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Sass G, Larwood DJ, Stevens DA. Synergy In Vitro of Nikkomycin Z with Azole Against the Invasive Form of Candida albicans. Mycopathologia 2023; 188:949-956. [PMID: 37713047 DOI: 10.1007/s11046-023-00788-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2023] [Accepted: 08/18/2023] [Indexed: 09/16/2023]
Abstract
In a previous study, therapeutic activity of nikkomycin Z (NZ) in a model of invasive candidiasis did not appear to correlate with lesser activity in vitro (using classical MIC methods) with planktonic organisms. However, NZ potency was much greater assaying activity in vitro against germ tubes, the initiator of the invasive mycelial form of the fungus, as occurs in infected tissues. Synergy has been demonstrated for NZ and other drugs, notably fluconazole (the most commonly used drug against candidiasis), in planktonic testing, which correlated with results in vivo. This raised the question whether activity shown by NZ alone against germ tubes would be reflected in drug combinations, and even whether synergy testing against germ tubes might be a better correlate of synergy in future in vivo studies. We show in this study significant NZ synergy with fluconazole against germ tubes, for several C. albicans isolates, with testing in many drug ratios. This observation opens the way for further explorations of this method of susceptibility testing for synergy, and correlation with combination therapy against candidiasis.
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Affiliation(s)
- Gabriele Sass
- California Institute for Medical Research, San Jose, CA, USA.
| | - David J Larwood
- California Institute for Medical Research, San Jose, CA, USA
- Valley Fever Solutions, Tucson, AZ, USA
| | - David A Stevens
- California Institute for Medical Research, San Jose, CA, USA
- Division of Infectious Diseases and Geographic Medicine, Stanford University Medical School, Stanford, CA, USA
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Vanreppelen G, Wuyts J, Van Dijck P, Vandecruys P. Sources of Antifungal Drugs. J Fungi (Basel) 2023; 9:jof9020171. [PMID: 36836286 PMCID: PMC9965926 DOI: 10.3390/jof9020171] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2022] [Revised: 01/22/2023] [Accepted: 01/26/2023] [Indexed: 01/31/2023] Open
Abstract
Due to their eukaryotic heritage, the differences between a fungal pathogen's molecular makeup and its human host are small. Therefore, the discovery and subsequent development of novel antifungal drugs are extremely challenging. Nevertheless, since the 1940s, researchers have successfully uncovered potent candidates from natural or synthetic sources. Analogs and novel formulations of these drugs enhanced the pharmacological parameters and improved overall drug efficiency. These compounds ultimately became the founding members of novel drug classes and were successfully applied in clinical settings, offering valuable and efficient treatment of mycosis for decades. Currently, only five different antifungal drug classes exist, all characterized by a unique mode of action; these are polyenes, pyrimidine analogs, azoles, allylamines, and echinocandins. The latter, being the latest addition to the antifungal armamentarium, was introduced over two decades ago. As a result of this limited arsenal, antifungal resistance development has exponentially increased and, with it, a growing healthcare crisis. In this review, we discuss the original sources of antifungal compounds, either natural or synthetic. Additionally, we summarize the existing drug classes, potential novel candidates in the clinical pipeline, and emerging non-traditional treatment options.
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Initial Results of the International Efforts in Screening New Agents against Candida auris. J Fungi (Basel) 2022; 8:jof8080771. [PMID: 35893139 PMCID: PMC9330594 DOI: 10.3390/jof8080771] [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: 06/17/2022] [Revised: 07/07/2022] [Accepted: 07/11/2022] [Indexed: 12/10/2022] Open
Abstract
BACKGROUND Candida auris is an emergent fungal pathogen and a global concern, mostly due to its resistance to many currently available antifungal drugs. OBJECTIVE Thus, in response to this challenge, we evaluated the in vitro activity of potential new drugs, diphenyl diselenide (PhSe)2 and nikkomycin Z (nikZ), alone and in association with currently available antifungals (azoles, echinocandins, and polyenes) against Candida auris. METHODS Clinical isolates of C. auris were tested in vitro. (PhSe)2 and nikZ activities were tested alone and in combination with amphotericin B, fluconazole, or the echinocandins, micafungin and caspofungin. RESULTS (PhSe)2 alone was unable to inhibit C. auris, and antagonism or indifferent effects were observed in the combination of this compound with the antifungals tested. NikZ appeared not active alone either, but frequently acted cooperatively with conventional antifungals. CONCLUSION Our data show that (PhSe)2 appears to not have a good potential to be a candidate in the development of new drugs to treat C. auris, but that nikZ is worthy of further study.
