Table 2 Discrepancies and error in the conventional identification method (Vitek 2) and MALDI-TOF for the identification of 267 Gram-positive bacteria
Final identification (no of isolates) | Number of isolates | ||||||
|---|---|---|---|---|---|---|---|
Conventional identification method (Vitek 2) | VITEK MS identification | Bruker MS identification | 16S rRNA sequence results (number of discrepant organism sequenced) | ||||
No ID | Mis-ID | No ID | Mis-ID | No ID | Mis-ID | Â | |
Staphylococcus aureus (53) | 0 | 0 | 0 | 0 | 0 | 0 | Â |
Staphylococcus epidermidis (34) | 0 | 1 (Staphylococcus capitis) | 0 | 1 (S. capitis) | 0 | 0 | S. epidermidis (2) |
Staphylococcus haemolyticus (11) | 0 | 0 | 0 | 0 | 0 | 0 | Â |
S. capitis (11) | 0 | 0 | 0 | 0 | 0 | 0 | Â |
Staphylococcus hominis (7) | 0 | 0 | 0 | 0 | 0 | 0 | Â |
Staphylococcus lugdunensis (4) | 0 | 0 | 0 | 0 | 0 | 0 | Â |
Staphylococcus caprae (1) | 0 | 0 | 0 | 0 | 0 | 1 (Staphylococcus auricularis) | S. caprae (1) |
Staphylococcus warneri (2) | 0 | 0 | 0 | S.auricularis | 0 | 1 (S. epidermidis) | S. warneri (1) |
Streptococcus agalactiae (46) | 0 | 0 | 0 | 1 (Nocardia asteroides) | 0 | 1 (Alloiococcus otitis), 1 (Lactobacillus sakei) | S. agalactiae (3) |
Rothia mucilaginosa (1) | 0 | 0 | 0 | 0 | 0 | 0 | Â |
Enterococcus faecalis (29) | 0 | 0 | 0 | 0 | 0 | 0 | Â |
Enterococcus faecium (6) | 0 | 0 | 0 | 0 | 0 | 0 | Â |
Enterococcus raffinosus (3) | 0 | 0 | 0 | 0 | 0 | 0 | Â |
Enterococcus avium (1) | 0 | 0 | 0 | 0 | 0 | 0 | Â |
Streptococcus pyogenes (7) | 0 | 0 | 0 | 0 | 0 | 0 | Â |
Micrococcus luteus/lylae (6) | 0 | 2 (Kocuria kristinae) | 0 | 0 | 0 | 3 (1 Clostridium beijeriuckii, 2 Propionibacterium acnes) | M. luteus (5) |
Rhodococcus equi (1) | NA | NA | NA | NA | 0 | 0 | R. equi (1) |
Streptococcus parasanguis (3) | 0 | 0 | 0 | 0 | 0 | 1 (Alloiococcus otitis) | S. parasanguis (1) |
Streptococcus salivarius (1) | 0 | 0 | 0 | 0 | 0 | 0 | Â |
Streptococcus lutetiensis (1) | 0 | 1 (Streptococcus infantarius) | 0 | 1 (Streptococcus infantarius) | 0 | 0 | S. lutetiensis (1) |
Streptococcus dysagalactiae (2) | 0 | 0 | 0 | 0 | 0 | 0 | Â |
Streptococcus mitis/oralis (26) | 0 | 3 (Streptococcus constellatus), 1 (Streptococcus peroris), 1 (Streptococcus pluranimalium), 1 (Streptococcus pentosaceus),1 (Streptococcus sanguis), 1 (Streptococcus thoraltensis) | 0 | 1 (S. constellatus) | 0 | 18 (Streptococcus pneumoniae) | S. mitis / oralis (26) |
Streptococcus anginosus (2) | 0 | 0 | 0 | 0 | 0 | 0 | Â |
Streptococcus gallolyticus (1) | 0 | 0 | 0 | 0 | 0 | 1 (Propionibacterium acnes) | S. gallolyticus (1) |
Granulicatella adiacens (2) | 0 | 2 (S. sanguinis, S. thoraltensis) | 0 | 0 | 0 | 2 (S. pneumoniae, Streptococcus oralis) | G. adiacens (2) |
S. pneumoniae (5) | 0 | 0 | 0 | 0 | 0 | 0 | Â |
Streptococcus mutans (1) | 0 | 0 | 0 | 0 | 0 | 1 (P. acnes) | S. mutans (1) |