51
|
Wang WX, Lei X, Ai HL, Bai X, Li J, He J, Li ZH, Zheng YS, Feng T, Liu JK. Cytochalasans from the Endophytic Fungus Xylaria cf. curta with Resistance Reversal Activity against Fluconazole-Resistant Candida albicans. Org Lett 2019; 21:1108-1111. [DOI: 10.1021/acs.orglett.9b00015] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Wen-Xuan Wang
- School of Pharmaceutical Sciences, South-Central University for Nationalities, Wuhan, Hubei 430074, P.R. China
| | - Xinxiang Lei
- School of Pharmaceutical Sciences, South-Central University for Nationalities, Wuhan, Hubei 430074, P.R. China
| | - Hong-Lian Ai
- School of Pharmaceutical Sciences, South-Central University for Nationalities, Wuhan, Hubei 430074, P.R. China
| | - Xue Bai
- Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650204, P.R. China
| | - Jing Li
- School of Pharmaceutical Sciences, South-Central University for Nationalities, Wuhan, Hubei 430074, P.R. China
| | - Juan He
- School of Pharmaceutical Sciences, South-Central University for Nationalities, Wuhan, Hubei 430074, P.R. China
| | - Zheng-Hui Li
- School of Pharmaceutical Sciences, South-Central University for Nationalities, Wuhan, Hubei 430074, P.R. China
| | - Yong-Sheng Zheng
- School of Pharmaceutical Sciences, South-Central University for Nationalities, Wuhan, Hubei 430074, P.R. China
| | - Tao Feng
- School of Pharmaceutical Sciences, South-Central University for Nationalities, Wuhan, Hubei 430074, P.R. China
| | - Ji-Kai Liu
- School of Pharmaceutical Sciences, South-Central University for Nationalities, Wuhan, Hubei 430074, P.R. China
| |
Collapse
|
52
|
Zhang J, Li L, Lv Q, Yan L, Wang Y, Jiang Y. The Fungal CYP51s: Their Functions, Structures, Related Drug Resistance, and Inhibitors. Front Microbiol 2019; 10:691. [PMID: 31068906 PMCID: PMC6491756 DOI: 10.3389/fmicb.2019.00691] [Citation(s) in RCA: 104] [Impact Index Per Article: 20.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2018] [Accepted: 03/19/2019] [Indexed: 12/18/2022] Open
Abstract
CYP51 (Erg11) belongs to the cytochrome P450 monooxygenase (CYP) superfamily and mediates a crucial step of the synthesis of ergosterol, which is a fungal-specific sterol. It is also the target of azole drugs in clinical practice. In recent years, researches on fungal CYP51 have stepped into a new stage attributing to the discovery of crystal structures of the homologs in Candida albicans, Cryptococcus neoformans and Aspergillus fumigatus. This review summarizes the functions, structures of fungal CYP51 proteins, and the inhibitors targeting these homologs. In particular, several drug-resistant mechanisms associated with the fungal CYP51s are introduced. The sequences and crystal structures of CYP51 proteins in different fungal species are also compared. These will provide new insights for the advancement of research on antifungal agents.
Collapse
Affiliation(s)
- Jingxiang Zhang
- Center for New Drug Research, School of Pharmacy, Second Military Medical University, Shanghai, China
| | - Liping Li
- Shanghai Tenth People’s Hospital, Tongji University School of Medicine, Shanghai, China
- Department of Pharmacology, Tongji University School of Medicine, Shanghai, China
| | - Quanzhen Lv
- Center for New Drug Research, School of Pharmacy, Second Military Medical University, Shanghai, China
| | - Lan Yan
- Center for New Drug Research, School of Pharmacy, Second Military Medical University, Shanghai, China
- *Correspondence: Lan Yan, Yan Wang, Yuanying Jiang,
| | - Yan Wang
- Center for New Drug Research, School of Pharmacy, Second Military Medical University, Shanghai, China
- *Correspondence: Lan Yan, Yan Wang, Yuanying Jiang,
| | - Yuanying Jiang
- Center for New Drug Research, School of Pharmacy, Second Military Medical University, Shanghai, China
- Shanghai Tenth People’s Hospital, Tongji University School of Medicine, Shanghai, China
- Department of Pharmacology, Tongji University School of Medicine, Shanghai, China
- *Correspondence: Lan Yan, Yan Wang, Yuanying Jiang,
| |
Collapse
|
53
|
Azole Resistance Reduces Susceptibility to the Tetrazole Antifungal VT-1161. Antimicrob Agents Chemother 2018; 63:AAC.02114-18. [PMID: 30397057 DOI: 10.1128/aac.02114-18] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2018] [Accepted: 10/29/2018] [Indexed: 01/07/2023] Open
Abstract
Tetrazole antifungals designed to target fungal lanosterol 14α-demethylase (LDM) appear to be effective against a range of fungal pathogens. In addition, a crystal structure of the catalytic domain of Candida albicans LDM in complex with the tetrazole VT-1161 has been obtained. We have addressed concern about artifacts that might arise from crystallizing VT-1161 with truncated recombinant CYP51s and measured the impact on VT-1161 susceptibility of genotypes known to confer azole resistance. A yeast system was used to overexpress recombinant full-length Saccharomyces cerevisiae LDM with a C-terminal hexahistidine tag (ScLDM6×His) for phenotypic analysis and crystallographic studies with VT-1161 or with the widely used triazole drug posaconazole (PCZ). We determined the effect of characterized mutations in LDM on VT-1161 activity and identified drug efflux pumps from fungi, including key fungal pathogens, that efflux VT-1161. The relevance of these yeast-based observations on drug efflux was verified using clinical isolates of C. albicans and Candida glabrata VT-1161 binding elicits a significant conformational difference between the full-length and truncated enzymes not found when posaconazole is bound. Susceptibility to VT-1161 is reduced by ATP-binding cassette (ABC) and major facilitator superfamily (MFS) drug efflux pumps, the overexpression of LDM, and mutations within the drug binding pocket of LDM that affect interaction with the tertiary alcohol of the drug.
Collapse
|
54
|
Lepesheva GI, Friggeri L, Waterman MR. CYP51 as drug targets for fungi and protozoan parasites: past, present and future. Parasitology 2018; 145:1820-1836. [PMID: 29642960 PMCID: PMC6185833 DOI: 10.1017/s0031182018000562] [Citation(s) in RCA: 75] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
The efficiency of treatment of human infections with the unicellular eukaryotic pathogens such as fungi and protozoa remains deeply unsatisfactory. For example, the mortality rates from nosocomial fungemia in critically ill, immunosuppressed or post-cancer patients often exceed 50%. A set of six systemic clinical azoles [sterol 14α-demethylase (CYP51) inhibitors] represents the first-line antifungal treatment. All these drugs were discovered empirically, by monitoring their effects on fungal cell growth, though it had been proven that they kill fungal cells by blocking the biosynthesis of ergosterol in fungi at the stage of 14α-demethylation of the sterol nucleus. This review briefs the history of antifungal azoles, outlines the situation with the current clinical azole-based drugs, describes the attempts of their repurposing for treatment of human infections with the protozoan parasites that, similar to fungi, also produce endogenous sterols, and discusses the most recently acquired knowledge on the CYP51 structure/function and inhibition. It is our belief that this information should be helpful in shifting from the traditional phenotypic screening to the actual target-driven drug discovery paradigm, which will rationalize and substantially accelerate the development of new, more efficient and pathogen-oriented CYP51 inhibitors.
