Table 4.
Identification by MALDI-TOF (direct and SepsiTyper (ST) methods) of Gram-positive cocci from positive blood cultures appearing monomicrobial at the Gram-stain, that resulted to be polymicrobial after subculture*
| No. of isolates | ||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Species | Identification by use of MALDI-TOF MS with score (S) of: | No. of unidentified isolates | Unidentified second species | Total samples | ||||||||
| S < 1.7 | 1.7 ≤ S < 2 | 2.0 ≥ S <2.3 | S ≥ 2.3 | |||||||||
| Direct | ST | Direct | ST | Direct | ST | Direct | ST | Direct | ST | |||
| S. aureus | 1 | 1 | S. capitis | |||||||||
| S. epidermidis | 1 | 1 | E. faecalis | |||||||||
| S. capitis | 1 | 1a | E. faecium | |||||||||
| S. capitis | 1 | 1a | S. epidermidis | |||||||||
| S. hominis | 1 | 1 | S. haemolyticus | |||||||||
| S. hominis | 1 | 1 | S. epidermidis | |||||||||
| E. faecium | 1 | 1 | S. epidermidis | |||||||||
| Total (%) | 1 (14 %) | 2 (29 %) | 3 (43 %) | 3 (43 %) | 1 (14 %) | 1 (14 %) | 2 (29 %) | 1 (14 %) | 7 | |||
*Using the results obtained with the routine methods by MALDI-TOF and Vitek 2 as comparators
aST correctly identified only the second species