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Pezzotti G, Kobara M, Nakaya T, Imamura H, Asai T, Miyamoto N, Adachi T, Yamamoto T, Kanamura N, Ohgitani E, Marin E, Zhu W, Nishimura I, Mazda O, Nakata T, Makimura K. Raman Study of Pathogenic Candida auris: Imaging Metabolic Machineries in Reaction to Antifungal Drugs. Front Microbiol 2022; 13:896359. [PMID: 35694304 PMCID: PMC9175029 DOI: 10.3389/fmicb.2022.896359] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2022] [Accepted: 04/25/2022] [Indexed: 12/02/2022] Open
Abstract
The multidrug-resistant Candida auris often defies treatments and presently represents a worldwide public health threat. Currently, the ergosterol-targeting Amphotericin B (AmB) and the DNA/RNA-synthesis inhibitor 5-flucytosine (5-FC) are the two main drugs available for first-line defense against life-threatening Candida auris infections. However, important aspects of their mechanisms of action require further clarification, especially regarding metabolic reactions of yeast cells. Here, we applied Raman spectroscopy empowered with specifically tailored machine-learning algorithms to monitor and to image in situ the susceptibility of two Candida auris clades to different antifungal drugs (LSEM 0643 or JCM15448T, belonging to the East Asian Clade II; and, LSEM 3673 belonging to the South African Clade III). Raman characterizations provided new details on the mechanisms of action against Candida auris Clades II and III, while also unfolding differences in their metabolic reactions to different drugs. AmB treatment induced biofilm formation in both clades, but the formed biofilms showed different structures: a dense and continuous biofilm structure in Clade II, and an extra-cellular matrix with a “fluffy” and discontinuous structure in Clade III. Treatment with 5-FC caused no biofilm formation but yeast-to-hyphal or pseudo-hyphal morphogenesis in both clades. Clade III showed a superior capacity in reducing membrane permeability to the drug through chemically tailoring chitin structure with a high degree of acetylation and fatty acids networks with significantly elongated chains. This study shows the suitability of the in situ Raman method in characterizing susceptibility and stress response of different C. auris clades to antifungal drugs, thus opening a path to identifying novel clinical solutions counteracting the spread of these alarming pathogens.
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Affiliation(s)
- Giuseppe Pezzotti
- Ceramic Physics Laboratory, Kyoto Institute of Technology, Kyoto, Japan
- Department of Immunology, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, Japan
- Department of Orthopedic Surgery, Tokyo Medical University, Tokyo, Japan
- Department of Dental Medicine, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, Japan
- The Center for Advanced Medical Engineering and Informatics, Osaka University, Osaka, Japan
- *Correspondence: Giuseppe Pezzotti
| | - Miyuki Kobara
- Division of Pathological Science, Department of Clinical Pharmacology, Kyoto Pharmaceutical University, Kyoto, Japan
| | - Tamaki Nakaya
- Ceramic Physics Laboratory, Kyoto Institute of Technology, Kyoto, Japan
| | - Hayata Imamura
- Ceramic Physics Laboratory, Kyoto Institute of Technology, Kyoto, Japan
| | - Tenma Asai
- Ceramic Physics Laboratory, Kyoto Institute of Technology, Kyoto, Japan
| | - Nao Miyamoto
- Department of Dental Medicine, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, Japan
| | - Tetsuya Adachi
- Department of Dental Medicine, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, Japan
| | - Toshiro Yamamoto
- Department of Dental Medicine, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, Japan
| | - Narisato Kanamura
- Department of Dental Medicine, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, Japan
| | - Eriko Ohgitani
- Department of Immunology, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, Japan
| | - Elia Marin
- Ceramic Physics Laboratory, Kyoto Institute of Technology, Kyoto, Japan
- Department of Dental Medicine, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, Japan
| | - Wenliang Zhu
- Ceramic Physics Laboratory, Kyoto Institute of Technology, Kyoto, Japan
| | - Ichiro Nishimura
- Division of Advanced Prosthodontics, The Jane and Jerry Weintraub Center for Reconstructive Biotechnology, UCLA School of Dentistry, Los Angeles, CA, United States
| | - Osam Mazda
- Department of Immunology, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, Japan
| | - Tetsuo Nakata
- Division of Pathological Science, Department of Clinical Pharmacology, Kyoto Pharmaceutical University, Kyoto, Japan
| | - Koichi Makimura
