Volume 24, Number 3—March 2018
Research
Capsule Typing of Haemophilus influenzae by Matrix-Assisted Laser Desorption/Ionization Time-of-Flight Mass Spectrometry1
Figure 5

Figure 5. Principal component analysis of matrix-assisted laser desorption/ionization time-of-flight mass spectra of NTHi in the original and supplemented databases. Isolates are color-coded according to database affiliation, and the first 3 principal components (PC0, PC1, and PC2) are shown in 2-dimensional plots. No clustering similar to that for encapsulated isolates was observed. NTHi reference isolates in the original capsule typing database (n = 9), representing different genetic clades, were evenly distributed in the group. Supplementing the reference database with another 19 isolates improved coverage of the heterogeneity of NTHi. NTHi, nontypeable H. influenzae; PCA, principal component analysis.
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.