMID: 33557026 PMCID: PMC7913650 DOI: 10.3390/jof7020113] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2021] [Revised: 01/28/2021] [Accepted: 02/02/2021] [Indexed: 12/18/2022] Open
Abstract
Systemic fungal infections are associated with high mortality rates despite adequate treatment. Moreover, acquired resistance to antifungals is increasing, which further complicates the therapeutic management. One strategy to overcome antifungal resistance is to use antifungal combinations. In vitro, several techniques are used to assess drug interactions, such as the broth microdilution checkerboard, agar-diffusion methods, and time-kill curves. Currently, the most widely used technique is the checkerboard method. The aim of all these techniques is to determine if the interaction between antifungal agents is synergistic, indifferent, or antagonistic. However, the interpretation of the results remains difficult. Several methods of analysis can be used, based on different theories. The most commonly used method is the calculation of the fractional inhibitory concentration index. Determination of the usefulness of combination treatments in patients needs well-conducted clinical trials, which are difficult. It is therefore important to study antifungal combinations in vivo, in experimental animal models of fungal infections. Although mammalian models have mostly been used, new alternative animal models in invertebrates look promising. To evaluate the antifungal efficacy, the most commonly used criteria are the mortality rate and the fungal load in the target organs.
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Affiliation(s)
- Anne-Laure Bidaud
- Parasitology-Mycology Unit, Microbiology Department, APHP, European Georges Pompidou Hospital, Paris-Descartes University, F-75015 Paris, France;
| | - Patrick Schwarz
- Department of Internal Medicine, Respiratory and Critical Care Medicine, University Hospital Marburg, Baldingerstraße, D-35043 Marburg, Germany;
- Center for Invasive Mycoses and Antifungals, Philipps University Marburg, D-35037 Marburg, Germany
| | | | - Eric Dannaoui
- Parasitology-Mycology Unit, Microbiology Department, APHP, European Georges Pompidou Hospital, Paris-Descartes University, F-75015 Paris, France;
- Dynamyc Research Group, Paris Est Créteil University (UPEC, EnvA), F-94010 Paris, France
- Correspondence: ; Tel.: +33-1-56-09-39-48; Fax: +33-1-56-09-24-46
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Chudzik B, Bonio K, Dabrowski W, Pietrzak D, Niewiadomy A, Olender A, Malodobry K, Gagoś M. Synergistic antifungal interactions of amphotericin B with 4-(5-methyl-1,3,4-thiadiazole-2-yl) benzene-1,3-diol. Sci Rep 2019; 9:12945. [PMID: 31506532 PMCID: PMC6737028 DOI: 10.1038/s41598-019-49425-1] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2019] [Accepted: 08/22/2019] [Indexed: 01/16/2023] Open
Abstract
Amphotericin B (AmB) is a very potent antifungal drug with very rare resistance among clinical isolates. Treatment with the AmB formulations available currently is associated with severe side effects. A promising strategy to minimize the toxicity of AmB is reducing its dose by combination therapy with other antifungals, showing synergistic interactions. Therefore, substances that display synergistic interactions with AmB are still being searched for. Screening tests carried out on several dozen of synthetic 1,3,4-thiadiazole derivatives allowed selection of a compound called 4-(5-methyl-1,3,4-thiadiazole-2-yl) benzene-1,3-diol (abbreviated as C1), which shows strong synergistic interaction with AmB and low toxicity towards human cells. The aim of the present study was to investigate the type of in vitro antifungal interactions of the C1 compound with AmB against fungal clinical isolates differing in susceptibility. The results presented in the present paper indicate that the C1 derivative shows strong synergistic interaction with AmB, which allows the use of a dozen to several dozen times lower AmB concentration necessary for 100% inhibition of the growth of pathogenic fungi in vitro. Synergistic interactions were noted for all tested strains, including strains with reduced sensitivity to AmB and azole-resistant isolates. These observations give hope for the possibility of application of the AmB - C1 combinatory therapy in the treatment of fungal infections.
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Affiliation(s)
- Barbara Chudzik
- Department of Cell Biology, Institute of Biology and Biochemistry, Maria Curie-Skłodowska University, Akademicka 19, 20-033, Lublin, Poland.
| | - Katarzyna Bonio
- Department of Cell Biology, Institute of Biology and Biochemistry, Maria Curie-Skłodowska University, Akademicka 19, 20-033, Lublin, Poland
| | - Wojciech Dabrowski
- Department of Anaesthesiology and Intensive Therapy Medical University of Lublin, Jaczewskiego 8, 20-954, Lublin, Poland.
| | - Daniel Pietrzak
- Department of Anaesthesiology and Intensive Therapy Medical University of Lublin, Jaczewskiego 8, 20-954, Lublin, Poland
| | - Andrzej Niewiadomy
- Institute of Industrial Organic Chemistry, Annopol 6, 03-236, Warsaw, Poland.,Department of Chemistry, University of Life Sciences in Lublin, Akademicka 15, 20-950, Lublin, Poland
| | - Alina Olender
- Chair and Department of Medical Microbiology, Medical University of Lublin, Chodźki 1, 20-093, Lublin, Poland
| | - Katarzyna Malodobry
- Department of Nurse and Health Science, Medical Division in University of Rzeszów, Al. Rejtana 16A, 35-310, Rzeszów, Poland
| | - Mariusz Gagoś
- Department of Cell Biology, Institute of Biology and Biochemistry, Maria Curie-Skłodowska University, Akademicka 19, 20-033, Lublin, Poland.
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6
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Khodavandi A, Alizadeh F, Jafarzadeh M. Synergistic Interaction of Fluconazole/Amphotericin B on Inhibition of Enzymes Contributes to the Pathogenesis of Candida Tropicalis. PHARMACEUTICAL SCIENCES 2018. [DOI: 10.15171/ps.2018.41] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
Background: Candidiasis has gained much attention in recent decades due to its increasing prevalence in immunocompromised patients. Usually, antifungals such as fluconazole and amphotricin B are used for treatment of candidiasis, but one of the major clinical problems is the emergence of antifungal resistance. Combination antifungal therapy is one of the most commonly used methods to alleviate the problem of antifungal resistance. Methods: The effect of fluconazole alone and in combination with amphotericin B on C. tropicalis isolates were performed using the Clinical and Laboratory Standards Institute (CLSI) reference method. Eventually hypha formation, time kill study, proteinase and phospholipase activity and expression of PLB and SAP2 genes were carried out to investigate the enzymes inhibitory properties of antifungal tested against C. tropicalis. Results: Results showed the significant synergic effect of fluconazole in combination with amphotericin B in inhibiting the growth of C. tropicalis isolates, with fractional inhibitory concentration indices ranging from 0.06 to 0.5. The combination of fluconazole with amphotericin B reduced the number of yeast form and inhibited the yeast to hyphae transition in C. tropicalis. The antifungals tested were able to show the effect of down regulating expression of the selected genes significantly in fluconazole/amphotericin B ranging from 1.42- to 2.27-fold. Conclusion: Our results demonstrated that the synergistic interaction of fluconazole/amphotericin B would be worth exploring for the management of candidiasis. In addition, PLB and SAP2 genes could be probable molecular targets in the synergistic interaction of fluconazole/amphotericin B in C. tropicalis.
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Affiliation(s)
- Alireza Khodavandi
- Department of Biology, Gachsaran Branch, Islamic Azad University, Gachsaran, Iran
| | - Fahimeh Alizadeh
- Department of Microbiology, Yasooj Branch, Islamic Azad University, Yasooj, Iran
| | - Mahsa Jafarzadeh
- Department of Microbiology, Yasooj Branch, Islamic Azad University, Yasooj, Iran
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7
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Combination of Posaconazole and Amphotericin B in the Treatment of Candida glabrata Biofilms. Microorganisms 2018; 6:microorganisms6040123. [PMID: 30518069 PMCID: PMC6313645 DOI: 10.3390/microorganisms6040123] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2018] [Revised: 11/27/2018] [Accepted: 11/29/2018] [Indexed: 12/17/2022] Open
Abstract
Candidemia cases have been increasing, especially among immunosuppressed patients. Candida glabrata is one of the most resistant Candida species, especially to the azole drugs, resulting in a high demand for therapeutic alternatives. The minimum inhibitory concentration (MIC), minimum fungicidal concentration (MFC), and minimum biofilm eradication concentration (MBEC) were determined for posaconazole (Pcz) and amphotericin B (AmB). The drug combinations of both drugs were evaluated on pre-formed biofilms of C. glabrata ATCC 2001, through XTT (2,3-bis (2-methoxy-4-nitro-5-sulfophenyl)-2H-tetrazolium-5-carboxanilide) assay, colony forming units (CFU), crystal violet, and the fractional inhibitory concentration index (FICI). C. glabrata revealed higher susceptibility and biofilm reduction in the presence of AmB alone, but both drugs revealed a good capacity in the biomass elimination. In the majority of the tested combinations, the interactions were defined as indifferent (FICI ≤ 4). The combination of the two drugs does not seem to bring a clear advantage in the treatment of biofilms of C. glabrata.