Collapse
Affiliation(s)
- Galina I. Lepesheva
- Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, Tennessee 37232, USA
| | - Laura Friggeri
- Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, Tennessee 37232, USA
| | - Michael R. Waterman
- Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, Tennessee 37232, USA
| |
Collapse
|
55
|
A Hyperactive Form of the Zinc Cluster Transcription Factor Stb5 Causes YOR1 Overexpression and Beauvericin Resistance in Candida albicans. Antimicrob Agents Chemother 2018; 62:AAC.01655-18. [PMID: 30249688 DOI: 10.1128/aac.01655-18] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2018] [Accepted: 09/14/2018] [Indexed: 11/20/2022] Open
Abstract
Gain-of-function mutations in the zinc cluster transcription factors Mrr1, Tac1, and Upc2, which result in constitutive overexpression of their target genes, are a frequent cause of fluconazole resistance in the pathogenic yeast Candida albicans In this study, we show that an activated form of another zinc cluster transcription factor, Stb5, confers resistance to the natural compound beauvericin via the overexpression of YOR1, encoding an efflux pump of the ATP-binding cassette transporter superfamily. Beauvericin was recently shown to potentiate the activity of azole drugs against C. albicans Although Yor1 did not contribute to fluconazole resistance when C. albicans cells were treated with the drug alone, Stb5-mediated YOR1 overexpression diminished the synergistic effect of the fluconazole-beauvericin combination, thereby enhancing fluconazole resistance in beauvericin-treated C. albicans cells. Stb5-mediated YOR1 overexpression also suppressed the inhibition of hyphal growth, an important virulence trait of C. albicans, by beauvericin. Therefore, activating mutations in Stb5, which result in constitutive YOR1 overexpression, may enable C. albicans to acquire resistance to beauvericin and thereby overcome both the sensitization to azole drugs and the inhibition of morphogenesis caused by this compound.
Collapse
|
56
|
Manohar K, Peroumal D, Acharya N. TLS dependent and independent functions of DNA polymerase eta (Polη/Rad30) from Pathogenic Yeast Candida albicans. Mol Microbiol 2018; 110:707-727. [PMID: 29907984 DOI: 10.1111/mmi.14004] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2018] [Revised: 06/03/2018] [Accepted: 06/06/2018] [Indexed: 02/06/2023]
Abstract
Polη, a unique TLS DNA polymerase that promotes efficient bypass of UV-induced CPDs and cisplatin adducts, has not been explored in Candida species yet. Here, we show that CaPolη plays a vital role in protecting Candida albicans genome from diverse array of DNA damaging agents, not limited to UV and cisplatin. Polη deficient strain did not exhibit any hyphal development in the presence of UV and cisplatin while the wild type strain profusely developed DNA damage induced filamentation. The polarized growth induced by HU and MMS was found to be Polη independent. No common regulatory pathway of morphogenesis operates in C. albicans due to genomic stress, rather Polη branches away from RAD53 dependent pathway to be specific to UV/cisplatin. Interestingly, serum that does not inflict any DNA damage also induces hyphal growth in C. albicans, and requires a functionally active Polη. Importantly, deletion of RAD30 sensitized the strain to amphotericin B; but its presence resulted in azole drug tolerance only in DNA damaging conditions. We suggest that the roles of CaPolη in genome stability and genotoxins induced filamentation are due to its TLS activities; whereas its TLS independent functions play a vital role in serum induced morphogenesis and amphotericin B resistance.
Collapse
Affiliation(s)
- Kodavati Manohar
- Laboratory of Genomic Instability and Diseases, Department of Infectious Disease Biology, Institute of Life Sciences, Bhubaneswar, India
| | - Doureradjou Peroumal
- Laboratory of Genomic Instability and Diseases, Department of Infectious Disease Biology, Institute of Life Sciences, Bhubaneswar, India
| | - Narottam Acharya
- Laboratory of Genomic Instability and Diseases, Department of Infectious Disease Biology, Institute of Life Sciences, Bhubaneswar, India
| |
Collapse
|
57
|
Ochiai A, Ogawa K, Fukuda M, Ohori M, Kanaoka T, Tanaka T, Taniguchi M, Sagehashi Y. Rice Defensin OsAFP1 is a New Drug Candidate against Human Pathogenic Fungi. Sci Rep 2018; 8:11434. [PMID: 30061724 PMCID: PMC6065317 DOI: 10.1038/s41598-018-29715-w] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2018] [Accepted: 07/17/2018] [Indexed: 12/28/2022] Open
Abstract
Fungal infections, such as candidiasis and aspergillosis, are some of the most frequent infections in humans. Although antifungal drugs are available for the treatment of these infections, antifungal agents with new mechanisms of action should be developed because of the increasing incidence of drug-resistant pathogens in recent years. In this study, a basic functional analysis of rice defensin OsAFP1, a novel antifungal drug candidate, was conducted. OsAFP1 exerted fungicidal activity against Candida albicans, the most common pathogenic fungus in humans, at 4 μM concentration, but it did not inhibit the growth of human pathogenic bacteria. In addition, OsAFP1 retained structural stability after heat treatment at 100 °C for 10 min and after serum treatment at 37 °C for 24 h. A propidium iodide (PI) uptake assay and mutational analysis revealed that amino acid residues within the C-terminal γ-core motif of OsAFP1, particularly Leu-39 and Lys-41, play an important role in its antifungal activity. Further, PI uptake and apoptosis assays suggested that OsAFP1 exerts its antifungal activity by inducing apoptosis of target cells. Immunohistochemistry showed that the OsAFP1 target molecule was located in the cell wall. These findings indicate that OsAFP1 may be developed into a potent antifungal drug.
