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Activity of antifungal drugs and Brazilian red and green propolis extracted with different methodologies against oral isolates of Candida spp. BMC Complement Med Ther 2021; 21:286. [PMID: 34814913 PMCID: PMC8611924 DOI: 10.1186/s12906-021-03445-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2020] [Accepted: 10/19/2021] [Indexed: 01/12/2023] Open
Abstract
Background Oral candidiasis is an opportunistic disease caused by fungi of the Candida genus. The occurrence of Candida spp. resistance to the commercial antifungal drugs points to the search for alternative treatments. Propolis has been successfully used in the treatment of infectious diseases for centuries. It has been proposed that an ultrasound pretreatment in the propolis extraction protocol can enhance the concentrations of molecules with antimicrobial activities in the final extract. Thus, this study aimed to compare the antifungal activity against oral Candida spp. isolates of green and red propolis extracts submitted or not to an ultrasound pretreatment before the extraction procedure. Methods Candida spp. were isolated from denture stomatitis lesions and identified by sequencing. Oral Candida spp. isolates and reference strains were submitted to broth microdilution assays using commercial antifungals and Brazilian green and red propolis extracts submitted or not to an ultrasound pretreatment. Minimal Inhibitory Concentrations (MIC) and Minimal Fungicide Concentrations (MFC) were determined and biofilm formation interference was evaluated for resistant isolates. Results C. albicans, Candida tropicalis and Candida dubliniensis were isolated from denture stomatitis lesions. Growth inhibition was observed in all Candida isolates incubated with all green and red propolis extracts. At lower doses, red propolis extracts presented significant antifungal activity. The ultrasound pretreatment did not promote an increase in the antifungal activity of green or red propolis. Three isolates, which were highly resistant to fluconazole and itraconazole, were susceptible to low doses of red propolis extracts. These same three specimens had their biofilm formation inhibted by red propolis ethanolic extract. Conclusions Thus, red propolis can be faced as a promising natural product to be used in the auxiliary antifungal therapy of denture stomatitis. Supplementary Information The online version contains supplementary material available at 10.1186/s12906-021-03445-5.
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Kleymann G, Werling HO. A Generally Applicable, High-Throughput Screening–Compatible Assay to Identify, Evaluate, and Optimize Antimicrobial Agents for Drug Therapy. ACTA ACUST UNITED AC 2016; 9:578-87. [PMID: 15475477 DOI: 10.1177/1087057104265291] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Efficacy and tolerability are the key criteria for a successful medication in the clinic. Therefore, a new test method to obtain selective and active lead molecules has been developed. Recently, this novel screening strategy enabled a breakthrough in drug discovery in the field of herpes viruses. Here the authors report that this assay is a generally applicable screening test, which allows not only for identifying tolerable and potent antimicrobial agents in compound libraries, but also covers all potential in vitro targets of both the pathogen and the host simultaneously. The test system mimics the smallest unit of a natural infection. Host cells are incubated in the presence of the test sample and are infected with microbes, such as viruses, bacteria, or fungi. Analogous to (lethal challenge) animal models, cell survival is determined. This assay maximizes the chances of success of anti-infective drug discovery, is sensitive, robust, time- and cost-efficient, and especially effective in optimizing screening hits to lead structures and development candidates. In addition to the minimal inhibitory concentration or dose, this test system simultaneously provides the selectivity index, a measure of tolerability in vitro. The authors propose the activity selectivity assay format as a new standard in anti-infective drug discovery and clinical development.
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Affiliation(s)
- Gerald Kleymann
- Bayer Health Care Pharma, Aprather Weg 18 a, D-42096 Wuppertal, Germany
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Mora-Navarro C, Caraballo-León J, Torres-Lugo M, Ortiz-Bermúdez P. Synthetic antimicrobial β-peptide in dual-treatment with fluconazole or ketoconazole enhances the in vitro inhibition of planktonic and biofilm Candida albicans. J Pept Sci 2015; 21:853-61. [PMID: 26470850 DOI: 10.1002/psc.2827] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2015] [Revised: 09/05/2015] [Accepted: 09/09/2015] [Indexed: 11/06/2022]
Abstract
Fungal infections are a pressing concern for human health worldwide, particularly for immunocompromised individuals. Current challenges such as the elevated toxicity of common antifungal drugs and the emerging resistance towards these could be overcome by multidrug therapy. Natural antimicrobial peptides, AMPs, in combination with other antifungal agents are a promising avenue to address the prevailing challenges. However, they possess limited biostability and susceptibility to proteases, which has significantly hampered their development as antifungal therapies. β-peptides are synthetic materials designed to mimic AMPs while allowing high tunability and increased biostability. In this work, we report for the first time the inhibition achieved in Candida albicans when treated with a mixture of a β-peptide model and fluconazole or ketoconazole. This combination treatment enhanced the biological activity of these azoles in planktonic and biofilm Candida, and also in a fluconazole-resistant strain. Furthermore, the in vitro cytotoxicity of the dual treatment was evaluated towards the human hepatoma cell line, HepG2, a widely used model derived from liver tissue, which is primarily affected by azoles. Analyses based on the LA-based method and the mass-action law principle, using a microtiter checkerboard approach, revealed synergism of the combination treatment in the inhibition of planktonic C. albicans. The dual treatment proved to be fungicidal at 48 and 72 h. Interestingly, it was also found that the viability of HepG2 was not significantly affected by the dual treatments. Finally, a remarkable enhancement in the inhibition of the highly azole-resistant biofilms and fluconazole resistant C. albicans strain was obtained.
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Affiliation(s)
- Camilo Mora-Navarro
- Department of Chemical Engineering, University of Puerto Rico, Mayagüez Campus, Mayagüez, 00680, Puerto Rico
| | - Jean Caraballo-León
- Department of Chemical Engineering, University of Puerto Rico, Mayagüez Campus, Mayagüez, 00680, Puerto Rico
| | - Madeline Torres-Lugo
- Department of Chemical Engineering, University of Puerto Rico, Mayagüez Campus, Mayagüez, 00680, Puerto Rico
| | - Patricia Ortiz-Bermúdez
- Department of Chemical Engineering, University of Puerto Rico, Mayagüez Campus, Mayagüez, 00680, Puerto Rico
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Wang K, Yan J, Dang W, Xie J, Yan B, Yan W, Sun M, Zhang B, Ma M, Zhao Y, Jia F, Zhu R, Chen W, Wang R. Dual antifungal properties of cationic antimicrobial peptides polybia-MPI: membrane integrity disruption and inhibition of biofilm formation. Peptides 2014; 56:22-9. [PMID: 24642357 DOI: 10.1016/j.peptides.2014.03.005] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/11/2013] [Revised: 03/06/2014] [Accepted: 03/09/2014] [Indexed: 12/14/2022]
Abstract
With the increasing emergence of resistant fungi, the discovery and development of novel antifungal therapeutics were urgently needed. Compared with conventional antibiotics, the limited propensity of AMPs to induce resistance in pathogens has attracted great interest. In the present study, the antifungal activity and its mechanism-of-action of polybia-MPI, a cationic peptide from the venom of Social wasp Polybia Paulista was investigated. We demonstrated that polybia-MPI could potently inhibit the growth of Candida albicans (C. albicans) and Candida glabrata (C. glabrata). The 50% inhibitory concentrations (IC50) of Polybia-MPI against cancer cells were much higher than the MICs against the tested C. albicans and C. glabrata cells, indicating that polybia-MPI had high selectivity between the fungal and mammalian cells. Our results also indicated that membrane disturbance mechanism was involved in the antifungal activity. Furthermore, polybia-MPI could inhibit the bio film forming of C. glabrata, which was frequently associated with clinically significant biofilm. These results suggest that polybia-MPI has great advantages in the development of antifungal agents.
