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Arruda MFC, da Silva Ramos RCP, de Oliveira NS, Rosa RT, Stuelp-Campelo PM, Bianchini LF, Villas-Bôas SG, Rosa EAR. Central Carbon Metabolism in Candida albicans Biofilms Is Altered by Dimethyl Sulfoxide. J Fungi (Basel) 2024; 10:337. [PMID: 38786692 PMCID: PMC11121877 DOI: 10.3390/jof10050337] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2024] [Revised: 03/25/2024] [Accepted: 04/04/2024] [Indexed: 05/25/2024] Open
Abstract
The effect of dimethyl sulfoxide (DMSO) on fungal metabolism has not been well studied. This study aimed to evaluate, by metabolomics, the impact of DMSO on the central carbon metabolism of Candida albicans. Biofilms of C. albicans SC5314 were grown on paper discs, using minimum mineral (MM) medium, in a dynamic continuous flow system. The two experimental conditions were control and 0.03% DMSO (v/v). After 72 h of incubation (37 °C), the biofilms were collected and the metabolites were extracted. The extracted metabolites were subjected to gas chromatography-mass spectrometry (GC/MS). The experiment was conducted using five replicates on three independent occasions. The GC/MS analysis identified 88 compounds. Among the 88 compounds, the levels of 27 compounds were markedly different between the two groups. The DMSO group exhibited enhanced levels of putrescine and glutathione and decreased levels of methionine and lysine. Additionally, the DMSO group exhibited alterations in 13 metabolic pathways involved in primary and secondary cellular metabolism. Among the 13 altered pathways, seven were downregulated and six were upregulated in the DMSO group. These results indicated a differential intracellular metabolic profile between the untreated and DMSO-treated biofilms. Hence, DMSO was demonstrated to affect the metabolic pathways of C. albicans. These results suggest that DMSO may influence the results of laboratory tests when it is used as a solvent. Hence, the use of DMSO as a solvent must be carefully considered in drug research, as the effect of the researched drugs may not be reliably translated into clinical practice.
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Affiliation(s)
- Maria Fernanda Cordeiro Arruda
- Graduate Program on Dentistry, School of Medicine and Life Sciences, Pontifical Catholic University of Paraná, Curitiba 80215-901, Brazil; (M.F.C.A.); (R.C.P.d.S.R.)
| | - Romeu Cassiano Pucci da Silva Ramos
- Graduate Program on Dentistry, School of Medicine and Life Sciences, Pontifical Catholic University of Paraná, Curitiba 80215-901, Brazil; (M.F.C.A.); (R.C.P.d.S.R.)
| | - Nicoly Subtil de Oliveira
- Graduate Program on Animal Sciences, School of Medicine and Life Sciences, Pontifical Catholic University of Paraná, Curitiba 80215-901, Brazil;
| | - Rosimeire Takaki Rosa
- Xenobiotics Research Unit, School of Medicine and Life Sciences, Pontifical Catholic University of Paraná, Curitiba 80215-901, Brazil; (R.T.R.); (P.M.S.-C.); (L.F.B.)
| | - Patrícia Maria Stuelp-Campelo
- Xenobiotics Research Unit, School of Medicine and Life Sciences, Pontifical Catholic University of Paraná, Curitiba 80215-901, Brazil; (R.T.R.); (P.M.S.-C.); (L.F.B.)
| | - Luiz Fernando Bianchini
- Xenobiotics Research Unit, School of Medicine and Life Sciences, Pontifical Catholic University of Paraná, Curitiba 80215-901, Brazil; (R.T.R.); (P.M.S.-C.); (L.F.B.)
| | | | - Edvaldo Antonio Ribeiro Rosa
- Graduate Program on Dentistry, School of Medicine and Life Sciences, Pontifical Catholic University of Paraná, Curitiba 80215-901, Brazil; (M.F.C.A.); (R.C.P.d.S.R.)
- Graduate Program on Animal Sciences, School of Medicine and Life Sciences, Pontifical Catholic University of Paraná, Curitiba 80215-901, Brazil;
- Xenobiotics Research Unit, School of Medicine and Life Sciences, Pontifical Catholic University of Paraná, Curitiba 80215-901, Brazil; (R.T.R.); (P.M.S.-C.); (L.F.B.)
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Wang B, Rutherfurd-Markwick K, Liu N, Zhang XX, Mutukumira AN. Evaluation of the probiotic potential of yeast isolated from kombucha in New Zealand. Curr Res Food Sci 2024; 8:100711. [PMID: 38524400 PMCID: PMC10958227 DOI: 10.1016/j.crfs.2024.100711] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2024] [Revised: 02/20/2024] [Accepted: 03/03/2024] [Indexed: 03/26/2024] Open
Abstract
The current study investigated the in vitro probiotic potential of yeast isolated from kombucha, a tea beverage fermented with a symbiotic culture of acetic acid bacteria and yeast. A total of 62 yeast strains were previously isolated from four different commercial kombucha samples sold in New Zealand. Fifteen representative isolates belonging to eight different species were evaluated for their growth under different conditions (temperature, low pH, concentrations of bile salts, and NaCl). Cell surface characteristics, functional and enzymatic activities of the selected strains were also studied in triplicate experiments. Results showed that six strains (Dekkera bruxellensis LBY1, Sachizosaccharomyces pombe LBY5, Hanseniaspora valbyensis DOY1, Brettanomyces anomalus DOY8, Pichia kudraivzevii GBY1, and Saccharomyces cerevisiae GBY2) were able to grow under low-acid conditions (at pH 2 and pH 3) and in the presence of bile salts. This suggests their potential to survive passage through the human gut. All 15 strains exhibited negative enzymatic activity reactions (haemolytic, gelatinase, phospholipase, and protease activities), and thus, they can be considered safe to consume. Notably, two of the fifteen strains (Pichia kudraivzevii GBY1 and Saccharomyces cerevisiae GBY2) exhibited desirable cell surface hydrophobicity (64.60-83.87%), auto-aggregation (>98%), co-aggregation, resistance to eight tested antibiotics (ampicillin, chloramphenicol, colistin sulphate, kanamycin, nalidixic acid, nitrofurantoin, streptomycin, and tetracycline), and high levels of antioxidant activities (>90%). Together, our data reveal the probiotic activities of two yeast strains GBY1 and GBY2 and their potential application in functional food production.
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Affiliation(s)
- Boying Wang
- School of Food and Advanced Technology, Massey University, Auckland, 0745, New Zealand
| | | | - Ninghui Liu
- School of Food and Advanced Technology, Massey University, Auckland, 0745, New Zealand
| | - Xue-Xian Zhang
- School of Natural Sciences, Massey University, Auckland, 0745, New Zealand
| | - Anthony N. Mutukumira
- School of Food and Advanced Technology, Massey University, Auckland, 0745, New Zealand
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Chomchalao P, Saelim N, Lamlertthon S, Sisopa P, Tiyaboonchai W. Mucoadhesive Hybrid System of Silk Fibroin Nanoparticles and Thermosensitive In Situ Hydrogel for Amphotericin B Delivery: A Potential Option for Fungal Keratitis Treatment. Polymers (Basel) 2024; 16:148. [PMID: 38201813 PMCID: PMC10780372 DOI: 10.3390/polym16010148] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2023] [Revised: 12/24/2023] [Accepted: 12/28/2023] [Indexed: 01/12/2024] Open
Abstract
The purpose of this work was to investigate the feasibility of a novel ophthalmic formulation of amphotericin B-encapsulated silk fibroin nanoparticles incorporated in situ hydrogel (AmB-FNPs ISG) for fungal keratitis (FK) treatment. AmB-FNPs ISG composites were successfully developed and have shown optimized physicochemical properties for ocular drug delivery. Antifungal effects against Candida albicans and in vitro ocular irritation using corneal epithelial cells were performed to evaluate the efficacy and safety of the composite formulations. The combined system of AmB-FNPs-ISG exhibited effective antifungal activity and showed significantly less toxicity to HCE cells than commercial AmB. In vitro and ex vivo mucoadhesive tests demonstrated that the combination of silk fibroin nanoparticles with in situ hydrogels could enhance the adhesion ability of the particles on the ocular surface for more than 6 h, which would increase the ocular retention time of AmB and reduce the frequency of administration during the treatment. In addition, AmB-FNP-PEG ISG showed good physical and chemical stability under storage condition for 90 days. These findings indicate that AmB-FNP-PEG ISG has a great potential and be used in mucoadhesive AmB eye drops for FK treatment.