Collapse
Affiliation(s)
- Akihito Ochiai
- Department of Materials Science and Technology, Faculty of Engineering, Niigata University, Niigata, Japan.
| | - Kodai Ogawa
- Department of Materials Science and Technology, Faculty of Engineering, Niigata University, Niigata, Japan
| | - Minami Fukuda
- Department of Materials Science and Technology, Faculty of Engineering, Niigata University, Niigata, Japan
| | - Masahiro Ohori
- Department of Materials Science and Technology, Faculty of Engineering, Niigata University, Niigata, Japan
| | - Takumi Kanaoka
- Department of Materials Science and Technology, Faculty of Engineering, Niigata University, Niigata, Japan
| | - Takaaki Tanaka
- Department of Materials Science and Technology, Faculty of Engineering, Niigata University, Niigata, Japan
| | - Masayuki Taniguchi
- Department of Materials Science and Technology, Faculty of Engineering, Niigata University, Niigata, Japan
| | - Yoshiyuki Sagehashi
- Hokkaido Agricultural Research Center, National Agriculture and Food Research Organization (NARO), Hokkaido, Japan.
| |
Collapse
|
58
|
Sobel JD, Sobel R. Current treatment options for vulvovaginal candidiasis caused by azole-resistant Candida species. Expert Opin Pharmacother 2018; 19:971-977. [PMID: 29932786 DOI: 10.1080/14656566.2018.1476490] [Citation(s) in RCA: 93] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
INTRODUCTION Clinicians are increasingly challenged by patients with refractory vulvovaginal candidiasis (VVC) caused by azole-resistant Candida species. Fluconazole resistant C.albicans is a growing and perplexing problem following years of indiscriminate drug prescription and unnecessary drug exposure and for which there are few therapeutic alternatives. Regrettably, although the azole class of drugs has expanded, new classes of antifungal drugs have not been forthcoming, limiting effective treatment options in patients with azole resistant Candida vaginitis. AREAS COVERED This review covers published data on epidemiology, pathophysiology and treatment options for women with azole-resistant refractory VVC. EXPERT OPINION Fluconazole resistant C.albicans adds to the challenge of azole resistant non-albicans Candida spp. Both issues follow years of indiscriminate drug prescription and unnecessary fluconazole exposure. Although an understanding of azole resistance in yeast has been established, this knowledge has not translated into useful therapeutic advantage. Treatment options for such women with refractory symptoms are extremely limited. New therapeutic options and strategies are urgently needed to meet this challenge of azole drug resistance.
Collapse
Affiliation(s)
- J D Sobel
- a Department of Internal Medicine , Wayne State University School of Medicine , Detroit , MI , USA
| | - R Sobel
- b Department of Obstetrics & Gynecology , Jefferson Medical College , Philadelphia , PA , USA
| |
Collapse
|
59
|
Panariello BHD, Klein MI, Mima EGDO, Pavarina AC. Fluconazole impacts the extracellular matrix of fluconazole-susceptible and -resistant Candida albicans and Candida glabrata biofilms. J Oral Microbiol 2018; 10:1476644. [PMID: 29887974 PMCID: PMC5990947 DOI: 10.1080/20002297.2018.1476644] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2018] [Accepted: 05/07/2018] [Indexed: 01/29/2023] Open
Abstract
Background: Fluconazole (FLZ) is a drug commonly used for the treatment of Candida infections. However, β-glucans in the extracellular matrices (ECMs) hinder FLZ penetration into Candida biofilms, while extracellular DNA (eDNA) contributes to the biofilm architecture and resistance. Methods: This study characterized biofilms of FLZ-sensitive (S) and -resistant (R) Candida albicans and Candida glabrata in the presence or absence of FLZ focusing on the ECM traits. Biofilms of C. albicans American Type Culture Collection (ATCC) 90028 (CaS), C. albicans ATCC 96901 (CaR), C. glabrata ATCC 2001 (CgS), and C. glabrata ATCC 200918 (CgR) were grown in RPMI medium with or without FLZ at 5× the minimum inhibitory concentration (37°C/48 h). Biofilms were assessed by colony-forming unit (CFU)/mL, biomass, and ECM components (alkali-soluble polysaccharides [ASP], water-soluble polysaccharides [WSP], eDNA, and proteins). Scanning electron microscopy (SEM) was also performed. Data were analyzed by parametric and nonparametric tests (α = 0.05). Results: In biofilms, FLZ reduced the CFU/mL of all strains (p < 0.001), except for CaS (p = 0.937). However, the ASP quantity in CaS was significantly reduced by FLZ (p = 0.034), while the drug had no effect on the ASP levels in other strains (p > 0.05). Total biomasses and WSP were significantly reduced by FLZ in the ECM of all yeasts (p < 0.001), but levels of eDNA and proteins were unaffected (p > 0.05). FLZ affected the cell morphology and biofilm structure by hindering hyphae formation in CaS and CaR biofilms, by decreasing the number of cells in CgS and CgR biofilms, and by yielding sparsely spaced cell agglomerates on the substrate. Conclusion: FLZ impacts biofilms of C. albicans and C. glabrata as evident by reduced biomass. This reduced biomass coincided with lowered cell numbers and quantity of WSPs. Hyphal production by C. albicans was also reduced.
Collapse
Affiliation(s)
- Beatriz Helena Dias Panariello
- Department of Cariology, Operative Dentistry and Dental Public Health, Indiana University- Purdue University Indianapolis, School of Dentistry, Indianapolis, IN, USA
| | - Marlise I Klein
- Department of Dental Materials and Prosthodontics, São Paulo State University (Unesp), School of Dentistry, Araraquara, São Paulo, Brazil
| | - Ewerton Garcia De Oliveira Mima
- Department of Dental Materials and Prosthodontics, São Paulo State University (Unesp), School of Dentistry, Araraquara, São Paulo, Brazil
| | - Ana Cláudia Pavarina
- Department of Dental Materials and Prosthodontics, São Paulo State University (Unesp), School of Dentistry, Araraquara, São Paulo, Brazil
| |
Collapse
|
60
|
dos Santos SB, Sabadin CES, Mario DN, Rigo L, Barbosa DA. Presence of Candida spp. and candidiasis in liver transplant patients. An Bras Dermatol 2018; 93:356-361. [PMID: 29924230 PMCID: PMC6001082 DOI: 10.1590/abd1806-4841.20186533] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2016] [Accepted: 03/16/2017] [Indexed: 11/22/2022] Open
Abstract
BACKGROUND Candidiasis is the most common opportunistic fungal infection of the oral cavity caused by fungi of the genus Candida and usually associated with immunosuppressed individuals. OBJECTIVES To evaluate the presence of oral candidiasis and identify the presence of Candida spp. in liver transplant recipients and assess the association between the presence of the fungus and sociodemographic variables, dietary habits and environmental exposure. METHODS A cross-sectional study was performed with 49 patients who had undergone liver transplants at Hospital São Vicente de Paulo in Passo Fundo - RS. Patient information was collected to obtain sociodemographic data, eating habits and environmental exposure. Fungal infections were screened by oral clinical examination and the presence of Candida spp by the collection of oral samples with a sterile swab, seeded in Sabouraud Dextrose Agar, incubated at 25°C and observed at 48 hours. To identify Candida albicans, the germ tube test was performed. RESULTS In 49 patient samples, 39% had the yeast of the genus Candida isolated and, of these patients, 12% had candidiasis, 66% of atrophic type and 34% pseudomembranous. Eleven yeast species were (58%) Candida non-albicans and eight (42%) Candida albicans. STUDY LIMITATIONS The present study presents as a limitation the inclusion of patients in different stages of immunosuppression. CONCLUSION The high incidence of Candida non-albicans in the oral cavity of transplant patients with a long period of transplantation is warning to a more effective control of the health of these individuals, especially those with older age.