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Affiliation(s)
- Kairong Wang
- Key Laboratory of Preclinical Study for New Drugs of Gansu Province, School of Basic Medical Sciences, Lanzhou University, 222 Tian Shui South Road, Lanzhou 730000, PR China
| | - Jiexi Yan
- Key Laboratory of Preclinical Study for New Drugs of Gansu Province, School of Basic Medical Sciences, Lanzhou University, 222 Tian Shui South Road, Lanzhou 730000, PR China
| | - Wen Dang
- Key Laboratory of Preclinical Study for New Drugs of Gansu Province, School of Basic Medical Sciences, Lanzhou University, 222 Tian Shui South Road, Lanzhou 730000, PR China
| | - Junqiu Xie
- Key Laboratory of Preclinical Study for New Drugs of Gansu Province, School of Basic Medical Sciences, Lanzhou University, 222 Tian Shui South Road, Lanzhou 730000, PR China
| | - Bo Yan
- Key Laboratory of Preclinical Study for New Drugs of Gansu Province, School of Basic Medical Sciences, Lanzhou University, 222 Tian Shui South Road, Lanzhou 730000, PR China
| | - Wenjin Yan
- Key Laboratory of Preclinical Study for New Drugs of Gansu Province, School of Basic Medical Sciences, Lanzhou University, 222 Tian Shui South Road, Lanzhou 730000, PR China
| | - Mengyang Sun
- Key Laboratory of Preclinical Study for New Drugs of Gansu Province, School of Basic Medical Sciences, Lanzhou University, 222 Tian Shui South Road, Lanzhou 730000, PR China
| | - Bangzhi Zhang
- Key Laboratory of Preclinical Study for New Drugs of Gansu Province, School of Basic Medical Sciences, Lanzhou University, 222 Tian Shui South Road, Lanzhou 730000, PR China
| | - Mingxia Ma
- Key Laboratory of Preclinical Study for New Drugs of Gansu Province, School of Basic Medical Sciences, Lanzhou University, 222 Tian Shui South Road, Lanzhou 730000, PR China
| | - Yanyan Zhao
- Key Laboratory of Preclinical Study for New Drugs of Gansu Province, School of Basic Medical Sciences, Lanzhou University, 222 Tian Shui South Road, Lanzhou 730000, PR China
| | - Fengjing Jia
- Key Laboratory of Preclinical Study for New Drugs of Gansu Province, School of Basic Medical Sciences, Lanzhou University, 222 Tian Shui South Road, Lanzhou 730000, PR China
| | - Ranran Zhu
- Key Laboratory of Preclinical Study for New Drugs of Gansu Province, School of Basic Medical Sciences, Lanzhou University, 222 Tian Shui South Road, Lanzhou 730000, PR China
| | - Wei Chen
- Key Laboratory of Preclinical Study for New Drugs of Gansu Province, School of Basic Medical Sciences, Lanzhou University, 222 Tian Shui South Road, Lanzhou 730000, PR China
| | - Rui Wang
- Key Laboratory of Preclinical Study for New Drugs of Gansu Province, School of Basic Medical Sciences, Lanzhou University, 222 Tian Shui South Road, Lanzhou 730000, PR China.
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Lee SE, Jo TM, Lee HY, Lee J, Jung KH. β-galactosidase-catalyzed synthesis of galactosyl chlorphenesin and its characterization. Appl Biochem Biotechnol 2013; 171:1299-312. [PMID: 23564435 DOI: 10.1007/s12010-013-0213-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2012] [Accepted: 03/21/2013] [Indexed: 10/27/2022]
Abstract
We synthesized galactosyl chlorphenesin (CPN-G) using β-gal-containing Escherichia coli (E. coli) cells in which the conversion yield of chlorphenesin (CPN) to CPN-G reached about 64 % during 12 h. CPN-G was identified and characterized using high-performance liquid chromatography, liquid chromatography-mass spectrometry, Fourier transform-infrared spectrometry, and nuclear magnetic resonance analysis ((1)H and (13)C). We verified that a galactose was covalently bound to a CPN alcohol group during CPN-G synthesis throughout these analyses. In particular, by the hydrolysis of CPN-G using β-gal, it was confirmed that a galactose was bound to CPN. The minimal inhibitory concentration (MIC) results showed that the CPN-G MICs were fairly similar to those of CPN. HACAT cell viability was significantly higher in CPN-G-treated cells than in CPN-treated cells at concentrations of 0.0-20.0 mM. Finally, we accomplished the synthesis of less toxic CPN-G, compared with CPN, using β-gal-containing E. coli cells as whole cells without changes in the MICs against microorganisms.
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Affiliation(s)
- Sang-Eun Lee
- Department of Biotechnology, Korea National University of Transportation, Jeungpyung, Chungbuk, 368-701, Republic of Korea
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Dornelas-Ribeiro M, Pinheiro EO, Guerra C, Braga-Silva LA, Carvalho SMFD, Santos ALSD, Rozental S, Fracalanzza SEL. Cellular characterisation of Candida tropicalis presenting fluconazole-related trailing growth. Mem Inst Oswaldo Cruz 2012; 107:31-8. [DOI: 10.1590/s0074-02762012000100005] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2011] [Accepted: 08/16/2011] [Indexed: 11/22/2022] Open
Affiliation(s)
- Marcos Dornelas-Ribeiro
- Instituto de Biologia do Exército, Brasil; Instituto Estadual de Hematologia, Brasil; Hospital Adventista Silvestre, Brasil; Instituto de Microbiologia Paulo de Góes
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Duarte C, Pulido N, Rivas P, Sánchez R, Cortés JA, Cuervo S, Parra C. Comparación de métodos de microdilución CLSI M27-A2 y EUCAST en aislamientos de Candida spp. en pacientes con cáncer. INFECTIO 2010. [DOI: 10.1016/s0123-9392(10)70128-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
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Crucigasterins A–E, antimicrobial amino alcohols from the Mediterranean colonial ascidian Pseudodistoma crucigaster. Tetrahedron 2010. [DOI: 10.1016/j.tet.2010.07.056] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
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Favalessa OC, Ribeiro LC, Tadano T, Fontes CJF, Dias FB, Coelho BPA, Hahn RC. [First description of phenotypic profile and in vitro drug susceptibility of Cryptococcus spp yeast isolated from HIV-positive and HIV-negative patients in State of Mato Grosso]. Rev Soc Bras Med Trop 2010; 42:661-5. [PMID: 20209351 DOI: 10.1590/s0037-86822009000600010] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2009] [Accepted: 10/19/2009] [Indexed: 11/21/2022] Open
Abstract
Thirty-seven isolates from 10 HIV-negative and 26 HIV-positive patients in Mato Grosso were evaluated. Direct examination, culturing and chemotyping of species were performed. Ketoconazole, itraconazole, voriconazole, fluconazole and amphotericin B were evaluated. Thirty-seven yeasts of Cryptococcus spp were identified, of which 26 were from HIV-positive patients (25 Cryptococcus neoformans and one Cryptococcus gattii) and 10 from HIV-negative patients (five Cryptococcus neoformans and five Cryptococcus gattii). The Cryptococcus neoformans clinical isolates from HIV-positive patients showed resistance (8% and 8.7%) and dose-dependent susceptibility (20% and 17.4%) to fluconazole and itraconazole, respectively. Among the Cryptococcus neoformans isolates from HIV-negative patients, there was dose-dependent susceptibility (40%) to fluconazole. Cryptococcus gattii isolates from HIV-negative patients were shown to be susceptible to all antifungal agents, except for one isolate of Cryptococcus gattii that showed dose-dependent susceptibility to fluconazole (20%). The Cryptococcus gattii isolate from an HIV-positive patient showed resistance to fluconazole (MIC > or = 256 (1/4)g/ml) and itraconazole (MIC = 3 (1/4)microg/ml).
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Affiliation(s)
- Olivia Cometti Favalessa
- Laboratório de Investigação (Micologia), Faculdade de Ciências Médicas, Universidade Federal de Mato Grosso, Cuiabá, MT
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Klip NT, Capan G, Gürsoy A, Uzun M, Satana D. Synthesis, structure, and antifungal evaluation of some novel 1,2,4-triazolylmercaptoacetylthiosemicarbazide and 1,2,4-triazolylmercaptomethyl-1,3,4-thiadiazole analogs. J Enzyme Inhib Med Chem 2010; 25:126-31. [PMID: 20030516 DOI: 10.3109/14756360903040439] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Novel 1-[[4-(4-bromophenyl)-5-(2-furyl)-4H-1,2,4-triazole-3-yl]mercaptoacetyl]-4-alkyl/aryl-3-thiosemicarbazides (5-12) were synthesized by the reaction of 4-(4-bromophenyl)-5-(2-furyl)-4H-1,2,4-triazole-3-ylmercaptoacetylhydrazide (4) with substituted isothiocyanates. Cyclodehydration of thiosemicarbazides with concentrated sulfuric acid yielded 2-[4-(4-bromophenyl)-5-(2-furyl)-4H-1,2,4-triazole-3-yl]mercaptomethyl-5-alkyl/arylamino-1,3, 4-thiadiazoles (13-17). The new compounds were evaluated for in vitro antifungal activity using the microdilution method. The tested compounds showed varying degrees of activity against Microsporum gypseum NCPF-580, Microsporum canis, Trichophyton mentagrophytes, Trichophyton rubrum, and Candida albicans ATCC 10231 (MIC 8-4 microg/mL).
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Affiliation(s)
- Nalan Terzioğlu Klip
- Department of Pharmaceutical Chemistry, Faculty of Pharmacy, Istanbul University, Istanbul, Turkey.
