Multicenter Study Demonstrates Standardization Requirements for Mold Identification by MALDI-TOF MS

Abstract

ObjectivesRapid and accurate mold identification is critical for guiding therapy for mold infections. MALDI-TOF MS has been widely adopted for bacterial and yeast identification; however, few clinical laboratories have applied this technology for routine mold identification due to limited database availability and lack of standardized processes. Here, we evaluated the versatility of the NIH Mold Database in a multicenter evaluation.MethodsThe NIH Mold Database was evaluated by eight US academic centers using a solid media extraction method and a challenge set of 80 clinical mold isolates. Multiple instrument parameters important for spectra optimization were evaluated, leading to the development of two specialized acquisition programs (NIH method and the Alternate-B method).ResultsA wide range in performance (33–77%) was initially observed across the eight centers when routine spectral acquisition parameters were applied. Use of the NIH or the Alternate-B specialized acquisition programs, which are different than those used routinely for bacterial and yeast spectral acquisition (MBT_AutoX), in combination with optimized instrument maintenance, improved performance, illustrating that acquisition parameters may be one of the key limiting variable in achieving successful performance.ConclusionSuccessful mold identification using the NIH Database for MALDI-TOF MS on Biotyper systems was demonstrated across multiple institutions for the first time following identification of critical program parameters combined with instrument optimization. This significantly advances our potential to implement MALDI-TOF MS for mold identification across many institutions. Because instrument variability is inevitable, development of an instrument performance standard specific for mold spectral acquisition is suggested to improve reproducibility across instruments.

Evaluation of the new Id‐Fungi plates from Conidia for MALDI‐TOF MS identification of filamentous fungi and comparison with conventional methods as identification tool for dermatophytes from nails, hair and skin samples

“…A lot of studies pointed out the need for adapted databases and the need to expand the Bruker current filamentous fungi database with new species and a greater number of entries to improve the sensitivity of the MALDI-TOF MS identification for dermatophytes 7,8,20,30,34,35 but also for the other filamentous fungi. 13,16,17,24,36 For this reason, we evaluated the results obtained by using the IDFP medium with the web-based MSI application comparing the identification results with those obtained by only using the original Bruker filamentous fungi 2.0 database.…”

Biosensors and Diagnostics for Fungal Detection

“…Fluorescence in situ hybridization methods have been described for Aspergillus and Candida species [ 140 , 141 ]. Matrix-assisted laser desorptionionization time of flight (MALDI-TOF) analysis now provides highly accurate and rapid identification strategies for Candida and other yeast species which are rapidly being adapted for filamentous fungi [ 109 , 142 ]. This technique is also being evaluated for its utility as a diagnostic method on primary patient samples.…”

“…Recent developments also suggest some utility in the detection of antifungal drug resistance [ 108 ]. Latterly, many mould species isolated from clinical specimens have also been added to databases, thus increasing the clinical utility of this approach [ 109 ]. However, there have also been direct applications to clinical samples, usually yeast detection in blood samples, in an attempt to reduce the time required for culture, thereby allowing for earlier diagnosis and identification of the infecting organism facilitating the prompt administration of appropriate antifungal therapy [ 110 , 111 , 112 ].…”

Scedosporium and Lomentospora Infections: Contemporary Microbiological Tools for the Diagnosis of Invasive Disease

“…The other commercial MALDI-TOF MS systems (MALDI Biotyper (Bruker Daltonics, Bremen, Germany), Andromas (Andromas SAS, Paris, France) and Axima@SARAMIS (Shimadzu/AnagnosTec, Duisburg, Germany)) are also inadequate for the identification of Scedosporium/Lomentospora when relying on their database alone [ 34 , 35 , 36 ]. As such, the success of MALDI-TOF MS is enabled by complementation of commercial databases by in-house libraries together with consistency of sample preparation methods used to generate these mass spectra [ 32 , 37 ].…”