scholarly journals Antifungal susceptibility testing of candida – Methods and issues in current practice

2019 ◽  
Vol 10 (3) ◽  
pp. 1778-1784
Author(s):  
Lakshmi Krishnasamy ◽  
Priya Santharam ◽  
Chitralekha Saikumar
Keyword(s):  
Current Practice ◽  
Antifungal Agents ◽  
Susceptibility Testing ◽  
Fungal Infections ◽  
Antifungal Susceptibility ◽  
Antifungal Susceptibility Testing ◽  
Antifungal Drugs ◽  
Testing Methods ◽  
Antifungal Drug Resistance ◽  
Resistant Strains

Despite the availability of many antifungal drugs in clinical practice, the occurrence of antifungal drug resistance is on the rise. Since the antifungal susceptibility testing (AFST) is not done routinely in many of the microbiology laboratories, it is very difficult to determine which antifungal agent is very effective for a particular infection. There is a real need for precise, reproducible and extrapolative antifungal susceptibility testing methods to aid the therapeutic management. The practice of empirical treatment for fungal infections further promotes the emergence of resistant strains. The AFST practice would essentially help the clinicians in appropriate decision making. Although conventional AFST methods are somewhat cumbersome, many novel AFST methods are currently available in many laboratory settings which would provide a quicker result many times. In essence, the application of AFST along with identification of the fungus up to species level would definitely be very helpful in selecting the primary antifungal agents for treatment especially in difficult to manage and invasive fungal infections. This review will throw light on the various AFST methods available and their issues in the current practice.

scholarly journals Identification of Fungal Pathogens in Otomycosis and Their Drug Sensitivity: Our Experience

2018 ◽  
Vol 22 (04) ◽  
pp. 400-403 ◽  
Author(s):  
Khaled Ali ◽  
Mahmood Hamed ◽  
Hameda Hassan ◽  
Amira Esmail ◽  
Abeer Sheneef
Keyword(s):  
Enzymatic Activity ◽  
Candida Species ◽  
Fungal Pathogens ◽  
Antifungal Agents ◽  
Susceptibility Testing ◽  
Antifungal Susceptibility ◽  
Antifungal Susceptibility Testing ◽  
Antifungal Drugs ◽  
High Recurrence Rate ◽  
Fungal Culture

Introduction Otomycosis is a common problem in otolaryngology practice. However, we usually encounter some difficulties in its treatment because many patients show resistance to antifungal agents, and present high recurrence rate. Objectives To determine the fungal pathogens that cause otomycosis as well as their susceptibility to the commonly used antifungal agents. Additionally, to discover the main reasons for antifungal resistance. Methods We conducted an experimental descriptive study on 122 patients clinically diagnosed with otomycosis from April 2016 to April 2017. Aural discharge specimens were collected for direct microscopic examination and fungal culture. In vitro antifungal susceptibility testing was performed against the commonly used antifungal drugs. We tested the isolated fungi for their enzymatic activity. Results Positive fungal infection was found in 102 samples. The most common fungal pathogens were Aspergillus and Candida species, with Aspergillus niger being the predominant isolate (51%). The antifungal susceptibility testing showed that mold isolates had the highest sensitivity to voriconazole (93.48%), while the highest resistance was to fluconazole (100%). For yeast, the highest sensitivity was to nystatin (88.24%), followed by amphotericin B (82.35%), and the highest resistance was to terbinafine (100%), followed by Itraconazole (94.12%). Filamentous fungi expressed a high enzymatic ability, making them more virulent. Conclusion The Aspergillus and Candida species are the most common fungal isolates in otomycosis. Voriconazole and Nystatin are the medications of choice for the treatment of otomycosis in our community. The high virulence of fungal pathogens is owed to their high enzymatic activity. Empirical use of antifungals should be discouraged.