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Affiliation(s)
- Pratthana Chomchalao
- Department of Pharmaceutical Technology, Faculty of Pharmaceutical Sciences, Naresuan University, Phitsanulok 65000, Thailand;
- College of Medicine and Public Health, Ubon Ratchathani University, Ubon Ratchathani 34190, Thailand
| | - Nuttawut Saelim
- Department of Pharmacy Practice, Faculty of Pharmaceutical Sciences, Naresuan University, Phitsanulok 65000, Thailand
| | - Supaporn Lamlertthon
- Centre of Excellence in Fungal Research, Department of Microbiology and Parasitology, Faculty of Medical Science, Naresuan University, Phitsanulok 65000, Thailand
| | - Premnapa Sisopa
- Department of Health and Cosmetic Product Development, Faculty of Food and Agricultural Technology, Pibulsongkram Rajabhat University, Phitsanulok 65000, Thailand
| | - Waree Tiyaboonchai
- Department of Pharmaceutical Technology, Faculty of Pharmaceutical Sciences, Naresuan University, Phitsanulok 65000, Thailand;
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Liu J, Zhang H, Zhang L, Li T, Liu N, Liu Q. Effect of various concentrations of common organic solvents on the growth and proliferation ability of Candida glabrata and their permissible limits for addition in drug susceptibility testing. PeerJ 2023; 11:e16444. [PMID: 38025727 PMCID: PMC10668856 DOI: 10.7717/peerj.16444] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2023] [Accepted: 10/20/2023] [Indexed: 12/01/2023] Open
Abstract
Objectives Dimethyl sulfoxide (DMSO), acetone, ethanol, and methanol are organic solvents commonly used for dissolving drugs in antimicrobial susceptibility testing. However, these solvents have certain antimicrobial activity. Currently, standardized criteria for the selection and dosage of drug solvents in drug susceptibility testing research are lacking. The study aims to provide experimental evidence for the selection and addition limit of drug solvents for the in vitro antifungal susceptibility test of Candida glabrata (C. glabrata). Methods According to the recommendation of the Clinical and Laboratory Standards Institute (CLSI) M27-A3, a 0.5 McFarland C. glabrata suspension was prepared and then diluted 1:1,000. Next, a gradient dilution method was used to prepare 20%, 10%, 5%, and 2.5% DMSO/acetone/ethanol/methanol. The mixture was plated onto a 96-well plate and incubated at a constant temperature of 35 °C for 48 h. The inhibitory effects of DMSO, acetone, ethanol, and methanol on C. glabrata growth and proliferation were analyzed by measuring optical density values at 600 nm (OD600 values). Results After 48 h incubation, the OD600 values of C. glabrata decreased to different extents in the presence of the four common organic solvents. The decrease in the OD600 values was greater with increasing concentrations within the experimental concentration range. When DMSO and acetone concentrations were higher than 2.5% (containing 2.5%) and methanol and ethanol concentrations were higher than 5.0% (containing 5.0%), the differences were statistically significant compared with the growth control wells without any organic solvent (P < 0.05). Conclusion All four organic solvents could inhibit C. glabrata growth and proliferation. When used as solvents for drug sensitivity testing in C. glabrata, the concentrations of DMSO, acetone, ethanol, and methanol should be below 2.5%, 2.5%, 5%, and 5%, respectively.
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Affiliation(s)
- Juan Liu
- Hebei Key Laboratory of Stomatology, Hebei Clinical Research Center for Oral Disease, School and Hospital of Stomatology, Hebei Medical University, Shijiazhuang, Hebei, China
| | - Hongxin Zhang
- Department of Emergency, The Second Hospital of Hebei Medical University, Shijiazhuang, Hebei, China
| | - Lifang Zhang
- Hebei Key Laboratory of Stomatology, Hebei Clinical Research Center for Oral Disease, School and Hospital of Stomatology, Hebei Medical University, Shijiazhuang, Hebei, China
| | - Ting Li
- Hebei Key Laboratory of Stomatology, Hebei Clinical Research Center for Oral Disease, School and Hospital of Stomatology, Hebei Medical University, Shijiazhuang, Hebei, China
| | - Na Liu
- Department of Preventive Dentistry, School and Hospital of Stomatology, Hebei Medical University, Shijiazhuang, Hebei, China
| | - Qing Liu
- Hebei Key Laboratory of Stomatology, Hebei Clinical Research Center for Oral Disease, School and Hospital of Stomatology, Hebei Medical University, Shijiazhuang, Hebei, China
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Montoya C, Kurylec J, Ossa A, Orrego S. Cyclic strain of poly (methyl methacrylate) surfaces triggered the pathogenicity of Candida albicans. Acta Biomater 2023; 170:415-426. [PMID: 37625677 DOI: 10.1016/j.actbio.2023.08.037] [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: 05/15/2023] [Revised: 07/21/2023] [Accepted: 08/17/2023] [Indexed: 08/27/2023]
Abstract
Candida albicans is an opportunistic yeast and the primary etiological factor in oral candidiasis and denture stomatitis. The pathogenesis of C. albicans could be triggered by several variables, including environmental, nutritional, and biomaterial surface cues. Specifically, biomaterial interactions are driven by different surface properties, including wettability, stiffness, and roughness. Dental biomaterials experience repetitive (cyclic) stresses from chewing and biomechanical movements. Pathogenic biofilms are formed over these biomaterial surfaces under cyclic strain. This study investigated the effect of the cyclic strain (deformation) of biomaterial surfaces on the virulence of Candida albicans. Candida biofilms were grown over Poly (methyl methacrylate) (PMMA) surfaces subjected to static (no strain) and cyclic strain with different levels (ε˜x=0.1 and 0.2%). To evaluate the biomaterial-biofilm interactions, the biofilm characteristics, yeast-to-hyphae transition, and the expression of virulent genes were measured. Results showed the biofilm biomass and metabolic activity to be significantly higher when Candida adhered to surfaces subjected to cyclic strain compared to static surfaces. Examination of the yeast-to-hyphae transition showed pseudo-hyphae cells (pathogenic) in cyclically strained biomaterial surfaces, whereas static surfaces showed spherical yeast cells (commensal). RNA sequencing was used to determine and compare the transcriptome profiles of cyclically strained and static surfaces. Genes and transcription factors associated with cell adhesion (CSH1, PGA10, and RBT5), biofilm formation (EFG1), and secretion of extracellular matrix (ECM) (CRH1, ADH5, GCA1, and GCA2) were significantly upregulated in the cyclically strained biomaterial surfaces compared to static ones. Genes and transcription factors associated with virulence (UME6 and HGC1) and the secretion of extracellular enzymes (LIP, PLB, and SAP families) were also significantly upregulated in the cyclically strained biomaterial surfaces compared to static. For the first time, this study reveals a biomaterial surface factor triggering the pathogenesis of Candida albicans, which is essential for understanding, controlling, and preventing oral infections. STATEMENT OF SIGNIFICANCE: Fungal infections produced by Candida albicans are a significant contributor to various health conditions. Candida becomes pathogenic when certain environmental conditions change, including temperature, pH, nutrients, and CO2 levels. In addition, surface properties, including wettability, stiffness, and roughness, drive the interactions between Candida and biomaterials. Clinically, Candida adheres to biomaterials that are under repetitive deformation due to body movements. In this work, we revealed that when Candida adhered to biomaterial surfaces subjected to repetitive deformation, the microorganism becomes pathogenic by increasing the formation of biofilms and the expression of virulent factors related to hyphae formation and secretion of enzymes. Findings from this work could aid the development of new strategies for treating fungal infections in medical devices or implanted biomaterials.
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Affiliation(s)
- Carolina Montoya
- Department of Oral Health Sciences, Kornberg School of Dentistry, Temple University, Philadelphia, PA, United States
| | - Julia Kurylec
- Department of Oral Health Sciences, Kornberg School of Dentistry, Temple University, Philadelphia, PA, United States
| | - Alex Ossa
- Production Engineering Department, School of Engineering, Universidad EAFIT, Medellín, Colombia
| | - Santiago Orrego
- Department of Oral Health Sciences, Kornberg School of Dentistry, Temple University, Philadelphia, PA, United States; Bioengineering Department, College of Engineering, Temple University, Philadelphia, PA, United States.
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Mujahid M, Trendafilova N, Rosair G, Kavanagh K, Walsh M, Creaven BS, Georgieva I. Structural and Spectroscopic Study of New Copper(II) and Zinc(II) Complexes of Coumarin Oxyacetate Ligands and Determination of Their Antimicrobial Activity. Molecules 2023; 28:molecules28114560. [PMID: 37299035 DOI: 10.3390/molecules28114560] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2023] [Revised: 05/19/2023] [Accepted: 05/30/2023] [Indexed: 06/12/2023] Open
Abstract
Tackling antimicrobial resistance is of increasing concern in a post-pandemic world where overuse of antibiotics has increased the threat of another pandemic caused by antimicrobial-resistant pathogens. Derivatives of coumarins, a naturally occurring bioactive compound, and its metal complexes have proven therapeutic potential as antimicrobial agents and in this study a series of copper(II) and zinc(II) complexes of coumarin oxyacetate ligands were synthesised and characterised by spectroscopic techniques (IR, 1H, 13C NMR, UV-Vis) and by X-ray crystallography for two of the zinc complexes. The experimental spectroscopic data were then interpreted on the basis of molecular structure modelling and subsequent spectra simulation using the density functional theory method to identify the coordination mode in solution for the metal ions in the complexes. Interestingly, the solid-state coordination environment of the zinc complexes is in good agreement with the simulated solution state, which has not been the case in our previous studies of these ligands when coordinated to silver(I). Previous studies had indicated excellent antimicrobial activity for Ag(I) analogues of these ligands and related copper and zinc complexes of coumarin-derived ligands, but in this study none of the complexes displayed antimicrobial activity against the clinically relevant methicillin-resistant Staphylococcus aureus (MRSA), Pseudomonas aeruginosa and Candida albicans.