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Li Y, Carbone M, Vitale RM, Amodeo P, Castelluccio F, Sicilia G, Mollo E, Nappo M, Cimino G, Guo YW, Gavagnin M. Rare casbane diterpenoids from the Hainan soft coral Sinularia depressa. JOURNAL OF NATURAL PRODUCTS 2010; 73:133-138. [PMID: 20121250 DOI: 10.1021/np900484k] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
A series of nine casbane diterpenes, compounds 5-13, exhibiting either cis or trans ring junctions were isolated from the Hainan soft coral Sinularia depressa. The structures of this group of compounds, the basic member of which was named depressin (5), were established by detailed spectroscopic analysis. In addition, the absolute configuration of the main metabolite, 10-hydroxydepressin (7), and of its epimer, 1-epi-10-hydroxydepressin (8), was determined by a combination of conformational analysis and the modified Mosher's method. A stereochemical relationship between all isolated molecules was investigated by analyzing their circular dichroism profiles. Antiproliferative and antibacterial activities of the depressins were also evaluated.
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Affiliation(s)
- Yan Li
- State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, People's Republic of China
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Manzo E, Ciavatta ML, Melck D, Schupp P, de Voogd N, Gavagnin M. Aromatic cyclic peroxides and related keto-compounds from the Plakortis sp. component of a sponge consortium. JOURNAL OF NATURAL PRODUCTS 2009; 72:1547-51. [PMID: 19618913 PMCID: PMC2842915 DOI: 10.1021/np900310j] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Six unreported aromatic compounds, 1-6, were isolated, along with the known compounds dehydrocurcuphenol and manoalide, from a sample of Plakortis sp., which was the main component of a Pacific sponge consortium. The new molecules were chemically characterized by spectroscopic methods. Compounds 1-4 contain a six-membered cyclic peroxide, whereas 5 and 6 display a terminal methyl ketone. The new metabolites were tested for antifungal and antibacterial properties. Compounds 1 and 4 were weakly active against S. aureus.
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Affiliation(s)
- Emiliano Manzo
- Istituto di Chimica Biomolecolare, CNR, Via Campi Flegrei 34, I 80078-Pozzuoli (Naples), Italy.
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14
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Silva PRD, Rabelo RADS, Terra APS, Teixeira DNS. [Susceptibility to antifungal agents among Cryptococcus neoformans varieties isolated from patients at a university hospital]. Rev Soc Bras Med Trop 2008; 41:158-62. [PMID: 18545836 DOI: 10.1590/s0037-86822008000200005] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2007] [Accepted: 03/10/2008] [Indexed: 11/22/2022] Open
Abstract
This study identified Cryptococcus neoformans varieties isolated from 35 patients at teaching hospital of the Federal University of the Triângulo Mineiro and evaluated the susceptibility to antifungal agents among these samples using the protocol M27-A2 from the National Committee for Clinical Laboratory Standards. The gattii variety was identified in 11.4% of the cases (n = 4). The minimum inhibitory concentration (mg/ml) of Cryptococcus neoformans neoformans isolates ranged from 0.062 to 2.000 (amphotericin B), 0.250 to 8.000 (fluconazole), 0.062 to 1.000 (itraconazole) and 0.125 to 1.000 (ketoconazole). The gattii variety presented a minimum inhibitory concentration range of 0.125 to 2.000 (amphotericin B), 0.250 to 16.00 (fluconazole), 0.062 to 1.000 (itraconazole) and 0.125 to 4.000 (ketoconazole). Two isolates resistant to itraconazole and two resistant to amphotericin B (one isolate of each variety per antifungal agent) were found. These data show the importance of determining the variety and minimum inhibitory concentration of Cryptococcus neoformans isolates, in order to monitor resistance development and enable better treatment for cryptococcosis.
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Affiliation(s)
- Paulo Roberto da Silva
- Departamento de Ciências Biológicas, Universidade Federal do Triângulo Mineiro, Uberaba, M.G
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Cho WM, Joshi BP, Cho H, Lee KH. Design and synthesis of novel antibacterial peptide-resin conjugates. Bioorg Med Chem Lett 2007; 17:5772-6. [PMID: 17827001 DOI: 10.1016/j.bmcl.2007.08.056] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2007] [Revised: 08/14/2007] [Accepted: 08/24/2007] [Indexed: 10/22/2022]
Abstract
We synthesized a novel peptide-resin conjugate by immobilizing beta-sheet antibacterial peptide on PEG-PS resin. The peptide-resin conjugate, similar to cationic antimicrobial peptides, demonstrated unique properties such as potent antibacterial activity, no hemolytic activity, lipid membrane perturbation activity, and potent synergism with vancomycin. Specially, the peptide-resin conjugate showed a more increased lipid membrane perturbation activity in comparison to unbound beta-sheet antibacterial peptide.
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Affiliation(s)
- Won-Mi Cho
- Bioorganic Chemistry Laboratory, Department of Chemistry, Inha University, 253 Younghyong-Dong, Nam-Gu, Inchon-City 402-751, South Korea
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Jensen J, Muñoz P, Guinea J, Rodríguez-Créixems M, Peláez T, Bouza E. Mixed Fungemia: Incidence, Risk Factors, and Mortality in a General Hospital. Clin Infect Dis 2007; 44:e109-14. [PMID: 17516389 DOI: 10.1086/518175] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2006] [Accepted: 02/28/2007] [Indexed: 11/03/2022] Open
Abstract
BACKGROUND Fungemia has been historically considered to be a disease caused by a single Candida species; the detection of >1 species of yeast in circulating blood was distinctly uncommon using traditional microbiological procedures. We describe episodes of mixed fungemia (MF), detected between 1985 and 2006, in a large teaching hospital. METHODS The study was divided into 2 periods that were separated by the introduction, in January 2005, of the CHROmagar Candida medium (CHROMagar) for the routine subculturing of blood cultures in which yeast has been identified. Overall, we documented 747 cases of fungemia. During the first period (1985-1994), we identified 217 episodes of fungemia and no single episode of MF; during the second period (1995-2006), 15 episodes of MF were detected among 530 episodes of fungemia (2.8%). Candida albicans was isolated in 13 patients, non-albicans species of Candida in 16 patients, and Saccharomyces cerevisiae in 1 patient. Each episode of MF was compared with 2 control episodes of monomicrobial fungemia. RESULTS Patients with MF had more frequently experienced organ transplantation (13% vs. 0%) and surgery (60% vs. 27%), had less frequently received parenteral nutrition (40% vs. 70%) or had intravenous lines (80% vs. 100%), and had a lower incidence of shock (6% vs. 37%) and a lower mortality (20% vs. 53%). CONCLUSIONS Despite the introduction of chromogenic agar, MF is still an uncommon disease and has a less severe outcome than does monomicrobial candidemia.
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Affiliation(s)
- Julia Jensen
- Clinical Microbiology and Infectious Diseases Department, Hospital General Universitario Gregorio Maranon, Universidad Complutense, Madrid, Spain
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Teixeira ABA, Moretti ML, Machado HC, Nishimura K, Taguchi H, Schreiber AZ. Evaluation of the inhibitory effect of amphotericin B on the apical growth ofF. solaniusing the BioCell-Tracer®System. Mycoses 2007; 50:183-8. [PMID: 17472613 DOI: 10.1111/j.1439-0507.2007.01367.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The BioCell-Tracer (BCT) system is an automatic microscopic method used for measuring the growth rate of a single fungal hyphae, which has not yet been applied to study Fusarium spp. Considering the large resistance of Fusarium species to the available chemotherapy and that hyphae is the morphological fungal form most often seen in vivo, in this work, Amphotericin B MIC and MFC values for a Fusarium solani strain were obtained by the conventional assay method testing conidia and also by the BCT monitoring system. Both MIC and MFC values of AMB against F. solani determined by broth dilution method resulted in 4.0 microg ml(-1). By the BCT system, their values were 1.0 microg ml(-1), with an inhibition rate of 99.5% (Exp-GR) and 100.0% (Post-GR), showing that when testing hyphae directly, MIC and MFC were determined at two lower dilutions than the MIC and MFC values obtained with conidia. Using the BCT system, 4.0, 2.0 and 1.0 microg ml(-1) of AMB concentrations inhibited hyphae growth in 50 min whereas 0.5 microg ml(-1) of AMB needed 100 min to start hyphae growth inhibition. These findings lead us to conclude that antifungal susceptibility varies between conidia and hyphae. For this strain of Fusarium solani, hyphae were more susceptible to AMB than conidia.