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Anti-Candida albicans natural products, sources of new antifungal drugs: A review. J Mycol Med 2016; 27:1-19. [PMID: 27842800 DOI: 10.1016/j.mycmed.2016.10.002] [Citation(s) in RCA: 97] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2016] [Revised: 10/09/2016] [Accepted: 10/11/2016] [Indexed: 01/17/2023]
Abstract
INTRODUCTION Candida albicans is the most prevalent fungal pathogen in humans. Due to the development of drug resistance, there is today a need for new antifungal agents for the efficient management of C. albicans infections. Therefore, we reviewed antifungal activity, mechanisms of action, possible synergism with antifungal drugs of all natural substances experimented to be efficient against C. albicans for future. METHODS An extensive and systematic review of the literature was undertaken and all relevant abstracts and full-text articles analyzed and included in the review. REVIEW A total of 111 documents were published and highlighted 142 anti-C. albicans natural products. These products are mostly are reported in Asia (44.37%) and America (28.17%). According to in vitro model criteria, from the 142 natural substances, antifungal activity can be considered as important for 40 (28.20%) and moderate for 24 (16.90%). Sixteen products have their antifungal activity confirmed by in vivo gold standard experimentation. Microbial natural products, source of antifungals, have their antifungal mechanism well described in the literature: interaction with ergosterol (polyenes), inhibition 1,3-β-d-glucan synthase (Echinocandins), inhibition of the synthesis of cell wall components (chitin and mannoproteins), inhibition of sphingolipid synthesis (serine palmitoyltransferase, ceramide synthase, inositol phosphoceramide synthase) and inhibition of protein synthesis (sordarins). Natural products from plants mostly exert their antifungal effects by membrane-active mechanism. Some substances from arthropods are also explored to act on the fungal membrane. Interestingly, synergistic effects were found between different classes of natural products as well as between natural products and azoles. CONCLUSION Search for anti-C. albicans new drugs is promising since the list of natural substances, which disclose activity against this yeast is today long. Investigations must be pursued not only to found more new anti-Candida compounds from plants and organisms but also to carried out details on molecules from already known anti-Candida compounds and to more elucidate mechanisms of action.
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Cui J, Ren B, Tong Y, Dai H, Zhang L. Synergistic combinations of antifungals and anti-virulence agents to fight against Candida albicans. Virulence 2016; 6:362-71. [PMID: 26048362 DOI: 10.1080/21505594.2015.1039885] [Citation(s) in RCA: 119] [Impact Index Per Article: 14.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Candida albicans, one of the pathogenic Candida species, causes high mortality rate in immunocompromised and high-risk surgical patients. In the last decade, only one new class of antifungal drug echinocandin was applied. The increased therapy failures, such as the one caused by multi-drug resistance, demand innovative strategies for new effective antifungal drugs. Synergistic combinations of antifungals and anti-virulence agents highlight the pragmatic strategy to reduce the development of drug resistant and potentially repurpose known antifungals, which bypass the costly and time-consuming pipeline of new drug development. Anti-virulence and synergistic combination provide new options for antifungal drug discovery by counteracting the difficulty or failure of traditional therapy for fungal infections.
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Affiliation(s)
- Jinhui Cui
- a CAS Key Laboratory of Pathogenic Microbiology and Immunology; Institute of Microbiology; Chinese Academy of Sciences ; Beijing , China
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Holden WM, Fites JS, Reinert LK, Rollins-Smith LA. Nikkomycin Z is an effective inhibitor of the chytrid fungus linked to global amphibian declines. Fungal Biol 2013; 118:48-60. [PMID: 24433676 DOI: 10.1016/j.funbio.2013.11.001] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2013] [Revised: 10/31/2013] [Accepted: 11/05/2013] [Indexed: 11/16/2022]
Abstract
Fungal infections in humans, wildlife, and plants are a growing concern because of their devastating effects on human and ecosystem health. In recent years, populations of many amphibian species have declined, and some have become extinct due to chytridiomycosis caused by the fungal pathogen Batrachochytrium dendrobatidis. For some endangered amphibian species, captive colonies are the best intermediate solution towards eventual reintroduction, and effective antifungal treatments are needed to cure chytridiomycosis and limit the spread of this pathogen in such survival assurance colonies. Currently, the best accepted treatment for infected amphibians is itraconazole, but its toxic side effects reduce its usefulness for many species. Safer antifungal treatments are needed for disease control. Here, we show that nikkomycin Z, a chitin synthase inhibitor, dramatically alters the cell wall stability of B. dendrobatidis cells and completely inhibits growth of B. dendrobatidis at 250 μM. Low doses of nikkomycin Z enhanced the effectiveness of natural antimicrobial skin peptide mixtures tested in vitro. These studies suggest that nikkomycin Z would be an effective treatment to significantly reduce the fungal burden in frogs infected by B. dendrobatidis.
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Affiliation(s)
- Whitney M Holden
- Department of Pathology, Microbiology and Immunology, Vanderbilt University School of Medicine, Nashville, TN 37232, USA.
| | - J Scott Fites
- Department of Biological Sciences, Vanderbilt University, Nashville, TN 37235, USA.
| | - Laura K Reinert
- Department of Pathology, Microbiology and Immunology, Vanderbilt University School of Medicine, Nashville, TN 37232, USA.
| | - Louise A Rollins-Smith
- Department of Pathology, Microbiology and Immunology, Vanderbilt University School of Medicine, Nashville, TN 37232, USA; Department of Biological Sciences, Vanderbilt University, Nashville, TN 37235, USA; Department of Pediatrics, Vanderbilt University School of Medicine, Nashville, TN 37232, USA.
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Munro CA. Chitin and glucan, the yin and yang of the fungal cell wall, implications for antifungal drug discovery and therapy. ADVANCES IN APPLIED MICROBIOLOGY 2013; 83:145-72. [PMID: 23651596 DOI: 10.1016/b978-0-12-407678-5.00004-0] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
The structural carbohydrate polymers glucan and chitin compliment and reinforce each other in a dynamic process to maintain the integrity and physical strength of the fungal cell wall. The assembly of chitin and glucan in the cell wall of the budding yeast Saccharomyces cerevisiae and the polymorphic human pathogen Candida albicans are essential processes that involve a range of fungal-specific enzymes and regulatory networks. The fungal cell wall is, therefore, an attractive target for novel therapies as host cells lack many cell wall-related proteins. The most recent class of antifungal drug approved for clinical use, the echinocandins, targets the synthesis of cell wall β(1-3)glucan. The echinocandins are effective at treating invasive and bloodstream Candida infections and are now widely used in the clinic. However, there have been sporadic reports of breakthrough infections in patients undergoing echinocandin therapy. The acquisition of point mutations in the FKS genes that encode the catalytic β(1-3)glucan synthase subunits, the target of the echinocandins, has emerged as a dominant resistance mechanism. Cells with elevated chitin levels are also less susceptible to echinocandins and in addition, treatment with sub-MIC echinocandin activates cell wall salvage pathways that increase chitin synthesis to compensate for reduced glucan production. The development of drugs targeting the cell wall has already proven to be beneficial in providing an alternative class of drug for use in the clinic. Other cell wall targets such as chitin synthesis still hold great potential for drug development but careful consideration should be given to the capacity of fungi to manipulate their walls in a dynamic response to cell wall perturbations.
