Determination of the ability of matrix-assisted laser desorption ionization time-of-flight mass spectrometry to identify high-biofilm-producing strains

• Published in: Frontiers in microbiology 2023-01, Vol.13, p.1104405-1104405
• Main Authors: Rodríguez-Temporal, David, Díez, Rafael, Díaz-Navarro, Marta, Escribano, Pilar, Guinea, Jesús, Muñoz, Patricia, Rodríguez-Sánchez, Belén, Guembe, María
• Format: Article
• Language: English
• Subjects: biofilm; classification; crystal violet; MALDI-TOF MS; mass spectrometry; Microbiology; Staphylococcus aureus
• ISSN: 1664-302X; 1664-302X
• DOI: 10.3389/fmicb.2022.1104405

The traditional method for assessing the capacity of a microorganism to produce biofilm is generally a static model in a multi-well plate using the crystal violet (CV) binding assay, which takes 96 h. Furthermore, while the method is simple to perform, its reproducibility is poor. We evaluated whether matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) could make it possible to differentiate between high-and low-biofilm-producing microorganisms on 24-h cultures of and . We included 157 strains of . and 91 strains of . obtained from the blood cultures of patients with bacteremia/candidemia. We tested biofilm production using the CV binding assay as the gold standard to classify strains as low or high biofilm producers. We then applied MALDI-TOF MS to create a machine learning-based predictive model using 40 strains of . and . , each with extreme absorbance values, and validated this approach with the remaining 117 and 51 strains using the random forest algorithm and the support vector machine algorithm, respectively. Overall, 81.2% of the . strains (95/117) and 74.5% of the . strains (38/51) used for validation were correctly categorized, respectively, as low and high-biofilm-producing. Classification based on MALDI-TOF MS protein spectra enables us to predict acceptable information about the capacity of 24-h cultures of . and . to form biofilm.