| Autor: |
Zvezdanova ME; Clinical Microbiology and Infectious Diseases Department, Hospital General Universitario Gregorio Marañón, Doctor Esquerdo, 46, 28007 Madrid, Spain.; Instituto de Investigación Sanitaria Gregorio Marañón, 28007 Madrid, Spain., Arroyo MJ; Clover Bioanalytical Software, Centro de Empresas del Parque Tecnológico de la Salud, Av. del Conocimiento, 41, 18016 Granada, Spain., Méndez G; Clover Bioanalytical Software, Centro de Empresas del Parque Tecnológico de la Salud, Av. del Conocimiento, 41, 18016 Granada, Spain., Guinea J; Clinical Microbiology and Infectious Diseases Department, Hospital General Universitario Gregorio Marañón, Doctor Esquerdo, 46, 28007 Madrid, Spain.; Instituto de Investigación Sanitaria Gregorio Marañón, 28007 Madrid, Spain.; CIBER de Enfermedades Respiratorias (CIBERES CB06/06/0058), 28029 Madrid, Spain., Mancera L; Clover Bioanalytical Software, Centro de Empresas del Parque Tecnológico de la Salud, Av. del Conocimiento, 41, 18016 Granada, Spain., Muñoz P; Clinical Microbiology and Infectious Diseases Department, Hospital General Universitario Gregorio Marañón, Doctor Esquerdo, 46, 28007 Madrid, Spain.; Instituto de Investigación Sanitaria Gregorio Marañón, 28007 Madrid, Spain.; CIBER de Enfermedades Respiratorias (CIBERES CB06/06/0058), 28029 Madrid, Spain.; Medicine Department, School of Medicine, Universidad Complutense de Madrid, 28040 Madrid, Spain., Rodríguez-Sánchez B; Clinical Microbiology and Infectious Diseases Department, Hospital General Universitario Gregorio Marañón, Doctor Esquerdo, 46, 28007 Madrid, Spain.; Instituto de Investigación Sanitaria Gregorio Marañón, 28007 Madrid, Spain., Escribano P; Clinical Microbiology and Infectious Diseases Department, Hospital General Universitario Gregorio Marañón, Doctor Esquerdo, 46, 28007 Madrid, Spain.; Instituto de Investigación Sanitaria Gregorio Marañón, 28007 Madrid, Spain. |
| Abstrakt: |
Matrix-assisted laser desorption-ionization/time of flight mass spectrometry (MALDI-TOF MS) has been widely implemented for the rapid identification of microorganisms. Although most bacteria, yeasts and filamentous fungi can be accurately identified with this method, some closely related species still represent a challenge for MALDI-TOF MS. In this study, two MALDI-TOF-based approaches were applied for discrimination at the species-level of isolates belonging to the Cryptococcus neoformans complex, previously characterized by Amplified Fragment Length Polymorphism (AFLP) and sequencing of the ITS1-5.8S-ITS2 region: (i) an expanded database was built with 26 isolates from the main Cryptococcus species found in our setting ( C. neoformans , C. deneoformans and AFLP3 interspecies hybrids) and (ii) peak analysis and data modeling were applied to the protein spectra of the analyzed Cryptococcus isolates. The implementation of the in-house database did not allow for the discrimination of the interspecies hybrids. However, the performance of peak analysis with the application of supervised classifiers (partial least squares-discriminant analysis and support vector machine) in a two-step analysis allowed for the 96.95% and 96.55% correct discrimination of C. neoformans from the interspecies hybrids, respectively. In addition, PCA analysis prior to support vector machine (SVM) provided 98.45% correct discrimination of the three analyzed species in a one-step analysis. This novel method is cost-efficient, rapid and user-friendly. The procedure can also be automatized for an optimized implementation in the laboratory routine. |
