Evaluation of the MALDI-TOF mass spectrometry technique for the identification of dermatophytes: Use of an extended database.

BACKGROUND: Identification of dermatophytes is usually performed through morphological analyses. However, it may be hindered due to the discovery of new species and complexes and, with some isolates, by the absence of fructification. Matrix-assisted laser desorption/ionisation-time-of-flight mass spectrometry (MALDI-TOF MS) seems to be an option for improving identification. AIMS: To develop a database (DB) for the identification of dermatophytes with MALDI-TOF MS, including 32 isolates from the Red de Micología de la Ciudad Autónoma de Buenos Aires [Mycology Network of the Autonomous City of Buenos Aires] (RMCABA) and one reference isolate (RMCABA DB), and evaluate its performance when added to the DB from the supplier, Bruker (Bruker DB). METHODS: All the isolates in the RMCABA DB were identified based on morphology and sequencing. To evaluate the performance of the extended DB (Bruker DB plus RMCABA DB), 136 clinical isolates were included. RESULTS: The percentages of identification at the species level increased from 45% to 88%, but the identification at the genus level decreased from 23% to 7%. CONCLUSIONS: MALDI-TOF MS yielded better performance in the identification of dermatophytes after including the RMCABA DB, which encompassed local isolates.

Evaluation of the MALDI-TOF mass spectrometry technique for the identification of dermatophytes: Use of an extended database / Evaluación de la técnica de espectrometría de masas MALDI-TOF para la identificación de dermatofitos: utilización de una base de datos ampliada

Background: Identification of dermatophytes is usually performed through morphological analyses. However, it may be hindered due to the discovery of new species and complexes and, with some isolates, by the absence of fructification. Matrix-assisted laser desorption/ionisation-time-of-flight mass spectrometry (MALDI-TOF MS) seems to be an option for improving identification. Aims: To develop a database (DB) for the identification of dermatophytes with MALDI-TOF MS, including 32 isolates from the Red de Micología de la Ciudad Autónoma de Buenos Aires [Mycology Network of the Autonomous City of Buenos Aires] (RMCABA) and one reference isolate (RMCABA DB), and evaluate its performance when added to the DB from the supplier, Bruker (Bruker DB). Methods: All the isolates in the RMCABA DB were identified based on morphology and sequencing. To evaluate the performance of the extended DB (Bruker DB plus RMCABA DB), 136 clinical isolates were included. Results: The percentages of identification at the species level increased from 45% to 88%, but the identification at the genus level decreased from 23% to 7%.Conclusions: MALDI-TOF MS yielded better performance in the identification of dermatophytes after including the RMCABA DB, which encompassed local isolates.(AU)

Antecedentes: La identificación de dermatofitos se realiza, usualmente, a través del análisis morfológico, pero puede verse dificultada por la aparición de nuevas especies y complejos de especies y, en algunos aislamientos, por la falta de elementos de fructificación. Matrix-assisted laser desorption/ionization-time of flight mass spectrometry (MALDI-TOF MS) aparece como una alternativa para mejorar la identificación. Objetivos: Construir una base de datos (BaDa) para la identificación de dermatofitos mediante MALDI-TOF MS, con 32 aislamientos de la Red de Micología de la Ciudad Autónoma de Buenos Aires (RMCABA) y una cepa de referencia (BaDa RMCABA), y evaluar su desempeño al incorporarla a la BaDa del proveedor Bruker (BaDa Bruker). Métodos: Todos los aislamientos incorporados a la BaDa RMCABA se identificaron por morfología y secuenciación. Para la evaluación de la BaDa ampliada (BaDa Bruker más BaDa RMCABA) se incluyeron 136 aislamientos clínicos. Resultados: El porcentaje de identificación a nivel de especie se incrementó del 45 al 88%, mientras que la identificación a nivel de género disminuyó del 23 al 7%. Conclusiones: Con la incorporación de la BaDa RMCABA, que contó con aislamientos regionales, se observó un mejor desempeño en la identificación de dermatofitos por MALDI-TOF MS.(AU)