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 isolatesMALDI scorelOrganism identified by MALDI (if discrepant)
<1.71.7–1.99>2.0
Actinomyces spp.22a
Bacillus spp.21a1a
Corynebacterium spp.21 (1)a1aBurkholderia saccharolyticusb
Enterococcus faecalis12111
Enterococcus faecium624
Facklamia hominis11
Gemella spp.11a
Lactobacillus spp.33a
Micrococcus leuteus21a1
Propionibacterium acnes32 (1)1Lactobacillus satsumensisc
Staphylococcus aureus1010
Staphylococcus capitisd211
Staphylococcus lugdunensis11
Staphylococcus epidermidise3211165
Staphylococcus hominisf413
Staphylococcus simulansg11
Streptococcus pyogenes413
Streptococcus agalactiae11
Streptococcus pneumoniae11
Streptococcus oralis32 (2)1 (1)Streptococcus pneumoniaeh (3 isolates)
Streptococcus viridans group52 (1)3 (3)Facklamia languida,i Lactobacillus curvatus,j Streptococcus pneumoniaek (2 isolates)
Streptococcus milleri group22a
Total no. of isolates100202753
% genus agreement90.096.398.1
% species agreement82.492.093.3
  • a Identified to the genus level only by using routine methods, not included in species agreement statistics.

  • b MALDI identification score was 1.37 (unacceptable), and Gram stain supported routine identification methods.

  • c MALDI identification score was 1.51 (unacceptable), and catalase test supported routine identification methods.

  • d Both isolates initially identified only as CoNS using routine methods, and species identification was confirmed using Vitek2.

  • e Twenty of 32 isolates initially identified only as CoNS using routine methods, and species identification was confirmed using Vitek2.

  • f Three of four isolates initially identified only as CoNS using routine methods, and species identification was confirmed using Vitek2.

  • g Isolate initially identified only as CoNS using routine methods, and species identification was confirmed using Vitek2.

  • h MALDI identification scores were 1.67, 1.88, and 1.91. All 3 isolates were optochin resistant, supporting routine identification.

  • i MALDI identification score was 1.79. Isolate was identified as F. languida by 16S rRNA gene sequencing, confirming MALDI identification.

  • j MALDI identification score was 2.05. Gram stain and vancomycin disk diffusion test support MALDI identification of L. curvatus.

  • k MALDI identification scores were 2.22 and 2.28. Both isolates were optochin resistant, supporting routine identification.

  • l Numbers in parentheses indicate the number of discrepant results in a given group.