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Chen C, Wang Y, Wu F, Hong W. Rapid Antifungal Susceptibility Testing Based on Single-Cell Metabolism Analysis Using Stimulated Raman Scattering Imaging. Anal Chem 2023; 95:15556-15565. [PMID: 37815933 DOI: 10.1021/acs.analchem.3c02243] [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: 10/12/2023]
Abstract
Rapid antifungal susceptibility testing (AFST) is urgently needed in clinics to treat invasive fungal infections with the appropriate antifungal drugs and to slow the emergence of antifungal resistance. However, current AFST methods are time-consuming (24-48 h) due to the slow growth of fungal cells and the methods not being able to work directly for clinical samples. Here, we demonstrate rapid AFST by measuring the metabolism in single fungal cells using stimulated Raman scattering imaging and deuterium probing. Distinct metabolic responses were observed in Candida albicans to different classes of antifungal drugs: while the metabolism was inhibited by amphotericin B, it was stimulated by azoles (fluconazole and voriconazole) and micafungin. Accordingly, we propose metabolism change as a biomarker for rapid AFST. The results were obtained in 4 h with 100% categorical agreement with the gold standard broth microdilution test. In addition, a protocol was developed for direct AFST from positive blood cultures. This method overcomes the limitation of slow growth in conventional methods and has the potential for the rapid diagnosis of candidemia and other clinical fungal infections.
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Affiliation(s)
- Chen Chen
- School of Biological Science and Medical Engineering, Beihang University; Beijing 100083, China
| | - Yi Wang
- Department of Clinical Laboratory, Beijing Bo'ai Hospital, China Rehabilitation Research Center, Capital Medical University, Beijing 100068, China
| | - Fan Wu
- School of Biological Science and Medical Engineering, Beihang University; Beijing 100083, China
| | - Weili Hong
- School of Biological Science and Medical Engineering, Beihang University; Beijing 100083, China
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Soriano A, Honore PM, Puerta-Alcalde P, Garcia-Vidal C, Pagotto A, Gonçalves-Bradley DC, Verweij PE. Invasive candidiasis: current clinical challenges and unmet needs in adult populations. J Antimicrob Chemother 2023:7176280. [PMID: 37220664 DOI: 10.1093/jac/dkad139] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/25/2023] Open
Abstract
Invasive candidiasis (IC) is a serious infection caused by several Candida species, and the most common fungal disease in hospitals in high-income countries. Despite overall improvements in health systems and ICU care in the last few decades, as well as the development of different antifungals and microbiological techniques, mortality rates in IC have not substantially improved. The aim of this review is to summarize the main issues underlying the management of adults affected by IC, focusing on specific forms of the infection: IC developed by ICU patients, IC observed in haematological patients, breakthrough candidaemia, sanctuary site candidiasis, intra-abdominal infections and other challenging infections. Several key challenges need to be tackled to improve the clinical management and outcomes of IC patients. These include the lack of global epidemiological data for IC, the limitations of the diagnostic tests and risk scoring tools currently available, the absence of standardized effectiveness outcomes and long-term data for IC, the timing for the initiation of antifungal therapy and the limited recommendations on the optimal step-down therapy from echinocandins to azoles or the total duration of therapy. The availability of new compounds may overcome some of the challenges identified and increase the existing options for management of chronic Candida infections and ambulant patient treatments. However, early identification of patients that require antifungal therapy and treatment of sanctuary site infections remain a challenge and will require further innovations.