Collapse
Affiliation(s)
| | | | - Débora Nunes Mario
- Department of Microbiology, Universidade Federal do Pampa
(Unipampa), Uruguaiana (RS), Brazil
| | - Lilian Rigo
- Department of Community Health, Escola de Odontologia, Faculdade
IMED, Passo Fundo (RS), Brazil
| | - Dulce Aparecida Barbosa
- Department of Clinical and Surgical Nursing, Escola Paulista de
Enfermagem, Universidade Federal de São Paulo (Unifesp), São Paulo
(SP), Brazil
| |
Collapse
|
61
|
Król J, Nawrot U, Bartoszewicz M. Anti-candidal activity of selected analgesic drugs used alone and in combination with fluconazole, itraconazole, voriconazole, posaconazole and isavuconazole. J Mycol Med 2018; 28:327-331. [DOI: 10.1016/j.mycmed.2018.03.002] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2017] [Revised: 02/28/2018] [Accepted: 03/05/2018] [Indexed: 10/17/2022]
|
62
|
Cataldi V, Di Campli E, Fazii P, Traini T, Cellini L, Di Giulio M. Candida species isolated from different body sites and their antifungal susceptibility pattern: Cross-analysis of Candida albicans and Candida glabrata biofilms. Med Mycol 2018; 55:624-634. [PMID: 27915303 DOI: 10.1093/mmy/myw126] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2016] [Accepted: 09/23/2016] [Indexed: 12/27/2022] Open
Abstract
Candida species are regular commensal in humans, but-especially in immunocompromised patients-they represent opportunistic pathogens giving rise to systemic infection. The aim of the present work was to isolate and characterize for their antifungal profile Candida species from different body sites and to analyze the biofilms produced by C. albicans and C. glabrata isolates. Eighty-one strains of Candida species from 77 patients were identified. Epidemiological study showed that the most isolated species were C. albicans (44), C. glabrata (13) and C. parapsilosis (13) mainly from Hematology, Infectious Diseases, Medicine, Neonatology and Oncology Divisions, the majority of the biological samples were swabs (44) and blood cultures (16). The analysis of the biofilm formation was performed at 24 and 48-hours comparing resistant and susceptible strains of C. albicans to resistant and susceptible strains of C. glabrata. Candida albicans has a greater ability to form biofilm compared to C. glabrata, both in the susceptible and resistant strains reaching maturity after 24 hours with a complex structure composed of blastospores, pseudohyphae, and hyphae embedded in a matrix. On the contrary, C. glabrata biofilm was composed exclusively of blastospores that in the resistant strain, after 24 hours, were organized in a compact multilayer different to the discontinuous structure observed in the susceptible analyzed strains. In conclusion, the increasing of the incidence of Candida species infection together with their emerging drug resistance also related to the biofilm forming capability underline the need to monitor their distribution and susceptibility patterns for improving the surveillance and for a correct management of the infection.
Collapse
Affiliation(s)
- Valentina Cataldi
- Departments of Pharmacy and Medical, Oral and Biotechnological Sciences, University "G. d'Annunzio," Chieti-Pescara, Chieti, Italy
| | - Emanuela Di Campli
- Departments of Pharmacy and Medical, Oral and Biotechnological Sciences, University "G. d'Annunzio," Chieti-Pescara, Chieti, Italy
| | - Paolo Fazii
- Clinical Microbiology and Virology, Spirito Santo Hospital, Pescara, Italy
| | - Tonino Traini
- Medical, Oral and Biotechnological Sciences, University "G.d'Annunzio", Chieti-Pescara, Chieti, Italy
| | - Luigina Cellini
- Departments of Pharmacy and Medical, Oral and Biotechnological Sciences, University "G. d'Annunzio," Chieti-Pescara, Chieti, Italy
| | - Mara Di Giulio
- Departments of Pharmacy and Medical, Oral and Biotechnological Sciences, University "G. d'Annunzio," Chieti-Pescara, Chieti, Italy
| |
Collapse
|
63
|
Sharifzadeh A, Khosravi AR, Shokri H, Shirzadi H. Potential effect of 2-isopropyl-5-methylphenol (thymol) alone and in combination with fluconazole against clinical isolates of Candida albicans, C. glabrata and C. krusei. J Mycol Med 2018; 28:294-299. [PMID: 29661606 DOI: 10.1016/j.mycmed.2018.04.002] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2018] [Revised: 04/04/2018] [Accepted: 04/05/2018] [Indexed: 01/06/2023]
Abstract
Limitations of antifungals used in the treatment of candidiasis, as the development of resistant strains, are known by the scientific community. In this context, the aim of this study was to investigate the activity of 2-isopropyl-5-methylphenol (thymol) in combination with fluconazole (FLZ) against clinical Candida strains. The antifungal activity of thymol along with FLZ was evaluated by the Clinical Laboratory Standards Institute (CLSI) M27-A2 broth microdilution method. In addition, synergism was observed for clinical strains of Candida spp. with combination of thymol-FLZ evaluated by the chequerboard microdilution method. The mean of minimum inhibitory concentration (MIC) values of thymol and FLZ were 49.37 and 0.475μg/ml for C. albicans, 51.25 and 18.80μg/ml for C. glabrata and 70 and 179.20μg/ml for C. krusei strains, respectively. Thymol in combination with FLZ exhibited the synergistic effects against all species of Candida tested. FICI values for thymol plus FLZ ranged from 0.366 to 0.607 for C. albicans strains, 0.367 to 0.482 for C. glabrata strains, and 0.375 to 0.563 for C. krusei strains. No antagonistic activity was seen in the strains tested. Thymol was found to have a fungicidal effect on Candida species and a synergistic effect when combined with FLZ.
Collapse
Affiliation(s)
- A Sharifzadeh
- Mycology Research Center, Faculty of Veterinary Medicine, University of Tehran, Azadi street, Tehran, Iran.
| | - A R Khosravi
- Mycology Research Center, Faculty of Veterinary Medicine, University of Tehran, Azadi street, Tehran, Iran
| | - H Shokri
- Department of Pathobiology, Faculty of Veterinary Medicine, Amol University of Special Modern Technologies, Amol, Iran
| | - H Shirzadi
- Mycology Research Center, Faculty of Veterinary Medicine, University of Tehran, Azadi street, Tehran, Iran
| |
Collapse
|
64
|
Staerck C, Godon C, Bouchara JP, Fleury MJJ. Varying susceptibility of clinical and environmental Scedosporium isolates to chemical oxidative stress in conidial germination. Arch Microbiol 2018; 200:517-523. [PMID: 29464281 DOI: 10.1007/s00203-018-1491-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2017] [Revised: 01/10/2018] [Accepted: 02/06/2018] [Indexed: 12/23/2022]
Abstract
Scedosporium species are opportunistic pathogens causing a great variety of infections in both immunocompetent and immunocompromised individuals. The Scedosporium genus ranks the second among the filamentous fungi colonizing the airways of patients with cystic fibrosis (CF), after Aspergillus fumigatus, and most species are capable to chronically colonize the respiratory tract of these patients. Nevertheless, few data are available regarding evasion of the inhaled conidia to the host immune response. Upon microbial infection, macrophages and neutrophils release reactive oxygen species (ROS). To colonize the respiratory tract, the conidia need to germinate despite the oxidative stress generated by phagocytic cells. Germination of spores from different clinical or environmental isolates of the major Scedosporium species was investigated in oxidative stress conditions. All tested species showed susceptibility to oxidative stress. However, when comparing clinical and environmental isolates, differences in germination capabilities under oxidative stress conditions were seen between species as well as within each species. Among environmental isolates, Scedosporium aurantiacum isolates were the most resistant to oxidative stress whereas Scedosporium dehoogii were the most susceptible. Overall, the differences observed between Scedosporium species in the capacity to germinate under oxidative stress conditions could explain their varying prevalence and pathogenicity.
