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.

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 The Emerging Terbinafine-Resistant Trichophyton Epidemic: What Is the Role of Antifungal Susceptibility Testing?

Dermatology ◽  
2021 ◽  
pp. 1-20
Author(s):  
Julia J. Shen ◽  
Maiken C. Arendrup ◽  
Shyam Verma ◽  
Ditte Marie L. Saunte
Keyword(s):  
Gene Mutation ◽  
Susceptibility Testing ◽  
Geometric Mean ◽  
Antifungal Susceptibility ◽  
Antifungal Susceptibility Testing ◽  
Squalene Epoxidase ◽  
Exclusion Criteria ◽  
Huge Variation

<b><i>Background:</i></b> Dermatophytosis is commonly encountered in the dermatological clinics. The main aetiological agents in dermatophytosis of skin and nails in humans are <i>Trichophyton</i> (<i>T</i>.) <i>rubrum</i>, <i>T. mentagrophytes</i> and <i>T. interdigitale</i> (former <i>T. mentagrophytes-</i>complex). Terbinafine therapy is usually effective in eradicating infections due to these species by inhibiting their squalene epoxidase (SQLE) enzyme, but increasing numbers of clinically resistant cases and mutations in the SQLE gene have been documented recently. Resistance to antimycotics is phenotypically determined by antifungal susceptibility testing (AFST). However, AFST is not routinely performed for dermatophytes and no breakpoints classifying isolates as susceptible or resistant are available, making it difficult to interpret the clinical impact of a minimal inhibitory concentration (MIC). <b><i>Summary:</i></b> PubMed was systematically searched for terbinafine susceptibility testing of dermatophytes on October 20, 2020, by two individual researchers. The inclusion criteria were <i>in vitro</i> terbinafine susceptibility testing of <i>Trichophyton (T.) rubrum</i>, <i>T. mentagrophytes</i> and <i>T. interdigitale</i> with the broth microdilution technique. The exclusion criteria were non-English written papers. Outcomes were reported as MIC range, geometric mean, modal MIC and MIC<sub>50</sub> and MIC<sub>90</sub> in which 50 or 90% of isolates were inhibited, respectively. The reported MICs ranged from &#x3c;0.001 to &#x3e;64 mg/L. The huge variation in MIC is partly explained by the heterogeneity of the <i>Trichophyton</i> isolates, where some originated from routine specimens (wild types) whereas others came from non-responding patients with a known SQLE gene mutation. Another reason for the great variation in MIC is the use of different AFST methods where MIC values are not directly comparable. High MICs were reported particularly in isolates with SQLE gene mutation. The following SQLE alterations were reported: F397L, L393F, L393S, H440Y, F393I, F393V, F415I, F415S, F415V, S443P, A448T, L335F/A448T, S395P/A448T, L393S/A448T, Q408L/A448T, F397L/A448T, I121M/V237I and H440Y/F484Y in terbinafine-resistant isolates.

Use of spectrophotometric reading for in vitro antifungal susceptibility testing ofAspergillusspp.

1999 ◽  
Vol 45 (10) ◽  
pp. 871-874 ◽  
Author(s):  
Eric Dannaoui ◽  
Florence Persat ◽  
Marie-France Monier ◽  
Elisabeth Borel ◽  
Marie-Antoinette Piens ◽  
...  
Keyword(s):  
Amphotericin B ◽  
Susceptibility Testing ◽  
Clinical Laboratory ◽  
Antifungal Susceptibility ◽  
Reference Method ◽  
Antifungal Susceptibility Testing ◽  
Aspergillus Species ◽  
National Committee ◽  
Broth Microdilution Method

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.