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8
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Farzanegan A, Roudbary M, Falahati M, Khoobi M, Gholibegloo E, Farahyar S, Karimi P, Khanmohammadi M. Synthesis, characterization and antifungal activity of a novel formulated nanocomposite containing Indolicidin and Graphene oxide against disseminated candidiasis. J Mycol Med 2018; 28:628-636. [PMID: 30126717 DOI: 10.1016/j.mycmed.2018.07.009] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2018] [Revised: 06/29/2018] [Accepted: 07/31/2018] [Indexed: 01/22/2023]
Abstract
OBJECTIVE Candidiasis is one of the most opportunistic fungal infections in immunocompromised patients. The emergence of multidrug-resistant Candida species necessitates the development of novel antifungal agents. Seeking to the discovery of natural antifungal agents, this study aimed to synthesize a novel formulated nanocomposite containing Indolicidin (IN), antimicrobial peptide, and Graphene oxide (GO), kind of nanomaterial, against Candida growth using in vitro and in vivo experiments for the first time. METHODS The formulated nanocomposite (GO-IN) synthetized and was characterized using scanning electron microscopy, X-ray power diffraction, and fourier transform infrared method analysis. The in vitro antifungal activity of fluconazole (FLU), GO, IN, and GO-IN was determined against Candida albicans (C. albicans) compared to control groups, cell cytotoxicity assay on human intestinal epithelial cells (IEP) and hemolytic activities were performed. Moreover, in vivo experiments of nanocomposite were assessed in BALB/c mice. RESULTS Our results showed that nanocomposite had the highest inhibitory effect against C. albicans (MIC 3.12μg/mL) compared with flu (MIC 4μg/mL), IN (MIC 12.5μg/mL), and GO (MIC 6.25μg/mL). Viability of human intestinal cell line at the MIC concentration (3.12μg/mL) of nanocomposite (GO-IN) was detected as 60% (P<0.05). The results of hemolytic activity showed that nanocomposite cause 2.73% of red blood cell membrane damage. For in vivo experiments, infected mice were successfully treated with GO-IN once a day within 7 days. GO-IN treated group eliminated the Candida infection in the spleen and liver of BALB/c mice (P=0.001) similar to fluconazole. There was no significant difference in histological manifestations between flu and GO-IN groups. CONCLUSION This study suggests that synergistic combination of GO and IN provide a new option, representing a potential therapeutic efficiency against disseminated candidiasis in an animal model as well as might be used as adjunct therapy in the management of candidiasis. However, further investigation is needed to evaluate the efficacy of the nanocomposite.
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Affiliation(s)
- A Farzanegan
- Department of Medical Mycology and Parasitology, School of Medicine, Iran University of Medical Sciences, 14496-14530 Tehran, Iran
| | - M Roudbary
- Department of Medical Mycology and Parasitology, School of Medicine, Iran University of Medical Sciences, 14496-14530 Tehran, Iran.
| | - M Falahati
- Department of Medical Mycology and Parasitology, School of Medicine, Iran University of Medical Sciences, 14496-14530 Tehran, Iran
| | - M Khoobi
- Nanobiomaterials group, Pharmaceutical Sciences Research Center, Tehran University of Medical Sciences, 141761411 Tehran, Iran; Department of Organic Chemistry, University of Zanjan, Zanjan, Iran
| | - E Gholibegloo
- Department of Chemistry, Faculty of Sciences, University of Zanjan, Zanjan, Iran
| | - S Farahyar
- Department of Medical Mycology and Parasitology, School of Medicine, Iran University of Medical Sciences, 14496-14530 Tehran, Iran
| | - P Karimi
- Department of Medical Mycology and Parasitology, School of Medicine, Iran University of Medical Sciences, 14496-14530 Tehran, Iran
| | - M Khanmohammadi
- Department of Medical Mycology and Parasitology, School of Medicine, Iran University of Medical Sciences, 14496-14530 Tehran, Iran
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Antifungal Potential of Host Defense Peptide Mimetics in a Mouse Model of Disseminated Candidiasis. J Fungi (Basel) 2018; 4:jof4010030. [PMID: 29495524 PMCID: PMC5872333 DOI: 10.3390/jof4010030] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2018] [Revised: 02/21/2018] [Accepted: 02/24/2018] [Indexed: 12/14/2022] Open
Abstract
Invasive candidiasis caused by Candida albicans and non-albicansCandida (NAC) present a serious disease threat. Although the echinocandins are recommended as the first line of antifungal drug class, resistance to these agents is beginning to emerge, demonstrating the need for new antifungal agents. Host defense peptides (HDP) exhibit potent antifungal activity, but as drugs they are difficult to manufacture efficiently, and they are often inactivated by serum proteins. HDP mimetics are low molecular weight non-peptide compounds that can alleviate these problems and were shown to be membrane-active against C. albicans and NAC. Here, we expand upon our previous works to describe the in vitro and in vivo activity of 11 new HDP mimetics that are active against C. albicans and NAC that are both sensitive and resistant to standard antifungal drugs. These compounds exhibit minimum inhibitory/fungicidal concentration (MIC/MFC) in the µg/mL range in the presence of serum and are inhibited by divalent cations. Rapid propidium iodide influx into the yeast cells following in vitro exposure suggested that these HDP mimetics were also membrane active. The lead compounds were able to kill C. albicans in an invasive candidiasis CD-1 mouse model with some mimetic candidates decreasing kidney burden by 3–4 logs after 24 h in a dose-dependent manner. The data encouraged further development of this new anti-fungal drug class for invasive candidiasis.
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Ghaleb A, Aouidate A, Ghamali M, Sbai A, Bouachrine M, Lakhlifi T. 3D-QSAR modeling and molecular docking studies on a series of 2,5 disubstituted 1,3,4-oxadiazoles. J Mol Struct 2017. [DOI: 10.1016/j.molstruc.2017.05.065] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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11
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Kakeya H, Izumikawa K, Yamada K, Obata Y, Nishino T, Takazono T, Kosai K, Kurihara S, Nakamura S, Imamura Y, Miyazaki T, Tsukamoto M, Yanagihara K, Tashiro T, Kohno S. Three cases of concurrent infection with Mycobacterium tuberculosis and Cryptococcus neoformans. Intern Med 2014; 53:1685-92. [PMID: 25088887 DOI: 10.2169/internalmedicine.53.1281] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Impaired cellular-mediated immunity is a known risk factor for both tuberculosis and cryptococcosis. However, pulmonary cryptococcosis associated with pulmonary tuberculosis is rare. We herein describe three cases of concurrent infection with Mycobacterium tuberculosis and Cryptococcus neoformans. All patients had underlying diseases; all three had uncontrolled diabetes mellitus, and other underlying diseases were liver cirrhosis, malignancy, and rheumatoid arthritis requiring long-term steroid use. We also review other relevant reports.
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Affiliation(s)
- Hiroshi Kakeya
- Department of Infection Control Science, Graduate School of Medicine, Osaka City University, Japan
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Abstract
The treatment of Candida infective endocarditis generally involves infected valve removal accompanied by antifungal therapy with amphotericin B or a lipid-based derivative, with or without flucytosine. While often used as chronic suppressive therapy in these patients, the precise role for fluconazole has not been established. We conducted a meta-analysis of 64 literature cases of Candida endocarditis whose management did not include valve replacement but who received fluconazole, alone or concurrently or in sequence with 1 or more other antifungal drugs.Forty-nine (77%) patients were cured (n = 44) or improved (n = 5), 4 relapsed (6%), and 11 failed (10 of whom died) (17%). Among 19 patients for whom fluconazole was administered as the sole antifungal therapy, 11 (58%) were cured or improved. In contrast, among 45 patients who received 1 or more other antifungal agents in addition to fluconazole, 38 (84%) were cured or improved (p = 0.02). Eighteen of 21 (86%) patients with native valve infection were cured or improved compared with 13 of 19 (68%) patients with prosthetic valve endocarditis (p = 0.13). The mean duration of successful fluconazole regimens was 134 days. Twenty of 21 (95%) patients who received fluconazole as chronic suppressive therapy for ≥6 months were cured. Prognosis was independent of Candida species or patient age. Among 23 historical controls managed with fluconazole-containing antifungal therapy plus valvular surgery, survival was 91%.In conclusion, fluconazole-containing, combination antifungal therapy, with or without concomitant valve replacement, and followed by prolonged, perhaps indefinite fluconazole suppression, is effective in patients with Candida endocarditis.