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Affiliation(s)
- Muhammad Mujahid
- Centre of Applied Science for Health, TU Dublin, Tallaght, D24 FKT9 Dublin, Ireland
| | - Natasha Trendafilova
- Institute of General and Inorganic Chemistry, Bulgarian Academy of Sciences, 11 Acad. G. Bonchev Str., 1113 Sofia, Bulgaria
| | - Georgina Rosair
- School of Engineering & Physical Sciences, Heriot-Watt University, Edinburgh EH14 4AS, UK
| | - Kevin Kavanagh
- Department of Biology, Maynooth University, W23 F2K8 Maynooth, Ireland
| | - Maureen Walsh
- Centre of Applied Science for Health, TU Dublin, Tallaght, D24 FKT9 Dublin, Ireland
| | - Bernadette S Creaven
- Centre of Applied Science for Health, TU Dublin, Tallaght, D24 FKT9 Dublin, Ireland
- School of Chemical and Pharmaceutical Sciences, TU Dublin, Central Quad, Grangegorman, D07 H6K8 Dublin, Ireland
| | - Ivelina Georgieva
- Institute of General and Inorganic Chemistry, Bulgarian Academy of Sciences, 11 Acad. G. Bonchev Str., 1113 Sofia, Bulgaria
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Makambi WK, Ikonomova SP, Karlsson AJ. Quantifying the Antifungal Activity of Peptides Against Candida albicans. J Vis Exp 2023:10.3791/64416. [PMID: 36715417 PMCID: PMC10115183 DOI: 10.3791/64416] [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] [Indexed: 01/15/2023] Open
Abstract
Traditional methods for performing antifungal susceptibility testing for Candida albicans are time-consuming and lack quantitative results. For example, a common approach relies on plating cells treated with different concentrations of antifungal molecules on agar plates and then counting the colonies to determine the relationship between molecule concentration and growth inhibition. This method requires many plates and substantial time to count the colonies. Another common approach eliminates the plates and counting of colonies by visually inspecting cultures treated with antifungal agents to identify the minimum concentration required to inhibit growth; however, visual inspection produces only qualitative results, and information on growth at subinhibitory concentrations is lost. This protocol describes a method for measuring the susceptibility of C. albicans to antifungal peptides. By relying on optical density measurements of cultures, the method reduces the time and materials needed to obtain quantitative results on culture growth at different peptide concentrations. The incubation of the fungus with peptides is performed in a 96-well plate using an appropriate buffer, with controls representing no growth inhibition and complete growth inhibition. Following the incubation with the peptide, the resulting cell suspensions are diluted to reduce peptide activity and then grown overnight. After overnight growth, the optical density of each well is measured and compared to the positive and negative controls to calculate the resulting growth inhibition at each peptide concentration. The results using this assay are comparable to the results using the traditional method of plating the cultures on agar plates, but this protocol reduces plastic waste and the time spent on counting colonies. Although the applications of this protocol have focused on antifungal peptides, the method will also be applicable to testing other molecules with known or suspected antifungal activity.
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Affiliation(s)
- Wright K Makambi
- Department of Chemical and Biomolecular Engineering, University of Maryland
| | | | - Amy J Karlsson
- Department of Chemical and Biomolecular Engineering, University of Maryland;
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Nas F, Aissaoui N, Mahjoubi M, Mosbah A, Arab M, Abdelwahed S, Khrouf R, Masmoudi AS, Cherif A, Klouche-Khelil N. A comparative GC-MS analysis of bioactive secondary metabolites produced by halotolerant Bacillus spp. isolated from the Great Sebkha of Oran. Int Microbiol 2021; 24:455-470. [PMID: 34100180 DOI: 10.1007/s10123-021-00185-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2020] [Revised: 05/16/2021] [Accepted: 05/24/2021] [Indexed: 11/28/2022]
Abstract
The reemergence of infectious diseases and resistant pathogens represents a serious problem for human life. Hence, the screening for new or alternative antimicrobial compounds is still urgent. Unusual ecosystems such as saline habitats are considered promising environments for the purposes of isolating bacterial strains able to produce potent natural products. The aim of this study is the identification of bioactive compounds biosynthesized by three halotolerant strains isolated from the Sebkha of Oran (Algeria) using gas chromatography coupled to mass spectrometry. Primary screening investigation of antimicrobial activities were performed against reference bacterial and fungal strains and revealed a broad-spectrum activity. Secondary metabolite extraction was carried out using ethyl acetate and chloroform. Crude extracts were tested for bioactivity using the disc diffusion method and subjected to GC-MS analysis. The extracts showed an important inhibitory effect against all tested strains. Fifty-six compounds were identified; they include tert-butyl phenol compounds, fatty acid methyl esters due to the methylation procedure, hydrocarbons, aldehydes, benzoquinones, pyrrols, and terpenes. Literature reports such compounds to have wide biological and pharmaceutical applications. The molecular identification of the three isolates was achieved using the 16S-23S rRNA gene intergenic spacer region (ITS) and 16S rRNA sequencing. Partial 16S rRNA gene sequencing showed very high similarity with many species of Bacillus. This study provided insights on the potential of halotolerant Bacillus as drug research target for bioactive metabolites. The findings suggest that the Great Sebkha of Oran is a valuable source of strains exhibiting variety of beneficial attributes that can be utilized in the development of biological antibiotics.
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Affiliation(s)
- Fatima Nas
- Laboratory of Applied Microbiology in Food, Biomedical and Environment (LAMAABE), Faculty of Nature and Life, Earth and Universe Sciences, Department of Biology, Aboubekr Belkaïd University of Tlemcen, Tlemcen, Algeria
| | - Nadia Aissaoui
- Laboratory of Applied Microbiology in Food, Biomedical and Environment (LAMAABE), Faculty of Nature and Life, Earth and Universe Sciences, Department of Biology, Aboubekr Belkaïd University of Tlemcen, Tlemcen, Algeria
| | - Mouna Mahjoubi
- Univ. Manouba, ISBST, BVBGR-LR11ES31, Biotechpole SidiThabe, 2020, Ariana, Tunisia
| | - Amor Mosbah
- Univ. Manouba, ISBST, BVBGR-LR11ES31, Biotechpole SidiThabe, 2020, Ariana, Tunisia
| | - Mounia Arab
- Laboratory of Applied Microbiology in Food, Biomedical and Environment (LAMAABE), Faculty of Nature and Life, Earth and Universe Sciences, Department of Biology, Aboubekr Belkaïd University of Tlemcen, Tlemcen, Algeria
| | - Soukaina Abdelwahed
- Univ. Manouba, ISBST, BVBGR-LR11ES31, Biotechpole SidiThabe, 2020, Ariana, Tunisia
| | - Rim Khrouf
- Univ. Manouba, ISBST, BVBGR-LR11ES31, Biotechpole SidiThabe, 2020, Ariana, Tunisia
| | | | - Ameur Cherif
- Univ. Manouba, ISBST, BVBGR-LR11ES31, Biotechpole SidiThabe, 2020, Ariana, Tunisia
| | - Nihel Klouche-Khelil
- Laboratory of Applied Microbiology in Food, Biomedical and Environment (LAMAABE), Faculty of Nature and Life, Earth and Universe Sciences, Department of Biology, Aboubekr Belkaïd University of Tlemcen, Tlemcen, Algeria. .,Laboratory of Experimental Surgery, Medical Faculty, Dental Surgery Department, Aboubekr Belkaïd University of Tlemcen, Tlemcen, Algeria.
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9
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Carvalho ÂR, Genz Bazana LC, Ferrão MF, Fuentefria AM. Curve fitting and linearization of UV-Vis spectrophotometric measurements to estimate yeast in inoculum preparation. Anal Biochem 2021; 625:114216. [PMID: 33933444 DOI: 10.1016/j.ab.2021.114216] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2020] [Revised: 03/24/2021] [Accepted: 04/16/2021] [Indexed: 11/29/2022]
Abstract
The counting of microorganisms is essential in the area of microbiology, especially in the preparation of inoculum. The main methods for obtaining inoculum are McFarland standard, Neubauer chamber, and plate count. However, the visual comparison is subjective while the counting in the chamber and the plating are technically time-consuming. For this reason, our article aims to correlate the absorbance of the spectrophotometer in the visible ultraviolet region (UV-Vis) with the cell counting in the Neubauer chamber. This study used suspensions of Candida spp. measured at three wavelengths (530, 600, and 700 nm) and counting in a Neubauer chamber. In the next step, curves were adjusted with different polynomials using absorbances and counts. The two best polynomial curve fittings were the Saturation Growth Rate (SGR) and Morgan-Mercer-Flodin (MMF). Therefore, the polynomials were linearized and a direct correlation between absorbance and the number of cells was made. The proposed method proved to be more accurate (5 ± 0.5 × 106) than the comparison with the McFarland turbidity (1-5 x 106) and more practical than plate counting. Predicting the number of cells by UV-Vis is an alternative that reduces the uncertainty of the cell count interval for inoculum preparation.
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Affiliation(s)
- Ânderson Ramos Carvalho
- Laboratório de Pesquisa em Micologia Aplicada, Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, RS, Brazil; Programa de Pós-Graduação em Ciências Farmacêuticas, Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, RS, Brazil.
| | - Luana Candice Genz Bazana
- Laboratório de Pesquisa em Micologia Aplicada, Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, RS, Brazil; Programa de Pós-Graduação em Ciências Farmacêuticas, Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, RS, Brazil
| | - Marco Flôres Ferrão
- Programa de Pós-Graduação em Química, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, 91501-970, Brazil
| | - Alexandre Meneghello Fuentefria
- Laboratório de Pesquisa em Micologia Aplicada, Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, RS, Brazil; Programa de Pós-Graduação em Ciências Farmacêuticas, Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, RS, Brazil
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10
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Yuan-Biao Q, Lan-Fang Z, Qi Q, Jia-Hui N, Ze-Mei R, Hai-Mei Y, Chen-Chen Z, Hong-Ju P, Nan-Nan D, Qing-Shan L. Antifungal resistance-modifying multiplexing action of Momordica charantia protein and phosphorylated derivatives on the basis of growth-dependent gene coregulation in Candida albicans. Med Mycol 2020; 59:myaa070. [PMID: 32871589 DOI: 10.1093/mmy/myaa070] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2020] [Accepted: 08/26/2020] [Indexed: 01/08/2023] Open
Abstract
Fungal growth-dependent gene coregulation is strongly implicated in alteration of gene-encoding target proteases ruling with an antifungal resistance niche and biology of resistant mutants. On the basis of multi-alterative processes in this platform, the resistance-modifying strategy is designed in ketoconazole resistant Candida albicans and evaluated with less selective Momordica charantia protein and allosterically phosphorylated derivatives at the Thr102, Thr24 and Thr255 sites, respectively. We demonstrate absolutely chemo-sensitizing efficacy regarding stepwise-modifying resistance in sensitivity, by a load of only 26.23-40.00 μg/l agents in Sabouraud's dextrose broth. Five successive modifying-steps realize the decreasing of ketoconazole E-test MIC50 from 11.10 to a lower level than 0.10 mg/l. With the ketoconazole resistance-modifying, colony undergoes a high-frequency morphological switch between high ploidy (opaque) and small budding haploid (white). A cellular event in the first modifying-step associates with relatively slow exponential growth (ie, a 4-h delay)-dependent action, mediated by agents adsorption. Moreover, multiple molecular roles are coupled with intracellularly and extracellularly binding to ATP-dependent RNA helicase dbp6; the 0.08-2.45 fold upregulation of TATA-box-binding protein, rRNA-processing protein and translation initiation factor 5A; and the 7.52-55.33% decrease of cytochrome P450 lanosterol 14α-demethylase, glucan 1, 3-β glucosidase, candidapepsin-1 and 1-acylglycerol-3-phosphate O-acyltransferase. Spatial and temporal gene coregulation, in the transcription and translation initiation stages with rRNA-processing, is a new coprocessing platform enabling target protease attenuations for resistance-impairing. An updated resistance-modifying measure of these agents in the low-dose antifungal strategic design may provide opportunities to a virtually safe therapy that is in high dose-dependency. LAY SUMMARY A new platform to modify resistance is fungal growth-dependent gene coregulation. MAP30 and phosphorylated derivatives are candidate resistance-modifying agents. Low-dose stepwise treatment absolutely modifies azole resistance in model fungus.