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Affiliation(s)
- Carol A Munro
- School of Medical Sciences, University of Aberdeen, Aberdeen, UK, E-mail:
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Kingsbury JM, Heitman J, Pinnell SR. Calcofluor white combination antifungal treatments for Trichophyton rubrum and Candida albicans. PLoS One 2012; 7:e39405. [PMID: 22792174 PMCID: PMC3391284 DOI: 10.1371/journal.pone.0039405] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2012] [Accepted: 05/24/2012] [Indexed: 12/31/2022] Open
Abstract
Superficial mycoses caused by dermatophyte fungi are among the most common infections worldwide, yet treatment is restricted by limited effective drugs available, drug toxicity, and emergence of drug resistance. The stilbene fluorescent brightener calcofluor white (CFW) inhibits fungi by binding chitin in the cell wall, disrupting cell wall integrity, and thus entails a different mechanism of inhibition than currently available antifungal drugs. To identify novel therapeutic options for the treatment of skin infections, we compared the sensitivity of representative strains of the dermatophyte Trichophyton rubrum and Candida albicans to CFW and a panel of fluorescent brighteners and phytoalexin compounds. We identified the structurally related stilbene fluorescent brighteners 71, 85, 113 and 134 as fungicidal to both T. rubrum and C. albicans to a similar degree as CFW, and the stilbene phytoalexins pinosylvan monomethyl ether and pterostilbene inhibited to a lesser degree, allowing us to develop a structure-activity relationship for fungal inhibition. Given the abilities of CFW to absorb UV(365 nm) and bind specifically to fungal cell walls, we tested whether CFW combined with UV(365 nm) irradiation would be synergistic to fungi and provide a novel photodynamic treatment option. However, while both treatments individually were cytocidal, UV(365 nm) irradiation reduced sensitivity to CFW, which we attribute to CFW photoinactivation. We also tested combination treatments of CFW with other fungal inhibitors and identified synergistic interactions between CFW and some ergosterol biosynthesis inhibitors in C. albicans. Therefore, our studies identify novel fungal inhibitors and drug interactions, offering promise for combination topical treatment regimes for superficial mycoses.
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Affiliation(s)
- Joanne M Kingsbury
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, North Carolina, United States of America.
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Studies on peptidyl nucleoside antibiotics: synthesis and antifungal evaluation of pyranosyl nucleoside analogs of nikkomycin. Future Med Chem 2009; 1:379-89. [DOI: 10.4155/fmc.09.18] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Background: The Streptomyces-derived nikkomycins are a unique class of peptidyl nucleoside natural products, with potent antifungal activity against a variety of pathogenic fungi. Results: In continuation of our structure–activity relationship studies on the nikkomycins, this paper describes the strategic design, synthesis and biological evaluation of a ‘doubly modified’ generation of nikkomycin analogs. The structural modifications included a ring-expanded carbohydrate core and a simplified peptidyl side chain. Biological screening of these novel analogs against clinical isolates of various human pathogenic fungi indicated that the described modifications of the structural features of nikkomycin could be a potentially beneficial strategy towards optimizing the antifungal potency of this class of peptidyl nucleoside antibiotics. Conclusion: Continued investigation of the pyranosyl nikkomycin analogs is warranted to fully explore and optimize the structural features of this novel lead for the desired development of a new class of therapeutically useful antifungal drugs.
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10
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Gooday GW. Section Review: Anti-infectives: The potential of novel antifungal drugs for the treatment of disease in the immunocompromised host. Expert Opin Investig Drugs 2008. [DOI: 10.1517/13543784.4.8.679] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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Hector RF, Davidson AP, Johnson SM. Comparison of susceptibility of fungal isolates to lufenuron and nikkomycin Z alone or in combination with itraconazole. Am J Vet Res 2005; 66:1090-3. [PMID: 16008236 DOI: 10.2460/ajvr.2005.66.1090] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
OBJECTIVE To evaluate and compare the in vitro antifungal properties of lufenuron and nikkomycin Z against isolates of Coccidioides immitis and Aspergillus fumigatus when used singly and in combination with the azole antifungal agent itraconazole. SAMPLE POPULATION 3 clinical isolates of A fumigatus and the Silveira strain of C immitis. PROCEDURE The fungal isolates were tested in vitro for susceptibility to the single and combination of compounds by use of microtiter-format susceptibility methods. Minimum inhibitory concentration end points were determined visually, and the contents of representative wells were examined microscopically for evidence of morphologic effects on fungi. RESULTS No evidence of inhibition, either by susceptibility testing or direct microscopic examination of treated cells, was obtained with lufenuron under experimental conditions. In contrast, nikkomycin Z, a known inhibitor of fungal chitin synthesis, had potent activity against C immitis when used singly. A synergistic interaction between nikkomycin Z and itraconazole was found against isolates of both species tested. CONCLUSIONS AND CLINICAL RELEVANCE On the basis of our in vitro data, lufenuron does not appear to possess antifungal properties.