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Affiliation(s)
- Raymond A Smego
- From Department of Medicine, The Commonwealth Medical College, Scranton, Pennsylvania
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Voriconazole-induced inhibition of the fungicidal activity of amphotericin B in Candida strains with reduced susceptibility to voriconazole: an effect not predicted by the MIC value alone. Antimicrob Agents Chemother 2011; 55:1629-37. [PMID: 21282443 DOI: 10.1128/aac.00791-10] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
An antagonistic effect of voriconazole on the fungicidal activity of sequential doses of amphotericin B has previously been demonstrated in Candida albicans strains susceptible to voriconazole. Because treatment failure and the need to switch to other antifungals are expected to occur more often in infections that are caused by resistant strains, it was of interest to study whether the antagonistic effect was still seen in Candida strains with reduced susceptibility to voriconazole. With the hypothesis that antagonism will not occur in voriconazole-resistant strains, C. albicans strains with characterized mechanisms of resistance against voriconazole, as well as Candida glabrata and Candida krusei strains with differences in their degrees of susceptibility to voriconazole were exposed to voriconazole or amphotericin B alone, to both drugs simultaneously, or to voriconazole followed by amphotericin B in an in vitro kinetic model. Amphotericin B administered alone or simultaneously with voriconazole resulted in fungicidal activity. When amphotericin B was administered after voriconazole, its activity was reduced (median reduction, 61%; range, 9 to 94%). Levels of voriconazole-dependent inhibition of amphotericin B activity differed significantly among the strains but were not correlated with the MIC values (correlation coefficient, -0.19; P = 0.65). Inhibition was found in C. albicans strains with increases in CDR1 and CDR2 expression but not in the strain with an increase in MDR1 expression. In summary, decreased susceptibility to voriconazole does not abolish voriconazole-dependent inhibition of the fungicidal activity of amphotericin B in voriconazole-resistant Candida strains. The degree of interaction could not be predicted by the MIC value alone.
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Jin J, Guo N, Zhang J, Ding Y, Tang X, Liang J, Li L, Deng X, Yu L. The synergy of honokiol and fluconazole against clinical isolates of azole-resistant Candida albicans. Lett Appl Microbiol 2010; 51:351-7. [PMID: 20681969 DOI: 10.1111/j.1472-765x.2010.02900.x] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
AIMS To evaluate the interaction of fluconazole (FLC) and honokiol (HNK) in vitro and vivo against azole-resistant (azole-R) clinical isolates of Candida albicans. METHODS AND RESULTS A checkerboard microdilution method was used to study the in vitro interaction of FLC and HNK in 24 azole-R clinical isolates of C. albicans. In vivo antifungal activity was performed to further analyse the interaction between FLC and HNK. In the in vitro study, synergism was observed in all 24 FLC-resistant strains tested as determined by fractional inhibitory concentration index (FICI), and in 22 strains by Delta E models. No antagonistic activity was observed in any of the strains tested. These positive interactions were also confirmed by using the time-killing test for the selected strain C. albicans YL371, which shows strong susceptible to the combination of HNK and FLC. In the in vivo study, the mice with candidiasis were treated successfully by a combination therapy of HNK with FLC, the results showed a decrease of the colony forming unit in infected and treated animals compared to the controls, at the conditions of the treatment used in this study. CONCLUSIONS Synergistic activity of HNK and FLC against clinical isolates of FLC-resistant C. albicans was observed in vitro and in vivo. SIGNIFICANCE AND IMPACT OF THE STUDY This report might provide a potential therapeutic method to overcome the problem of drug-resistance in C. albicans.
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Affiliation(s)
- J Jin
- Key Laboratory of Zoonosis Research, Ministry of Education, Institute of Zoonosis, College of Animal Science and Veterinary Medicine, Jilin University, Changchun, China
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15
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Méan M, Marchetti O, Calandra T. Bench-to-bedside review: Candida infections in the intensive care unit. CRITICAL CARE : THE OFFICIAL JOURNAL OF THE CRITICAL CARE FORUM 2008; 12:204. [PMID: 18279532 PMCID: PMC2374590 DOI: 10.1186/cc6212] [Citation(s) in RCA: 153] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Invasive mycoses are life-threatening opportunistic infections and have emerged as a major cause of morbidity and mortality in critically ill patients. This review focuses on recent advances in our understanding of the epidemiology, diagnosis and management of invasive candidiasis, which is the predominant fungal infection in the intensive care unit setting. Candida spp. are the fourth most common cause of bloodstream infections in the USA, but they are a much less common cause of bloodstream infections in Europe. About one-third of episodes of candidaemia occur in the intensive care unit. Until recently, Candida albicans was by far the predominant species, causing up to two-thirds of all cases of invasive candidiasis. However, a shift toward non-albicans Candida spp., such as C. glabrata and C. krusei, with reduced susceptibility to commonly used antifungal agents, was recently observed. Unfortunately, risk factors and clinical manifestations of candidiasis are not specific, and conventional culture methods such as blood culture systems lack sensitivity. Recent studies have shown that detection of circulating β-glucan, mannan and antimannan antibodies may contribute to diagnosis of invasive candidiasis. Early initiation of appropriate antifungal therapy is essential for reducing the morbidity and mortality of invasive fungal infections. For decades, amphotericin B deoxycholate has been the standard therapy, but it is often poorly tolerated and associated with infusion-related acute reactions and nephrotoxicity. Azoles such as fluconazole and itraconazole provided the first treatment alternatives to amphotericin B for candidiasis. In recent years, several new antifungal agents have become available, offering additional therapeutic options for the management of Candida infections. These include lipid formulations of amphotericin B, new azoles (voriconazole and posaconazole) and echinocandins (caspofungin, micafungin and anidulafungin).
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Affiliation(s)
- Marie Méan
- Infectious Diseases Service, Department of Medicine, Centre Hospitalier Universitaire Vaudois and University of Lausanne, Rue du Bugnon 46, CH-1011 Lausanne, Switzerland
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16
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Abstract
The past decade has seen a significant increase in the incidence of invasive fungal infections. The antifungal armamentarium for the treatment of serious fungal infections remains limited. A possible approach to overcoming antifungal drug resistance and high mortality rates seen in severe fungal infections is to combine two or three classes of antifungals, especially if the drugs have different mechanisms of action. Combinations of new agents along with more traditional antifungals have now been shown to possess some synergistic or at least additive activity against many fungi in in vitro and animal studies. On the other hand, caution is still needed since some antifungal combinations have also demonstrated antagonistic activity. Well-controlled clinical trials are still required to define the most efficacious antifungal regimen. Furthermore, these trials should also evaluate the side-effect potential of combination regimens and the pharmacoeconomic impact these regimens may have.
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Affiliation(s)
- Jose A Vazquez
- Henry Ford Hospital, Division of Infectious Diseases, Detroit, MI 48202, USA.
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17
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Cacciapuoti A, Gurnani M, Halpern J, Norris C, Patel R, Loebenberg D. Interaction between posaconazole and amphotericin B in concomitant treatment against Candida albicans in vivo. Antimicrob Agents Chemother 2005; 49:638-42. [PMID: 15673745 PMCID: PMC547236 DOI: 10.1128/aac.49.2.638-642.2005] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The interaction of posaconazole and amphotericin B was evaluated in concomitant treatment of Candida albicans systemic infections in immunocompetent mice by using four strains of C. albicans with different susceptibilities to fluconazole. Posaconazole and amphotericin B were each tested at four dose levels alone and in all possible combinations against each C. albicans strain. Survival curves of mice treated with combinations of posaconazole and amphotericin B were statistically compared with those of mice treated with the component monotherapies. Of the 64 total combinations evaluated against the C. albicans strains (16 combinations per strain), 20.3% were more effective in prolonging mouse survival than both of the monotherapies, 45.3% were more effective than one of the monotherapies, and 32.8% were similar to both monotherapies. No evidence of antagonism was observed between posaconazole and amphotericin B in this mouse model, consistent with in vitro results against the same strains.
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Affiliation(s)
- Anthony Cacciapuoti
- Schering-Plough Research Institute, 2015 Galloping Hill Rd., Kenilworth, NJ 07033, USA.