- Medical Mycology, Graduate School of Medicine, Teikyo University, Tokyo, Japan
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Ogunshe AAO, Adepoju AA, Oladimeji ME. Clinical efficacy and health implications of inconsistency in different production batches of antimycotic drugs in a developing country. J Pharm Bioallied Sci 2011; 3:158-64. [PMID: 21430967 PMCID: PMC3053515 DOI: 10.4103/0975-7406.76501] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2010] [Revised: 09/05/2010] [Accepted: 09/10/2010] [Indexed: 11/04/2022] Open
Abstract
OBJECTIVE This study aimed at evaluating the in vitro efficacy and health implications of inconsistencies in different production batches of antimycotic drugs. MATERIALS AND METHODS in vitro susceptibility profiles of 36 Candida spp. - C. albicans (19.4%), C. glabrata (30.6%), C. tropicalis (33.3%), and C. pseudotropicalis (16.7%) - obtained from human endocervical and high vaginal swabs (ECS/HVS) to two different batches (B1 and B2) of six antimycotic drugs (clotrimazole, doxycycline, iconazole, itraconazole, metronidazole and nystatin) was determined using modified agar well-diffusion method. RESULTS None of the Candida strains had entirely the same (100%) susceptibility / resistance profiles in both batches of corresponding antimycotic drugs; while, different multiple antifungal susceptibility (MAS) rates were also recorded in batches 1 and 2 for corresponding antifungals. Only 14.3%, 27.3%, 16.7-33.3%, and 8.3-25.0% of C. albicans, C. glabrata, C. pseudotropicalis, and C. tropicalis strains, respectively, had similar susceptibility/resistance profiles toward coressponding antifungal agents in both batches; while up to 57.1% of C. albicans, 45.5% of C. glabrata, 66.7% of C. pseudotropicalis, and 50.0% of C. tropicalis strains were susceptible to one batch of antifungals but resistant to corresponding antifungals in the second batch. As high as 71.4% (C. albicans), 73.0% (C. glabrata), 50.0% (C. pseudotropicalis), and 66.74% (C. tropicalis) strains had differences of ≥ 10.0 mm among corresponding antimycotic agents. CONCLUSIONS Candida strains exhibited different in vitro susceptibility / resistance patterns toward two batches of corresponding antimycotic agents, which has clinical implications on the efficacy of the drugs and treatment of patients. The findings of the present study will be of benefit in providing additional information in support of submission of drugs for registration to appropriate regulatory agencies.
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Affiliation(s)
- Adenike A O Ogunshe
- Applied Microbiology and Infectious Diseases, Department of Microbiology, University of Ibadan, Ibadan, Nigeria
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Mutational analysis of flucytosine resistance in Candida glabrata. Antimicrob Agents Chemother 2010; 54:4733-8. [PMID: 20823283 DOI: 10.1128/aac.00605-10] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
The antifungal flucytosine (5-fluorocytosine [5FC]) is a prodrug metabolized to its toxic form, 5-fluorouracil (5FU), only by organisms expressing cytosine deaminase. One such organism is Candida glabrata, which has emerged as the second most common agent of bloodstream and mucosal candidiasis. This emergence has been attributed to the high rate at which C. glabrata develops resistance to azole antifungals. As an oral agent, 5FC represents an attractive alternative or complement to azoles; however, the frequency of 5FC resistance mutations and the mechanisms by which these mutations confer resistance have been explored only minimally. On RPMI 1640 medium containing 1 μg/ml 5FC (32-fold above the MIC, but less than 1/10 of typical serum levels), resistant mutants occurred at a relatively low frequency (2 × 10⁻⁷). Three of six mutants characterized were 5FU cross-resistant, suggesting a mutation downstream of the Fcy1 gene (cytosine deaminase), which was confirmed by sequence analysis of the Fur1 gene (uracil phosphoribosyl transferase). The remaining three mutants had Fcy1 mutations. To ascertain the effects of 5FC resistance mutations on enzyme function, mutants were isolated in ura3 strains. Three of seven mutants harbored Fcy1 mutations and failed to grow in uridine-free, cytosine-supplemented medium, consistent with inactive Fcy1. The remainder grew in this medium and had wild-type Fcy1; further analysis revealed these to be mutated in the Fcy2L homolog of S. cerevisiae Fcy2 (purine-cytosine transporter). Based on this analysis, we characterized three 5FC-resistant clinical isolates, and mutations were identified in Fur1 and Fcy1. These data provide a framework for understanding 5FC resistance in C. glabrata and potentially in other fungal pathogens.