Collapse
Affiliation(s)
- Cindy Staerck
- Groupe d'Etude des Interactions Hôte-Pathogène (EA 3142), Institut de Biologie en Santé-IRIS, CHU, UNIV Angers, UNIV Brest, Université Bretagne-Loire, 4 rue Larrey, 49933, Angers, France
| | - Charlotte Godon
- Groupe d'Etude des Interactions Hôte-Pathogène (EA 3142), Institut de Biologie en Santé-IRIS, CHU, UNIV Angers, UNIV Brest, Université Bretagne-Loire, 4 rue Larrey, 49933, Angers, France
| | - Jean-Philippe Bouchara
- Groupe d'Etude des Interactions Hôte-Pathogène (EA 3142), Institut de Biologie en Santé-IRIS, CHU, UNIV Angers, UNIV Brest, Université Bretagne-Loire, 4 rue Larrey, 49933, Angers, France.,Laboratoire de Parasitologie-Mycologie, Centre Hospitalier Universitaire, Angers, France
| | - Maxime J J Fleury
- Groupe d'Etude des Interactions Hôte-Pathogène (EA 3142), Institut de Biologie en Santé-IRIS, CHU, UNIV Angers, UNIV Brest, Université Bretagne-Loire, 4 rue Larrey, 49933, Angers, France.
| |
Collapse
|
65
|
Carreira A, Ferreira JB, Pereira I, Ferreira J, Filipe P, Ferreira RB, Monteiro S. Blad-containing oligomer: a novel fungicide used in crop protection as an alternative treatment for tinea pedis and tinea versicolor. J Med Microbiol 2018; 67:198-207. [PMID: 29388537 DOI: 10.1099/jmm.0.000675] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
PURPOSE The lack of novel antifungal drugs and the increasing incidence and severity of fungal infections are major concerns worldwide. Herein, we tested the activity of the Blad-containing oligomer (BCO), a new antifungal molecule already in use for agriculture, on Malassezia spp. and dermatophytes, the causal agents of human tinea versicolor and tinea pedis. Given the lack of a standard method for Malassezia susceptibility testing and the plethora of published methods, we also developed an improved method for this genus. METHODOLOGY The efficacy of BCO was assessed in vitro and compared to that of the drugs currently utilized in the treatment of tinea versicolor (fluconazole and itraconazole) and tinea pedis (itraconazole and terbinafine). For dermatophytes, the standard microdilution broth-based method was used, with small adjustments, and several broth formulations and inocula sizes were tested to develop an improved susceptibility method for Malassezia spp. RESULTS We successfully developed a microdilution broth-based method with considerable advantages over other available methods, and used it for all in vitro susceptibility tests of Malassezia spp. isolates. We report that, on a molar basis, BCO was more effective than fluconazole or itraconazole on most strains of Malassezia spp. isolated from clinical samples (n=29). By contrast, BCO was less effective than itraconazole or terbinafine on the common dermatophytes Trichophyton rubrum and Trichophyton interdigitale. CONCLUSION These data place BCO as a promising drug for the treatment of Malassezia-associated skin diseases. Further in vivo studies are now required to ascertain its applicability in the clinical setting.
Collapse
Affiliation(s)
- Alexandra Carreira
- CEV, SA, Parque Industrial de Cantanhede/Biocant-Park, lote 120, 3060-197 Cantanhede, Portugal
| | - João Boavida Ferreira
- Hospital de Santa Maria, Faculdade de Medicina de Lisboa, Clínica Dermatológica Universitária, Avenida Prof. Egas Moniz, 1699 Lisboa Codex, Portugal
| | - Iliana Pereira
- CEV, SA, Parque Industrial de Cantanhede/Biocant-Park, lote 120, 3060-197 Cantanhede, Portugal
| | - João Ferreira
- Hospital de Santa Maria, Faculdade de Medicina de Lisboa, Clínica Dermatológica Universitária, Avenida Prof. Egas Moniz, 1699 Lisboa Codex, Portugal.,Unidade de Investigação em Dermatologia, Instituto de Medicina Molecular, Avenida Prof. Egas Moniz, 1699 Lisboa Codex, Portugal
| | - Paulo Filipe
- Hospital de Santa Maria, Faculdade de Medicina de Lisboa, Clínica Dermatológica Universitária, Avenida Prof. Egas Moniz, 1699 Lisboa Codex, Portugal.,Unidade de Investigação em Dermatologia, Instituto de Medicina Molecular, Avenida Prof. Egas Moniz, 1699 Lisboa Codex, Portugal
| | - Ricardo Boavida Ferreira
- LEAF - Linking Landscape, Environment, Agriculture and Food, Instituto Superior de Agronomia, Universidade de Lisboa, 1349-017 Lisboa, Portugal
| | - Sara Monteiro
- CEV, SA, Parque Industrial de Cantanhede/Biocant-Park, lote 120, 3060-197 Cantanhede, Portugal
| |
Collapse
|
66
|
|
67
|
Shabeer M, Barbosa LCA, Karak M, Coelho ACS, Takahashi JA. Thiobarbiturates as potential antifungal agents to control human infections caused by Candida and Cryptococcus species. Med Chem Res 2018. [DOI: 10.1007/s00044-017-2126-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
|
68
|
Cavalcanti Filho JRN, Silva TF, Nobre WQ, Oliveira de Souza LI, Silva e Silva Figueiredo CS, de Figueiredo RCBQ, de Gusmão NB, Silva MV, Nascimento da Silva LC, Correia MTDS. Antimicrobial activity of Buchenavia tetraphylla against Candida albicans strains isolated from vaginal secretions. PHARMACEUTICAL BIOLOGY 2017; 55:1521-1527. [PMID: 28376640 PMCID: PMC7011787 DOI: 10.1080/13880209.2017.1304427] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/15/2016] [Revised: 01/25/2017] [Accepted: 03/03/2017] [Indexed: 06/07/2023]
Abstract
CONTEXT Buchenavia tetraphylla (Aubl.) RA Howard (Combretaceae: Combretoideae) is an ethnomedicinal plant with reported antifungal action. OBJECTIVE This study evaluates the antimicrobial activity of B. tetraphylla leaf extracts against clinical isolates of Candida albicans. The morphological alterations, combinatory effects with fluconazole and the cytotoxicity of the active extract were analyzed. MATERIALS AND METHODS Extracts were obtained using different solvents (hexane: BTHE; chloroform: BTCE; ethyl acetate: BTEE; and methanol: BTME). Antimicrobial activity was determined by the broth microdilution method using nine strains of C. albicans isolated from vaginal secretions and one standard strain (UFPEDA 1007). RESULTS All extracts showed anti-C. albicans activity, including against the azole-resistant strains. The MIC values ranged from 156 to 2500 μg/mL for the BTHE; 156 to 1250 μg/mL for the BTCE; 625 to 1250 μg/mL for the BTME and 625 μg/mL to 2500 μg/mL for the BTEE. BTME showed the best anti-C. albicans activity. This extract demonstrated additive/synergistic interactions with fluconazole. Scanning electron microscopy analysis suggested that the BTME interferes with the cell division and development of C. albicans. BTME showed IC50 values of 981 and 3935 μg/mL, against J774 macrophages and human erythrocytes, respectively. This extract also enhanced the production of nitric oxide by J774 macrophages. DISCUSSION AND CONCLUSION Buchenavia tetraphylla methanolic extract (BTME) is a great source of antimicrobial compounds that are able to enhance the action of fluconazole against different C. albicans strains; this action seems related to inhibition of cell division.