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Almeida AMF, Matsumoto MT, Baeza LC, de Oliveira E Silva RB, Kleiner AAP, Melhem MDSC, Mendes Giannini MJS. Molecular typing and antifungal susceptibility of clinical sequential isolates of Cryptococcus neoformans from Sao Paulo State, Brazil. FEMS Yeast Res 2007; 7:152-64. [PMID: 17311593 DOI: 10.1111/j.1567-1364.2006.00128.x] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
The antifungal susceptibility profiles and the genetic variability of 83 sequential clinical isolates of Cryptococcus neoformans, including four Cryptococcus gattii isolates, obtained from 38 Sao Paulo AIDS patients with cryptococcal meningitis were assessed by electrophoretic karyotyping and random amplified polymorphic DNA (RAPD) analysis. The majority of the Cryptococcus neoformans isolates were highly susceptible to amphotericin B and fluconazole. Twenty percent of the minimum inhibitory concentration values for amphotericin B varied from 0.5 to 1 micro g mL(-1). For fluconazole, 22% occurred in the range 8-16 mug mL(-1). Sequential isolates from nine patients showed a trend towards lower susceptibility to fluconazole, flucytosine, itraconazole and amphotericin B. The results of molecular typing by electrophoretic karyotyping and RAPD analysis showed the presence of 22 electrophoretic karyotypes (EK) and 15 RAPD profiles that were highly correlated. Our results provided evidence for the occurrence of genetic changes in some strains associated with microevolution during the course of infection. We also observed both microevolution and simultaneous coinfection with two distinct Cryptococcus neoformans strains in one patient. In some patients, we found changed EK- and RAPD patterns in association with increased MIC values.
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Wittebolle V, Lemriss S, La Morella G, Errante J, Boiron P, Barret R, Sarciron ME. Antifungal effects of aminosulphoxide and disulphide derivatives. Mycoses 2006; 49:169-75. [PMID: 16681806 DOI: 10.1111/j.1439-0507.2006.01233.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
2-Benzenesulphinyl-(1,4)-naphtoquinone and 14 derivatives were synthesised and were used to evaluate their cytotoxicity against a human myelomonocyte cell line and their antifungal activity against two yeast, i.e. Candida albicans and C. tropicalis and against two filamentous fungi such as Aspergillus niger and Fusarium oxysporum and against one dermatophyte, namely Trichophyton tonsurans. The cytotoxicity and antifungal activities were investigated in comparison with amphotericin B as reference drug. No compound was significantly more toxic than amphotericin B at 0.2 microg ml(-1). The best results of antifungal activity were obtained with GFL 10, GFL 13 and GFL 30 on C. tropicalis, F. oxysporum and T. tonsurans. For C. albicans and A. niger, there was no difference between amphotericin B and the other molecules. The sterol quantitation, the time-kill curves were carried out for these three compounds in order to confirm their action in ergosterol synthesis. Time-kill curves showed a fungistatic activity. For C. tropicalis GFL 10, GFL 13 and GFL 30 increased the growth delay better than amphotericin B, in contrast to F. oxysporum. As for T. tonsurans, GFL10 and GFL13 gave a delay, but the effect of GFL 30 was a bit less marked.
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Affiliation(s)
- Veerle Wittebolle
- Department of Parasitology and Medical Mycology, Claude Bernard University, Lyon cedex, France
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21
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Ahn HS, Cho W, Kang SH, Ko SS, Park MS, Cho H, Lee KH. Design and synthesis of novel antimicrobial peptides on the basis of alpha helical domain of Tenecin 1, an insect defensin protein, and structure-activity relationship study. Peptides 2006; 27:640-8. [PMID: 16226345 DOI: 10.1016/j.peptides.2005.08.016] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/14/2005] [Revised: 08/30/2005] [Accepted: 08/31/2005] [Indexed: 11/21/2022]
Abstract
Tenecin 1, a peptide consisting of 43 amino acids, exhibits a potent bactericidal activity against various Gram-positive bacteria and shares a common structural feature of insect defensin family corresponding to cysteine stabilized alpha/beta motif. Our previous research indicated that an active fragment was successfully extracted from C-terminal beta sheet domain of Tenecin 1, whereas the fragment corresponding to the alpha helical region of the protein had no antibacterial activity. We chose this inactive fragment corresponding to alpha helical region of Tenecin 1 and synthesized derivatives with a different net positive charge by using rational design. Interestingly, we successfully endowed antibacterial activity as well as antifungal activity to the inactive alpha helical fragment by single or double amino acid replacement(s) without an increase of hemolytic activity. The leakage of dye from vesicles induced by the active peptides suggested that these peptides act on the membranes of pathogen as a primary mode of action. Structure-activity relationship study of a series of the active derivatives revealed that amphiphilic structure and high net positive charge were prerequisite factors for the activity and that there was a relationship between the antibacterial activity and the isoelectric point of the active peptides. In this work, we showed an efficient method to endow the antibacterial activity as well as antifungal activity to the inactive fragment derived from a cyclic insect defensin protein and suggested a facile method to screen for active fragments from cyclic host defense peptides.
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Affiliation(s)
- Hye-Sun Ahn
- Department of Chemistry, Inha University, 253 Younghyun-Dong, Nam-Gu, Inchon-City 402-751, Republic of Korea
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Muñoz P, Sánchez-Somolinos M, Alcalá L, Rodríguez-Créixems M, Peláez T, Bouza E. Candida krusei fungaemia: antifungal susceptibility and clinical presentation of an uncommon entity during 15 years in a single general hospital. J Antimicrob Chemother 2005; 55:188-93. [PMID: 15650001 DOI: 10.1093/jac/dkh532] [Citation(s) in RCA: 65] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
BACKGROUND Candida krusei fungaemia is an uncommon entity described in immunocompromised patients previously exposed to azole agents. METHODS From 1988 to 2003, 13 episodes of C. krusei fungaemia (2.3% of all fungaemias) were detected in our institution and compared with 39 Candida albicans controls. Susceptibility testing was carried out with the modified microdilution method according to NCCLS recommendations. RESULTS Underlying conditions were: HIV infection (4), haematological malignancies (4), organ transplantation (2), abdominal surgery (2) and lactose intolerance (1). Nine patients (69%) were not neutropenic. In comparison with C. albicans, patients with C. krusei infection had more commonly received antifungal agents (54% versus 15%, P = 0.006), had a haematological disease (31% versus 3%, P = 0.03), or a transplant (15% versus 3%, P = 0.08), were on corticosteroids (47% versus 13%, P = 0.01) and were neutropenic (31% versus 0%, P < 0.001). Patients with C. albicans had more surgical interventions (41% versus 15%, P = 0.09) and bladder catheters (61% versus 31%, P = 0.05). The most common origin for C. albicans was a catheter (41% versus 0%; P = 0.006) whereas for C. krusei the most common origin was unknown (69% versus 20%; P = 0.001). C. krusei presented more commonly with skin lesions in neutropenic patients (23% versus 5%; P = 0.05). Multivariate analysis of these differential characteristics showed that the only factor that independently predicted the presence of C. krusei fungaemia was the administration of antifungal agents before the fungaemia (RR: 6.4; P=0.009; 95%CI 1.6-25.99). Overall mortality of C. krusei fungaemia was 38% (C. albicans 49%). Except for voriconazole (MIC90 0.125 mg/L), azoles and 5-flucytosine had poor activity against C. krusei, whereas amphotericin (MIC90 1 mg/L) and LY-303366 (MIC90 0.06 mg/L) showed good activity. CONCLUSION C. krusei fungaemia incidence remains low despite widespread use of azoles. It may occur outside the setting of cancer patients with previous antifungal use. The presence of skin lesions should be a warning sign.
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Affiliation(s)
- Patricia Muñoz
- Clinical Microbiology and Infectious Diseases Department, Hospital General Universitario Gregorio Marañón, Doctor Esquerdo 47, 28006 Madrid, Spain.
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Raso TF, Werther K, Miranda ET, Mendes-Giannini MJS. Cryptococcosis outbreak in psittacine birds in Brazil. Med Mycol 2004; 42:355-62. [PMID: 15473361 DOI: 10.1080/13693780410001712061] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022] Open
Abstract
An outbreak of cryptococcosis occurred in a breeding aviary in São Paulo, Brazil. Seven psittacine birds (of species Charmosyna papou, Lorius lory, Trichoglossus goldiei, Psittacula krameri and Psittacus erithacus) died of disseminated cryptococcosis. Incoordination, progressive paralysis and difficulty in flying were seen in five birds, whereas superficial lesions coincident with respiratory alterations were seen in two birds. Encapsulated yeasts suggestive of Cryptococcus sp. were seen in faecal smears stained with India ink in two cases. Histological examination of the birds showed cryptococcal cells in various tissues, including the beak, choana, sinus, lungs, air sacs, heart, liver, spleen, kidneys, intestines and central nervous system. High titres of cryptococcal antigen were observed in the serum of an affected bird. In this case, titres increased during treatment and the bird eventually died. Yeasts were isolated from the nasal mass, faeces and liver of one bird. Cryptococcus neoformans var. gattii serovar B was identified based on biochemical, physiological and serological tests. These strains were resistant (minimum inhibitory concentration 64 microg/ml) to fluconazole. This is the first report of C. neoformans var. gattii occurring in psittacine birds in Brazil.
