Capsule typing of haemophilus influenzae by matrix-assisted laser Desorption/Ionization time-of-flight mass spectrometry

Research output: Contribution to journalArticle


Encapsulated Haemophilus influenzae strains belong to type-specific genetic lineages. Reliable capsule typing requires PCR, but a more efficient method would be useful. We evaluated capsule typing by using matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry. Isolates of all capsule types (a–f and nontypeable; n = 258) and isogenic capsule transformants (types a-d) were investigated. Principal component and biomarker analyses of mass spectra showed clustering, and mass peaks correlated with capsule type-specific genetic lineages. We used 31 selected isolates to construct a capsule typing database. Validation with the remaining isolates (n = 227) showed 100% sensitivity and 92.2% specificity for encapsulated strains (a–f; n = 61). Blinded validation of a supplemented database (n = 50) using clinical isolates (n = 126) showed 100% sensitivity and 100% specificity for encapsulated strains (b, e, and f; n = 28). MALDI-TOF mass spectrometry is an accurate method for capsule typing of H. influenzae.


External organisations
  • University of Michigan
  • Växjö Central Hospital
  • Aarhus University
  • Imperial College London
Research areas and keywords

Subject classification (UKÄ) – MANDATORY

  • Infectious Medicine
  • Microbiology in the medical area
Original languageEnglish
Pages (from-to)443-452
Number of pages10
JournalEmerging Infectious Diseases
Issue number3
Publication statusPublished - 2018 Mar 1
Publication categoryResearch

Related research output

Viktor Månsson, 2019, Lund: Lund University: Faculty of Medicine. 93 p.

Research output: ThesisDoctoral Thesis (compilation)

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