Afiliación

Servicio de Microbiología Clínica y Enfermedades Infecciosas Hospital Gregorio Marañón, Madrid

Título:

MALDI-TOF Mass Spectrometry and Machine Learning. Applications in Clinical Microbiology

Abstract:

MALDI-TOF Mass Spectrometry has become an essential identification tool in the clinical microbiology laboratories over the last decades. It has replaced many conventional identification methods based on biochemical tests, that are no longer in use due to the use-friendliness, reliability and cost-effectiveness of MALDI-TOF. Most bacterial species can be easily identified from the colonies grown overnight on agar plates. Yeasts and fungal species are becoming easier to identify by MALDI-TOF thanks to the improvement of the available databases and the sample preparation procedures. Besides, direct identification of pathogens from clinical samples (blood cultures, urine or cerebrospinal fluid) has been demonstrated to be a clinically impacting application of MALDI-TOF since the identification of microorganisms can be achieved in an early manner, allowing the streamlining of optimal antibiotic treatment. The detection of resistant mechanisms (beta-lactamases, carbapenemases) almost simultaneously to the identification of the host microorganisms has been another important milestone of MALDI-TOF, showing that the information contained in the protein spectra can provide much more information than the mere name of the microorganism analysed.

Our MALDI-TOF-based research group has initiated collaborations with bioinformaticians and biomedicine engineers in order to classify MALDI-TOF protein spectra according to the presence of antibiotic/antifungal resistance mechanisms, the sequence type (ST) or the serotype/ribotype they belong to or their connection with hospital outbreaks. The algorithms applied so far have allowed the correct classification of azole-resistant Aspergillus fumigatus, vancomycin-resistant Enteroccocus faecium or high-risk clones of Pseudomonas aeruginosa. Some of our studies are still in a preliminary stage, but the robustness of the results shows that MALDI-TOF is a promising tool for rapid screening of clinically important strains.