Collapse
Affiliation(s)
| | - Tiago Fonseca Silva
- Departamento de Bioquímica, Universidade Federal de Pernambuco, Recife, Brasil
- Curso de Farmácia, Faculdade Pernambucana de Saúde, Recife, Brasil
| | | | | | | | | | | | - Márcia Vanusa Silva
- Departamento de Bioquímica, Universidade Federal de Pernambuco, Recife, Brasil
| | - Luís Cláudio Nascimento da Silva
- Curso de Farmácia, Faculdade Pernambucana de Saúde, Recife, Brasil
- Programa de Pós-graduação, Universidade CEUMA, Sao Luis, Brasil
| | | |
Collapse
|
69
|
Li DD, Fuchs BB, Wang Y, Huang XW, Hu DD, Sun Y, Chai D, Jiang YY, Mylonakis E. Histone acetyltransferase encoded by NGG1 is required for morphological conversion and virulence of Candida albicans. Future Microbiol 2017; 12:1497-1510. [PMID: 29110536 DOI: 10.2217/fmb-2017-0084] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
AIM To assess the function of Ngg1 in Candida albicans and reveal the role of NGG1 in the morphological conversion and virulence of C. albicans. MATERIALS & METHODS C. albicans NGG1 gene was deleted in the wild-type strain SC5314 and the function of Ngg1 was assessed by western blot analysis. The phenotypes and the virulence of the ngg1 mutants were examined. Microarray analysis was performed to explore the mechanism. RESULTS The ngg1 mutants attenuated acetylated histone H3, obviously reduced filamentous growth and showed significantly diminished pathogenicity in all the infection models. CONCLUSION This study suggested the histone acetyltransferase activity of C. albicans Ngg1 and revealed the important role of NGG1 in morphological conversion and virulence of C. albicans. [Formula: see text].
Collapse
Affiliation(s)
- De-Dong Li
- Clinical Pharmacy Center, Department of Pharmacy, Chinese PLA General Hospital, Beijing 100853, China.,Division of Infectious Disease, Rhode Island Hospital, Alpert Medical School & Brown University, RI 02903, USA.,New Drug Research & Development Center, School of Pharmacy, Second Military Medical University, Shanghai 200433, China
| | - Beth Burgwyn Fuchs
- Division of Infectious Disease, Rhode Island Hospital, Alpert Medical School & Brown University, RI 02903, USA
| | - Yan Wang
- New Drug Research & Development Center, School of Pharmacy, Second Military Medical University, Shanghai 200433, China
| | - Xiao-Wen Huang
- Division of Infectious Disease, Rhode Island Hospital, Alpert Medical School & Brown University, RI 02903, USA.,Department of Dermatology, Nanfang Hospital, Southern Medical University, Guangzhou 510515, Guangdong, China
| | - Dan-Dan Hu
- New Drug Research & Development Center, School of Pharmacy, Second Military Medical University, Shanghai 200433, China
| | - Yan Sun
- Clinical Pharmacy Center, Department of Pharmacy, Chinese PLA General Hospital, Beijing 100853, China
| | - Dong Chai
- Clinical Pharmacy Center, Department of Pharmacy, Chinese PLA General Hospital, Beijing 100853, China
| | - Yuan-Ying Jiang
- New Drug Research & Development Center, School of Pharmacy, Second Military Medical University, Shanghai 200433, China
| | - Eleftherios Mylonakis
- Division of Infectious Disease, Rhode Island Hospital, Alpert Medical School & Brown University, RI 02903, USA
| |
Collapse
|
70
|
Candida albicans Swi/Snf and Mediator Complexes Differentially Regulate Mrr1-Induced MDR1 Expression and Fluconazole Resistance. Antimicrob Agents Chemother 2017; 61:AAC.01344-17. [PMID: 28807921 DOI: 10.1128/aac.01344-17] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2017] [Accepted: 08/09/2017] [Indexed: 02/07/2023] Open
Abstract
Long-term azole treatment of patients with chronic Candida albicans infections can lead to drug resistance. Gain-of-function (GOF) mutations in the transcription factor Mrr1 and the consequent transcriptional activation of MDR1, a drug efflux coding gene, is a common pathway by which this human fungal pathogen acquires fluconazole resistance. This work elucidates the previously unknown downstream transcription mechanisms utilized by hyperactive Mrr1. We identified the Swi/Snf chromatin remodeling complex as a key coactivator for Mrr1, which is required to maintain basal and induced open chromatin, and Mrr1 occupancy, at the MDR1 promoter. Deletion of snf2, the catalytic subunit of Swi/Snf, largely abrogates the increases in MDR1 expression and fluconazole MIC observed in MRR1GOF mutant strains. Mediator positively and negatively regulates key Mrr1 target promoters. Deletion of the Mediator tail module med3 subunit reduces, but does not eliminate, the increased MDR1 expression and fluconazole MIC conferred by MRR1GOF mutations. Eliminating the kinase activity of the Mediator Ssn3 subunit suppresses the decreased MDR1 expression and fluconazole MIC of the snf2 null mutation in MRR1GOF strains. Ssn3 deletion also suppresses MDR1 promoter histone displacement defects in snf2 null mutants. The combination of this work with studies on other hyperactive zinc cluster transcription factors that confer azole resistance in fungal pathogens reveals a complex picture where the induction of drug efflux pump expression requires the coordination of multiple coactivators. The observed variations in transcription factor and target promoter dependence of this process may make the search for azole sensitivity-restoring small molecules more complicated.