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Abstract
Combination antifungal therapy has been an area of research and clinical interest since systemic antifungals became available decades ago. In vitro and clinical data were generated for some of the more common invasive fungal infections, especially candidiasis, but until very recently few clinical studies were performed. The first invasive fungal infection to be examined in clinical trials with adequate statistical power was cryptococcal meningitis and several of these trials stand out as classical studies in the clinical evaluation of combination antifungal therapy. More recently, since the availability of the newer antifungal agents, including the echinocandins and extended-spectrum triazoles, there has been a growing interest in examining combination antifungal therapy for invasive fungal disease, especially invasive aspergillosis. This is by no means a comprehensive review of all existing experimental data. Instead, the focus is on the clinical data that have been generated to date and on providing insights into potential future clinical directions. For instance, recent clinical data for cryptococcosis confirm that amphotericin B plus flucytosine is the most active combination for patients with cryptococcal meningitis. A recently completed clinical trial in candidaemia suggests a trend towards improved outcomes among patients receiving amphotericin B plus fluconazole versus fluconazole alone. In aspergillosis, several experimental models suggest benefit of a variety of antifungal combinations, but have not been confirmed in prospective clinical trials. Ultimately, the goal is to provide the reader with a comprehensive but useful review to this complicated and often confusing therapeutic dilemma.
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Affiliation(s)
- John W Baddley
- Department of Medicine, Division of Infectious Diseases, University of Alabama at Birmingham, and Birmingham Veteran's Administration Medical Center, Birmingham, Alabama 35294-0006, USA
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Cuenca-Estrella M. Combinations of antifungal agents in therapy--what value are they? J Antimicrob Chemother 2004; 54:854-69. [PMID: 15375111 DOI: 10.1093/jac/dkh434] [Citation(s) in RCA: 103] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Concurrent or sequential antifungal treatment for invasive mycoses has been typically considered as an option to improve results of monotherapy. However, data on the efficacy of combination therapy are sparse and consist largely of results from studies in vitro and experimental animal models. These studies have yielded controversial results depending on the criteria used to evaluate the antifungal interaction. Several combinations that showed synergy in vitro failed to do so in animal models. Overall, apart from cryptococcal infections, combined antifungal therapy is not significantly better than monotherapy in terms of clinical efficacy. It is questionable whether combination therapy should be used in most cases as there is a lack of evidence from well-designed clinical trials. However, combination therapy could be an alternative to monotherapy for patients with invasive infections that are difficult to treat, such as those due to multi-resistant species and for those who fail to respond to standard treatment.
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Affiliation(s)
- Manuel Cuenca-Estrella
- Servicio de Micología, Centro Nacional de Microbiología, Instituto de Salud Carlos III, Ctra Majadahonda-Pozuelo Km 2, 28220 Majadahonda, Madrid, Spain.