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Affiliation(s)
- Alex Soriano
- Department of Infectious Diseases, Hospital Clinic of Barcelona, IDIBAPS, CIBERINF, University of Barcelona, Barcelona, Spain
| | - Patrick M Honore
- CHU UCL Godinne Namur, UCL Louvain Medical School, Namur, Belgium
| | - Pedro Puerta-Alcalde
- Department of Infectious Diseases, Hospital Clinic of Barcelona, IDIBAPS, CIBERINF, University of Barcelona, Barcelona, Spain
| | - Carolina Garcia-Vidal
- Department of Infectious Diseases, Hospital Clinic of Barcelona, IDIBAPS, CIBERINF, University of Barcelona, Barcelona, Spain
| | | | | | - Paul E Verweij
- Radboudumc-CWZ Center of Expertise for Mycology, Nijmegen, the Netherlands
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Husni R, Bou Zerdan M, Samaha N, Helou M, Mahfouz Y, Saniour R, Hourani S, Kolanjian H, Afif C, Azar E, El Jisr T, Mokhbat J, Abboud E, Feghali R, Abboud E, Matta H, Karayakouboglo G, Matar M, Moghnieh R, Daoud Z. Characterization and susceptibility of non-albicans Candida isolated from various clinical specimens in Lebanese hospitals. Front Public Health 2023; 11:1115055. [PMID: 36969669 PMCID: PMC10036786 DOI: 10.3389/fpubh.2023.1115055] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2022] [Accepted: 02/21/2023] [Indexed: 03/12/2023] Open
Abstract
BackgroundInvasive fungal infections have presented a challenge in treatment. In the past, it was known that the frontrunner in such infections is Candida albicans with little emphasis placed on non-albicans Candida species (NAC). Studies worldwide have shown a rise in fungal infections attributed to non-albicans Candida species. The aim of this study is to describe the epidemiology of NAC infections along with an overview of resistance in Lebanese hospitals.MethodsThis is a two-year observational multi-central descriptive study. Between September 2016 and May of 2018, a total of 1000 isolates were collected from 10 different hospitals distributed all over the country. For the culture, Sabouraud Dextrose Agar was used. Antifungal Susceptibility was evaluated by determining the Minimum Inhibitory Concentration (MIC) in broth (microdilution) of the different antifungal treatments.ResultsOut of the 1000 collected isolates, Candida glabrata, being the most isolated species (40.8%), followed by Candida tropicalis: 231(23.1%), Candida parapsilosis: 103(10.3%), and other NAC species at lower percentage. Most of these isolates (88.67%) were susceptible to posaconazole, 98.22% were susceptible to micafungin, and 10% were susceptible to caspofungin.ConclusionThe change of etiology of fungal infections involving a significant increase in NAC cases is alarming due to the different antifungal susceptibility patterns and the lack of local guidelines to guide the treatment. In this context, proper identification of such organisms is of utmost importance. The data presented here can help in establishing guidelines for the treatment of candida infections to decrease morbidity and mortality. Future surveillance data are needed.
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Affiliation(s)
- Rola Husni
- Lebanese American University, School of Medicine, Beirut, Lebanon
- Department of Internal Medicine, Lebanese American University-Rizk Hospital, Beirut, Lebanon
- *Correspondence: Rola Husni
| | - Maroun Bou Zerdan
- Department of Internal Medicine, SUNY Upstate Medical University Hospital, Syracuse, NY, United States
| | - Nadia Samaha
- Georgetown University School of Medicine, Washington, DC, United States
| | - Mariana Helou
- Lebanese American University, School of Medicine, Beirut, Lebanon
- Department of Internal Medicine, Lebanese American University-Rizk Hospital, Beirut, Lebanon
| | - Youssef Mahfouz
- Faculty of Medicine and Medical Sciences, University of Balamand, Tripoli, Lebanon
| | - Rim Saniour
- Faculty of Medicine and Medical Sciences, University of Balamand, Tripoli, Lebanon
| | - Sawsan Hourani
- Faculty of Medicine and Medical Sciences, University of Balamand, Tripoli, Lebanon
| | - Harout Kolanjian
- Lebanese American University, School of Medicine, Beirut, Lebanon
- Department of Internal Medicine, Lebanese American University-Rizk Hospital, Beirut, Lebanon
| | - Claude Afif
- Department of Internal Medicine, Saint George Hospital-University Medical Center, Beirut, Lebanon
| | - Eid Azar
- Department of Internal Medicine, Saint George Hospital-University Medical Center, Beirut, Lebanon
| | - Tamima El Jisr
- Department of Laboratory, Makased General Hospital, Beirut, Lebanon
| | - Jacques Mokhbat
- Lebanese American University, School of Medicine, Beirut, Lebanon
- Department of Internal Medicine, Lebanese American University-Rizk Hospital, Beirut, Lebanon
| | - Emma Abboud