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Affiliation(s)
- Richard F Hector
- Department of Epidemiology and Biostatistics, University of California, San Francisco, CA 94143, USA
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Bhaket P, Stauffer CS, Datta A. Complex Peptidyl Nucleoside Antibiotics: Efficient Syntheses of the Glycosyl Nucleoside Amino Acid Cores. J Org Chem 2004; 69:8594-601. [PMID: 15575734 DOI: 10.1021/jo048586l] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Employing an amino acid chiral template strategy, the present research describes a general and highly efficient protocol for the rapid construction of enantiopure furanosyl and pyranosyl nucleoside amino acid cores as present in various complex peptidyl nucleoside antibiotics. Starting from easily available d-serine, the strategy and the approach involve rapid and efficient stereoselective synthesis of five- or six-membered lactone amino alcohols, followed by incorporation of the required functionalities of the target molecules on these strategically functionalized chiral templates.
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Affiliation(s)
- Pushpal Bhaket
- Department of Medicinal Chemistry, University of Kansas, 1251 Wescoe Hall Drive, Lawrence, KS 66045, USA
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Klis FM, Groot PD, Hellingwerf K. Molecular organization of the cell wall ofCandida albicans. Med Mycol 2001. [DOI: 10.1080/mmy.39.1.1.8-0] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022] Open
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Graybill JR. The role of murine models in the development of antifungal therapy for systemic mycoses. Drug Resist Updat 2000; 3:364-383. [PMID: 11498404 DOI: 10.1054/drup.2000.0171] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Animal testing is crucial to the development of new antifungal compounds. This review describes the role that murine and other animal models have played in the development of three classes of antifungal agents: the polyenes, the triazoles and the echinocandins and the ways in which these models have been either the positive link in the path from in vitro studies to the patient, or have foreclosed later clinical evaluation. Efficacy studies in particular mycoses are discussed, as well as studies designed to determine whether combinations of antifungal drugs may have value over single agents. Copyright 2000 Harcourt Publishers Ltd.
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Bigliardi E, Bernuzzi AM, Corona S, Gatti S, Scaglia M, Sacchi L. In vitro efficacy of nikkomycin Z against the human isolate of the microsporidian species Encephalitozoon hellem. Antimicrob Agents Chemother 2000; 44:3012-6. [PMID: 11036015 PMCID: PMC101595 DOI: 10.1128/aac.44.11.3012-3016.2000] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Since 1985 microsporidia have been recognized as a cause of emerging infections in humans, mainly in immunocompromised human immunodeficiency virus-positive subjects. As chitin is a basic component of the microsporidian infective stage, the spore, we evaluated in vitro the susceptibility of a human-derived strain of Encephalitozoon hellem to nikkomycin Z, a peptide-nucleoside antibiotic known as a competitive inhibitor of chitin synthase enzymes. Transmission electron microscopy showed that this drug, at 25 microgram/ml, reduced the number of parasitic foci by about 35% +/- standard deviation after 7 days of culture (P < 0.0001) and induced cell damage of both mature and immature spores and also other sporogonic and merogonic stages. In particular, an irregular outline of the cell shape and an abnormally condensed cytoplasm in meronts and sporonts were documented. Also, the polar tubule and the polaroplast membranes appeared disarrayed in the sporoblast stage. The spore wall showed an enlarged endospore and delaminated exospore. Mature spores had a complete cytoplasmic disorganization and a swollen and delaminated cell wall. No ultrastructural cell damage was observed in uninfected control cultures treated with the drug.
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Affiliation(s)
- E Bigliardi
- Department of Evolutionary Biology, University of Siena, Pavia, Italy
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Yücesoy M, Oktem IM, Gülay Z. In-vitro synergistic effect of fluconazole with nonsteroidal anti-inflammatory agents against Candida albicans strains. J Chemother 2000; 12:385-9. [PMID: 11128557 DOI: 10.1179/joc.2000.12.5.385] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
Abstract
The in-vitro interaction and synergistic activity of the combination of fluconazole with some nonsteroidal anti-inflammatory drugs (sodium salicylate, piroxicam, tenoxicam and diclofenac sodium) were investigated in Candida albicans strains (n=7) by the microdilution checkerboard assay. The results were evaluated visually and by a spectrophotometric microplate reader at 492 nm wavelength. Fractional inhibitory index was calculated for every strain and combination according to the minimal inhibitory concentration (MICs). The combination of fluconazole with sodium salicylate, tenoxicam and diclofenac sodium showed synergy against 5, 5 and 3 of the C. albicans strains, respectively. The effect of fluconazole with piroxicam was synergistic against one strain but indifferent/additive against the others. These data suggest that combinations of sodium salicylate, tenoxicam and diclofenac sodium with fluconazole may prove to be useful as chemotherapeutic agents for the treatment of C. albicans infections caused by especially fluconazole-resistant strains. However, additional preclinical work and in vivo studies are necessary to determine their definite clinical use.
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Affiliation(s)
- M Yücesoy
- Dokuz Eylül University, School of Medicine, Department of Microbiology and Clinical Microbiology, Izmir, Turkey.
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Stevens DA. Drug interaction studies of a glucan synthase inhibitor (LY 303366) and a chitin synthase inhibitor (Nikkomycin Z) for inhibition and killing of fungal pathogens. Antimicrob Agents Chemother 2000; 44:2547-8. [PMID: 10952614 PMCID: PMC90104 DOI: 10.1128/aac.44.9.2547-2548.2000] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The interaction between inhibitors of components of the fungal cell wall, glucan and chitin, was studied in vitro with the respective synthase enzyme inhibitors LY 303366 and nikkomycin Z. With Aspergillus fumigatus synergy was noted for inhibition and killing, and synergistic activity was also noted for some isolates of other species presently regarded as difficult to treat.