Antifungal susceptibility testing and resistance

2017 ◽  
Author(s):  
Elizabeth M. Johnson
Keyword(s):  
Antifungal Agents ◽  
Susceptibility Testing ◽  
Clinical Laboratory ◽  
Antifungal Susceptibility ◽  
Invasive Disease ◽  
Fungal Species ◽  
Antifungal Susceptibility Testing ◽  
Limiting Factors ◽  
Antifungal Drug Resistance

The availability of choice of systemically active antifungal agents and the proliferation in the number of fungal species implicated in invasive disease have meant that clinicians are increasingly looking for guidance from clinical laboratory results to help select the most appropriate agent. There are now well-established and predictable patterns of innate in vitro resistance to one or more antifungal agents associated with many yeast and mould species. This chapter provides definitions for the most frequently used terminology and outlines some of the issues surrounding antifungal susceptibility testing with yeast and mould isolates. Reference methods published by the Clinical Laboratory Standards Institute (CLSI) and the European Committee on Antimicrobial Susceptibility Testing (EUCAST) are discussed. Both innate and emergent antifungal drug resistance are increasingly recognized as limiting factors in the selection of antifungal agents, and the epidemiology and mechanisms of resistance are described for each of the major classes of antifungal agent.

scholarly journals ANTIFUNGAL SUSCEPTIBILITY TESTING: CURRENT ROLE FROM THE CLINICAL LABORATORY PERSPECTIVE

2014 ◽  
Vol 6 (1) ◽  
pp. e2014030 ◽  
Author(s):  
Brunella Posteraro ◽  
Riccardo Torelli ◽  
Elena De Carolis ◽  
Patrizia Posteraro ◽  
Maurizio Sanguinetti
Keyword(s):  
Drug Exposure ◽  
Antifungal Agents ◽  
Susceptibility Testing ◽  
Clinical Laboratory ◽  
Antifungal Susceptibility ◽  
Antifungal Susceptibility Testing ◽  
Clinical Resistance ◽  
Therapeutic Decision Making ◽  
Short Time

Despite availability of many antifungal agents, antifungal clinical resistance occurs, perhaps as a result of an infecting organism found to be resistant in vitro to one or more antifungals tested. Thus, antifungal susceptibility testing (AFST) results, if timely generated by the clinical microbiology and communicated to clinicians, can aid them in the therapeutic decision making, especially for difficult-to-treat invasive candidiasis and aspergillosis. Although recently refined AFST methods are commercially available to allow a close antifungal resistance surveillance in many clinical setting, novel assays, relying on short-time antifungal drug exposure of fungal isolates, are upcoming tools for AFST. Based on emerging technologies such as flow cytometry, MALDI-TOF mass spectrometry, and isothermal microcalorimetry, these assays could provide a reliable means for quicker and sensitive assessment of AFST.

scholarly journals Antifungal susceptibility testing of Aspergillus niger on silicon microwells by intensity-based reflectometric interference spectroscopy

2019 ◽  
Author(s):  
Christopher Heuer ◽  
Heidi Leonard ◽  
Nadav Nitzan ◽  
Ariella Lavy-Alperovitch ◽  
Naama Massad-Ivanir ◽  
...  
Keyword(s):  
Aspergillus Niger ◽  
Susceptibility Testing ◽  
Fungal Infections ◽  
Antifungal Susceptibility ◽  
Fungal Growth ◽  
Antifungal Susceptibility Testing ◽  
Label Free ◽  
Broth Microdilution ◽  
Silicon Phase ◽  
Reflectometric Interference Spectroscopy

AbstractThe increasing number of invasive fungal infections among immunocompromised patients and the emergence of antifungal resistant pathogens has resulted in the need for rapid and reliable antifungal susceptibility testing (AFST). Accelerating antifungal susceptibility testing allows for advanced treatment decisions and the reduction in future instances of antifungal resistance. In this work, we demonstrate the application of a silicon phase grating as sensor for the detection of growth of Aspergillus niger (A. niger) by intensity-based reflectometric interference spectroscopy and its use as an antifungal susceptibility test. The silicon gratings provide a solid-liquid interface to capture micron-sized Aspergillus conidia within microwell arrays. Fungal growth is optically tracked and detected by the reduction in the intensity of reflected light from the silicon grating. The growth of A. niger in the presence of various concentrations of the antifungal agents voriconazole and amphotericin B is investigated by intensity-based reflectometric interference spectroscopy and used for the determination of the minimal inhibitory concentrations (MIC), which are compared to standard broth microdilution testing. This assay allows for expedited detection of fungal growth and provides a label-free alternative to standard antifungal susceptibility testing methods, such as broth microdilution and agar diffusion methods.

scholarly journals Candida antifungal drug resistance in sub-Saharan African populations: A systematic review