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Affiliation(s)
- T F Raso
- Departamento de Patologia Veterinária (FCAV/UNESP), Jaboticabal, SP Brazil
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24
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Stringaro A, Molinari A, Calcabrini A, Arancia G, Ceddia PG, Cianfriglia M, Poloni F, Mondello F, Angiolella L, De Bernardis F, Cassone A. Detection of human P-glycoprotein-like molecule in azole-resistant Candida albicans from HIV+ patients. Microb Drug Resist 2003; 8:235-44. [PMID: 12363014 DOI: 10.1089/107662902760326968] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Azole resistance in Candida albicans may be due to several mechanisms. It has been demonstrated that C. albicans possesses sequences with a high degree of homology with the human MDR-1 gene coding for P-glycoprotein (P-gp), belonging to the ATP-binding cassette transporter (ABC) superfamily and responsible for the multidrug resistance (MDR) in tumor cells. On this basis, the expression and intracellular localization of human P-gp-like molecule in C. albicans strains showing different sensitivity to fluconazole were investigated by flow cytometry and immunoelectron microscopy. Post-embedding immunolabeling revealed that monoclonal antibody (mAb) MM4.17, which recognizes an external epitope of human P-gp, reacted with both fluconazole-sensitive (3153 and CO 23-1) and fluconazole-resistant (AIDS 68 and CO 23-2, isolated from AIDS patient and in vitro drug-selected, respectively) strains of C. albicans. However, the resistant strains displayed a number of MM4.17-reactive epitopes much higher than the drug-sensitive ones. The C. krusei ATCC 6458 strain, whose resistance is not mediated by the presence of ABC transporters, was not reactive at all with mAb MM4.17. The specificity of the immunolabeling was confirmed by a competitive inhibition assay performed by using phage clone particles capable of mimicking the MM4.17-reactive epitope. The flow cytometric analysis confirmed a higher level of intracytoplasmic P-gp expression in azole-resistant strains of C. albicans. Both cyclosporin A and verapamil, which are well-known MDR inhibitors, strongly reduced the MICs for fluconazole and itraconazole of the tested azole-resistant AIDS 68 strain, while they did not influence the MICs of either the sensitive 3153 strain of C. albicans or the ATCC 6458 strain of C. krusei. Overall, our data suggest the existence of a P-gp-like drug efflux pump in C. albicans that may participate in the mechanisms of azole-resistance of this fungus.
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Affiliation(s)
- Annarita Stringaro
- Laboratorio di Ultrastrutture, Istituto Superiore di Sanità, Rome, Italy
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25
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Muñoz P, Fernández-Turégano CP, Alcalá L, Rodríguez-Créixems M, Peláez T, Bouza E. Frequency and clinical significance of bloodstream infections caused by C albicans strains with reduced susceptibility to fluconazole. Diagn Microbiol Infect Dis 2002; 44:163-7. [PMID: 12458123 DOI: 10.1016/s0732-8893(02)00432-7] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Reduced susceptibility to fluconazole (RSF) is relatively common in non-albicans Candida isolates and in Candida albicans recovered from HIV-infected patients with relapsing Candida stomatitis or esophagitis. However, little clinical data on bloodstream infections caused by C. albicans with RSF is available. We analyzed 116 episodes of C. albicans fungemia detected over an 11-year period. Four patients (3.4%) had a blood isolate of C. albicans with RSF. Fluconazole MICs were 16 (3 SDD strains) and 128 microg/ml (1 resistant strain), respectively. Three of the patients were HIV (+) and the fourth was a liver transplant recipient. All of them had been previously treated with an azole compound. The liver recipient had breakthrough fungemia while being treated with 400 mg of preemptive fluconazole despite having an MIC of 16 microg/ml. Fluconazole clinical failure was documented in two of the remaining three cases. Only five other patients with C. albicans fungemia caused by fluconazole-resistant strains (>or=64 microg/ml) are described in the literature. Candida albicans fungemia produced by strains with RSF is still uncommon. It should be suspected in patients previously treated with azole agents or with breakthrough fungemia. In our experience, fluconazole remains a safe option for the treatment of most C. albicans fungemias, although surveillance seems advisable.
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Affiliation(s)
- Patricia Muñoz
- Clinical Microbiology and Infectious Diseases Department, Hospital General Universitario "Gregorio Marañón", Madrid, Spain.
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26
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Cuenca-Estrella M, Rodríguez-Tudela JL. Present status of the detection of antifungal resistance: the perspective from both sides of the ocean. Clin Microbiol Infect 2002; 7 Suppl 2:46-53. [PMID: 11525218 DOI: 10.1111/j.1469-0691.2001.tb00009.x] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The NCCLS reference methodology for antifungal susceptibility testing is a new milestone of the evolution of medical mycology. The use of this methodology however, is not problem-free. At present, major limitations are a trailing phenomenon with azoles, unreliable detection of resistance to amphotericin B, poor growth of some organisms and unpractical procedures for the clinical laboratory. Herein a overview of NCCLS guidelines for yeasts and filamentous fungi is presented. Likewise, a review of studies conducted trying to overcome the limitations of reference procedures is also included. Several alternative approaches are reviewed as alternative media, inoculum size and incubation time. Modifications of reading procedure and endpoint determination are also evaluated. Agar diffusion methods and other methods for susceptibility testing are cited. Finally, we discuss the data on correlation of the in vitro results with the in vivo activity.
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Affiliation(s)
- M Cuenca-Estrella
- Servicio de Micrología, Centro Nacional de Microbiología, Instituto de Salud Carlos III, Majadahonda, Madrid, Spain.
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Pfaller MA, Yu WL. Antifungal susceptibility testing. New technology and clinical applications. Infect Dis Clin North Am 2001; 15:1227-61. [PMID: 11780273 DOI: 10.1016/s0891-5520(05)70192-6] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
The state of the art for susceptibility testing of yeasts is comparable with that of bacteria. Standardized methods for performing antifungal susceptibility testing are reproducible, accurate, and available in clinical laboratories. The development of quality control limits and interpretive criteria for a limited number of antifungal agents provides a basis for the application of this testing in the clinical laboratory. A proficiency testing program is available as a quality assurance measure for laboratories and has documented steady improvement among laboratories using the NCCLS method. As with antibacterial agents, surveillance programs are now in place using reference quality testing methods to monitor antifungal resistance trends on a global scale. It is clear that antifungal susceptibility testing can predict outcome in several clinical situations. Susceptibility testing is most helpful in dealing with infection caused by non-albicans species of Candida, and susceptibility testing of azoles is increasingly important in the management of candidiasis in critically ill patients. Susceptibility testing also has been standardized for filamentous fungi that cause invasive infections. Studies are ongoing to further refine this approach and evaluate the in vivo correlation with the in vitro data for molds. Future efforts must be directed toward establishing and validating interpretive break-points for licensed antifungals such as amphotericin B, and for new antifungals that are not yet licensed. Finally, procedures must be optimized for testing non-Candida yeasts (e.g., C. neoformans) and molds.
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Affiliation(s)
- M A Pfaller
- Medical Microbiology Division, Department of Pathology, University of Iowa College of Medicine, Iowa City, Iowa, USA.
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28
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Jain P, Khan ZK, Bhattacharya E, Ranade SA. Variation in random amplified polymorphic DNA (RAPD) profiles specific to fluconazole-resistant and -sensitive strains of Candida albicans. Diagn Microbiol Infect Dis 2001; 41:113-9. [PMID: 11750163 DOI: 10.1016/s0732-8893(01)00292-9] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Random amplified polymorphic DNA analysis was used to detect genotype relatedness among clinical fluconazole-resistant and -sensitive strains of Candida albicans recovered from twenty HIV-infected patients having oropharyngeal candidiasis. Sensitive strains were obtained from a local hospital and were from patients that had not been treated with azole drugs while resistant strains were recovered from patients in different parts of Europe and their resistance was a consequence of drug-treatment given to the patients. On amplification with different arbitrary sequence decamer primers, the results demonstrated a homogeneous banding pattern for all sensitive strains that was distinct from that obtained in case of the resistant strains. The DNA profiles of strains were thus broadly clustered into two major groups of resistant and sensitive strains. The RAPD technique may be useful in differentiating fluconazole-resistant strains from the -sensitive ones for early identification of resistant isolates from AIDS patients.