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Affiliation(s)
- D A Stevens
- Division of Infectious Diseases, Department of Medicine, Santa Clara Valley Medical Center, and California Institute for Medical Research, San Jose, California 95128, USA.
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Múcková M, Bujdáková H, Kuchta T. Synergy between 6-amino-2-n-pentylthiobenzothiazole and ergosterol biosynthesis-inhibiting antimycotics against Candida albicans in vitro. Int J Antimicrob Agents 2000; 15:153-4. [PMID: 10854813 DOI: 10.1016/s0924-8579(00)00160-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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Chiou CC, Groll AH, Walsh TJ. New drugs and novel targets for treatment of invasive fungal infections in patients with cancer. Oncologist 2000; 5:120-35. [PMID: 10794803 DOI: 10.1634/theoncologist.5-2-120] [Citation(s) in RCA: 86] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Invasive fungal infections have emerged as important causes of morbidity and mortality in profoundly immunocompromised patients with cancer. Current treatment strategies for these infections are limited by antifungal resistance, toxicity, drug interactions, and expense. In order to overcome these limitations, new antifungal compounds are being developed, which may improve our therapeutic armamentarium for prevention and treatment of invasive mycoses in high-risk patients with neoplastic diseases.
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Affiliation(s)
- C C Chiou
- National Cancer Institute, Bethesda, Maryland, USA
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Li RK, Rinaldi MG. In vitro antifungal activity of nikkomycin Z in combination with fluconazole or itraconazole. Antimicrob Agents Chemother 1999; 43:1401-5. [PMID: 10348760 PMCID: PMC89286 DOI: 10.1128/aac.43.6.1401] [Citation(s) in RCA: 88] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Nikkomycins are nucleoside-peptide antibiotics produced by Streptomyces species with antifungal activities through the inhibition of chitin synthesis. We investigated the antifungal activities of nikkomycin Z alone and in combination with fluconazole and itraconazole. Checkerboard synergy studies were carried out by a macrobroth dilution procedure with RPMI 1640 medium at pH 6.0. At least 10 strains of the following fungi were tested: Candida albicans, other Candida spp., Cryptococcus neoformans, Coccidioides immitis, Aspergillus spp., and dematiacious fungi (including Exophiala jeanselmei, Exophiala spinifera, Bipolaris spicifera, Wangiella dermatitidis, Ochroconis humicola, Phaeoannellomyces werneckii, and Cladophialophora bantiana), and 2 strains each of Fusarium, Scedosporium, Paecilomyces, Penicillium, and Trichoderma spp. A total of 110 isolates were examined. Inocula of fungal elements were standardized by hemacytometer counting or spectrophotometrically. MICs and minimum lethal concentrations (MLCs) were determined visually by comparison of growth in drug-treated tubes with growth in drug-free control tubes. Additive and synergistic interactions between nikkomycin and either fluconazole or itraconazole were observed against C. albicans, Candida parapsilosis, Cryptococcus neoformans, and Coccidioides immitis. Marked synergism was also observed between nikkomycin and itraconazole against Aspergillus fumigatus and Aspergillus flavus. No antagonistic interaction between the drugs was observed with any of the strains tested.
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Affiliation(s)
- R K Li
- Department of Pathology, The University of Texas Health Science Center at San Antonio, San Antonio, Texas 28284, USA.
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De Lucca AJ, Walsh TJ. Antifungal peptides: novel therapeutic compounds against emerging pathogens. Antimicrob Agents Chemother 1999; 43:1-11. [PMID: 9869556 PMCID: PMC89011 DOI: 10.1128/aac.43.1.1] [Citation(s) in RCA: 212] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Affiliation(s)
- A J De Lucca
- Southern Regional Research Center, Agricultural Research Service, U. S. Department of Agriculture, New Orleans, Louisiana 70124, USA.
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Graybill JR, Najvar LK, Bocanegra R, Hector RF, Luther MF. Efficacy of nikkomycin Z in the treatment of murine histoplasmosis. Antimicrob Agents Chemother 1998; 42:2371-4. [PMID: 9736565 PMCID: PMC105835 DOI: 10.1128/aac.42.9.2371] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Immune-competent ICR and BALB/c athymic (nude) mice were infected intravenously with Histoplasma capsulatum and treated with either fluconazole or nikkomycin Z or 5% dextrose (controls). In immune-competent ICR mice, fluconazole and nikkomycin Z both prolonged survival when given at 5 mg/kg of body weight twice daily. When administered in doses as low as 2.5 mg/kg twice daily, nikkomycin Z reduced fungal counts in both the spleen and liver. When both drugs were combined, there was no antagonism, and in combined therapy spleen and liver counts were reduced more than for either drug alone. However, nikkomycin Z had no effect on brain fungal burden. In nude mice fluconazole and nikkomycin Z had an additive effect in prolongation of survival and reduction of liver and spleen burden. Nikkomycin Z is well tolerated, is at least as effective as fluconazole, and may interact beneficially with fluconazole for treatment of murine histoplasmosis.