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Affiliation(s)
- Qiao Yuan-Biao
- Shanxi Key Laboratory of Innovative Drugs for the Treatment of Serious Diseases Basing on Chronic Inflammation, College of Traditional Chinese Medicines, Shanxi University of Chinese Medicine, Taiyuan, Shanxi 030619, P. R. China
- Graduate Institute of Pharmaceutical Chemistry, Luliang University, Luliang, Shanxi 033001, P. R. China
| | - Zhang Lan-Fang
- Shanxi Key Laboratory of Innovative Drugs for the Treatment of Serious Diseases Basing on Chronic Inflammation, College of Traditional Chinese Medicines, Shanxi University of Chinese Medicine, Taiyuan, Shanxi 030619, P. R. China
| | - Qiao Qi
- Department of Medical Biochemistry and Microbiology, Uppsala Biomedical Center, Uppsala University, Husargatan 3, Box 582, SE-751 23 Uppsala, Sweden
| | - Niu Jia-Hui
- Graduate Institute of Pharmaceutical Chemistry, Luliang University, Luliang, Shanxi 033001, P. R. China
| | - Ren Ze-Mei
- Graduate Institute of Pharmaceutical Chemistry, Luliang University, Luliang, Shanxi 033001, P. R. China
| | - Yang Hai-Mei
- Graduate Institute of Pharmaceutical Chemistry, Luliang University, Luliang, Shanxi 033001, P. R. China
| | - Zhu Chen-Chen
- Graduate Institute of Pharmaceutical Chemistry, Luliang University, Luliang, Shanxi 033001, P. R. China
| | - Pan Hong-Ju
- Graduate Institute of Pharmaceutical Chemistry, Luliang University, Luliang, Shanxi 033001, P. R. China
| | - Duan Nan-Nan
- Graduate Institute of Pharmaceutical Chemistry, Luliang University, Luliang, Shanxi 033001, P. R. China
| | - Li Qing-Shan
- Shanxi Key Laboratory of Innovative Drugs for the Treatment of Serious Diseases Basing on Chronic Inflammation, College of Traditional Chinese Medicines, Shanxi University of Chinese Medicine, Taiyuan, Shanxi 030619, P. R. China
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Enayatifard R, Akbari J, Babaei A, Rostamkalaei SS, Hashemi SMH, Habibi E. Anti-Microbial Potential of Nano-Emulsion form of Essential Oil Obtained from Aerial Parts of Origanum Vulgare L. as Food Additive. Adv Pharm Bull 2020; 11:327-334. [PMID: 33880355 PMCID: PMC8046398 DOI: 10.34172/apb.2021.028] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2019] [Revised: 02/12/2020] [Accepted: 02/23/2020] [Indexed: 11/09/2022] Open
Abstract
Purpose: Foodborne diseases are still a serious problem in public health and natural compounds are being widely considered for their potential industrial protective additive in food products. Origanum vulgare L. has been known as an antimicrobial effective herb. This present study was carried out to examine the antimicrobial effect of O. vulgare essential oil nanoemulsion in comparison with conventional emulsion. Methods: The essential oil was obtained by hydrodistillation, analyzed by GC-Mass and formulated as a nanoemulsion to improve water dispersion by high-energy emulsification method. The antimicrobial activity of the prepared formulation was assessed by measuring the minimum inhibitory concentration (MIC), minimum bactericidal/fungicidal concentration (MBC/MFC) and zone of inhibition against some main foodborne pathogen microorganisms. Results: The main component of the oregano essential oil was carvacrol (78%) and the selected nanoemulsion formulation demonstrated low polydispersity (0.11) and mean droplet (72.26 nm) and it was stable even after 30 days of storage. The nanoemulsion form displayed significant activity against the Staphylococcus aureus, Candida albicans and Aspergillus niger with inhibition zones ranging from 8.7-22.3 mm. The MIC of nanoemulsion against the tested bacteria was within the range of 0.156 to 0.312 (mg/mL) and against the tested fungi were in the range of 0.078 to 0.156 (mg/mL). The MBC/MFC of nanoemulsion against the tested microorganisms were in the range of 0.312 to 5 (mg/mL). Conclusion: The study's results demonstrated the possibility of using the nanoemulsion form of oregano essential oil as a food additive to inhibit the growth of some foodborne microorganisms and extending the shelf life of food products.
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Affiliation(s)
- Reza Enayatifard
- Department of Pharmaceutics, Faculty of Pharmacy, Mazandaran University of Medical Sciences, Sari, Iran
| | - Jafar Akbari
- Department of Pharmaceutics, Faculty of Pharmacy, Mazandaran University of Medical Sciences, Sari, Iran
| | - Amirhossein Babaei
- Student Research Committee, Department of Pharmaceutics, Faculty of Pharmacy, Mazandaran University of Medical Sciences, Sari, Iran
| | | | - Seyyed Mohammad Hassan Hashemi
- Student Research Committee, Department of Pharmaceutics, Faculty of Pharmacy, Mazandaran University of Medical Sciences, Sari, Iran
| | - Emran Habibi
- Department of Pharmacognosy and Biotechnology, Pharmaceutical Sciences Research Center, Hemoglobinopathy Institute, Faculty of Pharmacy, Mazandaran University of Medical Sciences, Sari, Iran
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12
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Saeed A, Haider A, Zahid S, Khan SA, Faryal R, Kaleem M. In-vitro antifungal efficacy of tissue conditioner-chitosan composites as potential treatment therapy for denture stomatitis. Int J Biol Macromol 2019; 125:761-766. [DOI: 10.1016/j.ijbiomac.2018.12.091] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2018] [Revised: 11/20/2018] [Accepted: 12/09/2018] [Indexed: 11/25/2022]
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13
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Mirmortazavi A, Rajati Haghi H, Fata A, Zarrinfar H, Bagheri H, Mehranfard A. Kinetics of antifungal activity of home-generated ozonated water on Candida albicans. Curr Med Mycol 2018; 4:27-31. [PMID: 30324154 PMCID: PMC6181063 DOI: 10.18502/cmm.4.2.67] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Background and Purpose: Candida-associated denture stomatitis is one of the most common forms of oral candidiasis among denture wearers. Regarding this, the aim of the present study was to evaluate the antifungal effects of home-generated ozonated water on the adhesion of the C. albicans attached to the surface of the denture base acrylic resins. Materials and Methods: For the purpose of the study, different concentrations of C. albicans were added to the tubes containing acrylic resin blocks, and then incubated for 2 h at 35°C. The samples were assigned into three groups, each of which contained 42 samples, including normal saline (NS) solution as the negative control, nystatin (N) solution as the positive control, and ozonated water as the test group. The samples were washed and placed in an ultrasonic bath. Subsequently, the saline solution was cultured on Sabouraud dextrose agar. The concentrations of Candida were evaluated during the contact times. Results: The test group (i.e., ozonated water) with 114 colony-forming units (CFU) showed a significant reduction of Candida colonies, compared to the NS group with 2,172 CFU. The 120- and 1-minute incubation with ozonated water showed the highest and lowest effects on the viability of Candida adhered to the acrylic resin, respectively. Conclusion: Based on the findings, home-generated ozonated water can be applied to remove the Candida attached to the surface of the denture plates.
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Affiliation(s)
- Amirtaher Mirmortazavi
- Department of Prosthodontics, School of Dentistry, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Hamidreza Rajati Haghi
- Department of Prosthodontics, School of Dentistry, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Abdolmajid Fata
- Cutaneous Leishmaniasis Research Center, Mashhad University of Medical Sciences, Mashhad, Iran.,Department of Parasitology and Mycology, School of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Hossein Zarrinfar
- Allergy Research Center, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Hossein Bagheri
- Dental Materials Research Center, Department of Operative Dentistry, School of Dentistry, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Amirhossein Mehranfard
- Department of Prosthodontics, School of Dentistry, Mashhad University of Medical Sciences, Mashhad, Iran
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14
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Synthesis, interfacial properties, and antimicrobial activity of a new cationic gemini surfactant. KOREAN J CHEM ENG 2018. [DOI: 10.1007/s11814-018-0133-6] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
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15
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Yun CS, Motoyama T, Osada H. Regulatory Mechanism of Mycotoxin Tenuazonic Acid Production in Pyricularia oryzae. ACS Chem Biol 2017; 12:2270-2274. [PMID: 28820236 DOI: 10.1021/acschembio.7b00353] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Tenuazonic acid (TeA) is a mycotoxin produced by the rice blast fungus Pyricularia oryzae and some plant pathogenic fungi. We previously demonstrated that TeA is biosynthesized in P. oryzae by TeA synthetase 1 (TAS1) and that its production is induced by osmo-sensory MAPK-encoding gene (OSM1) deletion or the addition of 1% DMSO to cultures; however, the regulatory mechanisms of TeA production were unknown. Here, we identify a Zn(II)2-Cys6-type transcription factor in the upstream region of TAS1, which is encoded by TAS2 and regulates TeA production. We also find PoLAE1, which is a homologue of LaeA, a regulator of fungal secondary metabolism. Analysis of PoLAE1 deletion and overexpression strains indicate that PoLAE1 drives TeA production. We also demonstrate that two TeA-inducing signals, 1% DMSO addition and OSM1 deletion, were transmitted through PoLAE1. Our results indicate that TeA production is regulated by two specific regulators, TAS2 and PoLAE1, in P. oryzae.