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18
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Mukherjee PK, Sheehan DJ, Hitchcock CA, Ghannoum MA. Combination treatment of invasive fungal infections. Clin Microbiol Rev 2005; 18:163-94. [PMID: 15653825 PMCID: PMC544182 DOI: 10.1128/cmr.18.1.163-194.2005] [Citation(s) in RCA: 209] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The persistence of high morbidity and mortality from systemic fungal infections despite the availability of novel antifungals points to the need for effective treatment strategies. Treatment of invasive fungal infections is often hampered by drug toxicity, tolerability, and specificity issues, and added complications often arise due to the lack of diagnostic tests and to treatment complexities. Combination therapy has been suggested as a possible approach to improve treatment outcome. In this article, we undertake a historical review of studies of combination therapy and also focus on recent studies involving newly approved antifungal agents. The limitations surrounding antifungal combinations include nonuniform interpretation criteria, inability to predict the likelihood of clinical success, strain variability, and variations in pharmacodynamic/pharmacokinetic properties of antifungals used in combination. The issue of antagonism between polyenes and azoles is beginning to be addressed, but data regarding other drug combinations are not adequate for us to draw definite conclusions. However, recent data have identified potentially useful combinations. Standardization of assay methods and adoption of common interpretive criteria are essential to avoid discrepancies between different in vitro studies. Larger clinical trials are needed to assess whether combination therapy improves survival and treatment outcome in the most seriously debilitated patients afflicted with life-threatening fungal infections.
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Affiliation(s)
- Pranab K Mukherjee
- Center for Medical Mycology, Department of Dermatology, Case Western Reserve University and University Hospitals of Cleveland, 11100 Euclid Ave., LKS-5028, Cleveland, OH 44106-5028, USA
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19
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Barchiesi F, Spreghini E, Maracci M, Fothergill AW, Baldassarri I, Rinaldi MG, Scalise G. In vitro activities of voriconazole in combination with three other antifungal agents against Candida glabrata. Antimicrob Agents Chemother 2004; 48:3317-22. [PMID: 15328091 PMCID: PMC514763 DOI: 10.1128/aac.48.9.3317-3322.2004] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Candida glabrata has recently emerged as a significant pathogen involved in both superficial and deep-seated infections. In the present study, a checkerboard broth microdilution method was performed to investigate the in vitro activities of voriconazole (VOR) in combination with terbinafine (TRB), amphotericin B (AMB), and flucytosine (5FC) against 20 clinical isolates of C. glabrata. Synergy, defined as a fractional inhibitory concentration (FIC) index of < or = 0.50, was observed in 75% of VOR-TRB, 10% of VOR-AMB, and 5% of VOR-5FC interactions. None of these combinations yielded antagonistic interactions (FIC index > 4). When synergy was not achieved, there was still a decrease in the MIC of one or both drugs used in the combination. In particular, the MICs were reduced to < or = 1.0 microg/ml as a result of the combination for all isolates for which the AMB MIC at the baseline was > or = 2.0 microg/ml. By a disk diffusion assay, the halo diameters produced by antifungal agents in combination were greater that those produced by each drug alone. Finally, killing curves showed that VOR-AMB exhibited synergistic interactions, while VOR-5FC sustained fungicidal activities against C. glabrata. These studies demonstrate that the in vitro activity of VOR against this important yeast pathogen can be enhanced upon combination with other drugs that have different modes of action or that target a different step in the ergosterol pathway. Further studies are warranted to elucidate the potential beneficial effects of such combination regimens in vivo.
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Affiliation(s)
- Francesco Barchiesi
- Istituo di Malattie Infettive e Medicina Pubblica, Università Politecnica delle Marche, Azienda Ospedaliera Umberto I degrees, Via Conca, 60020 Torrette di Ancona, Ancona, Italy
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20
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Barchiesi F, Spreghini E, Schimizzi AM, Maracci M, Giannini D, Carle F, Scalise G. Posaconazole and amphotericin B combination therapy against Cryptococcus neoformans infection. Antimicrob Agents Chemother 2004; 48:3312-6. [PMID: 15328090 PMCID: PMC514762 DOI: 10.1128/aac.48.9.3312-3316.2004] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
To investigate the effects of posaconazole (POS) and amphotericin B (AMB) combination therapy in cryptococcal infection, we established an experimental model of systemic cryptococcosis in CD1 mice by intravenous injection of three distinct clinical isolates of Cryptococcus neoformans. Therapy was started 24 h after the infection and continued for 10 consecutive days. POS was given at 3 and 10 mg/kg of body weight/day, while AMB was given at 0.3 mg/kg/day. Combination therapy consisted of POS given at a low (combo 3) or at a high (combo 10) dose plus AMB. Survival studies showed that combo 3 was significantly more effective than POS at 3 mg/kg for two isolates tested (P value, < or = 0.001), while combo 10 was significantly more effective than POS at 10 mg/kg for all three isolates (P values ranging from <0.001 to 0.005). However, neither combination regimen was more effective than AMB alone. For two isolates, combination therapy was significantly more effective than each single drug at reducing the fungal burden in the brain (P values ranging from 0.001 to 0.015) but not in the lungs. This study demonstrates that the major impact of POS and AMB combination therapy is on brain fungal burden rather than on survival.
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Affiliation(s)
- Francesco Barchiesi
- Istituo di Malattie Infettive e Medicina Pubblica, Università Politecnica delle Marche, Azienda Ospedaliera Umberto I, Via Conca, 60020 Torrette di Ancona, Ancona, Italy
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21
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Cuenca-Estrella M. Combinations of antifungal agents in therapy--what value are they? J Antimicrob Chemother 2004; 54:854-69. [PMID: 15375111 DOI: 10.1093/jac/dkh434] [Citation(s) in RCA: 103] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Concurrent or sequential antifungal treatment for invasive mycoses has been typically considered as an option to improve results of monotherapy. However, data on the efficacy of combination therapy are sparse and consist largely of results from studies in vitro and experimental animal models. These studies have yielded controversial results depending on the criteria used to evaluate the antifungal interaction. Several combinations that showed synergy in vitro failed to do so in animal models. Overall, apart from cryptococcal infections, combined antifungal therapy is not significantly better than monotherapy in terms of clinical efficacy. It is questionable whether combination therapy should be used in most cases as there is a lack of evidence from well-designed clinical trials. However, combination therapy could be an alternative to monotherapy for patients with invasive infections that are difficult to treat, such as those due to multi-resistant species and for those who fail to respond to standard treatment.
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Affiliation(s)
- Manuel Cuenca-Estrella
- Servicio de Micología, Centro Nacional de Microbiología, Instituto de Salud Carlos III, Ctra Majadahonda-Pozuelo Km 2, 28220 Majadahonda, Madrid, Spain.
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22
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Johnson MD, MacDougall C, Ostrosky-Zeichner L, Perfect JR, Rex JH. Combination antifungal therapy. Antimicrob Agents Chemother 2004; 48:693-715. [PMID: 14982754 PMCID: PMC353116 DOI: 10.1128/aac.48.3.693-715.2004] [Citation(s) in RCA: 395] [Impact Index Per Article: 19.8] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Affiliation(s)
- Melissa D Johnson
- Departments of Medicine, Duke University Medical Center, Durham, North Carolina 27710, USA.
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23
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Jimenez-Valera M, Moreno E, Amat MA, Ruiz-Bravo A. Modification of mitogen-driven lymphoproliferation by ceftriaxone in normal and immunocompromised mice. Int J Antimicrob Agents 2003; 22:607-12. [PMID: 14659659 DOI: 10.1016/j.ijantimicag.2003.04.001] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Cyclophosphamide-treated mice are proposed as a model to assay immunomodulation by antimicrobial agents in immunocompromised animals. Cyclophosphamide-treated BALB/c mice developed temporary leukopenia, myelopenia and spleen atrophy that was followed by splenomegaly. Cells from both atrophic and hypertrophic spleens exhibited impaired responses to mitogens and suppressed the mitogen-driven proliferation of normal splenocytes. This experimental model was applied to the study of immunomodulation by ceftriaxone. Ceftriaxone did not worsen the cyclophosphamide-damaged immunity mechanisms. On the contrary, cyclophosphamide-induced suppression of lymphoproliferation in response to concanavalin A was attenuated by ceftriaxone.