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Affiliation(s)
- J R Graybill
- Audie Murphy Memorial Veterans Hospital, San Antonio, Texas 78284, USA
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23
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Zwolińska-Wcisło M, Budak A, Trojanowska D, Bogdał J, Stachura J. Fungal colonization of the stomach and its clinical relevance. Mycoses 1998; 41:327-34. [PMID: 9861839 DOI: 10.1111/j.1439-0507.1998.tb00346.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The aim of this study was to estimate the frequency of fungal colonization of the stomach of patients suffering from gastric ulcer (GU) and chronic gastritis (CG) and the influence of fungal colonization of the stomach on the process of ulcer healing. We investigated 293 patients aged 20-80 years. Before and after 4 weeks of sucralfate treatment they underwent endoscopy of the stomach, histological examination of biopsies taken from the ulcer margin or inflamed gastric mucosa and mycological examinations of the gastric juice, surface brushing and biopsies. The studies revealed a high concentration of fungi in 54.2% patients with GU and 10.3% with CG. Candida albicans was the most frequently isolated organism. Fungal colonization of the stomach impairs the process of gastric ulcer healing. Control examination after 4 weeks of sucralfate therapy showed the ratio of GU healing in 62% of patients with a high concentration of fungi in comparison with 78% of patients not colonized with fungi (P < 0.05). A significantly longer duration of ulcer symptoms in the group of patients with a high concentration of fungi in the stomach was also observed. There was no correlation between the level of fungal antibodies, of Candida antigen in the serum and the concentration of fungi in the stomach.
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Affiliation(s)
- M Zwolińska-Wcisło
- Department of Gastroenterology, Collegium Medicum, Jagiellonian University, Kraków, Poland
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24
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Buurman ET, Westwater C, Hube B, Brown AJ, Odds FC, Gow NA. Molecular analysis of CaMnt1p, a mannosyl transferase important for adhesion and virulence of Candida albicans. Proc Natl Acad Sci U S A 1998; 95:7670-5. [PMID: 9636208 PMCID: PMC22718 DOI: 10.1073/pnas.95.13.7670] [Citation(s) in RCA: 114] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/1998] [Accepted: 04/06/1998] [Indexed: 02/07/2023] Open
Abstract
There is an immediate need for identification of new antifungal targets in opportunistic pathogenic fungi like Candida albicans. In the past, efforts have focused on synthesis of chitin and glucan, which confer mechanical strength and rigidity upon the cell wall. This paper describes the molecular analysis of CaMNT1, a gene involved in synthesis of mannoproteins, the third major class of macromolecule found in the cell wall. CaMNT1 encodes an alpha-1, 2-mannosyl transferase, which adds the second mannose residue in a tri-mannose oligosaccharide structure which represents O-linked mannan in C. albicans. The deduced amino acid sequence suggests that CaMnt1p is a type II membrane protein residing in a medial Golgi compartment. The absence of CaMnt1p reduced the ability of C. albicans cells to adhere to each other, to human buccal epithelial cells, and to rat vaginal epithelial cells. Both heterozygous and homozygous Camnt1 null mutants of C. albicans showed strong attenuation of virulence in guinea pig and mouse models of systemic candidosis, which, in guinea pigs, could be attributed to a decreased ability to reach and/or adhere internal organs. Therefore, correct CaMnt1p-mediated O-linked mannosylation of proteins is critical for adhesion and virulence of C. albicans.
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Affiliation(s)
- E T Buurman
- Department of Molecular and Cell Biology, Institute of Medical Sciences, University of Aberdeen, Foresterhill, Aberdeen AB25 2ZD, United Kingdom
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25
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Groll AH, Piscitelli SC, Walsh TJ. Clinical pharmacology of systemic antifungal agents: a comprehensive review of agents in clinical use, current investigational compounds, and putative targets for antifungal drug development. ADVANCES IN PHARMACOLOGY (SAN DIEGO, CALIF.) 1998; 44:343-500. [PMID: 9547888 DOI: 10.1016/s1054-3589(08)60129-5] [Citation(s) in RCA: 288] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Affiliation(s)
- A H Groll
- Immunocompromised Host Section, National Cancer Institute, National Institutes of Health, Bethesda, Maryland 20892, USA
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26
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Henderson DP, Shelton MC, Cotterill IC, Toone EJ. Stereospecific Preparation of the N-Terminal Amino Acid Moiety of Nikkomycins K(X) and K(Z) via a Multiple Enzyme Synthesis. J Org Chem 1997; 62:7910-7911. [PMID: 11671888 DOI: 10.1021/jo971549s] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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27
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Alexander BD, Perfect JR. Antifungal resistance trends towards the year 2000. Implications for therapy and new approaches. Drugs 1997; 54:657-78. [PMID: 9360056 DOI: 10.2165/00003495-199754050-00002] [Citation(s) in RCA: 116] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Medical advances have led to increased numbers of immunocompromised patients living longer. Coinciding with this increase in the immunocompromised patient population is an increase in the number of clinically significant fungal infections. Unfortunately, widespread use of the limited numbers of antifungal agents to treat these infections has led to the development of drug resistance. Thus, in an attempt to sort out the mechanisms of resistance for each of the systemically useful antifungal agents, a comprehensive review of the literature has been carried out. The most common mechanisms for the development of resistance involve changes in the enzymatic pathways which serve as the drug targets. For instance, changes in enzymes responsible for the biosynthesis of ergosterol, the target of azole activity, lead to azole resistance. Another common mechanism used by fungi to avoid drug toxicity includes reduced intracellular accumulation of the drug through both decreased permeability and energy-dependent efflux pumps. Using our current understanding of the mechanisms of drug resistance as a template, several strategies to overcome resistance have been identified. These include improvement of host immune function, the use of adjuvant surgery, the development of new drug delivery systems for currently available drugs and the development of new classes of antifungal agents. Also, clinical trials to establish appropriate drug doses and duration of therapy are needed, as well as the benefits of antifungal prophylaxis explored and the use of combination therapies entertained. The war against drug resistant fungi has been identified as we approach the year 2000. With careful and cogent investigations, we do have the tools to fight back against these opportunists. Of all the strategies reviewed, however, in our opinion, the development of new antifungal drugs is likely to have the most significant future impact on our management of drug resistance in fungal infections.