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Affiliation(s)
- Choong-Soo Yun
- Chemical Biology Research
Group, RIKEN Center for Sustainable Resource Science, 2-1 Hirosawa, Wako-shi, Saitama 351-0198, Japan
| | - Takayuki Motoyama
- Chemical Biology Research
Group, RIKEN Center for Sustainable Resource Science, 2-1 Hirosawa, Wako-shi, Saitama 351-0198, Japan
| | - Hiroyuki Osada
- Chemical Biology Research
Group, RIKEN Center for Sustainable Resource Science, 2-1 Hirosawa, Wako-shi, Saitama 351-0198, Japan
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16
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In Vitro Antibiofilm Activity of Eucarobustol E against Candida albicans. Antimicrob Agents Chemother 2017; 61:AAC.02707-16. [PMID: 28584159 DOI: 10.1128/aac.02707-16] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2016] [Accepted: 05/20/2017] [Indexed: 12/23/2022] Open
Abstract
Formyl-phloroglucinol meroterpenoids (FPMs) are important types of natural products with various bioactivities. Our antifungal susceptibility assay showed that one of the Eucalyptus robusta-derived FPMs, eucarobustol E (EE), exerted a strong inhibitory effect against Candida albicans biofilms at a concentration of 16 μg/ml. EE was found to block the yeast-to-hypha transition and reduce the cellular surface hydrophobicity of the biofilm cells. RNA sequencing and real-time reverse transcription-PCR analysis showed that exposure to 16 μg/ml of EE resulted in marked reductions in the levels of expressions of genes involved in hyphal growth (EFG1, CPH1, TEC1, EED1, UME6, and HGC1) and cell surface protein genes (ALS3, HWP1, and SAP5). Interestingly, in response to EE, genes involved in ergosterol biosynthesis were downregulated, while the farnesol-encoding gene (DPP3) was upregulated, and these findings were in agreement with those from the quantification of ergosterol and farnesol. Combined with the obvious elevation of negative regulator genes (TUP1, NRG1), we speculated that EE's inhibition of carbon flow to ergosterol triggered the mechanisms of the negative regulation of hyphal growth and eventually led to biofilm inhibition.
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17
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Benhamou RI, Bibi M, Steinbuch KB, Engel H, Levin M, Roichman Y, Berman J, Fridman M. Real-Time Imaging of the Azole Class of Antifungal Drugs in Live Candida Cells. ACS Chem Biol 2017; 12:1769-1777. [PMID: 28472585 DOI: 10.1021/acschembio.7b00339] [Citation(s) in RCA: 47] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Azoles are the most commonly used class of antifungal drugs, yet where they localize within fungal cells and how they are imported remain poorly understood. Azole antifungals target lanosterol 14α-demethylase, a cytochrome P450, encoded by ERG11 in Candida albicans, the most prevalent fungal pathogen. We report the synthesis of fluorescent probes that permit visualization of antifungal azoles within live cells. Probe 1 is a dansyl dye-conjugated azole, and probe 2 is a Cy5-conjugated azole. Docking computations indicated that each of the probes can occupy the active site of the target cytochrome P450. Like the azole drug fluconazole, probe 1 is not effective against a mutant that lacks the target cytochrome P450. In contrast, the azole drug ketoconazole and probe 2 retained some antifungal activity against mutants lacking the target cytochrome P450, implying that both act against more than one target. Both fluorescent azole probes colocalized with the mitochondria, as determined by fluorescence microscopy with MitoTracker dye. Thus, these fluorescent probes are useful molecular tools that can lead to detailed information about the activity and localization of the important azole class of antifungal drugs.
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Affiliation(s)
- Raphael I. Benhamou
- School of Chemistry, Raymond & Beverly Sackler Faculty of Exact Sciences, Tel Aviv University, Tel Aviv, 6997801, Israel
| | - Maayan Bibi
- Dept. of Molecular Microbiology & Biotechnology, School of Molecular Cell Biology and Biotechnology, George Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv, 6997801, Israel
| | - Kfir B. Steinbuch
- School of Chemistry, Raymond & Beverly Sackler Faculty of Exact Sciences, Tel Aviv University, Tel Aviv, 6997801, Israel
| | - Hamutal Engel
- Blavatnik
Center for Drug Discovery, Tel Aviv University, Tel Aviv, 6997801, Israel
| | - Maayan Levin
- School of Chemistry, Raymond & Beverly Sackler Faculty of Exact Sciences, Tel Aviv University, Tel Aviv, 6997801, Israel
| | - Yael Roichman
- School of Chemistry, Raymond & Beverly Sackler Faculty of Exact Sciences, Tel Aviv University, Tel Aviv, 6997801, Israel
| | - Judith Berman
- Dept. of Molecular Microbiology & Biotechnology, School of Molecular Cell Biology and Biotechnology, George Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv, 6997801, Israel
| | - Micha Fridman
- School of Chemistry, Raymond & Beverly Sackler Faculty of Exact Sciences, Tel Aviv University, Tel Aviv, 6997801, Israel
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18
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Mujahid M, Trendafilova N, Arfa-Kia AF, Rosair G, Kavanagh K, Devereux M, Walsh M, McClean S, Creaven BS, Georgieva I. Novel silver(I) complexes of coumarin oxyacetate ligands and their phenanthroline adducts: Biological activity, structural and spectroscopic characterisation. J Inorg Biochem 2016; 163:53-67. [DOI: 10.1016/j.jinorgbio.2016.07.010] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2016] [Revised: 07/05/2016] [Accepted: 07/13/2016] [Indexed: 12/29/2022]
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19
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Guo BL, Han P, Guo LC, Cao YQ, Li AD, Kong JZ, Zhai HF, Wu D. The Antibacterial Activity of Ta-doped ZnO Nanoparticles. NANOSCALE RESEARCH LETTERS 2015; 10:1047. [PMID: 26293495 PMCID: PMC4546064 DOI: 10.1186/s11671-015-1047-4] [Citation(s) in RCA: 73] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/12/2015] [Accepted: 08/10/2015] [Indexed: 05/21/2023]
Abstract
A novel photocatalyst of Ta-doped ZnO nanoparticles was prepared by a modified Pechini-type method. The antimicrobial study of Ta-doped ZnO nanoparticles on several bacteria of Gram-positive Bacillus subtilis (B. subtilis) and Staphylococcus aureus (S. aureus) and Gram-negative Escherichia coli (E. coli) and Pseudomonas aeruginosa (P. aeruginosa) were performed using a standard microbial method. The Ta-doping concentration effect on the minimum inhibitory concentration (MIC) of various bacteria under dark ambient has been evaluated. The photocatalytical inactivation of Ta-doped ZnO nanoparticles under visible light irradiation was examined. The MIC results indicate that the incorporation of Ta(5+) ions into ZnO significantly improve the bacteriostasis effect of ZnO nanoparticles on E. coli, S. aureus, and B. subtilis in the absence of light. Compared to MIC results without light irradiation, Ta-doped ZnO and pure ZnO nanoparticles show much stronger bactericidal efficacy on P. aeruginosa, E. coli, and S. aureus under visible light illumination. The possible antimicrobial mechanisms in Ta-doped ZnO systems under visible light and dark conditions were also proposed. Ta-doped ZnO nanoparticles exhibit more effective bactericidal efficacy than pure ZnO in dark ambient, which can be attributed to the synergistic effect of enhanced surface bioactivity and increased electrostatic force due to the incorporation of Ta(5+) ions into ZnO. Based on the antibacterial tests, 5 % Ta-doped ZnO is a more effective antimicrobial agent than pure ZnO.
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Affiliation(s)
- Bing-Lei Guo
- />National Laboratory of Solid State Microstructures, Materials Science and Engineering Department, College of Engineering and Applied Sciences, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, 210093 People’s Republic of China
| | - Ping Han
- />National Laboratory of Solid State Microstructures, Materials Science and Engineering Department, College of Engineering and Applied Sciences, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, 210093 People’s Republic of China
| | - Li-Chuan Guo
- />College of Life Science, Nanjing University, Nanjing, 210093 People’s Republic of China
| | - Yan-Qiang Cao
- />National Laboratory of Solid State Microstructures, Materials Science and Engineering Department, College of Engineering and Applied Sciences, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, 210093 People’s Republic of China
| | - Ai-Dong Li
- />National Laboratory of Solid State Microstructures, Materials Science and Engineering Department, College of Engineering and Applied Sciences, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, 210093 People’s Republic of China
| | - Ji-Zhou Kong
- />National Laboratory of Solid State Microstructures, Materials Science and Engineering Department, College of Engineering and Applied Sciences, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, 210093 People’s Republic of China
| | - Hai-Fa Zhai
- />National Laboratory of Solid State Microstructures, Materials Science and Engineering Department, College of Engineering and Applied Sciences, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, 210093 People’s Republic of China
| | - Di Wu
- />National Laboratory of Solid State Microstructures, Materials Science and Engineering Department, College of Engineering and Applied Sciences, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, 210093 People’s Republic of China
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20
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Three unusual indole diketopiperazine alkaloids from a terrestrial-derived endophytic fungus, Aspergillus sp. Tetrahedron Lett 2015. [DOI: 10.1016/j.tetlet.2015.04.058] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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21
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Yu J, Zhang W, Li Y, Wang G, Yang L, Jin J, Chen Q, Huang M. Synthesis, characterization, antimicrobial activity and mechanism of a novel hydroxyapatite whisker/nano zinc oxide biomaterial. ACTA ACUST UNITED AC 2014; 10:015001. [PMID: 25534679 DOI: 10.1088/1748-6041/10/1/015001] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Postoperative infections remain a risk factor that leads to failures in oral and maxillofacial artificial bone transplantation. This study aimed to synthesize and evaluate a novel hydroxyapatite whisker (HAPw) / nano zinc oxide (n-ZnO) antimicrobial bone restorative biomaterial. A scanning electron microscope (SEM), energy dispersive spectroscopy (EDS) and x-ray diffraction (XRD) were employed to characterize and analyze the material. Antibacterial capabilities against Staphylococcus aureus, Escherichia coli, Candida albicans and Streptococcus mutans were determined by minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC), and kinetic growth inhibition assays were performed under darkness and simulated solar irradiation. The mode of antibiotic action was observed by transmission electron microscopy (TEM) and confocal laser scanning microscopy (CLSM). The MIC and MBC were 0.078-1.250 mg ml(-1) and 0.156-2.500 mg ml(-1), respectively. The inhibitory function on the growth of the microorganisms was achieved even under darkness, with gram-positive bacteria found to be more sensitive than gram-negative, and enhanced antimicrobial activity was exhibited under simulated solar excitation compared to darkness. TEM and CLSM images revealed a certain level of bacterial cell membrane destruction after treatment with 1 mg ml(-1) of the material for 12 h, causing the leakage of intracellular contents and bacteria death. These results suggest favorable antibiotic properties and a probable mechanism of the biomaterial for the first time, and further studies are needed to determine its potential application as a postoperative anti-inflammation method in bone transplantation.