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Dannaoui E, Lortholary O, Dromer F. In vitro evaluation of double and triple combinations of antifungal drugs against Aspergillus fumigatus and Aspergillus terreus. Antimicrob Agents Chemother 2004; 48:970-8. [PMID: 14982791 PMCID: PMC353155 DOI: 10.1128/aac.48.3.970-978.2004] [Citation(s) in RCA: 88] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Microdilution broth checkerboard techniques based on the National Committee for Clinical Laboratory Standards methodology were used to study double and triple antifungal combinations against clinical isolates of Aspergillus fumigatus and A. terreus. The influences of the end-point definition (partial or complete inhibition) and the mode of reading (visually or spectrophotometrically) were determined. Interactions between antifungal drugs were also evaluated by agar diffusion tests. Combinations of caspofungin with either amphotericin B or voriconazole were additive for all the isolates, and antagonism was not observed. The interaction between caspofungin and flucytosine was synergistic for 62% of the isolates. In contrast, the interaction between voriconazole and flucytosine was never synergistic and antagonism was noted for 93% of the isolates. The triple combination of caspofungin with flucytosine and amphotericin B was synergistic for all the isolates tested. The triple combination of caspofungin with flucytosine and voriconazole was also mostly synergistic; but complex interactions were obtained for some isolates, with synergy or antagonism depending on the concentrations of caspofungin and voriconazole. Analysis of the influence of the reading technique on the results showed that spectrophotometric reading was a good alternative to the recommended visual reading. The results of these in vitro tests suggest that the activity of flucytosine as part of a double combination with caspofungin and as part of a triple combination with caspofungin and amphotericin B against Aspergillus spp. warrants further investigations. Animal studies are needed to evaluate the in vivo efficacies of these combinations.
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Affiliation(s)
- Eric Dannaoui
- Centre National de Référence Mycologie et Antifongiques, Unité de Mycologie Moléculaire, Institut Pasteur, 75724 Paris Cedex 15, France.
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Noël T, François F, Paumard P, Chastin C, Brèthes D, Villard J. Flucytosine-fluconazole cross-resistance in purine-cytosine permease-deficient Candida lusitaniae clinical isolates: indirect evidence of a fluconazole uptake transporter. Antimicrob Agents Chemother 2003; 47:1275-84. [PMID: 12654658 PMCID: PMC152504 DOI: 10.1128/aac.47.4.1275-1284.2003] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
An unusual interaction between flucytosine and fluconazole was observed when a collection of 60 Candida lusitaniae clinical isolates was screened for cross-resistance. Among eight isolates resistant to flucytosine (MIC >/= 128 micro g/ml) and susceptible to fluconazole (0.5 < MIC < 2 micro g/ml), four became flucytosine-fluconazole cross resistant when both antifungals were used simultaneously. Fluconazole resistance occurred only in the presence of high flucytosine concentrations, and the higher the fluconazole concentration used, the greater the flucytosine concentration necessary to trigger the cross-resistance. When the flucytosine- and fluconazole-resistant cells were grown in the presence of fluconazole alone, the cells reversed to fluconazole susceptibility. Genetic analyses of the progeny from crosses between resistant and sensitive isolates showed that resistance to flucytosine was derived from a recessive mutation in a single gene, whereas cross-resistance to fluconazole seemed to vary like a quantitative trait. We further demonstrated that the four clinical isolates were susceptible to 5-fluorouracil and that cytosine deaminase activity was unaffected. Kinetic transport studies with [(14)C]flucytosine showed that flucytosine resistance was due to a defect in the purine-cytosine permease. Our hypothesis was that extracellular flucytosine would subsequently behave as a competitive inhibitor of fluconazole uptake transport. Finally, in vitro selection of spontaneous and induced mutants indicated that such a cross-resistance mechanism could also affect other Candida species, including C. albicans, C. tropicalis, and C. glabrata. This is the first report of a putative fluconazole uptake transporter in Candida species and of a possible resistance mechanism associated with a deficiency in the uptake of this drug.
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Affiliation(s)
- Thierry Noël
- Laboratoire des Sciences Végétales, Faculté de Pharmacie, Université René Descartes-Paris 5, Paris 75006, USA.
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