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Affiliation(s)
- B D Alexander
- Division of Infectious Diseases, Duke University Medical Center, Durham, North Carolina, USA
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Clemons KV, Stevens DA. Efficacy of nikkomycin Z against experimental pulmonary blastomycosis. Antimicrob Agents Chemother 1997; 41:2026-8. [PMID: 9303408 PMCID: PMC164059 DOI: 10.1128/aac.41.9.2026] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Nikkomycin Z is a chitin synthetase inhibitor. In vitro, nikkomycin Z had good activity against Blastomyces dermatitidis, with an MIC of 0.78 microg/ml and a minimal fungicidal concentration of 3.1 microg/ml. The efficacies of various treatment durations (3, 5, or 10 days) and doses (200, 400, or 1,000 mg/kg of body weight) of nikkomycin Z given twice daily were compared with those of itraconazole at 200 mg/kg given twice daily and amphotericin B at 6.25 mg/kg in a murine model of pulmonary blastomycosis. All treatments prolonged survival compared with untreated controls (P < 0.05 to 0.01); 100% survival was achieved with 5 or 10 days of any nikkomycin Z dose or with amphotericin B. Amphotericin B and nikkomycin Z, but not itraconazole, reduced infection compared with controls. Amphotericin B and the 10-day regimens of all nikkomycin Z doses were equivalent and superior to itraconazole or nikkomycin Z for < or = 5 days at any dose (P < 0.05 to 0.01). Increased duration and/or dosage improved the efficacy of nikkomycin Z, with 10 days of each dose curing 50 to 90% of the animals. Only a 1,000-mg/kg/day dose of nikkomycin Z was curative when treatment lasted less than 10 days. In contrast, itraconazole cured no mice, while amphotericin B cured all mice. Based on the total amount of drug given, amphotericin B was estimated to be 32 times as active as nikkomycin Z and nikkomycin Z was estimated to be 3 times as active as itraconazole. Overall, nikkomycin Z given orally was well tolerated, had good activity against blastomycosis, and could result in biological cure, thus producing results equivalent to those of parenteral amphotericin B.
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Affiliation(s)
- K V Clemons
- California Institute for Medical Research, Department of Medicine, Santa Clara Valley Medical Center, San Jose, California 95128, USA.
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Graybill JR, Burgess DS, Hardin TC. Key issues concerning fungistatic versus fungicidal drugs. Eur J Clin Microbiol Infect Dis 1997; 16:42-50. [PMID: 9063673 DOI: 10.1007/bf01575120] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Are there any fungicidal drugs available today? A critical issue in answering this question is that of definition. The simplest, most stringent definitions identify fungistatic drugs as those that inhibit growth, whereas fungicidal drugs kill fungal pathogens. The immunocompetent host is usually far better equipped to eliminate fungal pathogens than the immunosuppressed host. Therefore, it would be especially desirable to have a truly fungicidal drug, one that absolutely kills and fungi, as a treatment option for the immunosuppressed patient. The critical question would be whether a fungicidal drug can be delivered to the target site in a concentration high enough for a sufficient time to reduce the intralesional fungal counts to zero. By this simple definition, there are no fungicidal drugs available today. However, an accepted alternative definition is that often used by the bacteriologist: Fungicidal drugs are those that lead to a reduction of 99.9% of the initial inocula. Although this less restrictive in vitro standard is more easily met, it has serious limitations. Whether the 99.9% kill should be an acceptable standard remains uncertain. As an alternative, the minimum inhibitory concentration, though indicating static activity, has served well; perhaps it should be the only information reported for fungal susceptibility testing.
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Affiliation(s)
- J R Graybill
- Department of Medicine, University of Texas Health Science Center at San Antonio 78284, USA
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30
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Georgopapadakou NH, Walsh TJ. Antifungal agents: chemotherapeutic targets and immunologic strategies. Antimicrob Agents Chemother 1996; 40:279-91. [PMID: 8834867 PMCID: PMC163103 DOI: 10.1128/aac.40.2.279] [Citation(s) in RCA: 330] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Affiliation(s)
- N H Georgopapadakou
- Department of Oncology, Roche Research Center, Nutley, New Jersey 07110, USA
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31
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Tariq VN, Scott EM, McCain NE. Use of decimal assay for additivity to demonstrate synergy in pair combinations of econazole, nikkomycin Z, and ibuprofen against Candida albicans in vitro. Antimicrob Agents Chemother 1995; 39:2615-9. [PMID: 8592989 PMCID: PMC162999 DOI: 10.1128/aac.39.12.2615] [Citation(s) in RCA: 27] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
Interactions between six compounds (econazole, miconazole, amphotericin B, nystatin, nikkomycin Z, and ibuprofen) were investigated for their antifungal activities against Candida albicans by using pair combinations in an in vitro decimal assay for additivity based on disk diffusion. Additive interactions were observed between miconazole and econazole, amphotericin B and nystatin, and amphotericin B and ibuprofen, while an antagonistic interaction was observed between econazole and amphotericin B. Synergistic interactions were recorded for the combinations of econazole and ibuprofen, econazole and nikkomycin Z, and ibuprofen and nikkomycin Z.