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Affiliation(s)
- Jian Yu
- Department of Stomatology, Kunming General Hospital of Chengdu Military Region, #212 Daguan Road, Xishan District, Kunming, Yunnan Province, People's Republic of China. Clinical College of Kunming Medical University, Kunming, People's Republic of China
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22
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Assal FEE, Paula JAM, Capeletti LS, Abrão FY, Ataídes FS, Sá FADS, Costa CR, Fernandes ODFL, Souza LKH, Silva MDRR. Pimenta pseudocaryophyllus inhibits virulence factors and promotes metabolic changes in Candidayeast. Rev Soc Bras Med Trop 2014; 47:618-23. [DOI: 10.1590/0037-8682-0135-2014] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2014] [Accepted: 10/10/2014] [Indexed: 11/21/2022] Open
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23
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Hazen KC. Influence of DMSO on antifungal activity during susceptibility testing in vitro. Diagn Microbiol Infect Dis 2013; 75:60-3. [DOI: 10.1016/j.diagmicrobio.2012.09.002] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2012] [Revised: 08/31/2012] [Accepted: 09/05/2012] [Indexed: 11/30/2022]
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Effects of Pimenta pseudocaryophyllus (Gomes) L. R. Landrum, on Melanized and Non-melanized Cryptococcus neoformans. Mycopathologia 2012; 174:421-8. [DOI: 10.1007/s11046-012-9574-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2011] [Accepted: 08/14/2012] [Indexed: 12/25/2022]
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25
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Fai PB, Grant A. A comparative study of Saccharomyces cerevisiae sensitivity against eight yeast species sensitivities to a range of toxicants. CHEMOSPHERE 2009; 75:289-296. [PMID: 19185901 DOI: 10.1016/j.chemosphere.2008.12.059] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/18/2008] [Revised: 11/13/2008] [Accepted: 12/16/2008] [Indexed: 05/27/2023]
Abstract
Fungi are widespread and very important in many ecosystems but the extensive use of pesticides can adversely affect beneficial fungi. The yeast, Saccharomyces cerevisiae has been proposed for the toxicological assessment of the effects of environmental pollutants on non-target fungi. To assess whether S. cerevisiae is a good representative of the immense ecological and phylogenetic diversity of yeasts, we compare the sensitivity of eight other yeasts from diverse phylogenetic taxa to a range of toxicants and environmental samples. Sensitivity was assessed using both the growth inhibition and alamar blue (resorufin fluorescence inhibition) bioassays. The growth inhibition bioassay showed that all yeast species had similar dose-response curves for the five organic fungicides and two environmental samples used. However, two yeast species, Trichosporon dulcitum and Pseudozyma fusiformata, were a great deal more sensitive than all others to CuSO4 and K2Cr2O7 while S. cerevisiae was the most tolerant to these chemicals. S. cerevisiae, however, showed similar sensitivity as other species to all toxicants in the resorufin fluorescence inhibition bioassay. It can therefore be used as a representative yeast species for assessing effects of environmental contaminants to non-target fungi and in the screening of chemical libraries for fungicidal activity.
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Affiliation(s)
- Patricia Bi Fai
- Centre for Ecology, Evolution and Conservation (CEEC), School of Environmental Sciences, University of East Anglia, Norwich NR47TJ, UK.
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26
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Fai PB, Grant A. A rapid resazurin bioassay for assessing the toxicity of fungicides. CHEMOSPHERE 2009; 74:1165-1170. [PMID: 19138785 DOI: 10.1016/j.chemosphere.2008.11.078] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/29/2008] [Revised: 11/13/2008] [Accepted: 11/26/2008] [Indexed: 05/27/2023]
Abstract
Fungicides are widely used in agriculture, and released in large amounts to the environment. Methods used for antifungal susceptibility testing are cumbersome and time-consuming. As a result, very little attention has been paid to including fungal tests in the routine screening of pesticides and there are no reports in the literature of fungicide focussed effects directed analysis (EDA). In addition very little is known on the toxicity of fungicides to environmentally significant fungi. Here we report a rapid microplate-based resorufin fluorescence inhibition bioassay and compare it with a 24h microplate-based yeast growth inhibition bioassay using eight fungicides. The growth inhibition bioassay was sensitive, giving IC50 and IC90 values comparable to previously reported IC50 or MICs of these fungicides for Saccharomyces cerevisiae and other fungi. The resorufin fluorescence inhibition bioassay was both faster and more sensitive than the growth inhibition bioassay. Inhibitory concentrations obtained just after 30min of incubation with amphotericin B (AMB) and captan were at least a hundred fold lower than IC50s in the literature for fungi. The fluorescence bioassay showed only a small response to pyrazophos and thiabendazole but these only inhibited growth at high concentrations so this may reflect low sensitivity of S. cerevisiae to these particular fungicides. This bioassay can detect toxic effects of a range of fungicides from different chemical classes with different modes of action. It will be valuable for screening chemical libraries for fungicides and as a biomarker for detecting the effects of fungicides to non-target fungi.
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Affiliation(s)
- Patricia Bi Fai
- Centre for Ecology, Evolution and Conservation (CEEC), School of Environmental Sciences, University of East Anglia, Norwich NR47TJ, UK.
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Reliability of the WIDERYST susceptibility testing system for detection of in vitro antifungal resistance in yeasts. Antimicrob Agents Chemother 2008; 52:1062-5. [PMID: 18195057 DOI: 10.1128/aac.01016-07] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
This study evaluated the WIDERYST system, a commercially available computer-assisted image-processing device for the antifungal susceptibility testing of yeasts. A collection of 90 clinical isolates selected to represent ranges of susceptibilities in vitro as broad as possible was tested. An evaluation compared the results obtained by the new system with those achieved by both the Clinical and Laboratory Standards Institute (CLSI) microdilution reference procedure and the antifungal susceptibility standard of the European Committee for Antimicrobial Susceptibility Testing (EUCAST). Overall, the agreement and the correlation index between results obtained by the EUCAST method and the WIDERYST system were 89% and 0.84 (P < 0.01), respectively, and agreement and correlation index between data obtained by the CLSI procedure and the WIDERYST system were 90% and 0.86 (P < 0.01), respectively. The system was able to detect amphotericin B-resistant isolates. All Candida sp. isolates with resistance in vitro to azole agents were detected as well. The system misclassified some isolates belonging to the slowly growing genera Dipodascus and Pichia. A total of 2.7% very major errors were detected for fluconazole. The WIDERYST system is an alternative to reference procedures for antifungal susceptibility testing of clinical isolates of yeasts, particularly for Candida and Cryptococcus species.
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Akram Randhawa M. Dimethyl Sulfoxide (DMSO) Inhibits the Germination of Candida albicans and the Arthrospores of Trichophyton mentagrophytes. ACTA ACUST UNITED AC 2008; 49:125-8. [DOI: 10.3314/jjmm.49.125] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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Pfaller MA, Diekema DJ, Procop GW, Rinaldi MG. Multicenter comparison of the VITEK 2 antifungal susceptibility test with the CLSI broth microdilution reference method for testing amphotericin B, flucytosine, and voriconazole against Candida spp. J Clin Microbiol 2007; 45:3522-8. [PMID: 17913927 PMCID: PMC2168477 DOI: 10.1128/jcm.00403-07] [Citation(s) in RCA: 87] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
A fully automated commercial antifungal susceptibility test system (VITEK 2; bioMérieux, Inc., Hazelwood, MO) was compared in three different laboratories with the Clinical and Laboratory Standards Institute (formerly the NCCLS) reference broth microdilution method (BMD) by testing 2 quality control strains, 10 reproducibility strains, and 426 isolates of Candida spp. against amphotericin B, flucytosine, and voriconazole. Reference BMD MIC endpoints were established after 24 and 48 h of incubation. VITEK 2 system MIC endpoints were determined spectrophotometrically after 9.1 to 27.1 h of incubation (mean, 12 to 14 h). Excellent essential agreement (within 2 dilutions) between the VITEK 2 system and the 24- and 48-h BMD MICs was observed for all three antifungal agents: amphotericin B, 99.1% and 97%, respectively; flucytosine, 99.1% and 98.8%, respectively; and voriconazole, 96.7% and 96%, respectively. Both intra- and interlaboratory agreements were >98% for all three drugs. The overall categorical agreements between the VITEK 2 system and BMD for flucytosine and voriconazole were 98.1 to 98.6% at the 24-h BMD time point and 96.9 to 97.4% at the 48-h BMD time point. The VITEK 2 system reliably detected flucytosine and voriconazole resistance among Candida spp. and demonstrated excellent quantitative and qualitative agreement with the reference BMD method.