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Affiliation(s)
- P Jain
- Medical Mycology Division, Central Drug Research Institute, P.O. Box 173, 226 001, Lucknow, India
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29
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Cuenca-Estrella M, Mellado E, Díaz-Guerra TM, Monzón A, Rodríguez-Tudela JL. Azasordarins: susceptibility of fluconazole-susceptible and fluconazole-resistant clinical isolates of Candida spp. to GW 471558. Antimicrob Agents Chemother 2001; 45:1905-7. [PMID: 11353650 PMCID: PMC90570 DOI: 10.1128/aac.45.6.1905-1907.2001] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The in vitro activity of the azasordarin GW 471558 was compared with those of amphotericin B, flucytosine, itraconazole, and ketoconazole against 177 clinical isolates of Candida spp. GW 471558 showed potent activity against Candida albicans, Candida glabrata, and Candida tropicalis, even against isolates with decreased susceptibility to azoles. Candida krusei, Candida parapsilosis, Candida lusitaniae, and Candida guilliermondii are resistant to GW 471558 in vitro (MICs, >128 microg/ml).
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Affiliation(s)
- M Cuenca-Estrella
- Servicio de Micología, Centro Nacional de Microbiología, Instituto de Salud Carlos III, 28220 Majadahonda Madrid, Spain.
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30
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Abstract
With the rising frequency of fungal infections, as well as increasing reports of resistance to antifungal agents, it is imperative that clinically applicable antifungal susceptibility testing be available. In 1997 the National Committee for Clinical Laboratory Standards published standard guidelines for antifungal susceptibility testing of Candida sp and Cryptococcus neoformans with amphotericin B, flucytosine, fluconazole, itraconazole, and ketoconazole. Although the methods are standard, they are time consuming, can be difficult to interpret, and are approved only for testing limited organisms and drugs. Modifications to the methods and alternative approaches have been proposed to make these tests more convenient and efficient, applicable to a greater number of species, and appropriate for performing in the clinical laboratory.
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Affiliation(s)
- H L Hoffman
- College of Pharmacy, University of Iowa, Iowa City 52242, USA
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31
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Rodríguez-Tudela JL, Cuenca-Estrella M, Díaz-Guerra TM, Mellado E. Standardization of antifungal susceptibility variables for a semiautomated methodology. J Clin Microbiol 2001; 39:2513-7. [PMID: 11427562 PMCID: PMC88178 DOI: 10.1128/jcm.39.7.2513-2517.2001] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Recently, the methodology that will serve as a basis of the standard for antifungal susceptibility testing of fermentative yeasts of the European Committee on Antibiotic Susceptibility Testing has been described. This procedure employs a spectrophotometric method for both inoculum adjustment and endpoint determination. However, the utilization of a spectrophotometer requires studies for standardization. The present work analyzes the following parameters: (i) accuracy of inoculum preparation, (ii) correlation between optical density and CFU per milliliter, (iii) influence of the wavelength on the endpoint determination, and (iv) influence of the dimethyl sulfoxide concentration on the growth kinetics. The main results can be summarized as follows: (i) inoculum preparation following the methodology recommended by the National Committee for Clinical Laboratory Standards is an exact procedure; (ii) the relationship between optical density and CFU per milliliter is linear (coefficient of determination, r(2) = 0.84); (iii) MICs obtained by means of spectrophotometric readings at different wavelengths are identical (for amphotericin B, an intraclass correlation coefficient of 0.98 was obtained; for fluconazole, the intraclass correlation coefficient was 1); and (iv) a 2% concentration of dimethyl sulfoxide produces a significantly slower and lower growth curve of Candida spp. than other concentrations.
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Affiliation(s)
- J L Rodríguez-Tudela
- Servicio de Micología, Centro Nacional de Microbiología, Instituto de Salud Carlos III, 28220 Majadahonda, Spain.
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Cuenca-Estrella M, Díaz-Guerra TM, Mellado E, Rodríguez-Tudela JL. Influence of glucose supplementation and inoculum size on growth kinetics and antifungal susceptibility testing of Candida spp. J Clin Microbiol 2001; 39:525-32. [PMID: 11158101 PMCID: PMC87770 DOI: 10.1128/jcm.39.2.525-532.2001] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The influences of inoculum size and glucose supplementation on the growth kinetics of 60 Candida spp. clinical isolates (Candida albicans, Candida tropicalis, Candida parapsilosis, Candida glabrata, Candida krusei, and Candida lusitaniae [10 isolates each]) are assessed. The combined influence of growth and reading method (visual or spectrophotometric) on the determination of the MICs of amphotericin B, flucytosine, fluconazole, itraconazole, ketoconazole, and voriconazole is also analyzed, and the MICs are compared with those determined by the National Committee for Clinical Laboratory Standards standard microdilution method (NCCLS document M27-A). Glucose supplementation and inoculum size had a significant influence on the growth cycles of these yeasts, and a statistically significant denser growth (optical density at 540 nm) was seen for both incubation periods, 24 and 48 h (P < 0.01). A longer exponential phase and shorter lag phase were also observed. The A540 values at 24 h of incubation with medium containing glucose and an inoculum of 10(5) CFU/ml were >0.4 U for all species, with the exception of that for C. parapsilosis (A540 = 0.26 +/- 0.025). The MICs at 24 h determined by testing with 2% glucose and an inoculum of 10(5) CFU/ml showed the strongest agreement (96.83%) with MICs determined by the reference method. MICs were not falsely elevated, and good correlation indexes were obtained. The reproducibility of results with this medium-inoculum combination was high (intraclass correlation coefficient, 0.955). The best agreement and reproducibility of results for spectrophotometric readings were achieved with endpoints of 50% growth inhibition for flucytosine and azoles and 95% for amphotericin B. Supplementation of test media with glucose and an inoculum size of 10(5) CFU/ml yielded a reproducible technique that shows elevated agreement with the reference procedures and a shorter incubation period for obtaining reliable MIC determinations. The spectrophotometric method offers an advantage over the visual method by providing a more objective and automated MIC determination.
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Affiliation(s)
- M Cuenca-Estrella
- Servicio de Micología, Centro Nacional de Microbiología, Instituto de Salud Carlos III, 28220 Majadahonda, Madrid, Spain.
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33
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Rodríguez-Tudela JL, Martín-Díez F, Cuenca-Estrella M, Rodero L, Carpintero Y, Gorgojo B. Influence of shaking on antifungal susceptibility testing of Cryptococcus neoformans: a comparison of the NCCLS standard M27A medium, buffered yeast nitrogen base, and RPMI-2% glucose. Antimicrob Agents Chemother 2000; 44:400-4. [PMID: 10639369 PMCID: PMC89690 DOI: 10.1128/aac.44.2.400-404.2000] [Citation(s) in RCA: 33] [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
Cryptococcus neoformans is a nonfermentative yeast that requires oxygen for growth. The shaking of culture media achieves good oxygenation, promoting the growth of cryptococci. In this study, three test media (RPMI 1640, RPMI 1640-2% glucose, and buffered yeast nitrogen base ¿BYNB) recommended in the National Committee for Clinical Laboratory Standards M27A standard were examined. Growth abilities and minimum inhibitory concentrations (MICs) in microplates incubated at 35 degrees C for 48 h were determined. The results indicated that shaking and an inoculum size of 10(5) CFU/ml yielded optimal growth of this yeast. Compared to RPMI 1640, supplementation of RPMI 1640 with 2% glucose did not significantly improve growth of C. neoformans and resulted in an 8.7-h delay of exponential growth. Cryptococcal growth in RPMI 1640 at 24 h was notably better than that in RPMI-2% glucose, although by 48 h the growths were comparable. The MIC range of amphotericin B observed for the C. neoformans strains grown in RPMI 1640 with or without glucose was too narrow to allow the separation of susceptible and resistant strains based on clinical outcome. The widest ranges of MICs of flucytosine and fluconazole were obtained with BYNB. This work demonstrates the need for a new antifungal susceptibility test for C. neoformans.