- Department of Laboratory, Mount Liban Hospital, Hazmiyeh, Lebanon
| | - Rita Feghali
- Department of Laboratory, Rafic Hariri University Hospital, Beirut, Lebanon
| | - Edmond Abboud
- Department of Laboratory, The Middle East Institute of Health University Hospital, Mount Lebanon, Lebanon
| | - Hiam Matta
- Saint Georges Ajaltoun Hospital, Ajaltoun, Lebanon
| | | | - Madonna Matar
- Department of Internal Medicine, Notre Dame de Secours University Hospital, Byblos, Lebanon
| | - Rima Moghnieh
- Lebanese American University, School of Medicine, Beirut, Lebanon
- Department of Internal Medicine, Lebanese American University-Rizk Hospital, Beirut, Lebanon
| | - Ziad Daoud
- College of Medicine, Central Michigan University, Saginaw, MI, United States
- Department of Clinical Microbiology and Infection Prevention, Michigan Health Clinics, Saginaw, MI, United States
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Abstract
The discovery of amphotericin B, a polyene antifungal compound, in the 1950s, and the formulation of this compound in a liposomal drug delivery system, has resulted in decades of use in systemic fungal infections. The use of liposomal amphotericin B formulation is referenced in many international guidelines for the treatment of fungal infections such as Aspergillus and cryptococcal disease and Candida infections, as well as other less common infections such as visceral leishmaniasis. With the development of liposomal amphotericin B, an improved therapeutic index could be achieved that allowed the attainment of higher drug concentrations in both the plasma and tissue while simultaneously lowering the toxicity compared with amphotericin B deoxycholate. In over 30 years of experience with this drug, a vast amount of information has been collected on preclinical and clinical efficacy against a wide variety of pathogens, as well as evidence on its toxicity. This article explores the history and nature of the liposomal formulation, the key clinical studies that developed the pharmacokinetic, safety and efficacy profile of the liposomal formulation, and the available microbiological data.
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Affiliation(s)
- R J Brüggemann
- Department of Pharmacy, and Radboudumc Institute of Health Sciences, Radboud University Medical Center, Nijmegen, The Netherlands
- Center of Expertise in Mycology Radboudumc/CWZ, Radboud University Medical Center, Nijmegen, The Netherlands
| | - G M Jensen
- Pharmaceutical Development and Manufacturing, Gilead Sciences Inc., La Verne, CA, USA
| | - C Lass-Flörl
- Department of Hygiene, Medical Microbiology and Public Health, Institute of Hygiene and Medical Microbiology, Medical University of Innsbruck, Innsbruck, Austria
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5
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Chen M, Tian Y, Zhang D, Ren W, Wang W. An improved method for rapid identification of hook effect samples in HBsAg quantitative assay. J Virol Methods 2022; 309:114606. [PMID: 35963582 DOI: 10.1016/j.jviromet.2022.114606] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2021] [Revised: 08/05/2022] [Accepted: 08/09/2022] [Indexed: 12/24/2022]
Abstract
Quantitative hepatitis B surface antigen assay is widely used for diagnosis of hepatitis B virus infection; however, specimens with high levels of the antigen can cause false-negative results (Hook effect), which needs to be resolved. The hook effect samples and non-hook effect samples were detected on the LiCA® 500 instrument using three methods, viz., 1, 2, and 3. Method 1, the currently used procedure, was performed in two steps with a total reaction time of 25 min in a final volume of 250 µL: first incubation was with two reagents for 15 min and then with one other reagent for 10 min. In Method 2, all three reagents were added in one step with a final volume of 250 µL, and the total reaction time was still 25 min. In Method 3, the improved method, all three reagents were added in one step while the final volume was only 130 µL and the total reaction time was only 1 min. Signal values of the non-hook effect samples obtained using Method 2 were significantly lower than those with Method 1, showing competitive inhibition. The hook effect samples tested with Method 2 approximated those obtained using Method 1. Method 3 took 1 min and differentiated hook effect samples successfully, similar to the results with Method 2 which took 25 min. Changing the timing of one reagent addition and incubation time in Method 3 provided a rapid and effective method for the identification of hook effect. The results were more clearly distinguishable due to the phenomenon of competitive inhibition. Method 3 can be considered an improvement on the chemiluminescence platform.