Vaginitis Due To Pichia fermentans in a Patient Affected by Endometrial Cancer: A Novel Case Report

2021 ◽  
Vol 17 ◽  
Author(s):  
Zarifeh Adampour ◽  
Malihe Hasanzadeh ◽  
Hossein Zarrinfar ◽  
Maryam Nakhaei ◽  
Monika Novak Babič
Keyword(s):  
Endometrial Cancer ◽  
Susceptibility Testing ◽  
Antifungal Susceptibility ◽  
Female Genital Tract ◽  
Antifungal Susceptibility Testing ◽  
Vein Thrombosis ◽  
Microbial Infections ◽  
Life Threatening ◽  
In Vitro Antifungal Susceptibility

Introduction: Endometrial cancer is one of the most common malignancies of the female genital tract, which can be serious or life-threatening. Microbial infections can be one of the underlying causes of this type of cancer. Case Presentation: The present study describes the isolation of Pichia fermentans (Candida firmentaria var. firmentaria) from the vaginal secretions of a 61-year-old woman affected by endometrial cancer. She reported abdominal pain and vaginal discharge for 3 months, and had a history of diabetes, hypertension, Deep Vein Thrombosis (DVT), and Acute Myeloid Leukemia (AML). The isolated yeast was identified based on nuclear ribosomal internal transcribed spacer (ITS1-ITS2 rDNA) sequence analysis. The in vitro antifungal susceptibility testing showed a higher effect for ketoconazole against P. fermentans than fluconazole, itraconazole and voriconazole. Conclusion: Correct differentiation between P. fermentans and other yeast should be considered. The in vitro antifungal susceptibility testing is recommended for rare yeast, and will help the physicians in providing the best treatment.

scholarly journals Standardized Method for In Vitro Antifungal Susceptibility Testing of Candida albicansBiofilms

2001 ◽  
Vol 45 (9) ◽  
pp. 2475-2479 ◽  
Author(s):  
Gordon Ramage ◽  
Kacy Vande Walle ◽  
Brian L. Wickes ◽  
José L. López-Ribot
Keyword(s):  
Antimicrobial Agents ◽  
Susceptibility Testing ◽  
Colorimetric Assay ◽  
Antifungal Susceptibility ◽  
Antifungal Susceptibility Testing ◽  
Phenotypic Traits ◽  
Salt Reduction ◽  
Treatment Regimens ◽  
In Vitro Antifungal Susceptibility

ABSTRACT Candida albicans is implicated in many biomaterial-related infections. Typically, these infections are associated with biofilm formation. Cells in biofilms display phenotypic traits that are dramatically different from those of their free-floating planktonic counterparts and are notoriously resistant to antimicrobial agents. Consequently, biofilm-related infections are inherently difficult to treat and to fully eradicate with normal treatment regimens. Here, we report a rapid and highly reproducible microtiter-based colorimetric assay for the susceptibility testing of fungal biofilms, based on the measurement of metabolic activities of the sessile cells by using a formazan salt reduction assay. The assay was used for in vitro antifungal susceptibility testing of severalC. albicans strains grown as biofilms against amphotericin B and fluconazole and the increased resistance of C. albicans biofilms against these antifungal agents was demonstrated. Because of its simplicity, compatibility with a widely available 96-well microplate platform, high throughput, and automation potential, we believe this assay represents a promising tool for the standardization of in vitro antifungal susceptibility testing of fungal biofilms.

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 Etest Cannot Be Recommended forIn VitroSusceptibility Testing of Mucorales

2015 ◽  
Vol 59 (6) ◽  
pp. 3663-3665 ◽  
Author(s):  
Rita Caramalho ◽  
Elisabeth Maurer ◽  
Ulrike Binder ◽  
Ricardo Araújo ◽  
Somayeh Dolatabadi ◽  
...  
Keyword(s):  
Amphotericin B ◽  
Antimicrobial Susceptibility ◽  
Active Drug ◽  
Susceptibility Testing ◽  
Antifungal Susceptibility ◽  
Antifungal Susceptibility Testing ◽  
Broth Microdilution ◽  
European Committee ◽  
Susceptibility Patterns

ABSTRACTAmphotericin B and posaconazole susceptibility patterns were determined for the most prevalent Mucorales, following EUCAST (European Committee on Antimicrobial Susceptibility Testing) broth microdilution guidelines. In parallel, Etest was performed and evaluated against EUCAST. The overall agreement of MICs gained with Etest and EUCAST was 75.1%; therefore, Etest cannot be recommended for antifungal susceptibility testing of Mucorales. Amphotericin B was the most active drug against Mucorales speciesin vitro, while the activities of posaconazole were more restricted.

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