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Affiliation(s)
- M A Pfaller
- Medical Microbiology Division, C606 GH, Department of Pathology, University of Iowa College of Medicine, Iowa City, IA 52242, USA.
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Uppuluri P, Mekala S, Chaffin WL. Farnesol-mediated inhibition ofCandida albicansyeast growth and rescue by a diacylglycerol analogue. Yeast 2007; 24:681-93. [PMID: 17583896 DOI: 10.1002/yea.1501] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
During Candida albicans yeast cell growth to early stationary phase, metabolites accumulate in the medium, including the quorum-sensing molecule farnesol. We found that besides germ tube inhibition, 40 microM farnesol also inhibited C. albicans yeast growth under yeast growth permissive conditions. Consistent with this observation, transcriptional analysis of yeast cells resuspended in fresh medium with 40 microM farnesol revealed that genes involved in hyphal formation, GTPase activation, mitosis and DNA replication were downregulated many-fold. Farnesol-mediated inhibition of yeast growth was dependent on the growth phase of the C. albicans cells. The growth defect was relieved by addition of a diacylglycerol analogue, implicating phosphatidylinositol signalling in the delay. Although diacylglycerol is an activator of protein kinase C (PKC) in mammalian cells, there is some question about activation of fungal PKCs. A mutant strain deleted for PKC1 responded to farnesol and the diacylglycerol analogue similar to wild-type, suggesting that PKC is not the target of the diacylglycerol analogue.
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Affiliation(s)
- Priya Uppuluri
- Department of Microbiology and Immunology, Texas Tech University Health Sciences Center, Lubbock, TX 79430, USA
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Arcaya NM, Mesa LM, Pineda MR, Beltrán-Luengo H, Milagros Calvo B. Perfil de sensibilidad antifúngica de especies de Candida aisladas de hemocultivos en un Hospital Universitario, Maracaibo, Venezuela. Rev Iberoam Micol 2006; 23:97-100. [PMID: 16854186 DOI: 10.1016/s1130-1406(06)70022-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022] Open
Abstract
The aim of this study was to determine the in vitro susceptibility of amphotericin B, fluconazole and itraconazole, to several Candida spp recovered from blood cultures on hospitalized patients at the University Hospital of Maracaibo, Venezuela. The determination of the antifungal susceptibility was carried out according to the microdilution method in broth developed by The European Committee for Antimicrobial Susceptibility Testing (EUCAST). The profile of susceptibility of the 74 isolates showed that all the studied species were susceptible to amphotericin B, and 97.2% and 89.2% to fluconazole and itraconazole, respectively.
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Affiliation(s)
- Noris Margarita Arcaya
- Universidad Nacional Experimental Francisco de Miranda, Facultad de Medicina Departamento de Estudios Morfofuncionales, Coro, Estado Falcón, Venezuela.
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Uchida K, Nishiyama Y, Yamaguchi H. [Studies on the correlation of the method currently used by the Japanese Society for Medical Mycology and its modified method with the NCCLS M27-A2 microdilution method for azole susceptibility testing of Candida species]. NIHON ISHINKIN GAKKAI ZASSHI = JAPANESE JOURNAL OF MEDICAL MYCOLOGY 2006; 47:209-17. [PMID: 16940956 DOI: 10.3314/jjmm.47.209] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
To evaluate the currently used Japanese Society for Medical Mycology (JSMM) method for testing the azole susceptibility of yeasts, the activities of fluconazole and itraconazole were tested against recently collected clinical isolates of Candida spp. (n=946) and compared with the National Committee for Clinical Laboratory Standards (NCCLS) M27-A2 microdilution reference method. Favorable correlation with the M27-A2 method was not seen for isolates of C. albicans, C. tropicalis or other Candida spp., particularly their trailing-growth isolates. However, the degree of correlation and agreement of MIC values were markedly improved when testing was performed by the modified JSMM method in which the end-point to be read was changed from IC80 (for the current JSMM method) to IC50. These results suggest that there is an urgent need to revise the current JSMM method.
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Affiliation(s)
- Katsuhisa Uchida
- Teikyo University Research Institute of Medical Mycology, Tokyo, Japan
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Abstract
Dimethyl sulfoxide(DMSO) is frequently used as a solvent for antifungal drugs in various studies to determine their MICs. Reports on comparative evaluation of methods for the susceptibility testing of antifungal drugs have shown there is poor agreement among methods. Besides other factors which could cause variability in the results, one important factor might be the effect of DMSO on the growth of fungi. The effect of DMSO on the growth of some species of Candida has been reported in the literature. The present study aimed at determination of the effect of different concentrations of DMSO (0.125 to 10%) on the growth of dermatophytes by agar diffusion method. There was no growth of fungi in 10% DMSO, between 1.25 and 5% there was a rather linear dose-related inhibitory effect on the growth, significantly different from the controls, and below 1% there was a variable effect among the species. DMSO down to 0.25% significantly inhibited the growth of most strains of M. canis. The lower concentrations of DMSO, which apparently do not affect the growth of fungi, may potentiate the effect of antifungal drugs.
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Affiliation(s)
- Muhammad Akram Randhawa
- Department of Pharmacology, College of Medicine, King Faisal University, Dammam, Saudi Arabia
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Espinel-Ingroff A, Barchiesi F, Cuenca-Estrella M, Pfaller MA, Rinaldi M, Rodriguez-Tudela JL, Verweij PE. International and multicenter comparison of EUCAST and CLSI M27-A2 broth microdilution methods for testing susceptibilities of Candida spp. to fluconazole, itraconazole, posaconazole, and voriconazole. J Clin Microbiol 2005; 43:3884-9. [PMID: 16081926 PMCID: PMC1233914 DOI: 10.1128/jcm.43.8.3884-3889.2005] [Citation(s) in RCA: 106] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The aim of this study was to compare MICs of fluconazole, itraconazole, posaconazole, and voriconazole obtained by the European Committee on Antibiotic Susceptibility Testing (EUCAST) and CLSI (formerly NCCLS) methods in each of six centers for 15 Candida albicans (5 fluconazole-resistant and 4 susceptible-dose-dependent [S-DD] isolates), 10 C. dubliniensis, 7 C. glabrata (2 fluconazole-resistant isolates), 5 C. guilliermondii (2 fluconazole-resistant isolates), 10 C. krusei, 9 C. lusitaniae, 10 C. parapsilosis, and 5 C. tropicalis (1 fluconazole-resistant isolate) isolates. CLSI MICs were obtained visually at 24 and 48 h and spectrophotometric EUCAST MICs at 24 h. The agreement (within a 3-dilution range) between the methods was species, drug, and incubation time dependent and due to lower EUCAST than CLSI MICs: overall, 94 to 95% with fluconazole and voriconazole and 90 to 91% with posaconazole and itraconazole when EUCAST MICs were compared against 24-h CLSI results. The agreement was lower (85 to 94%) against 48-h CLSI endpoints. The overall interlaboratory reproducibility by each method was > or =92%. When the comparison was based on CLSI breakpoint categorization, the agreement was 68 to 76% for three of the four species that included fluconazole-resistant and S-DD isolates; 9% very major discrepancies (< or =8 microg/ml versus > or =64 microg/ml) were observed among fluconazole-resistant isolates and 50% with voriconazole (< or =1 microg/ml versus > or =4 microg/ml). Similar results were observed with itraconazole for seven of the eight species evaluated (28 to 77% categorical agreement). Posaconazole EUCAST MICs were also substantially lower than CLSI MIC modes (0.008 to 1 microg/ml versus 1 to > or =8 microg/ml) for some of these isolates. Therefore, the CLSI breakpoints should not be used to interpret EUCAST MIC data.
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Affiliation(s)
- A Espinel-Ingroff
- VCU Medical Center, Medical Mycology Research Laboratory, 1101 E. Marshall St., Sanger Hall Room 7049, P.O. Box 980049, Richmond, VA 23298-0049, USA.
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Araujo R, Rodrigues AG, Pina-Vaz C. A fast, practical and reproducible procedure for the standardization of the cell density of an Aspergillus suspension. J Med Microbiol 2004; 53:783-786. [PMID: 15272066 DOI: 10.1099/jmm.0.05425-0] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The progressive increase of invasive disease and reports of resistance among Aspergillus species emphasizes the need for reproducible antifungal susceptibility testing. Inoculum standardization is a crucial step in such procedures. The objective of this study was to develop a fast and precise method of evaluating the cell density of an Aspergillus spore suspension, as an alternative to spectrometric readings or cell-counting with a haemocytometer. Densimat (bioMérieux) is a portable photometer that shows a good correlation with spectrometric readings and can advantageously replace the cumbersome, time-consuming method of cell-counting. Thus, Densimat brings significant improvement to the reproducibility and feasibility of standardization of a fungal inoculum.