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Affiliation(s)
- Mingxin Chen
- The First Affiliated Hospital of Henan University of Chinese Medicine, Zhengzhou City, Henan Province, China
| | - Yu Tian
- The First Affiliated Hospital of Henan University of Chinese Medicine, Zhengzhou City, Henan Province, China
| | - Dai Zhang
- The First Affiliated Hospital of Henan University of Chinese Medicine, Zhengzhou City, Henan Province, China
| | - Weihong Ren
- The First Affiliated Hospital of Henan University of Chinese Medicine, Zhengzhou City, Henan Province, China.
| | - Wei Wang
- The First Affiliated Hospital of Henan University of Chinese Medicine, Zhengzhou City, Henan Province, China.
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Head-to-head comparison of CLSI, EUCAST, Etest and Vitek2 results for Candida auris susceptibility testing. Int J Antimicrob Agents 2022; 59:106558. [DOI: 10.1016/j.ijantimicag.2022.106558] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2021] [Revised: 01/24/2022] [Accepted: 02/20/2022] [Indexed: 11/24/2022]
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Durand C, Maubon D, Cornet M, Wang Y, Aldebert D, Garnaud C. Can We Improve Antifungal Susceptibility Testing? Front Cell Infect Microbiol 2021; 11:720609. [PMID: 34568095 PMCID: PMC8461061 DOI: 10.3389/fcimb.2021.720609] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2021] [Accepted: 08/23/2021] [Indexed: 11/24/2022] Open
Abstract
Systemic antifungal agents are increasingly used for prevention or treatment of invasive fungal infections, whose prognosis remains poor. At the same time, emergence of resistant or even multi-resistant strains is of concern as the antifungal arsenal is limited. Antifungal susceptibility testing (AFST) is therefore of key importance for patient management and antifungal stewardship. Current AFST methods, including reference and commercial types, are based on growth inhibition in the presence of an antifungal, in liquid or solid media. They usually enable Minimal Inhibitory Concentrations (MIC) to be determined with direct clinical application. However, they are limited by a high turnaround time (TAT). Several innovative methods are currently under development to improve AFST. Techniques based on MALDI-TOF are promising with short TAT, but still need extensive clinical validation. Flow cytometry and computed imaging techniques detecting cellular responses to antifungal stress other than growth inhibition are also of interest. Finally, molecular detection of mutations associated with antifungal resistance is an intriguing alternative to standard AFST, already used in routine microbiology labs for detection of azole resistance in Aspergillus and even directly from samples. It is still restricted to known mutations. The development of Next Generation Sequencing (NGS) and whole-genome approaches may overcome this limitation in the near future. While promising approaches are under development, they are not perfect and the ideal AFST technique (user-friendly, reproducible, low-cost, fast and accurate) still needs to be set up routinely in clinical laboratories.
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Affiliation(s)
| | - Danièle Maubon
- TIMC, Univ Grenoble Alpes, CNRS, Grenoble INP, Grenoble, France.,Parasitology-Mycology, CHU Grenoble Alpes, Grenoble, France
| | - Muriel Cornet
- TIMC, Univ Grenoble Alpes, CNRS, Grenoble INP, Grenoble, France.,Parasitology-Mycology, CHU Grenoble Alpes, Grenoble, France
| | | | | | - Cécile Garnaud
- TIMC, Univ Grenoble Alpes, CNRS, Grenoble INP, Grenoble, France.,Parasitology-Mycology, CHU Grenoble Alpes, Grenoble, France
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8
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Knoll MA, Ulmer H, Lass-Flörl C. Rapid Antifungal Susceptibility Testing of Yeasts and Molds by MALDI-TOF MS: A Systematic Review and Meta-Analysis. J Fungi (Basel) 2021; 7:63. [PMID: 33477533 PMCID: PMC7835946 DOI: 10.3390/jof7010063] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2020] [Revised: 12/04/2020] [Accepted: 01/14/2021] [Indexed: 12/12/2022] Open
Abstract
Due to the growing burden of fungal infections and a recent rise in antifungal resistance, antifungal susceptibility testing (AFST) is of increasing importance. The common methods of AFST have turnaround times of 24 to 48 h, and the available rapid methods are limited by applicability, cost-efficiency or accuracy. Given the urgency of adequate antifungal treatment in invasive mycoses, the need for the rapid and reliable detection of resistance is evident. In this systematic review and meta-analysis, we evaluated the diagnostic accuracy of AFST based on matrix-assisted laser desorption ionization time of flight mass spectrometry (MALDI-TOF MS). Twelve studies were reviewed, and data for the comparative analysis of their accuracy and methodology were systematically extracted. Compared to broth dilution as the gold standard, MALDI-TOF MS-based AFST reached a pooled sensitivity and specificity of 91% (95% Confidence Interval [CI], 84% to 96%) and 95% (95% CI, 90% to 98%), respectively. A comparative analysis showed that the sensitivity was higher for the semi-quantitative matrix-assisted laser desorption ionization Biotyper antibiotic susceptibility test rapid assay (MBT ASTRA) technique (96%) than for the correlate composite index (CCI) approach (85%), which is based on spectrum changes. Turnaround times below eight hours reached better diagnostic values than longer incubation periods, qualifying MALDI-TOF MS-based AFST as a rapid and accurate method for the detection of antifungal resistance.