F1000Research ◽  
2017 ◽  
Vol 5 ◽  
pp. 2832 ◽  
Author(s):  
Charlene Wilma Joyce Africa ◽  
Pedro Miguel dos Santos Abrantes
Keyword(s):  
Drug Resistance ◽  
Susceptibility Testing ◽  
Antifungal Susceptibility ◽  
Antifungal Drugs ◽  
Antifungal Drug ◽  
Sub Saharan Africa ◽  
African Countries ◽  
Antifungal Drug Resistance ◽  
Resistance Patterns ◽  
Sub Saharan

Background:Candidainfections are responsible for increased morbidity and mortality rates in at-risk patients, especially in developing countries where there is limited access to antifungal drugs and a high burden of HIV co-infection. Objectives:This study aimed to identify antifungal drug resistance patterns within the subcontinent of Africa. Methods: A literature search was conducted on published studies that employed antifungal susceptibility testing on clinicalCandidaisolates from sub-Saharan African countries using Pubmed and Google Scholar. Results: A total of 21 studies from 8 countries constituted this review. Only studies conducted in sub-Saharan Africa and employing antifungal drug susceptibility testing were included. Regional differences inCandidaspecies prevalence and resistance patterns were identified. Discussion: The outcomes of this review highlight the need for a revision of antifungal therapy guidelines in regions most affected byCandidadrug resistance.  Better controls in antimicrobial drug distribution and the implementation of regional antimicrobial susceptibility surveillance programmes are required in order to reduce the highCandidadrug resistance levels seen to be emerging in sub-Saharan Africa.

scholarly journals SUSCEPTIBILITY TEST FOR FUNGI: CLINICAL AND LABORATORIAL CORRELATIONS IN MEDICAL MYCOLOGY

2015 ◽  
Vol 57 (suppl 19) ◽  
pp. 57-64 ◽  
Author(s):  
Ana ALASTRUEY-IZQUIERDO ◽  
Marcia S.C. MELHEM ◽  
Lucas X. BONFIETTI ◽  
Juan L. RODRIGUEZ-TUDELA
Keyword(s):  
Susceptibility Testing ◽  
Fungal Infections ◽  
Antifungal Susceptibility ◽  
Fungal Species ◽  
Medical Mycology ◽  
Candida Spp ◽  
Disease Epidemiology ◽  
Resistant Strains ◽  
European Standards

SUMMARYDuring recent decades, antifungal susceptibility testing has become standardized and nowadays has the same role of the antibacterial susceptibility testing in microbiology laboratories. American and European standards have been developed, as well as equivalent commercial systems which are more appropriate for clinical laboratories. The detection of resistant strains by means of these systems has allowed the study and understanding of the molecular basis and the mechanisms of resistance of fungal species to antifungal agents. In addition, many studies on the correlation of in vitro results with the outcome of patients have been performed, reaching the conclusion that infections caused by resistant strains have worse outcome than those caused by susceptible fungal isolates. These studies have allowed the development of interpretative breakpoints for Candida spp. and Aspergillus spp., the most frequent agents of fungal infections in the world. In summary, antifungal susceptibility tests have become essential tools to guide the treatment of fungal diseases, to know the local and global disease epidemiology, and to identify resistance to antifungals.

scholarly journals Antifungal Susceptibility Testing: Current Approaches

2020 ◽  
Vol 33 (3) ◽  
Author(s):  
Elizabeth L. Berkow ◽  
Shawn R. Lockhart ◽  
Luis Ostrosky-Zeichner
Keyword(s):  
Susceptibility Testing ◽  
Antifungal Susceptibility ◽  
Epidemiological Studies ◽  
Antifungal Susceptibility Testing ◽  
Antifungal Drug Resistance ◽  
Development Organizations ◽  
Gradient Diffusion ◽  
Antibacterial Susceptibility ◽  
Automated Instruments

SUMMARY Although not as ubiquitous as antibacterial susceptibility testing, antifungal susceptibility testing (AFST) is a tool of increasing importance in clinical microbiology laboratories. The goal of AFST is to reliably produce MIC values that may be used to guide patient therapy, inform epidemiological studies, and track rates of antifungal drug resistance. There are three methods that have been standardized by standards development organizations: broth dilution, disk diffusion, and azole agar screening for Aspergillus. Other commonly used methods include gradient diffusion and the use of rapid automated instruments. Novel methodologies for susceptibility testing are in development. It is important for laboratories to consider not only the method of testing but also the interpretation (or lack thereof) of in vitro data.

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