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Affiliation(s)
- Maria Jimenez-Valera
- Department of Microbiology, Faculty of Pharmacy, University of Granada, 18071 Granada, Spain
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24
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Matthews RC, Rigg G, Hodgetts S, Carter T, Chapman C, Gregory C, Illidge C, Burnie J. Preclinical assessment of the efficacy of mycograb, a human recombinant antibody against fungal HSP90. Antimicrob Agents Chemother 2003; 47:2208-16. [PMID: 12821470 PMCID: PMC161838 DOI: 10.1128/aac.47.7.2208-2216.2003] [Citation(s) in RCA: 182] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Mycograb (NeuTec Pharma plc) is a human genetically recombinant antibody against fungal heat shock protein 90 (HSP90). Antibody to HSP90 is closely associated with recovery in patients with invasive candidiasis who are receiving amphotericin B (AMB). Using in vitro assays developed for efficacy assessment of chemotherapeutic antifungal drugs, Mycograb showed activity against a wide range of yeast species (MICs against Candida albicans [fluconazole [FLC]-sensitive and FLC-resistant strains], Candida krusei, Candida tropicalis, Candida glabrata, and Candida parapsilosis, 128 to 256 microg/ml). Mycograb (4 or 8 microg/ml) showed synergy with AMB, the fractional inhibitory index being 0.09 to 0.31. Synergy was not evident with FLC, except for FLC-sensitive C. albicans. Murine kinetics showed that Mycograb at 2 mg/kg produced a maximum concentration of drug in serum of 4.7 microg/ml, a half-life at alpha phase of 3.75 min, a half-life at beta phase of 2.34 h, and an area under the concentration-time curve from 0 to t h of 155 microg. min/ml. Mycograb (2 mg/kg) alone produced significant improvement in murine candidiasis caused by each species: (i). a reduction (Scheffe's test, P < 0.05) in the mean organ colony count for the FLC-resistant strain of C. albicans (kidney, liver, and spleen), C. krusei (liver and spleen), C. glabrata (liver and spleen), C. tropicalis (kidney), and C. parapsilosis (kidney, liver, and spleen) and (ii). a statistically significant increase in the number of negative biopsy specimens (Fisher's exact test, P < 0.05) for C. glabrata (kidney), C. tropicalis (liver and spleen), and C. parapsilosis (liver). AMB (0.6 mg/kg) alone cleared the C. tropicalis infection but failed to clear infections caused by C. albicans, C. krusei, C. glabrata, or C. parapsilosis. Synergy with AMB, defined as an increase (Fisher's exact test, P < 0.05) in the number of negative biopsy specimens compared with those obtained using AMB alone, occurred with the FLC-resistant strain of C. albicans (kidney), C. krusei (spleen), C. glabrata (spleen), and C. parapsilosis (liver and spleen). Only by combining Mycograb with AMB was complete resolution of infection achieved for C. albicans, C. krusei, and C. glabrata.
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Affiliation(s)
- Ruth C Matthews
- Department of Medical Microbiology, University of Manchester, Manchester M13 9WL, United Kingdom
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25
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Lupetti A, Nibbering PH, Campa M, Del Tacca M, Danesi R. Molecular targeted treatments for fungal infections: the role of drug combinations. Trends Mol Med 2003; 9:269-76. [PMID: 12829016 DOI: 10.1016/s1471-4914(03)00091-1] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Invasive mycoses are associated with a high mortality rate, and their incidence is increased in immunologically deficient patients. From a diagnostic and therapeutic perspective, these infections represent a significant challenge to medicine. In addition to new antifungal agents, drug combinations are an important therapeutic resource, which might be exploited clinically, owing to the multiplicity of fungal targets against which currently available agents are active. In this review, we examine the experimental data regarding the combination of conventional antifungal agents with cytokines, antibacterial agents, calcineurin inhibitors and drugs under development characterized by novel mechanisms of action.
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Affiliation(s)
- Antonella Lupetti
- Section of Microbiology, Department of Experimental Pathology, Medical Biotechnologies, Infectious Diseases and Epidemiology, University of Pisa, 56126 Pisa, Italy
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26
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Vazquez JA. Combination antifungal therapy againstCandidaspecies: the new frontier-are we there yet? Med Mycol 2003; 41:355-68. [PMID: 14653512 DOI: 10.1080/13693780310001616528] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022] Open
Abstract
In the past decade, we have seen a significant increase in the incidence of invasive fungal infections. In addition, opportunistic fungal infections resistant to antifungal agents have become increasingly common and their frequency will more than likely continue to increase. The antifungal armamentarium for the treatment of serious fungal infections remains limited. A possible approach to overcoming antifungal drug resistance and high mortality rates seen in severe fungal infections is to combine two or three classes of antifungals, especially if the drugs have different mechanisms of action. The unique properties of newer antifungals now provide us with the opportunity to investigate antifungal combinations that may become the standard of care for serious fungal infections. Combinations of new agents along with more traditional antifungals have now been shown to possess some synergistic or at least additive activity against Candida in clinical trials. On the other hand, caution is still needed since other antifungal combinations have demonstrated antagonistic activity in vitro. Well-controlled clinical trials are needed to define the most efficacious antifungal regimen. Furthermore, these trials should also evaluate the side effect potential of combination regimens and the pharmacoeconomic impact these regimens may have. Thus, while much optimism exists for combination therapy, there is much yet to be done.
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Affiliation(s)
- J A Vazquez
- Division of Infectious Diseases, Wayne State University School of Medicine, Detroit, Michigan, USA.
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27
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Masiá Canuto M, Gutiérrez Rodero F. Antifungal drug resistance to azoles and polyenes. THE LANCET. INFECTIOUS DISEASES 2002; 2:550-63. [PMID: 12206971 DOI: 10.1016/s1473-3099(02)00371-7] [Citation(s) in RCA: 217] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
There is an increased awareness of the morbidity and mortality associated with fungal infections caused by resistant fungi in various groups of patients. Epidemiological studies have identified risk factors associated with antifungal drug resistance. Selection pressure due to the continuous exposure to azoles seems to have an essential role in developing resistance to fluconazole in Candida species. Haematological malignancies, especially acute leukaemia with severe and prolonged neutropenia, seem to be the main risk factors for acquiring deep-seated mycosis caused by resistant filamentous fungi, such us Fusarium species, Scedosporium prolificans, and Aspergillus terreus. The still unacceptably high mortality rate associated with some resistant mycosis indicates that alternatives to existing therapeutic options are needed. Potential measures to overcome antifungal resistance ranges from the development of new drugs with better antifungal activity to improving current therapeutic strategies with the present antifungal agents. Among the new antifungal drugs, inhibitors of beta glucan synthesis and second-generation azole and triazole derivatives have characteristics that render them potentially suitable agents against some resistant fungi. Other strategies including the use of high doses of lipid formulations of amphotericin B, combination therapy, and adjunctive immune therapy with cytokines are under investigation. In addition, antifungal control programmes to prevent extensive and inappropriate use of antifungals may be needed.
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Affiliation(s)
- Mar Masiá Canuto
- Infectious Diseases Unit, Elche University General Hospital, Alicante, Spain
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28
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Kirkpatrick WR, Perea S, Coco BJ, Patterson TF. Efficacy of caspofungin alone and in combination with voriconazole in a Guinea pig model of invasive aspergillosis. Antimicrob Agents Chemother 2002; 46:2564-8. [PMID: 12121933 PMCID: PMC127374 DOI: 10.1128/aac.46.8.2564-2568.2002] [Citation(s) in RCA: 242] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The antifungal activity of caspofungin acetate (CAS) alone and in combination with voriconazole (VRC) was evaluated in an immunosuppressed transiently neutropenic guinea pig model of invasive aspergillosis. Guinea pigs were immunosuppressed with triamcinolone at 20 mg/kg of body weight/day subcutaneously beginning 4 days prior to lethal intravenous challenge with Aspergillus fumigatus and were made temporarily neutropenic with cyclophosphamide administered at 150 mg/kg intraperitoneally (i.p.) 1 day prior to challenge. Therapy with i.p. CAS at 1 and 2.5 mg/kg/day (with and without oral VRC at 5 mg/kg/day), oral VRC at 5 mg/kg/day, or i.p. amphotericin B (AMB) at 1.25 mg/kg/day was begun 24 h after challenge and was continued for 5 days. Mortality occurred in 12 of 12 untreated controls, whereas mortality occurred in 4 of 12 and 6 of 12 guinea pigs treated with CAS at 1 and 2.5 mg/kg/day, respectively, and in 3 of 12 guinea pigs treated with AMB. No mortality occurred among animals treated with CAS at 1 mg/kg/day plus VRC at 5 mg/kg/day, CAS at 2.5 mg/kg/day plus VRC at 5 mg/kg/day, or VRC at 5 mg/kg/day alone. Both CAS regimens increased the survival times and reduced the colony counts in tissue compared with those for the controls. Treatment with VRC and AMB significantly reduced the colony counts in the tissues of selected animals compared with those in the tissues of the controls. Treatment with VRC and AMB also resulted in reductions in colony counts in tissues compared with those in the tissues of animals treated with CAS (the difference was not statistically significant) and improved the survival times but did not sterilize tissues. Combination therapies with CAS plus VRC at either dose reduced colony counts in tissues 1,000-fold over those for the controls and were the only regimens that significantly reduced the numbers of positive cultures. The combinations of CAS plus VRC were highly effective in this model and should be further evaluated for use against invasive aspergillosis.
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Affiliation(s)
- William R Kirkpatrick
- Department of Medicine, The University of Texas Health Science Center at San Antonio, 7703 Floyd Curl Drive, Mail Code 7881, San Antonio, TX 78229-3900, USA.