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Affiliation(s)
- Miriam Alisa Knoll
- Institute of Hygiene and Medical Microbiology, Medical University of Innsbruck, 6020 Innsbruck, Austria;
| | - Hanno Ulmer
- Department of Medical Statistics, Informatics and Health Economics, Medical University of Innsbruck, 6020 Innsbruck, Austria;
| | - Cornelia Lass-Flörl
- Institute of Hygiene and Medical Microbiology, Medical University of Innsbruck, 6020 Innsbruck, Austria;
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Arastehfar A, Gabaldón T, Garcia-Rubio R, Jenks JD, Hoenigl M, Salzer HJF, Ilkit M, Lass-Flörl C, Perlin DS. Drug-Resistant Fungi: An Emerging Challenge Threatening Our Limited Antifungal Armamentarium. Antibiotics (Basel) 2020; 9:antibiotics9120877. [PMID: 33302565 PMCID: PMC7764418 DOI: 10.3390/antibiotics9120877] [Citation(s) in RCA: 91] [Impact Index Per Article: 22.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2020] [Revised: 11/02/2020] [Accepted: 12/03/2020] [Indexed: 12/14/2022] Open
Abstract
The high clinical mortality and economic burden posed by invasive fungal infections (IFIs), along with significant agricultural crop loss caused by various fungal species, has resulted in the widespread use of antifungal agents. Selective drug pressure, fungal attributes, and host- and drug-related factors have counteracted the efficacy of the limited systemic antifungal drugs and changed the epidemiological landscape of IFIs. Species belonging to Candida, Aspergillus, Cryptococcus, and Pneumocystis are among the fungal pathogens showing notable rates of antifungal resistance. Drug-resistant fungi from the environment are increasingly identified in clinical settings. Furthermore, we have a limited understanding of drug class-specific resistance mechanisms in emerging Candida species. The establishment of antifungal stewardship programs in both clinical and agricultural fields and the inclusion of species identification, antifungal susceptibility testing, and therapeutic drug monitoring practices in the clinic can minimize the emergence of drug-resistant fungi. New antifungal drugs featuring promising therapeutic profiles have great promise to treat drug-resistant fungi in the clinical setting. Mitigating antifungal tolerance, a prelude to the emergence of resistance, also requires the development of effective and fungal-specific adjuvants to be used in combination with systemic antifungals.
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Affiliation(s)
- Amir Arastehfar
- Center for Discovery and Innovation, Hackensack Meridian Health, Nutley, NJ 07110, USA; (A.A.); (R.G.-R.)
| | - Toni Gabaldón
- Life Sciences Programme, Supercomputing Center (BSC-CNS), Jordi Girona, 08034 Barcelona, Spain;
- Mechanisms of Disease Programme, Institute for Research in Biomedicine (IRB), 08024 Barcelona, Spain
- Catalan Institution for Research and Advanced Studies. Pg. Lluís Companys 23, 08010 Barcelona, Spain
| | - Rocio Garcia-Rubio
- Center for Discovery and Innovation, Hackensack Meridian Health, Nutley, NJ 07110, USA; (A.A.); (R.G.-R.)
