Table 1.
Performance of MALDI-TOF/Sepsityper for identification of Gram-positive bacteria from positive blood culture bottles
| Organism (identified by routine methods) | No. of isolates | MALDI scorel |
Organism identified by MALDI (if discrepant) | ||
|---|---|---|---|---|---|
| <1.7 | 1.7–1.99 | >2.0 | |||
| Actinomyces spp. | 2 | 2a | |||
| Bacillus spp. | 2 | 1a | 1a | ||
| Corynebacterium spp. | 2 | 1 (1)a | 1a | Burkholderia saccharolyticusb | |
| Enterococcus faecalis | 12 | 1 | 11 | ||
| Enterococcus faecium | 6 | 2 | 4 | ||
| Facklamia hominis | 1 | 1 | |||
| Gemella spp. | 1 | 1a | |||
| Lactobacillus spp. | 3 | 3a | |||
| Micrococcus leuteus | 2 | 1a | 1 | ||
| Propionibacterium acnes | 3 | 2 (1) | 1 | Lactobacillus satsumensisc | |
| Staphylococcus aureus | 10 | 10 | |||
| Staphylococcus capitisd | 2 | 1 | 1 | ||
| Staphylococcus lugdunensis | 1 | 1 | |||
| Staphylococcus epidermidise | 32 | 11 | 16 | 5 | |
| Staphylococcus hominisf | 4 | 1 | 3 | ||
| Staphylococcus simulansg | 1 | 1 | |||
| Streptococcus pyogenes | 4 | 1 | 3 | ||
| Streptococcus agalactiae | 1 | 1 | |||
| Streptococcus pneumoniae | 1 | 1 | |||
| Streptococcus oralis | 3 | 2 (2) | 1 (1) | Streptococcus pneumoniaeh (3 isolates) | |
| Streptococcus viridans group | 5 | 2 (1) | 3 (3) | Facklamia languida,iLactobacillus curvatus,jStreptococcus pneumoniaek (2 isolates) | |
| Streptococcus milleri group | 2 | 2a | |||
| Total no. of isolates | 100 | 20 | 27 | 53 | |
| % genus agreement | 90.0 | 96.3 | 98.1 | ||
| % species agreement | 82.4 | 92.0 | 93.3 | ||
Identified to the genus level only by using routine methods, not included in species agreement statistics.
MALDI identification score was 1.37 (unacceptable), and Gram stain supported routine identification methods.
MALDI identification score was 1.51 (unacceptable), and catalase test supported routine identification methods.
Both isolates initially identified only as CoNS using routine methods, and species identification was confirmed using Vitek2.
Twenty of 32 isolates initially identified only as CoNS using routine methods, and species identification was confirmed using Vitek2.
Three of four isolates initially identified only as CoNS using routine methods, and species identification was confirmed using Vitek2.
Isolate initially identified only as CoNS using routine methods, and species identification was confirmed using Vitek2.
MALDI identification scores were 1.67, 1.88, and 1.91. All 3 isolates were optochin resistant, supporting routine identification.
MALDI identification score was 1.79. Isolate was identified as F. languida by 16S rRNA gene sequencing, confirming MALDI identification.
MALDI identification score was 2.05. Gram stain and vancomycin disk diffusion test support MALDI identification of L. curvatus.
MALDI identification scores were 2.22 and 2.28. Both isolates were optochin resistant, supporting routine identification.
Numbers in parentheses indicate the number of discrepant results in a given group.