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Affiliation(s)
- Ricardo Araujo
- Department of Microbiology, Faculty of Medicine, University of Porto, 4200-319 Porto, Portugal 2IPATIMUP, University of Porto, Portugal
| | - Acacio G Rodrigues
- Department of Microbiology, Faculty of Medicine, University of Porto, 4200-319 Porto, Portugal 2IPATIMUP, University of Porto, Portugal
| | - Cidalia Pina-Vaz
- Department of Microbiology, Faculty of Medicine, University of Porto, 4200-319 Porto, Portugal 2IPATIMUP, University of Porto, Portugal
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Abstract
Currently, use of standard antifungal therapies can be limited because of toxicity, low efficacy rates, and drug resistance. New formulations are being prepared to improve absorption and efficacy of some of these standard therapies. Various new antifungals have demonstrated therapeutic potential. These new agents may provide additional options for the treatment of superficial fungal infections and they may help to overcome the limitations of current treatments. Liposomal formulations of AmB have a broad spectrum of activity against invasive fungi, such as Candida spp., C. neoformans, and Aspergillus spp., but not dermatophyte fungi. The liposomal AmB is associated with significantly less toxicity and good rates of efficacy, which compare or exceed that of standard AmB. These factors may provide enough of an advantage to patients to overcome the increased costs of these formulations. Three new azole drugs have been developed, and may be of use in both systemic and superficial fungal infections. Voriconazole, ravuconazole, and posaconazole are triazoles, with broad-spectrum activity. Voriconazole has a high bioavailability, and has been used with success in immunocompromised patients with invasive fungal infections. Ravuconazole has shown efficacy in candidiasis in immunocompromised patients, and onychomycosis in healthy patients. Preliminary in vivo studies with posaconazole indicated potential use in a variety of invasive fungal infections including oropharyngeal candidiasis. Echinocandins and pneumocandins are a new class of antifungals, which act as fungal cell wall beta-(1,3)-D-glucan synthase enzyme complex inhibitors. Caspofungin (MK-0991) is the first of the echinocandins to receive Food and Drug Administration approval for patients with invasive aspergillosis not responding or intolerant to other antifungal therapies, and has been effective in patients with oropharyngeal and esophageal candidiasis. Standardization of MIC value determination has improved the ability of scientists to detect drug resistance in fungal species. Cross-resistance of fungal species to antifungal drugs must be considered as a potential problem to future antifungal treatment, and so determination of susceptibility of fungal species to antifungal agents is an important component of information in development of new antifungal agents. Heterogeneity in susceptibility of species to azole antifungals has been noted. This heterogeneity suggests that there are differences in activity of azoles, and different mechanisms of resistance to the azoles, which may explain the present lack of cross-resistance between some azoles despite apparent structural similarities. The mechanisms of azole action and resistance themselves are not well understood, and further studies into azole susceptibility patterns are required.
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Affiliation(s)
- Aditya K Gupta
- Division of Dermatology, Department of Medicine, Sunnybrook and Women's College Health Science Center (Sunnybrook Site), University of Toronto, 2075 Bayview Avenue, Toronto, Ontario M4N 3M5, Canada.
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Cuenca-Estrella M, Moore CB, Barchiesi F, Bille J, Chryssanthou E, Denning DW, Donnelly JP, Dromer F, Dupont B, Rex JH, Richardson MD, Sancak B, Verweij PE, Rodríguez-Tudela JL. Multicenter evaluation of the reproducibility of the proposed antifungal susceptibility testing method for fermentative yeasts of the Antifungal Susceptibility Testing Subcommittee of the European Committee on Antimicrobial Susceptibility Testing (AFST-EUCAST). Clin Microbiol Infect 2003; 9:467-74. [PMID: 12848721 DOI: 10.1046/j.1469-0691.2003.00592.x] [Citation(s) in RCA: 123] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
OBJECTIVE To evaluate the intra- and inter-laboratory reproducibility of a new standard for susceptibility testing of fermentative yeasts. This standard is based on the M27-A procedure of the National Committee for Clinical Laboratory Standards (NCCLS), but incorporates several modifications, including spectrophotometric growth-dependent endpoint reading. METHODS Nine laboratories participated in the study. Common material lots were used to test six Candida species (one each of C. albicans, C. tropicalis, C. parapsilosis, C. glabrata, C. krusei, and C. lusitaniae), and two quality control strains (C. krusei ATCC6258 and C. parapsilosis ATCC22019). Triplicate testing on three separate days was performed in microtiter format with RPMI-2% glucose, pH 7.0. Flucytosine, fluconazole and itraconazole were tested. In total, 3888 MIC values were included in the analyses. Reproducibility was calculated by means of agreement (percentage of MICs within one two-fold dilution of the mode) and intraclass correlation coefficient (ICC, maximum value of 1). RESULTS The average intra-laboratory agreements were 99% and 96% after 24 h and 48 h of incubation, respectively, with ICCs of 0.98 and 0.97 (P < 0.05). Two strains exhibiting a trailing effect showed intra-laboratory agreement of 92% and ICCs of < 0.91 at 48 h. The inter-laboratory agreement was 94% and 88% after 24 h and 48 h, respectively, with ICCs of 0.93 and 0.91 (P < 0.05). Lower values of agreement and ICCs were obtained for strains exhibiting trailing after 48 h of incubation. Itraconazole yielded the lowest values of reproducibility. CONCLUSION The new procedure of EUCAST for antifungal susceptibility testing is a reproducible method within and between laboratories and offers several advantages over the NCCLS approved method.
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Cuenca-Estrella M, Lee-Yang W, Ciblak MA, Arthington-Skaggs BA, Mellado E, Warnock DW, Rodriguez-Tudela JL. Comparative evaluation of NCCLS M27-A and EUCAST broth microdilution procedures for antifungal susceptibility testing of candida species. Antimicrob Agents Chemother 2002; 46:3644-7. [PMID: 12384382 PMCID: PMC128746 DOI: 10.1128/aac.46.11.3644-3647.2002] [Citation(s) in RCA: 92] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
A two-laboratory study was performed to evaluate the correlation between the NCCLS M27-A and EUCAST microdilution procedures for antifungal testing of Candida spp. A panel of 109 bloodstream isolates was tested against amphotericin B, flucytosine, fluconazole, and itraconazole. Overall, the agreement was 92% and the intraclass correlation coefficient was 0.90 (P < 0.05).
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Affiliation(s)
- Manuel Cuenca-Estrella
- Servicio de Micología, Centro Nacional de Microbiología, Instituto de Salud Carlos III, Majadahonda, Spain
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Bauters TGM, Dhont MA, Temmerman MIL, Nelis HJ. Prevalence of vulvovaginal candidiasis and susceptibility to fluconazole in women. Am J Obstet Gynecol 2002; 187:569-74. [PMID: 12237629 DOI: 10.1067/mob.2002.125897] [Citation(s) in RCA: 99] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
OBJECTIVE The purpose of this study was to determine the prevalence of vaginal colonization by Candida with the use of a rapid detection method, to examine the determinants of vaginal candidiasis, and to evaluate susceptibility for fluconazole. STUDY DESIGN Vaginal swabs were collected from unselected women at the outpatient clinic of the Department of Obstetrics and Gynecology. A differentiation was made between patients with a positive and a negative potassium hydroxide examination. RESULTS Six hundred twelve women were recruited, of whom 39 women (6.3%) had clinical candidiasis. The overall rate of yeast colonization was 20.1%. Candida albicans was isolated most frequently(68.3%), followed by C glabrata (16.3%) and C parapsilosis (8.9%). Clinical candidiasis was related positively with the state of estrogen impregnation. In vitro susceptibility testing by the National Committee for Clinical Laboratory Standards method for fluconazole revealed that 21.1% of the isolates were resistant. CONCLUSION More than 20% of the unselected women were colonized with Candida species. Hyperestrogenemia was associated with an increased vulvovaginal colonization by Candida. Surprisingly, 21% of the isolates was resistant to fluconazole, according to the National Committee for Clinical Laboratory Standards method.
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Affiliation(s)
- Tiene G m Bauters
- Department of Pharmaceutical Analysis, Laboratory of Pharmaceutical Microbiology, Ghent University, Belgium
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Arthington-Skaggs BA, Lee-Yang W, Ciblak MA, Frade JP, Brandt ME, Hajjeh RA, Harrison LH, Sofair AN, Warnock DW. Comparison of visual and spectrophotometric methods of broth microdilution MIC end point determination and evaluation of a sterol quantitation method for in vitro susceptibility testing of fluconazole and itraconazole against trailing and nontrailing Candida isolates. Antimicrob Agents Chemother 2002; 46:2477-81. [PMID: 12121921 PMCID: PMC127334 DOI: 10.1128/aac.46.8.2477-2481.2002] [Citation(s) in RCA: 128] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Visual determination of MIC end points for azole antifungal agents can be complicated by the trailing growth phenomenon. To determine the incidence of trailing growth, we performed testing of in vitro susceptibility to fluconazole and itraconazole using the National Committee for Clinical Laboratory Standards broth microdilution M27-A reference procedure and 944 bloodstream isolates of seven Candida spp., obtained through active population-based surveillance between 1998 and 2000. Of 429 C. albicans isolates, 78 (18.2%) showed trailing growth at 48 h in tests with fluconazole, and 70 (16.3%) showed trailing in tests with itraconazole. Of 118 C. tropicalis isolates, 70 (59.3%) showed trailing growth in tests with fluconazole, and 35 (29.7%) showed trailing in tests with itraconazole. Trailing growth was not observed with any of the other five Candida spp. tested (C. dubliniensis, C. glabrata, C. krusei, C. lusitaniae, and C. parapsilosis). To confirm whether or not isolates that showed trailing growth in fluconazole and/or itraconazole were resistant in vitro to these agents, all isolates that showed trailing growth were retested by the sterol quantitation method, which measures cellular ergosterol content rather than growth inhibition after exposure to azoles. By this method, none of the trailing isolates was resistant in vitro to fluconazole or itraconazole. For both agents, a 24-h visual end point or a spectrophotometric end point of 50% reduction in growth relative to the growth control after 24 or 48 h of incubation correlated most closely with the result of sterol quantitation. Our results indicate that MIC results determined by either of these end point rules may be more predictive of in vivo outcome for isolates that give unclear visual end points at 48 h due to trailing growth.
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Affiliation(s)
- Beth A Arthington-Skaggs
- Mycotic Diseases Branch, Division of Bacterial and Mycotic Diseases, National Center for Infectious Diseases, Centers for Disease Control and Prevention, 1600 Clifton Road NE, Atlanta, GA 30333, USA.
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