Evaluation of protein mass Fingerprint-MS of clinical isolates of Candida spp. by MALDI-TOF MS

Abstract

Invasive fungal infections have high levels of mortality, especially in immunocompromised patients. Clinical isolates of Candida spp. are responsible for more than 50% of the researched examples. Matrix Assisted Laser Desorption Ionization Time of Flight (MALDI-TOF) offers fast and accurate identification of the microorganism, optimizing the beginning of antifungal therapy. In recent years, studies are being carried out on the applicability of MALDI-TOF in fungal identification. However, few data were found on fingerprint-MS in different species of Candida. The present study aims to evaluate a Protein Mass Fingerprint (PMF) of clinical isolates of Candida spp identified by MALDI-TOF MS. For this purpose, it was performed a multivariate analysis of the spectra. There was a consistent spectrum profile among Candida species between 3 and 15 KDa. The most intense peaks being between 3 and 8 KDa. It was noted the existence of characteristic signs between species. C. albicans shows two intense signs, the first at 4.3 and 4.4 KDa and the other at 5.1 and 5.2 KDa. The others species show an intense signal in 4.4 - 4.5 KDa.  C. lusitaniae shows intense signals between 6.0 - 6.1 and 6.6 - 6.7 KDa, C. guilhermondii between 6.0 - 6.1 and 6.1 –6.2 KDa. C. glabrata an intense signal in 5.5 - 5.6 KDa and a less intense signal in 11.0-11.1 Kda. Thus, it is possible to outline a spectral profile of Candida spp. The characterization of the spectral profile can help in the critical evaluation of fingerprint-MS, assisting the analyst in the decision-making process and in the expansion of reference library.