3.5. MALDI-TOF MS spectral analysis of CFEC- ESBL bacteria
Although general information was obtained firstly with PCA analyses of all 122 CFEC bacteria, the study focused on comparing the results of MALDI-TOF MS-based PCA analysis of 35 E. coli bacteria with ESBL detected with the results of other phenotypic methods. A representative mass spectrum (CFEC-ESBL-68) showing ESBL characteristics and gel images (virtual gel images; VGI) of 35 CFEC-ESBLs are given in Figure 2. In this respect, when the mass spectrum of the CFEC-ESBL-68 isolate in Figure 2A and the VGIs of all CFEC-ESBLs are examined, especially the high abundance (intensity) peptide (m/z; 5107 Da, 6270 Da, 7290 Da, 9085 Da) and 9762 Da) protein (m/z; 10489 Da) projections appear to be nearly identical for each. In this context, it is considered that there is no major difference when looked at roughly. However, when detailed analyzes of all components of PCA analyses were made (dendrogram, 2D/3D scatter plotting, variance, composite correlation index, etc.), it was determined that there were significant differences between theseE. coli with ESBL characteristics.