scholarly journals Susceptibility Testing of Fungi to Antifungal Drugs

2018 ◽  
Vol 4 (3) ◽  
pp. 110 ◽  
Author(s):  
Maurizio Sanguinetti ◽  
Brunella Posteraro
Keyword(s):  
Susceptibility Testing ◽  
Fungal Infections ◽  
Antifungal Susceptibility ◽  
Antifungal Drugs ◽  
Laser Desorption Ionization ◽  
Ionization Time ◽  
European Committee ◽  
Flight Mass Spectrometry ◽  
Sterile Site ◽  
Phenotypic Methods

Susceptibility testing of fungi against antifungal drugs commonly used for therapy is a key component of the care of patients with invasive fungal infections. Antifungal susceptibility testing (AFST) has progressed in recent decades to finally become standardized and available as both Clinical and Laboratory Standards Institute (CLSI) and European Committee on Antimicrobial Susceptibility Testing (EUCAST) reference methods and in commercial manual/automated phenotypic methods. In clinical practice, the Sensititre YeastOne and Etest methods are widely used for AFST, particularly for sterile site isolates of Candida. Nevertheless, AFST is moving toward new phenotypic methods, such as matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS), that are capable of providing rapid, and potentially more actionable, results for the treating clinician. Our objective is to summarize updated data on phenotypic methods for AFST of Candida and Aspergillus species and to assess their significance in view of opposing, but emerging, molecular genotypic methods.

scholarly journals Antifungal Susceptibility Testing of Aspergillus spp. by Using a Composite Correlation Index (CCI)-Based Matrix-Assisted Laser Desorption Ionization–Time of Flight Mass Spectrometry Method Appears To Not Offer Benefit over Traditional Broth Microdilution Testing

2017 ◽  
Vol 55 (7) ◽  
pp. 2030-2034 ◽  
Author(s):  
Melissa R. Gitman ◽  
Lisa McTaggart ◽  
Joanna Spinato ◽  
Rahgavi Poopalarajah ◽  
Erin Lister ◽  
...  
Keyword(s):  
Susceptibility Testing ◽  
Antifungal Susceptibility ◽  
Laser Desorption Ionization ◽  
Wild Type ◽  
Ionization Time ◽  
Content Type ◽  
Maldi Tof Ms ◽  
Maldi Tof ◽  
Flight Mass Spectrometry ◽  
Tof Ms

ABSTRACT Aspergillus spp. cause serious invasive lung infections, and Aspergillus fumigatus is the most commonly encountered clinically significant species. Voriconazole is considered to be the drug of choice for treating A. fumigatus infections; however, rising resistance rates have been reported. We evaluated a matrix-assisted laser desorption ionization–time of flight mass spectrometry (MALDI-TOF MS)-based method for the differentiation between wild-type and non-wild-type isolates of 20 Aspergillus spp. (including 2 isolates of Aspergillus ustus and 1 of Aspergillus calidoustus that were used as controls due their intrinsic low azole susceptibility with respect to the in vitro response to voriconazole). At 30 and 48 h of incubation, there was complete agreement between Cyp51A sequence analysis, broth microdilution, and MALDI-TOF MS classification of isolates as wild type or non-wild type. In this proof-of-concept study, we demonstrated that MALDI-TOF MS can be used to accurately detect A. fumigatus strains with reduced voriconazole susceptibility. However, rather than proving to be a rapid and simple method for antifungal susceptibility testing, this particular MS-based method showed no benefit over conventional testing methods.

scholarly journals Multidrug-Resistant Candida auris Misidentified as Candida haemulonii: Characterization by Matrix-Assisted Laser Desorption Ionization–Time of Flight Mass Spectrometry and DNA Sequencing and Its Antifungal Susceptibility Profile Variability by Vitek 2, CLSI Broth Microdilution, and Etest Method

2015 ◽  
Vol 53 (6) ◽  
pp. 1823-1830 ◽  
Author(s):  
Shallu Kathuria ◽  
Pradeep K. Singh ◽  
Cheshta Sharma ◽  
Anupam Prakash ◽  
Aradhana Masih ◽  
...  
Keyword(s):  
Antifungal Susceptibility ◽  
Laser Desorption ◽  
Multidrug Resistant ◽  
Laser Desorption Ionization ◽  
Candida Auris ◽  
Ionization Time ◽  
Content Type ◽  
Flight Mass Spectrometry ◽  
Vitek 2 ◽  
Matrix Assisted Laser

Candida aurisis a multidrug-resistant yeast that causes a wide spectrum of infections, especially in intensive care settings. We investigatedC. aurisprevalence among 102 clinical isolates previously identified asCandida haemuloniiorCandida famataby the Vitek 2 system. Internal transcribed spacer region (ITS) sequencing confirmed 88.2% of the isolates asC. auris, and matrix-assisted laser desorption ionization–time of flight mass spectrometry (MALDI-TOF MS) easily separated all related species,viz.,C. auris(n= 90),C. haemulonii(n= 6),C. haemuloniivar.vulnera(n= 1), andCandida duobushaemulonii(n= 5). Thein vitroantifungal susceptibility was determined using CLSI broth microdilution (CLSI-BMD), the Vitek 2 antifungal susceptibility test, and the Etest method.C. aurisisolates revealed uniformly elevated fluconazole MICs (MIC50, 64 μg/ml), and an alarming percentage of isolates (37%) exhibited elevated caspofungin MICs by CLSI-BMD. Notably, 34% ofC. aurisisolates had coexisting elevated MICs (≥2 μg/ml) for both fluconazole and voriconazole, and 10% of the isolates had elevated coexisting MICs (≥2 μg/ml) to two additional azoles, i.e., posaconazole and isavuconazole. In contrast to reduced amphotericin B MICs by CLSI-BMD (MIC50, 1 μg/ml) forC. auris, elevated MICs were noted by Vitek 2 (MIC50, 8 μg/ml), which were statistically significant.Candida aurisremains an unnoticed pathogen in routine microbiology laboratories, as 90% of the isolates characterized by commercial identification systems are misidentified asC. haemulonii. MALDI-TOF MS proved to be a more robust diagnostic technique for rapid identification ofC. auris. Considering that misleading elevated MICs of amphotericin B by the Vitek AST-YS07 card may lead to the selection of inappropriate therapy, a cautionary approach is recommended for laboratories relying on commercial systems for identification and antifungal susceptibility testing of rare yeasts.

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.

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