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29
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Wang Z, Zheng L, Liu H, Wang Q, Hauser M, Kauffman S, Becker JM, Szaniszlo PJ. WdChs2p, a class I chitin synthase, together with WdChs3p (class III) contributes to virulence in Wangiella (Exophiala) dermatitidis. Infect Immun 2001; 69:7517-26. [PMID: 11705928 PMCID: PMC98842 DOI: 10.1128/iai.69.12.7517-7526.2001] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The chitin synthase structural gene WdCHS2 was isolated by screening a subgenomic DNA library of Wangiella dermatitidis by using a 0.6-kb PCR product of the gene as a probe. The nucleotide sequence revealed a 2,784-bp open reading frame, which encoded 928 amino acids, with a 59-bp intron near its 5' end. Derived protein sequences showed highest amino acid identities with those derived from the CiCHS1 gene of Coccidioides immitis and the AnCHSC gene of Aspergillus nidulans. The derived sequence also indicated that WdChs2p is an orthologous enzyme of Chs1p of Saccharomyces cerevisiae, which defines the class I chitin synthases. Disruptions of WdCHS2 produced strains that showed no obvious morphological defects in yeast vegetative growth or in ability to carry out polymorphic transitions from yeast cells to hyphae or to isotropic forms. However, assays showed that membranes of wdchs2Delta mutants were drastically reduced in chitin synthase activity. Other assays of membranes from a wdchs1Deltawdchs3Deltawdchs4Delta triple mutant showed that their residual chitin synthase activity was extremely sensitive to trypsin activation and was responsible for the majority of zymogenic activity. Although no loss of virulence was detected when wdchs2Delta strains were tested in a mouse model of acute infection, wdchs2Deltawdchs3Delta disruptants were considerably less virulent in the same model, even though wdchs3Delta strains also had previously shown no loss of virulence. This virulence attenuation in the wdchs2Deltawdchs3Delta mutants was similarly documented in a limited fashion in more-sensitive cyclophosphamide-induced immunocompromised mice. The importance of WdChs2p and WdChs3p to the virulence of W. dermatitidis was then confirmed by reconstituting virulence in the double mutant by the reintroduction of either WdCHS2 or WdCHS3 into the wdchs2Deltawdchs3Delta mutant background.
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Affiliation(s)
- Z Wang
- Section of Molecular Genetics and Microbiology, School of Biological Science and Institute for Cellular and Molecular Biology, The University of Texas at Austin, 78712, USA
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Barchiesi F, Schimizzi AM, Najvar LK, Bocanegra R, Caselli F, Di Cesare S, Giannini D, Di Francesco LF, Giacometti A, Carle F, Scalise G, Graybill JR. Interactions of posaconazole and flucytosine against Cryptococcus neoformans. Antimicrob Agents Chemother 2001; 45:1355-9. [PMID: 11302795 PMCID: PMC90473 DOI: 10.1128/aac.45.5.1355-1359.2001] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
A checkerboard methodology, based on standardized methods proposed by the National Committee for Clinical Laboratory Standards for broth microdilution antifungal susceptibility testing, was applied to study the in vitro interactions of flucytosine (FC) and posaconazole (SCH 56592) (FC-SCH) against 15 isolates of Cryptococcus neoformans. Synergy, defined as a fractional inhibitory concentration (FIC) index of <0.50, was observed for 33% of the isolates tested. When synergy was not achieved, there was still a decrease in the MIC of one or both drugs when they were used in combination. Antagonism, defined as a FIC of >4.0, was not observed. The in vitro efficacy of combined therapy was confirmed by quantitative determination of the CFU of C. neoformans 486, an isolate against which the FC-SCH association yielded a synergistic interaction. To investigate the potential beneficial effects of this combination therapy in vivo, we established two experimental murine models of cryptococcosis by intracranial or intravenous injection of cells of C. neoformans 486. At 1 day postinfection, the mice were randomized into different treatment groups. One group each received each drug alone, and one group received the drugs in combination. While combination therapy was not found to be significantly more effective than each single drug in terms of survival, tissue burden experiments confirmed the potentiation of antifungal activity with the combination. Our study demonstrates that SCH and FC combined are significantly more active than either drug alone against C. neoformans in vitro as well in vivo. These findings suggest that this therapeutic approach could be useful in the treatment of cryptococcal infections.
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Affiliation(s)
- F Barchiesi
- Istituto di Malattie Infettive e Medicina Pubblica, Biostatistica e Informatica Medica, Università degli Studi di Ancona, Ancona, Italy.
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31
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Louie A, Kaw P, Banerjee P, Liu W, Chen G, Miller MH. Impact of the order of initiation of fluconazole and amphotericin B in sequential or combination therapy on killing of Candida albicans in vitro and in a rabbit model of endocarditis and pyelonephritis. Antimicrob Agents Chemother 2001; 45:485-94. [PMID: 11158745 PMCID: PMC90317 DOI: 10.1128/aac.45.2.485-494.2001] [Citation(s) in RCA: 44] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
In vitro time-kill studies and a rabbit model of endocarditis and pyelonephritis were used to define the impact that the order of exposure of Candida albicans to fluconazole (FLC) and amphotericin B (AMB), as sequential and combination therapies, had on the susceptibility of C. albicans to AMB and on the outcome. The contribution of FLC-induced resistance to AMB for C. albicans also was assessed. In vitro, AMB monotherapy rapidly killed each of four C. albicans strains; FLC alone was fungistatic. Preincubation of these fungi with FLC for 18 h prior to exposure to AMB decreased their susceptibilities to AMB for 8 to >40 h. Induced resistance to AMB was transient, but the duration of resistance increased with the length of FLC preincubation. Yeast sequentially incubated with FLC followed by AMB plus FLC (FLC-->AMB+FLC) showed fungistatic growth kinetics similar to that of fungi that were exposed to FLC alone. This antagonistic effect persisted for at least 24 h. Simultaneous exposure of C. albicans to AMB and FLC [AMB+FLC(simult)] demonstrated activity similar to that with AMB alone for AMB concentrations of > or =1 microg/ml; antagonism was seen using an AMB concentration of 0.5 microg/ml. The in vitro findings accurately predicted outcomes in our rabbit infection model. In vivo, AMB monotherapy and treatment with AMB for 24 h followed by AMB plus FLC (AMB-->AMB+FLC) rapidly sterilized kidneys and cardiac vegetations. AMB+FLC(simult) and FLC-->AMB treatments were slower in clearing fungi from infected tissues. FLC monotherapy and FLC-->AMB+FLC were both fungistatic and were the least active regimens. No adverse interaction was observed between AMB and FLC for the AMB-->FLC regimen. However, FLC-->AMB treatment was slower than AMB alone in clearing fungi from tissues. Thus, our in vitro and in vivo studies both demonstrate that preexposure of C. albicans to FLC reduces fungal susceptibility to AMB. The length of FLC preexposure and whether AMB is subsequently used alone or in combination with FLC determine the duration of induced resistance to AMB.
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Affiliation(s)
- A Louie
- Division of Infectious Diseases, Department of Medicine, Albany Medical College, Albany Medical College and Wadsworth Center for Laboratories and Research, New York State Department of Health, Albany, New York 12208, USA.
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Marchetti O, Entenza JM, Sanglard D, Bille J, Glauser MP, Moreillon P. Fluconazole plus cyclosporine: a fungicidal combination effective against experimental endocarditis due to Candida albicans. Antimicrob Agents Chemother 2000; 44:2932-8. [PMID: 11036003 PMCID: PMC101583 DOI: 10.1128/aac.44.11.2932-2938.2000] [Citation(s) in RCA: 88] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Recent observations demonstrated that fluconazole plus cyclosporine (Cy) synergistically killed Candida albicans in vitro. This combination was tested in rats with C. albicans experimental endocarditis. The MICs of fluconazole and Cy for the test organism were 0.25 and >10 mg/liter, respectively. Rats were treated for 5 days with either Cy, amphotericin B, fluconazole, or fluconazole-Cy. Although used at high doses, the peak concentrations of fluconazole in the serum of rats (up to 4.5 mg/liter) were compatible with high-dose fluconazole therapy in humans. On the other hand, Cy concentrations in serum (up to 4.5 mg/liter) were greater than recommended therapeutic levels. Untreated rats demonstrated massive pseudohyphal growth in both the vegetations and the kidneys. However, only the kidneys displayed concomitant polymorphonuclear infiltration. The therapeutic results reflected this dissociation. In the vegetations, only the fungicidal fluconazole-Cy combination significantly decreased fungal densities compared to all groups, including amphotericin B (P < 0.0001). In the kidneys, all regimens except the Cy regimen were effective, but fluconazole-Cy remained superior to amphotericin B and fluconazole alone in sterilizing the organs (P < 0.0001). While the mechanism responsible for the fluconazole-Cy interaction is hypothetical, this observation opens new perspectives for fungicidal combinations between azoles and other drugs.