Collapse
|
71
|
Behbehani J, Shreaz S, Irshad M, Karched M. The natural compound magnolol affects growth, biofilm formation, and ultrastructure of oral Candida isolates. Microb Pathog 2017; 113:209-217. [PMID: 29074435 DOI: 10.1016/j.micpath.2017.10.040] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2017] [Revised: 09/29/2017] [Accepted: 10/20/2017] [Indexed: 12/18/2022]
Abstract
The incidence of oral candidosis has increased in recent years due to the escalation in HIV-infection, cancer treatments, organ transplantation, and diabetes. In addition, corticosteroid use, dentures, and broad-spectrum antibiotic use have also contributed to the problem. Treatment of oral candidosis has continued to be problematic because of the potential toxicity of antifungals in clinical use, and, above all, development of drug resistance among patients. In this study, the antifungal effect of magnolol was investigated against 64 strains of Candida spp. (four standard and 60 oral isolates) through minimum inhibitory concentration (MIC) and growth curve assays. Insight into the mechanisms of the antifungal action has been gained through ultrastructural studies using confocal scanning laser microscopy (CSLM), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Molecular docking was done for predicting the interactions of magnolol with ergosterol at supramolecular level. The toxicity of magnolol on human erythrocytes was measured by in vitro hemolytic assay. MIC values of magnolol ranged from 16-64 μg/ml, respectively. All tested isolates showed a marked sensitivity towards magnolol in growth curve assays. Biofilm results suggested that magnolol showed strong anti-biofilm activity. The results obtained for four different Candida spp. demonstrated that MBIC values of magnolol showed the average biofilm inhibition by 69.5%, respectively. CLSM experiments showed that cells exposed to magnolol (MIC) exhibited cell membrane disruption. SEM analysis of magnolol treated cells resulted in deformed cells. TEM micrographs showed rupturing of the cell wall and plasma membrane, releasing the intracellular content, and swelling of the cell wall. Hemolytic activity of magnolol is 11.9% at its highest MIC compared to an activity level of 25.4% shown by amphotericin B (Amp B) at 1 μg/ml. Lipinski's parameters calculated for magnolol suggested its good oral bioavailability. Docking studies indicated that magnolol might be interacting with ergosterol in the fungal cell membranes. Together, the present study provides enough evidence for further work on magnolol so that better strategies could be employed to treat oral candidosis.
Collapse
Affiliation(s)
- Jawad Behbehani
- Department of Restorative Sciences, Faculty of Dentistry, Health Sciences Center, Kuwait University, P.O. Box 24923, Safat, 13110, Kuwait
| | - Sheikh Shreaz
- Department of Bioclinical Sciences, Faculty of Dentistry, Health Sciences Center, Kuwait University, P.O. Box 24923, Safat, 13110, Kuwait; Environment and Life Sciences Research Center, Kuwait Institute for Scientific Research, P. O. Box 24885, 13109 Safat, Kuwait.
| | - Mohammad Irshad
- Department of Bioclinical Sciences, Faculty of Dentistry, Health Sciences Center, Kuwait University, P.O. Box 24923, Safat, 13110, Kuwait
| | - Maribassapa Karched
- Department of Bioclinical Sciences, Faculty of Dentistry, Health Sciences Center, Kuwait University, P.O. Box 24923, Safat, 13110, Kuwait
| |
Collapse
|
72
|
Hampe IAI, Friedman J, Edgerton M, Morschhäuser J. An acquired mechanism of antifungal drug resistance simultaneously enables Candida albicans to escape from intrinsic host defenses. PLoS Pathog 2017; 13:e1006655. [PMID: 28953977 PMCID: PMC5633205 DOI: 10.1371/journal.ppat.1006655] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2017] [Revised: 10/09/2017] [Accepted: 09/19/2017] [Indexed: 12/23/2022] Open
Abstract
The opportunistic fungal pathogen Candida albicans frequently produces genetically altered variants to adapt to environmental changes and new host niches in the course of its life-long association with the human host. Gain-of-function mutations in zinc cluster transcription factors, which result in the constitutive upregulation of their target genes, are a common cause of acquired resistance to the widely used antifungal drug fluconazole, especially during long-term therapy of oropharyngeal candidiasis. In this study, we investigated if C. albicans also can develop resistance to the antimicrobial peptide histatin 5, which is secreted in the saliva of humans to protect the oral mucosa from pathogenic microbes. As histatin 5 has been shown to be transported out of C. albicans cells by the Flu1 efflux pump, we screened a library of C. albicans strains that contain artificially activated forms of all zinc cluster transcription factors of this fungus for increased FLU1 expression. We found that a hyperactive Mrr1, which confers fluconazole resistance by upregulating the multidrug efflux pump MDR1 and other genes, also causes FLU1 overexpression. Similarly to the artificially activated Mrr1, naturally occurring gain-of-function mutations in this transcription factor also caused FLU1 upregulation and increased histatin 5 resistance. Surprisingly, however, Mrr1-mediated histatin 5 resistance was mainly caused by the upregulation of MDR1 instead of FLU1, revealing a previously unrecognized function of the Mdr1 efflux pump. Fluconazole-resistant clinical C. albicans isolates with different Mrr1 gain-of-function mutations were less efficiently killed by histatin 5, and this phenotype was reverted when MRR1 was deleted. Therefore, antimycotic therapy can promote the evolution of strains that, as a consequence of drug resistance mutations, simultaneously have acquired increased resistance against an innate host defense mechanism and are thereby better adapted to certain host niches. The yeast Candida albicans is part of the normal microflora of most healthy persons, but it can also cause symptomatic infections when host defenses are compromised. C. albicans frequently generates genetically altered variants that are better adapted to changes in its environment during colonization and infection. We investigated if C. albicans can evolve resistance to histatin 5 (Hst 5), an antimicrobial peptide that is produced in the saliva of humans and protects the oral cavity against this pathogen. We found that activated forms of the transcription factor Mrr1 reduce the susceptibility of C. albicans to killing by Hst 5, a phenotype that was partially caused by Mrr1-mediated overexpression of the multidrug efflux pump MDR1. Gain-of-function (GOF) mutations in Mrr1 are a frequent cause of resistance to the antifungal drug fluconazole, especially during long-term treatment of oropharyngeal candidiasis in AIDS patients, but they may also reduce the fitness of the fungus in the absence of the drug. Fluconazole-resistant clinical C. albicans isolates containing GOF mutations in Mrr1 displayed enhanced Hst 5 resistance, demonstrating that antimycotic therapy can promote the evolution of strains that simultaneously have acquired increased resistance against an innate host defense mechanism and are thereby better adapted to specific host niches.
