TABLE 2.

Retrospective analysis of identification of bacteria and yeasts by MALDI-TOF MS

OrganismsSample data (no.) MALDI-TOF MS analysis (no. [%])a
IsolatesGeneraSpeciesGenus correctSpecies correctMajor errorMinor errorNo IDNo uniform ID
Enterobacteriaceae 8992389 (100)86 (96.6)0 (0)3 (3.4)0 (0)0 (0)
Nonfermentatitve Gram-negative bacteria557945 (81.8)41 (74.5)2 (3.6)1 (1.8)2 (3.6)6 (10.9)
Gram-positive cocci8762685 (97.7)70 (80.5)0 (0)1 (1.1)2 (2.3)0 (0)
Miscellaneous bacteria7771373 (94.8)65 (84.4)1 (1.3)2 (2.6)0 (0)1 (1.3)
Yeasts192819 (100)18 (94.7)0 (0)0 (0)0 (0)0 (0)
Total3272980311 (95.1)280 (85.6)3 (0.9%)7 (2.1)6 (1.8)7 (2.1)
  • a MALDI-TOF MS identifications were compared to final identification (ID) based on biochemical phenotypic methods and/or 16S sequencing. Isolates were tested in duplicate for MALDI-TOF MS identification. A major error occurred when the genus was incorrect; a minor error occurred when the genus was correct but the species was incorrect. No uniform results between duplicate results were scored.