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Affiliation(s)
- O Marchetti
- Division of Infectious Diseases, Department of Internal Medicine, Centre Hospitalier Universitaire Vaudois, 1011 Lausanne, Switzerland
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33
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Barchiesi F, Schimizzi AM, Caselli F, Novelli A, Fallani S, Giannini D, Arzeni D, Di Cesare S, Di Francesco LF, Fortuna M, Giacometti A, Carle F, Mazzei T, Scalise G. Interactions between triazoles and amphotericin B against Cryptococcus neoformans. Antimicrob Agents Chemother 2000; 44:2435-41. [PMID: 10952592 PMCID: PMC90082 DOI: 10.1128/aac.44.9.2435-2441.2000] [Citation(s) in RCA: 61] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The interaction of amphotericin B (AmB) and azole antifungal agents in the treatment of fungal infections is still a controversial issue. A checkerboard titration broth microdilution-based method that adhered to the recommendations of the National Committee for Clinical Laboratory Standards was applied to study the in vitro interactions of AmB with fluconazole (FLC), itraconazole (ITC), and the new investigational triazole SCH 56592 (SCH) against 15 clinical isolates of Cryptococcus neoformans. Synergy, defined as a fractional inhibitory concentration (FIC) index of < or =0.50, was observed for 7% of the isolates in studies of the interactions of both FLC-AmB and ITC-AmB and for 33% of the isolates in studies of the SCH-AmB interactions; additivism (FICs, >0.50 to 1.0) was observed for 67, 73, and 53% of the isolates in studies of the FLC-AmB, ITC-AmB, and SCH-AmB interactions, respectively; indifference (FICs, >1.0 to < or =2.0) was observed for 26, 20, and 14% of the isolates in studies of the FLC-AmB, ITC-AmB, and SCH-AmB interactions, respectively. Antagonism (FIC >2.0) was not observed. When synergy was not achieved, there was still a decrease, although not as dramatic, in the MIC of one or both drugs when they were used in combination. To investigate the effects of FLC-AmB combination therapy in vivo, we established an experimental model of systemic cryptococcosis in BALB/c mice by intravenous injection of cells of C. neoformans 2337, a clinical isolate belonging to serotype D against which the combination of FLC and AmB yielded an additive interaction in vitro. Both survival and tissue burden studies showed that combination therapy was more effective than FLC alone and that combination therapy was at least as effective as AmB given as a single drug. On the other hand, when cells of C. neoformans 2337 were grown in FLC-containing medium, a pronounced increase in resistance to subsequent exposures to AmB was observed. In particular, killing experiments conducted with nonreplicating cells showed that preexposure to FLC abolished the fungicidal activity of the polyene. However, this apparent antagonism was not observed in vivo. Rather, when the two drugs were used sequentially for the treatment of systemic murine cryptococcosis, a reciprocal potentiation was often observed. Our study shows that (i) the combination of triazoles and AmB is significantly more active than either drug alone against C. neoformans in vitro and (ii) the concomitant or sequential use of FLC and AmB for the treatment of systemic murine cryptococcosis results in a positive interaction.
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Affiliation(s)
- F Barchiesi
- Istituto di Malattie Infettive e Medicina Pubblica, Italy.
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34
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Martinez R, Malta MH, Verceze AV, Arantes MR. Comparative efficacy of fluconazole and amphotericin B in the parenteral treatment of experimental paracoccidioidomycosis in the rat. Mycopathologia 2000; 146:131-4. [PMID: 10823185 DOI: 10.1023/a:1007013808797] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Patients with severe and complicated paracoccidioidomycosis are treated with amphotericin B by the intravenous route. Fluconazole is active in vitro against Paracoccidioides brasiliensis and can also be administered intravenously, but few clinical or experimental data are available about its action against the infection caused by this fungus. In the present study, the efficacy of fluconazole and amphotericin B was assessed comparatively in rats inoculated parenterally with P. brasiliensis. The treatment was performed 3 times a week for 4 weeks starting one week after infection. Fluconazole administered intraperitoneally (14 mg/kg body weight/dose) was more effective (P < 0.001) than amphotericin B (2 mg/kg body weight/dose) in reducing the number of colony forming units in the lungs and spleen. When administered intravenously at the dose of 3 mg/kg body weight, fluconazole was as effective as amphotericin B (0.8 mg/kg body weight) in reducing the pulmonary fungal burden. Under these conditions, the rats treated with fluconazole had a smaller number of colony forming units than untreated animals (P < 0.001), but amphotericin B was more effective than fluconazole in reducing spleen infection (P < 0.005). Except for this result obtained with a low dose, fluconazole showed an antifungal action equal to or higher than that of amphotericin B. The activity of fluconazole at doses equivalent to those used for human treatment suggests that this antifungal agent may be an alternative to amphotericin B for the early intravenous treatment of patients with paracoccidioidomycosis.
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Affiliation(s)
- R Martinez
- Department of Medicine, Faculty of Medicine of Ribeirão Preto, University of São Paulo, Brazil
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35
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Abstract
A variety of pharmacologic agents are currently available to treat house rabbits. In many cases, dosages are based on extrapolation from other species or empirical data. Dosing in rabbits is further complicated by individual variation. An understanding of rabbit physiology and the pharmacology of prescribed medications helps ensure that the agents are used as effectively and safely as possible. In this article, basic rabbit pharmacobiology is reviewed and techniques for drug administration are described. A formulary for house rabbits is provided.
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Affiliation(s)
- E S Ivey
- Avian/Exotic Service, Animal Medical Center, New York, New York, USA
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36
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Louie A, Liu W, Miller DA, Sucke AC, Liu QF, Drusano GL, Mayers M, Miller MH. Efficacies of high-dose fluconazole plus amphotericin B and high-dose fluconazole plus 5-fluorocytosine versus amphotericin B, fluconazole, and 5-fluorocytosine monotherapies in treatment of experimental endocarditis, endophthalmitis, and pyelonephritis due to Candida albicans. Antimicrob Agents Chemother 1999; 43:2831-40. [PMID: 10582868 PMCID: PMC89573 DOI: 10.1128/aac.43.12.2831] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
We compared the efficacies of fluconazole (Flu), amphotericin B (AmB), and 5-fluorocytosine (5FC) monotherapies with the combination of Flu plus 5FC and Flu plus AmB in a rabbit model of Candida albicans endocarditis, endophthalmitis, and pyelonephritis. The dose of Flu used was that which resulted in an area under the concentration-time curve in rabbits equivalent to that seen in humans who receive Flu at 1,600 mg/day, the highest dose not associated with central nervous system toxicity in humans. Quantitative cultures of heart valve vegetations, the choroid-retina, vitreous humor, and kidney were conducted after 1, 5, 14, and 21 days of therapy. All untreated controls died within 6 days of infection; animals treated with 5FC monotherapy all died within 18 days. In contrast, 93% of animals in the other treatment groups appeared well and survived until they were sacrificed. At day 5, the relative decreases in CFU per gram in the vitreous humor were greater in groups that received Flu alone and in combination with 5FC or AmB than in groups receiving AmB or 5FC monotherapies (P < 0. 005) but were similar thereafter. In the choroid-retina, 5FC was the least-active drug. However, there were no differences in choroidal fungal densities between the other treatment groups. On days 5 and 14 of therapy, fungal densities in kidneys of AmB recipients were lower than those resulting from the other therapies (P < 0.001 and P < or = 0.038, respectively) and AmB-plus-Flu therapy was antagonistic; however, all therapies for fungal pyelonephritis were similar by treatment day 21. While fungal counts in cardiac valves of Flu recipients were similar to those of controls on day 5 of therapy and did not change from days 1 to 21, AmB therapy significantly decreased valvular CFUs versus Flu at days 5, 14, and 21 (P < 0.005 at each time point). 5FC plus Flu demonstrated enhanced killing in cardiac vegetations compared with Flu or 5FC as monotherapies (P < 0. 03). Similarly, the combination of AmB and Flu was more active than Flu in reducing the fungal density in cardiac vegetations (P < 0.03). However, as in the kidney, AmB plus Flu demonstrated antagonism versus AmB monotherapy in the treatment of C. albicans endocarditis (P < 0.05, P = 0.036, and P < 0.008 on days 5, 14, and 21, respectively).
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Affiliation(s)
- A Louie
- Divisions of Infectious Diseases, Albany Medical College, Albany, New York 12208, USA.