Collapse
Affiliation(s)
- Irene A. I. Hampe
- Institute for Molecular Infection Biology, University of Würzburg, Würzburg, Germany
| | - Justin Friedman
- Department of Oral Biology, University at Buffalo, Buffalo, New York, United States of America
| | - Mira Edgerton
- Department of Oral Biology, University at Buffalo, Buffalo, New York, United States of America
| | - Joachim Morschhäuser
- Institute for Molecular Infection Biology, University of Würzburg, Würzburg, Germany
- * E-mail:
| |
Collapse
|
73
|
Sinha K, Rule GS. The Structure of Thymidylate Kinase from Candida albicans Reveals a Unique Structural Element. Biochemistry 2017; 56:4360-4370. [DOI: 10.1021/acs.biochem.7b00498] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Kaustubh Sinha
- Department of Biological
Sciences, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, United States
| | - Gordon S. Rule
- Department of Biological
Sciences, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, United States
| |
Collapse
|
74
|
Pinheiro AM, Carreira A, Prescott TAK, Ferreira RB, Monteiro SA. Bridging the Gap to Non-toxic Fungal Control: Lupinus-Derived Blad-Containing Oligomer as a Novel Candidate to Combat Human Pathogenic Fungi. Front Microbiol 2017; 8:1182. [PMID: 28702011 PMCID: PMC5487463 DOI: 10.3389/fmicb.2017.01182] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2017] [Accepted: 06/12/2017] [Indexed: 01/17/2023] Open
Abstract
The lack of antifungal drugs with novel modes of action reaching the clinic is a serious concern. Recently a novel antifungal protein referred to as Blad-containing oligomer (BCO) has received regulatory approval as an agricultural antifungal agent. Interestingly its spectrum of antifungal activity includes human pathogens such as Candida albicans, however, its mode of action has yet to be elucidated. Here we demonstrate that BCO exerts its antifungal activity through inhibition of metal ion homeostasis which results in apoptotic cell death in C. albicans. HIP HOP profiling in Saccharomyces cerevisiae using a panel of signature strains that are characteristic for common modes of action identified hypersensitivity in yeast lacking the iron-dependent transcription factor Aft1 suggesting restricted iron uptake as a mode of action. Furthermore, global transcriptome profiling in C. albicans also identified disruption of metal ion homeostasis as a potential mode of action. Experiments were carried out to assess the effect of divalent metal ions on the antifungal activity of BCO revealing that BCO activity is antagonized by metal ions such as Mn2+, Zn2+, and Fe2+. The transcriptome profile also implicated sterol synthesis as a possible secondary mode of action which was subsequently confirmed in sterol synthesis assays in C. albicans. Animal models for toxicity showed that BCO is generally well tolerated and presents a promising safety profile as a topical applied agent. Given its potent broad spectrum antifungal activity and novel multitarget mode of action, we propose BCO as a promising new antifungal agent for the topical treatment of fungal infections.
Collapse
Affiliation(s)
- Ana M Pinheiro
- Linking Landscape, Environment, Agriculture and Food, Instituto Superior de Agronomia, Universidade de LisboaLisboa, Portugal
| | - Alexandra Carreira
- CEV, SA, Parque Industrial de Cantanhede/Biocant-ParkCantanhede, Portugal
| | | | - Ricardo B Ferreira
- Linking Landscape, Environment, Agriculture and Food, Instituto Superior de Agronomia, Universidade de LisboaLisboa, Portugal
| | - Sara A Monteiro
- Linking Landscape, Environment, Agriculture and Food, Instituto Superior de Agronomia, Universidade de LisboaLisboa, Portugal.,CEV, SA, Parque Industrial de Cantanhede/Biocant-ParkCantanhede, Portugal
| |
Collapse
|
75
|
Hargrove TY, Friggeri L, Wawrzak Z, Qi A, Hoekstra WJ, Schotzinger RJ, York JD, Guengerich FP, Lepesheva GI. Structural analyses of Candida albicans sterol 14α-demethylase complexed with azole drugs address the molecular basis of azole-mediated inhibition of fungal sterol biosynthesis. J Biol Chem 2017; 292:6728-6743. [PMID: 28258218 DOI: 10.1074/jbc.m117.778308] [Citation(s) in RCA: 213] [Impact Index Per Article: 30.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2017] [Revised: 02/20/2017] [Indexed: 12/27/2022] Open
Abstract
With some advances in modern medicine (such as cancer chemotherapy, broad exposure to antibiotics, and immunosuppression), the incidence of opportunistic fungal pathogens such as Candida albicans has increased. Cases of drug resistance among these pathogens have become more frequent, requiring the development of new drugs and a better understanding of the targeted enzymes. Sterol 14α-demethylase (CYP51) is a cytochrome P450 enzyme required for biosynthesis of sterols in eukaryotic cells and is the major target of clinical drugs for managing fungal pathogens, but some of the CYP51 key features important for rational drug design have remained obscure. We report the catalytic properties, ligand-binding profiles, and inhibition of enzymatic activity of C. albicans CYP51 by clinical antifungal drugs that are used systemically (fluconazole, voriconazole, ketoconazole, itraconazole, and posaconazole) and topically (miconazole and clotrimazole) and by a tetrazole-based drug candidate, VT-1161 (oteseconazole: (R)-2-(2,4-difluorophenyl)-1,1-difluoro-3-(1H-tetrazol-1-yl)-1-(5-(4-(2,2,2-trifluoroethoxy)phenyl)pyridin-2-yl)propan-2-ol). Among the compounds tested, the first-line drug fluconazole was the weakest inhibitor, whereas posaconazole and VT-1161 were the strongest CYP51 inhibitors. We determined the X-ray structures of C. albicans CYP51 complexes with posaconazole and VT-1161, providing a molecular mechanism for the potencies of these drugs, including the activity of VT-1161 against Candida krusei and Candida glabrata, pathogens that are intrinsically resistant to fluconazole. Our comparative structural analysis outlines phylum-specific CYP51 features that could direct future rational development of more efficient broad-spectrum antifungals.
Collapse
Affiliation(s)
- Tatiana Y Hargrove
- From the Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, Tennessee 37232
| | - Laura Friggeri
- From the Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, Tennessee 37232
| | - Zdzislaw Wawrzak
- the Synchrotron Research Center, Life Science Collaborative Access Team, Northwestern University, Argonne, Illinois 60439
| | - Aidong Qi
- From the Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, Tennessee 37232
| | | | | | - John D York
- From the Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, Tennessee 37232
| | - F Peter Guengerich
- From the Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, Tennessee 37232
| | - Galina I Lepesheva
- From the Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, Tennessee 37232, .,the Center for Structural Biology, Vanderbilt University, Nashville, Tennessee 37232
| |
Collapse
|
76
|
Fluconazole-Pyridoxine Bis-Triazolium Compounds with Potent Activity against Pathogenic Bacteria and Fungi Including Their Biofilm-Embedded Forms. J CHEM-NY 2017. [DOI: 10.1155/2017/4761650] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Two novel quaternary ammonium salts, bis-triazolium derivatives of fluconazole and pyridoxine, were synthesized by reaction of fluconazole with pyridoxine-based synthetic intermediates. The leading compound demonstrated pronounced antimycotic and antibacterialin vitroactivity, comparable to or exceeding that of the reference antifungal (fluconazole, terbinafine) and antibacterial/antiseptic (miramistin, benzalkonium chloride) agents. In contrast to many antimicrobials, the leading compound was also active against biofilm-embedded staphylococci andEscherichia coli. While no biofilm structure destruction occurred, all compounds were able to diffuse into the matrix and reduce the number of colony-forming units by three orders of magnitude at 16 × MBC. The leading compound was significantly less toxic than miramistin and benzalkonium chloride and more toxic than the reference antifungal drugs. The obtained results make the described chemotype a promising starting point for the development of new broad-spectrum antimicrobial therapies with powerful effect on fungal and bacterial pathogens including their biofilm-embedded forms.
Collapse
|
77
|
|