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Affiliation(s)
- J L Rodríguez-Tudela
- Servicio de Micología, Centro Nacional de Microbiología, Instituto de Salud Carlos III, Ctra. Majadahonda-Pozuelo km.2, 28220 Majadahonda, Spain
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Hong SY, Oh JE, Lee KH. Effect of D-amino acid substitution on the stability, the secondary structure, and the activity of membrane-active peptide. Biochem Pharmacol 1999; 58:1775-80. [PMID: 10571252 DOI: 10.1016/s0006-2952(99)00259-2] [Citation(s) in RCA: 181] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Several diastereomers and an enantiomer of KKVVFKVKFKK, an antimicrobial peptide that acts on the lipid membrane of pathogens were synthesized to investigate the effect of D-amino acid substitution on stability, secondary structure, and activity. The stability of the peptide in serum was improved greatly by the D-amino acid substitutions. D-Amino acid substitutions at the N- and/or C-terminal of the peptide, which had little effect on the alpha-helical structure, and all D-amino acid substitutions that formed a left-handed alpha-helix maintained antimicrobial activity, whereas D-amino acid substitutions in the middle of the amino acid sequence disrupted the alpha-helical structure, resulting in the complete loss of activity. This result confirmed that the peptide did not interact with chiral receptors, enzymes, or any chiral component of the membrane. D-Amino acid substitutions at the termini reduced the inhibition of the activity by heat-inactivated serum, which indicated that local change of chirality or change of secondary structure induced by D-amino acid substitutions might affect the interactions between the peptide and certain components in the serum. The present study suggests that partial D-amino acid substitution is a useful technique to improve the in vivo activity of antimicrobial peptides.
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Affiliation(s)
- S Y Hong
- Protein Chemistry Laboratory, Mogam Biotechnology Research Institute, Youngin City, Kyunggi-Do, Korea
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35
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Oh JE, Hong SY, Lee KH. The comparison of characteristics between membrane-active antifungal peptide and its pseudopeptides. Bioorg Med Chem 1999; 7:2509-15. [PMID: 10632060 DOI: 10.1016/s0968-0896(99)00176-5] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
By the introduction of various amide surrogates, novel pseudopeptides corresponding to a membrane active depsipeptide were synthesized and their native characteristics compared with that of the peptide. The pseudopeptides had more resistance to serum proteases than the peptide and similar antimicrobial activities to that of the peptide without hemolytic activity. The pseudopeptides like the peptide were active against current drug resistant fungi and pathogenic fungi isolated from patients, and also had a strong synergism with current antifungal drugs against Candida albicans. The leakage assay suggested that the pseudopeptides also acted on the lipid membrane of pathogenic cells. These results indicated that the novel pseudopeptides had advantages over the peptide as a candidate for a novel antifungal drug and backbone modifications can be a tool in the development of a novel antifungal agent from membrane-active peptides isolated from natural sources or chemically synthesized.
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Affiliation(s)
- J E Oh
- Protein Chemistry Laboratory, Mogam Biotechnology Research Institute, Yongin-city, Kyunggi-Do, South Korea
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36
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Arthington-Skaggs BA, Jradi H, Desai T, Morrison CJ. Quantitation of ergosterol content: novel method for determination of fluconazole susceptibility of Candida albicans. J Clin Microbiol 1999; 37:3332-7. [PMID: 10488201 PMCID: PMC85559 DOI: 10.1128/jcm.37.10.3332-3337.1999] [Citation(s) in RCA: 255] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
MIC end points for the most commonly prescribed azole antifungal drug, fluconazole, can be difficult to determine because its fungistatic nature can lead to excessive "trailing" of growth during susceptibility testing by National Committee for Clinical Laboratory Standards broth macrodilution and microdilution methods. To overcome this ambiguity, and because fluconazole acts by inhibiting ergosterol biosynthesis, we developed a novel method to differentiate fluconazole-susceptible from fluconazole-resistant isolates by quantitating ergosterol production in cells grown in 0, 1, 4, 16, or 64 microg of fluconazole per ml. Ergosterol was isolated from whole yeast cells by saponification, followed by extraction of nonsaponifiable lipids with heptane. Ergosterol was identified by its unique spectrophotometric absorbance profile between 240 and 300 nm. We used this sterol quantitation method (SQM) to test 38 isolates with broth microdilution end points of </=8 microg/ml (susceptible), 16 to 32 microg/ml (susceptible dose-dependent [SDD]), or >/=64 microg/ml (resistant) and 10 isolates with trailing end points by the broth microdilution method. No significant differences in mean ergosterol content were observed between any of the isolates grown in the absence of fluconazole. However, 18 susceptible isolates showed a mean reduction in ergosterol content of 72% after exposure to 1 microg of fluconazole/ml, an 84% reduction after exposure to 4 microg/ml, and 95 and 100% reductions after exposure to 16 and 64 microg of fluconazole/ml, respectively. Ten SDD isolates showed mean ergosterol reductions of 38, 57, 73, and 99% after exposure to 1, 4, 16, and 64 microg of fluconazole/ml, respectively. In contrast, 10 resistant isolates showed mean reductions in ergosterol content of only 25, 38, 53, and 84% after exposure to the same concentrations of fluconazole. The MIC of fluconazole, by using the SQM, was defined as the lowest concentration of the drug which resulted in 80% or greater inhibition of overall mean ergosterol biosynthesis compared to that in the drug-free control. Of 38 isolates which gave clear end points by the broth microdilution method, the SQM MIC was within 2 dilutions of the broth microdilution MIC for 33 (87%). The SQM also discriminated between resistant and highly resistant isolates and was particularly useful for discerning the fluconazole susceptibilities of 10 additional isolates which gave equivocal end points by the broth microdilution method due to trailing growth. In contrast to the broth microdilution method, the SQM determined trailing isolates to be susceptible rather than resistant, indicating that the SQM may predict clinical outcome more accurately. The SQM may provide a means to enhance current methods of fluconazole susceptibility testing and may provide a better correlation of in vitro with in vivo results, particularly for isolates with trailing end points.
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Affiliation(s)
- B A Arthington-Skaggs
- Mycotic Diseases Branch, Division of Bacterial and Mycotic Diseases, National Center for Infectious Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia 30333, USA
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Dannaoui E, Persat F, Monier MF, Borel E, Piens MA, Picot S. Use of spectrophotometric reading for in vitro antifungal susceptibility testing ofAspergillusspp. Can J Microbiol 1999. [DOI: 10.1139/w99-075] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
A comparative study of visual and spectrophotometric MIC endpoint determinations for antifungal susceptibility testing of Aspergillus species was performed. A broth microdilution method adapted from the National Committee for Clinical Laboratory Standards (NCCLS) was used for susceptibility testing of 180 clinical isolates of Aspergillus species against amphotericin B and itraconazole. MICs were determined visually and spectrophotometrically at 490 nm after 24, 48, and 72h of incubation, and MIC pairs were compared. The agreement between the two methods was 99% for amphotericin B and ranged from 95 to 98% for itraconazole. It is concluded that spectrophotometric MIC endpoint determination is a valuable alternative to the visual reference method for susceptibility testing of Aspergillus species.Key words: antifungal, susceptibility testing, Aspergillus, spectrophotometric reading.
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Diaz-Guerra TM, Mellado E, Cuenca Estrella M, Laguna F, Rodriguez-Tudela JL. Molecular characterization by PCR-fingerprinting of Candida dubliniensis strains isolated from two HIV-positive patients in Spain. Diagn Microbiol Infect Dis 1999; 35:113-9. [PMID: 10579091 DOI: 10.1016/s0732-8893(99)00072-3] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Six Candida dubliniensis isolates were recovered from two HIV-infected individuals in the course of a prospective study of recurrent oral candidosis among HIV-positive patients in Spain. Candida albicans strains as well as non-albicans strains were also obtained from these two patients. C. dubliniensis strains were germ-tube-positive and produced abundant chlamydospores. Fingerprinting the genomic DNAs of these six C. dubliniensis with the C. albicans-specific probe 27A as well as karyotyping was performed to confirm the identification of these isolates. Further analysis of their genomic DNAs was performed by PCR-fingerprinting with the core sequence of phage M13, and they exhibited species-specific multilocus band patterns, clearly distinct from those of C. albicans isolates analyzed in this study and in a previous one (Diaz-Guerra 1997). Intraspecies variation was also seen among PCR patterns yielded by C. dubliniensis isolates from different patients. Although few strains have been analyzed, the use of this PCR-fingerprinting procedure is a promising tool for further epidemiologic studies with C. dubliniensis. The isolation of C. dubliniensis from Spanish HIV-infected patients contributes to the idea of widespread geographic distribution of this species.
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Affiliation(s)
- T M Diaz-Guerra
- Unidad de Micología, Centro Nacional de Microbiología, Majadahonda, Madrid, Spain
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Hong SY, Oh JE, Lee KH. In vitro antifungal activity and cytotoxicity of a novel membrane-active peptide. Antimicrob Agents Chemother 1999; 43:1704-7. [PMID: 10390226 PMCID: PMC89347 DOI: 10.1128/aac.43.7.1704] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
In the present study, we investigated the antifungal activity and cytotoxicity of a novel membrane-active peptide, KKVVFKVKFKK (MP). MP inhibited the growth of various pathogenic fungi isolated from patients and of fluconazole-resistant fungi at concentrations of 2 to 32 microg/ml. MP had potent fungicidal activity; the minimal fungicidal concentrations of the peptide were no more than fourfold greater than the MICs. Time course experiments of MP-induced killing of Candida albicans ATCC 36232 showed that the rate of killing was rapid and depended on the concentration of MP. MP had a strong synergism with other antifungal drugs; the fractional inhibitory concentration index values of MP with amphotericin B and fluconazole for C. albicans were 0.16 and 0.02, respectively. The 50% inhibitory concentrations of MP for NIH 3T3 and Jurkat cells were approximately 100 times higher than the MIC for C. albicans ATCC 36232, indicating that MP had high selectivity between the fungal and mammalian cells. These results suggest that MP has great advantages in the development of antifungal agents.