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37
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Louie A, Banerjee P, Drusano GL, Shayegani M, Miller MH. Interaction between fluconazole and amphotericin B in mice with systemic infection due to fluconazole-susceptible or -resistant strains of Candida albicans. Antimicrob Agents Chemother 1999; 43:2841-7. [PMID: 10582869 PMCID: PMC89574 DOI: 10.1128/aac.43.12.2841] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The interaction between fluconazole (Flu) and amphotericin B (AmB) was evaluated in a murine model of systemic candidiasis for one Flu-susceptible strain (MIC, 0.5 microg/ml), two strains with intermediate Flu resistance (Flu mid-resistant strains) (MIC, 64 and 128 microg/ml), and one highly Flu-resistant strain (MIC, 512 microg/ml) of Candida albicans. Differences in fungal densities in kidneys of infected mice after 24 h of therapy and in survival rates at 62 days of mice treated with an antifungal drug or a combination of antifungal drugs for 4 days were compared. For the Flu-susceptible and Flu mid-resistant strains, the combination of Flu and AmB was antagonistic, as shown by both quantitative culture results and survival. The interaction was additive for the highly Flu-resistant strain. These results suggest that the combination of Flu and AmB should be used with caution in infections due to fungi that are usually susceptible to both antifungal agents and as empirical antifungal drug therapy.
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Affiliation(s)
- A Louie
- Division of Infectious Diseases, Department of Medicine, Albany Medical College, Albany, New York 12208, USA.
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38
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Guhad FA, Jensen HE, Hau J. Experimental murine mycotic mastitis: a sensitive and lenient model for studies of antifungal chemotherapy. FEMS IMMUNOLOGY AND MEDICAL MICROBIOLOGY 1999; 26:125-30. [PMID: 10536298 DOI: 10.1111/j.1574-695x.1999.tb01379.x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
The murine model of mycotic mastitis was used to study the efficacy of amphotericin B (AmB). Twenty-four BALB/cJ mice at the fifth day of lactation were anesthetized and inoculated through the teat canal (two glands) with 50 microl suspension containing 5.0 x 10(7) cfu ml(-1) Candida albicans blastospores. Mice were randomly divided into two groups: untreated controls and AmB treated. Animals were euthanized 3 and 6 days after infection and treatment (4 mg kg(-1) per day intraperitoneally). The fungal burden of the mammary gland was determined by quantitative cultures. The number of C. albicans cells recovered from mammary gland homogenates were significantly lower in the AmB treated animals (both 3 and 6 days post-infection) than in the untreated controls (P<0.007 and P<0.003, respectively). The mammary glands of all untreated control animals showed marked neutrophilic infiltration, severe necrosis, and presence of blastospores, hyphae and pseudohyphae. In contrast, 10 of 12 animals treated with AmB showed only a mild neutrophilic infiltration which was restricted to alveoli and excretory ducts. All extra-mammary organs were free of infection in both groups. The results demonstrate that the murine mycotic mastitis model is suitable for investigations of new antifungal compounds. In addition, this model is more lenient than the systemic candidiasis models.
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Affiliation(s)
- F A Guhad
- Division of Comparative Medicine, Department of Physiology, Uppsala University, BMC Box 570, SE-75123, Uppsala, Sweden
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Abstract
Major developments in research into the azole class of antifungal agents during the 1990s have provided expanded options for the treatment of many opportunistic and endemic fungal infections. Fluconazole and itraconazole have proved to be safer than both amphotericin B and ketoconazole. Despite these advances, serious fungal infections remain difficult to treat, and resistance to the available drugs is emerging. This review describes present and future uses of the currently available azole antifungal agents in the treatment of systemic and superficial fungal infections and provides a brief overview of the current status of in vitro susceptibility testing and the growing problem of clinical resistance to the azoles. Use of the currently available azoles in combination with other antifungal agents with different mechanisms of action is likely to provide enhanced efficacy. Detailed information on some of the second-generation triazoles being developed to provide extended coverage of opportunistic, endemic, and emerging fungal pathogens, as well as those in which resistance to older agents is becoming problematic, is provided.
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Affiliation(s)
- D J Sheehan
- Pfizer Pharmaceuticals Group, Pfizer Inc., New York, New York 10017-5755, USA.
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41
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Ernst EJ, Klepser ME, Pfaller MA. In vitro interaction of fluconazole and amphotericin B administered sequentially against Candida albicans: effect of concentration and exposure time. Diagn Microbiol Infect Dis 1998; 32:205-10. [PMID: 9884837 DOI: 10.1016/s0732-8893(98)00099-6] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
This study investigated the potential antagonism of fluconazole on amphotericin B activity against Candida albicans when administered sequentially in vitro. Yeast cells were exposed to fluconazole for time periods ranging from 0 to 24 h before the addition of amphotericin B. The combination showed fungicidal (> or = 3 log 10 reduction in CFU/mL) activity. After 4 h of exposure to fluconazole, amphotericin B activity was partially inhibited at the lower concentration tested (0.25 x MIC). Amphotericin B activity was dramatically decreased by previous exposure to fluconazole for greater than or equal to 8 h at both the high and low concentrations tested. The activity of amphotericin B against yeast exposed to fluconazole for at least 8 h was indistinguishable from fluconazole alone and was fungistatic (< or = 2 log 10 reduction in CFU/mL). This inhibition of amphotericin B activity persisted for a very short period (< 6 h) after removal of fluconazole from the culture medium, indicating the need for continued exposure to fluconazole for lasting inhibition of amphotericin B activity.
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Affiliation(s)
- E J Ernst
- College of Pharmacy, University of Iowa, Iowa City 52242, USA
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42
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White TC, Marr KA, Bowden RA. Clinical, cellular, and molecular factors that contribute to antifungal drug resistance. Clin Microbiol Rev 1998; 11:382-402. [PMID: 9564569 PMCID: PMC106838 DOI: 10.1128/cmr.11.2.382] [Citation(s) in RCA: 896] [Impact Index Per Article: 34.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
In the past decade, the frequency of diagnosed fungal infections has risen sharply due to several factors, including the increase in the number of immunosuppressed patients resulting from the AIDS epidemic and treatments during and after organ and bone marrow transplants. Linked with the increase in fungal infections is a recent increase in the frequency with which these infections are recalcitrant to standard antifungal therapy. This review summarizes the factors that contribute to antifungal drug resistance on three levels: (i) clinical factors that result in the inability to successfully treat refractory disease; (ii) cellular factors associated with a resistant fungal strain; and (iii) molecular factors that are ultimately responsible for the resistance phenotype in the cell. Many of the clinical factors that contribute to resistance are associated with the immune status of the patient, with the pharmacology of the drugs, or with the degree or type of fungal infection present. At a cellular level, antifungal drug resistance can be the result of replacement of a susceptible strain with a more resistant strain or species or the alteration of an endogenous strain (by mutation or gene expression) to a resistant phenotype. The molecular mechanisms of resistance that have been identified to date in Candida albicans include overexpression of two types of efflux pumps, overexpression or mutation of the target enzyme, and alteration of other enzymes in the same biosynthetic pathway as the target enzyme. Since the study of antifungal drug resistance is relatively new, other factors that may also contribute to resistance are discussed.
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Affiliation(s)
- T C White
- Department of Pathobiology, School of Public Health and Community Medicine, University of Washington, Seattle Biomedical Research Institute, Washington, USA.
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43
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Sugar AM. Antifungal combination therapy: where we stand. Drug Resist Updat 1998; 1:89-92. [PMID: 16904393 DOI: 10.1016/s1368-7646(98)80022-8] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/1998] [Revised: 12/16/1998] [Accepted: 12/18/1998] [Indexed: 10/25/2022]
Abstract
Amphotericin B has been used in combination, simultaneously or sequentially, with fluconazole and itraconazole. However, there are no data from clinical trials to suggest the most appropriate use of these drug combinations. In vitro work has consistently described antagonism of polyenes and azoles, but new work suggests that hydrophilic azoles (e.g. fluconazole) with amphotericin B may not result in antagonistic effects, whereas lipophilic azoles (e.g. ketoconazole, itraconazole) antagonize the antifungal effects of amphotericin B. Experimental studies in animals with invasive candidiasis show that fluconazole and amphotericin B are not antagonistic and may be additive in their effects. In contrast, itraconazole and amphotericin B are antagonistic in this same murine candidiasis model. In animals infected with Aspergillus, itraconazole plus amphotericin B seem to be antagonistic when used simultaneously and possibly when used sequentially. Nevertheless, initial therapy with amphotericin B followed by itraconazole in patients with aspergillosis is a common clinical strategy. Recent data and concepts concerning the combined use of available antifungal drugs are discussed in this paper.
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Affiliation(s)
- A M Sugar
- Evans Memorial Department of Clinical Research and Department of Medicine, Boston Medical Center, Boston, Massachusetts 02181, USA.
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