| | - Jeffrey D. Jenks
- Department of Medicine, University of California San Diego, San Diego, CA 92103, USA;
- Clinical and Translational Fungal-Working Group, University of California San Diego, La Jolla, CA 92093, USA;
- Division of Infectious Diseases and Global Public Health, Department of Medicine, University of California San Diego, La Jolla, CA 92093, USA
| | - Martin Hoenigl
- Clinical and Translational Fungal-Working Group, University of California San Diego, La Jolla, CA 92093, USA;
- Division of Infectious Diseases and Global Public Health, Department of Medicine, University of California San Diego, La Jolla, CA 92093, USA
- Section of Infectious Diseases and Tropical Medicine, Department of Internal Medicine, Medical University of Graz, 8036 Graz, Austria
| | | | - Macit Ilkit
- Division of Mycology, University of Çukurova, 01330 Adana, Turkey
- Correspondence: (M.I.); (D.S.P.); Tel.: +90-532-286-0099 (M.I.); +1-201-880-3100 (D.S.P.)
| | - Cornelia Lass-Flörl
- Institute of Hygiene and Medical Microbiology, Medical University of Innsbruck, 6020 Innsbruck, Austria;
| | - David S. Perlin
- Center for Discovery and Innovation, Hackensack Meridian Health, Nutley, NJ 07110, USA; (A.A.); (R.G.-R.)
- Correspondence: (M.I.); (D.S.P.); Tel.: +90-532-286-0099 (M.I.); +1-201-880-3100 (D.S.P.)
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Antifungal In Vitro Activity of Pilosulin- and Ponericin-Like Peptides from the Giant Ant Dinoponera quadriceps and Synergistic Effects with Antimycotic Drugs. Antibiotics (Basel) 2020; 9:antibiotics9060354. [PMID: 32585881 PMCID: PMC7344683 DOI: 10.3390/antibiotics9060354] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2020] [Revised: 06/17/2020] [Accepted: 06/20/2020] [Indexed: 02/06/2023] Open
Abstract
Venoms from ants comprise a rich source of bioactive peptides, including antimicrobial peptides. From the proteome and peptidome of the giant ant Dinoponera quadriceps venom, members of five known classes of antimicrobial peptides were disclosed (e.g., dermaseptin-, defensin-, ICK-, pilosulin- and ponericin-like types). Based on comparative analysis, these family members have structural determinants that indicate they could display antimicrobial activities. In previous works, pilosulin- and ponericin-like peptides were demonstrated to be active against bacteria, fungi, and parasites. Herein, the antifungal activity of ponericin- and pilosulin-like peptides were assessed, aiming at the expansion of the knowledge about AMPs in predatory ants and the development of new microbicide strategies to deal with difficult-to-treat fungal infections. Synthetic pilosulin- (Dq-2562, Dq-1503, and Dq-1319) and ponericin-like (Dq-3162) peptides were evaluated for their fungicide and fungistatic activities against different species of Candida, including a drug-resistant clinical strain. The MICs and MLCs were determined for all peptides individually and in combination with general antifungal drugs by the microdilution method. The time-kill kinetic curves were set up by means of a luminescent reagent, of which the light signal is proportional to the number of viable cells. The candicidal synergism observed by the combination of subinhibitory concentrations of peptides and general antimycotic drugs were quantified by the checkerboard test and fluorescent dye permeation assay. The influence of ergosterol on the antifungal activity was verified by supplementation of culture medium. The pilosulin- (Dq-2562 and Dq-1503) and ponericin-like (Dq-3162) were the most active peptides, displaying a broad spectrum of antifungal activity in vitro, with MICs in the range of 0.625 to 10 µM. The combination of peptides and conventional antimycotic drugs displayed a synergistic reduction in the MIC values of individual peptides and drugs, while soluble ergosterol in the culture medium increased the MICs. The fungicide and fungistatic activity of the individual peptides and peptides in combination with antimycotics were time-dependent with a rapid onset of action and long-lasting effect, which involved membrane disruption as an underlying mechanism of their action. Altogether, pilosulin- and ponericin-like peptides from the giant ant D. quadriceps venom display a broad-spectrum of candicidal activity, what allows their inclusion in the row of the antifungal peptides and gives support for further studies on the development of strategies to fight candidiasis.
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