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Affiliation(s)
- V N Tariq
- School of Biology and Biochemistry, Queen's University of Belfast, Northern Ireland, United Kingdom
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32
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Nakajima R, Kitamura A, Someya K, Tanaka M, Sato K. In vitro and in vivo antifungal activities of DU-6859a, a fluoroquinolone, in combination with amphotericin B and fluconazole against pathogenic fungi. Antimicrob Agents Chemother 1995; 39:1517-21. [PMID: 7492096 PMCID: PMC162773 DOI: 10.1128/aac.39.7.1517] [Citation(s) in RCA: 46] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
DU-6859a is an investigational fluoroquinolone agent with potent bactericidal activity, but by itself it has no antifungal activity. When combined with amphotericin B (AmB), however, DU-6859a clearly enhanced the in vitro antifungal activity of AmB against Candida albicans, Candida tropicalis, Candida krusei, Candida glabrata, and Cryptococcus neoformans in microdilution checkerboard studies. Positive interactions of DU-6859a with AmB against Aspergillus fumigatus were dependent on the medium used; yeast nitrogen base supplemented with amino acids, ammonium sulfate, and 1% glucose was better for demonstrating synergism, while in RPMI 1640 medium, unexpected antagonism between the drugs occurred against three of the strains tested. In combination with fluconazole (Flu), DU-6859a increased the activity of Flu against C. albicans both in synthetic amino acid medium fungal and in supplemented yeast nitrogen base. An in vitro time-kill study revealed that DU-6859a combined with AmB significantly suppressed the regrowth of C. albicans compared with the suppression brought about by AmB used alone in a concentration-dependent fashion. Furthermore, in a model of C. albicans infection in mice, the fungal load in infected kidneys was significantly less in mice given the combination treatment of DU-6859a plus either AmB or Flu, and thus, the combination treatment resulted in prolonged survival of infected mice compared with treatment with either antifungal alone. The prolonged survival in mice given the combined treatment was also observed in mice with A. fumigatus infection, indicating that DU-6859a potentiated the actions of the antifungal agents in vivo as well as in vitro.
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Affiliation(s)
- R Nakajima
- Exploratory Research Laboratories I, Daiichi Pharmaceutical Co., Ltd., Tokyo, Japan
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Graybill JR. Antifungal drugs and resistance. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 1995; 390:217-34. [PMID: 8718616 DOI: 10.1007/978-1-4757-9203-4_19] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Affiliation(s)
- J R Graybill
- Department of Medicine, Audie Murphy V.A. Hospital, San Antonio, TX, USA
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35
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el-Sherbeini M, Clemas JA. Nikkomycin Z supersensitivity of an echinocandin-resistant mutant of Saccharomyces cerevisiae. Antimicrob Agents Chemother 1995; 39:200-7. [PMID: 7695307 PMCID: PMC162509 DOI: 10.1128/aac.39.1.200] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Echinocandins and nikkomycins are antibiotics that inhibit the synthesis of the essential cell wall polysaccharide polymers 1,3-beta-glucan and chitin, respectively. Some 40 echinocandin-resistant Saccharomyces cerevisiae mutants were isolated and assigned to five complementation groups. Four complementation groups contained mutants with 38 recessive mutations. The fifth complementation group comprised mutants with one dominant mutation, etg1-3 (strain MS10), and one semidominant mutation, etg1-4 (strain MS14). MS10 and MS14 are resistant to the semisynthetic pneumocandin B, L-733,560, and to aculeacin A but not to papulacandin. In addition, microsomal membranes of both mutant strains contain 1,3-beta-glucan synthase activity that is resistant to L-733,560 but not to papulacandin. Furthermore, MS14 is also supersensitive to nikkomycin Z. The echinocandin resistance and the nikkomycin Z supersensitivity of MS14 cosegregated in genetic crosses. The wild-type gene (designated ETG1 [C. Douglas, J. A. Marrinan, and M. B. Kurtz, J. Bacteriol. 176:5686-5696, 1994, and C. Douglas, F. Foor, J. A. Marrinan, N. Morin, J. B. Nielsen, A. Dahl, P. Mazur, W. Baginsky, W. Li, M. El-Sherbeini, J. A. Clemas, S. Mandala, B. R. Frommer, and M. B. Kurtz, Proc. Natl. Acad. Sci. USA, in press]) was isolated from a genomic library in the plasmid YCp50 by functional complementation of the nikkomycin Z supersensitivity phenotype. The cloned DNA also partially complements the echinocandin resistance phenotype, indicating that the two phenotypes are due to single mutations. The existence of a single mutation, in MS14, simultaneously affecting sensitivity to a glucan synthase inhibitor and a chitin synthase inhibitor implies a possible interaction between the two polymers at the cell surface.
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Affiliation(s)
- M el-Sherbeini
- Microbial Chemotherapeutics and Molecular Genetics, Merck Research Laboratories, Rahway, New Jersey 07065
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37
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Affiliation(s)
- J W Payne
- School of Biological Sciences, University of Wales, UK
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38
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Abstract
A number of substances that directly or indirectly affect the cell walls of fungi have been identified. Those that actively interfere with the synthesis or degradation of polysaccharide components share the property of being produced by soil microbes as secondary metabolites. Compounds specifically interfering with chitin or beta-glucan synthesis have proven effective in studies of preclinical models of mycoses, though they appear to have a restricted spectrum of coverage. Semisynthetic derivatives of some of the natural products have offered improvements in activity, toxicology, or pharmacokinetic behavior. Compounds which act on the cell wall indirectly or by a secondary mechanism of action, such as the azoles, act against diverse fungi but are usually fungistatic in nature. Overall, these compounds are attractive candidates for further development.
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Affiliation(s)
- R F Hector
- Cutter Biological, Berkeley, California 94710
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