Volume 24, Number 3—March 2018
Research
Capsule Typing of Haemophilus influenzae by Matrix-Assisted Laser Desorption/Ionization Time-of-Flight Mass Spectrometry1
Table 2
Validation of the supplemented MALDI-TOF mass spectrometry capsule typing database (n = 50) by classification of 126 invasive isolates of Haemophilus influenzae from Sweden*
Capsule type | No. tested | No. correct† | No inconclusive‡ | No. incorrect§ | Sensitivity, % | Specificity, % |
---|---|---|---|---|---|---|
Hib | 8 | 8¶ | 0 | 0 | 100 | 100 |
Hie | 5 | 5 | 0 | 0 | 100 | 100 |
Hif | 15 | 15# | 0 | 0 | 100 | 100 |
All encapsulated isolates (b, e, and f) | 28 | 28 | 0 | 0 | 100 | 100 |
NTHi | 98 | 93 | 5 | 0 | 94.9 | 100 |
*Hib, H. influenzae type b; Hie, H. influenzae type e; Hif, H. influenza type f; MALDI-TOF, matrix-assisted laser desorption/ionization time-of-flight; ST, sequence type.
†>5/6 spectra classified to the same correct type.
‡<4/6 spectra classified to the same type.
§>5/6 spectra classified to the same incorrect type.
¶All classified to the ST6-related Hib lineage.
#All classified to the established ST124-related Hif lineage.
1Preliminary results from this study were presented at the IDWeek 2016 Conference, October 26−30, 2016, New Orleans, Louisiana, USA.
2These senior authors contributed equally to this article.