TABLE 2.
Overview of misidentifications by MALDI-TOF MS
| Organisma | No. (%) of isolates | MALDI-TOF MS resultsb |
Homology to 16S rRNA reference sequencec | ||
|---|---|---|---|---|---|
| Misidentification as: | Misidentification at cutoff 2.0 | Misidentification at cutoff 1.7 | |||
| Aggregatibacter sp. | 3 | A. aphrophilus | No | Yes | 97.7%–98.3% A. aphrophilus |
| Capnocytophaga sp. | 1 | C. sputigena | No | Yes | 98.5% C. ochracea |
| Dysgonomonas capnocytophagoides | 1 | D. gadei | Yes | Yes | 100% D. capnocytophagoides |
| Haemophilus sp. | 1 | H. influenzae | Yes | Yes | 96.8% H. haemolyticus |
| Neisseria sp. | 2 | N. zoodegmatis | No | Yes | 97.8%–97.9% N. zoodegmatis |
| Pasteurella stomatis | 1 | P. canis | No | Yes | 99.6% P. stomatis |
| Pasteurella sp. | 1 | P. canis | No | Yes | 98.4% P. stomatis |
a
Identification by 16S rRNA gene sequence analysis and biochemical methods according to de Melo Oliveira et al. (6).
b
MALDI-TOF MS identification applying direct transfer plus formic acid preparation, a genus cutoff value of 1.7, and a species cutoff value of 2.0 with Bruker database V.3.1.2.0 (3,995 entries).
c
Species identification when sequence homology is ≥99% and a sequence divergence with the next homologous species is ≥0.5%; genus assignment when sequence homology is <99% and ≥95%.