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Affiliation(s)
- S Y Hong
- Protein Chemistry Laboratory, Mogam Biotechnology Research Institute, Kyunggi-Do, 449-910, Korea
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Nguyen MH, Yu CY. Influence of incubation time, inoculum size, and glucose concentrations on spectrophotometric endpoint determinations for amphotericin B, fluconazole, and itraconazole. J Clin Microbiol 1999; 37:141-5. [PMID: 9854079 PMCID: PMC84190 DOI: 10.1128/jcm.37.1.141-145.1999] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
We addressed the influence of the incubation time (24 h versus 48 h), starting inoculum size (standard inoculum size, approximately 10(3) CFU/ml, versus large inoculum size, approximately 10(4) CFU/ml), and supplementation with 2% glucose of RPMI 1640 medium on the spectrophotometric determination of the MICs of amphotericin B, fluconazole, and itraconazole. We compared the MICs determined spectrophotometrically with those determined by the standard broth macrodilution method (National Committee for Clinical Laboratory Standards approved guideline M27-A). The agreement between the results of the spectrophotometric and standard methods for amphotericin B testing was 100%; this agreement was independent of the inoculum size and incubation time. On the other hand, the agreement for the results for fluconazole testing and itraconazole testing was dependent on the inoculum size and incubation time. With large inoculum size, excellent agreement can be achieved at 24 h. With standard inoculum size, acceptable agreement can be achieved only at 48 h. In contrast to previous observations, the addition of 2% glucose did not have any significant impact on the growth density at 24 h, nor did it improve the agreement with the standard method. Furthermore, supplemental glucose might falsely elevate the MIC at 48 h.
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Affiliation(s)
- M H Nguyen
- Department of Medicine, University of Florida College of Medicine, and Gainesville VA Medical Center, Gainesville, Florida 32610, USA.
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Hong SY, Oh JE, Kwon M, Choi MJ, Lee JH, Lee BL, Moon HM, Lee KH. Identification and characterization of novel antimicrobial decapeptides generated by combinatorial chemistry. Antimicrob Agents Chemother 1998; 42:2534-41. [PMID: 9756752 PMCID: PMC105883 DOI: 10.1128/aac.42.10.2534] [Citation(s) in RCA: 75] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/1998] [Accepted: 07/15/1998] [Indexed: 11/20/2022] Open
Abstract
Novel combinatorial libraries consisting of simplified amino acid sequences were designed to screen for peptides active against the Candida albicans membrane. A novel decapeptide, KKVVFKVKFK, that had a unique primary amino acid sequence was identified in this work. This peptide irreversibly inhibited the growth of C. albicans and showed a broad range of antibacterial activity but no hemolytic activity. Circular dichroism spectra revealed that the predominant secondary structure of this peptide strongly depended on the membrane-mimetic environments; the peptide preferred to form an amphipathic alpha-helical structure in the presence of 50% trifluoroethanol, while it preferred to adopt a distorted alpha-helical structure in the presence of sodium dodecyl sulfate micelles. Experiments in which dye was released from vesicles indicated that this novel antimicrobial peptide killed microorganisms through the action on the membrane as its primary target. Replacement of amino acids in this active decapeptide on the basis of information from the libraries could provide unique information about factors affecting its antimicrobial activity such as its secondary structure, net positive charge, and hydrophobicity.
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Affiliation(s)
- S Y Hong
- Protein Chemistry Laboratory, Mogam Biotechnology Research Institute, Kyunggi-Do, 449-910, Korea
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Diaz-Guerra TM, Martinez-Suarez JV, Laguna F, Valencia E, Rodriguez-Tudela JL. Change in fluconazole susceptibility patterns and genetic relationship among oral Candida albicans isolates. AIDS 1998; 12:1601-10. [PMID: 9764778 DOI: 10.1097/00002030-199813000-00006] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
OBJECTIVE To assess the genetic homogeneity or heterogeneity within each set of Candida albicans isolates colonizing/infecting the oral cavities of HIV-infected patients undergoing azole therapy when changes in susceptibility to fluconazole were detected. DESIGN Fourteen HIV-positive patients suffering recurrent episodes of oral candidosis were prospectively followed from the first episode to the isolation of strains with decreased susceptibility to fluconazole. The strains of C. albicans isolated either from episodes or controls throughout the prospective study were analysed. METHODS Electrophoretic karyotyping and hybridization with the repeated sequence probe 27A were used to delineate sequential isolates. In vitro susceptibility tests to fluconazole and ketoconazole were also performed. The results obtained by DNA fingerprinting with the probe combined with computer-assisted analysis were used to assess the genetic relationships amongst the strains. In addition, comparison with the genetic relatedness of a group of geographically unrelated strains was made. RESULTS Isogenic populations of sequential isolates were observed only in two patients; 12 patients harboured heterogenic populations over time, although in 11 patients there was a predominant strain that was isolated more than once, and only one of these patients carried strains with a similarity index less than 80%. With the exception of two patients, each patient carried a major strain that became less susceptible to fluconazole. The similarity index for the unrelated strains was 59%. CONCLUSIONS HIV-infected patients may carry a mixed population of strains, but the strains tend to be related to each other. The strains were maintained throughout the course of infection and at least one developed secondary resistance to fluconazole.
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Affiliation(s)
- T M Diaz-Guerra
- Unidad de Micología, Centro Nacional de Microbiología, Majadahonda, Instituto de Salud Carlos III, Madrid, Spain
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Gould IM, Milne K, Wood W, Kunova A. Comparison of the E test with broth microdilution for antifungal susceptibility testing of yeasts. J Chemother 1998; 10:3-6. [PMID: 9531068 DOI: 10.1179/joc.1998.10.1.3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
Abstract
The susceptibilities of 26 recent invasive clinical isolates to amphotericin B (AMP), 5-flucytosine (5FC), fluconazole (FLU) and itraconazole (ITR) were determined by a broth microdilution modification of the NCCLS M27P method and also by E test. Using breakpoint criteria each result was classified as either sensitive (S), intermediate (I) or resistant (R). Taking the optical density (OD)80 as the standard, the results were further classified into major (M) or minor (m) errors. E test: AMP = 0M 0m, 5FC = 0M 5m, FLU = 1M 12m, ITR = 1M 5m errors. Minimal inhibitory concentrations (MIC): AMP = 0M 2m, 5FC = 0M 0m, FLU = 3M 4m, ITR = 1M 7m errors. The E test was quick and relatively simple to perform. Results using the E test compared favourably with those of the OD80 and it should be suitable for the routine susceptibility testing of yeasts to antifungal agents.
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Affiliation(s)
- I M Gould
- Dept. of Microbiology, Royal Infirmary, Foresterhill, Aberdeen, UK
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Fortún J, López-San Román A, Velasco JJ, Sánchez-Sousa A, de Vicente E, Nuño J, Quereda C, Bárcena R, Monge G, Candela A, Honrubia A, Guerrero A. Selection of Candida glabrata strains with reduced susceptibility to azoles in four liver transplant patients with invasive candidiasis. Eur J Clin Microbiol Infect Dis 1997; 16:314-8. [PMID: 9177967 DOI: 10.1007/bf01695638] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
The cases of four liver transplant recipients who developed invasive candidiasis (2 cholangitis, 1 perihepatic abscess, 1 candidemia) due to azole-resistant, Candida glabrata are reported. Three patients were receiving azolic compounds (2 itraconazole, 1 fluconazole) when the infection was diagnosed. All four patients received fluconazole as intestinal decontamination during the first three weeks post transplantation. The infections occurred two months after transplantation in all patients, and in one patient Candida infection was the direct cause of death. Infection of the biliary tree was the origin of candidiasis in three patients; the fourth patient developed neutropenic-related candidemia. Fluconazole MICs exceeded 16 micrograms/ml in all cases; itraconazole MICs were 16, 2, 1, and 2 micrograms/ml, respectively. The potential role of Candida species other than albicans in these patients after administration of azole agents is discussed.
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Affiliation(s)
- J Fortún
- Department of Clinical Microbiology and Infectious Diseases, Ramón y Cajal Hospital, Madrid, Spain
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