Poster Presentation Australian Society for Microbiology Annual Scientific Meeting 2016

Diversity of Haemophilus influenzae and Haemophilus parainfluenzae amongst Australian indigenous children characterised using MALDI-TOF (#255)

Hanna E. Sidjabat 1 , Kyra Cottrell 2 , Xin Yi Lim 3 , Joshua P Tambunan 2 , Andrea Coleman 4 5 , Amanda Wood 6 , Greg Flohr 7 , Matthew Brown 6 , Anders Cervin 2 4 8
  1. University of Queensland Centre for Clinical Research, Brisbane, QLD, Australia
  2. The University of Queensland Centre for Clinical Research, Brisbane, QLD, Australia
  3. The Peter Doherty for Infection and Immunity , The University of Melbourne, Melbourne, Victoria, Australia
  4. School of Medicine, The University of Queensland, Brisbane, Queensland, Australia
  5. The Townsville Hospital, Queensland Health, Townsville, Queensland, Australia
  6. Deadly Ears, Queensland Health, Brisbane, Queensland, Australia
  7. Pathology Queensland, Queensland Health, Brisbane, Queensland, Australia
  8. Department of Otolaryngology, Head and Neck Surgery, Royal Brisbane and Women's Hospital, Brisbane, Queensland, Australia

Background: H. influenzae, especially type b is a significant respiratory pathogen that can cause meningitis and sepsis. In contrast, H. parainfluenzae has been considered as opportunistic pathogen. Vitek MS, a MALDI-TOF, has been used routinely in the diagnostic setting to differentiate these species. We validated the use of a research based MALDI-TOF, Sciex 5800, to differentiate H. influenzae and H. parainfluenzae; and define their clonal relationship.

Materials and methods: Swabs from the nose, tonsil and buccal areas of 34 Australian indigenous children aged two to seven years collected in 2015 were screened for Haemophilus spp.. The species of up to 20 Haemophilus-like colonies per swab were identified by Vitek MS and followed by Sciex 5800. The mass spectra were acquired in linear positive mode with a set mass range of 3,000 to 10,000Da with Sciex 5800. Sciex 5800 was used to identify the unknown Haemophilus spp. by Vitek MS and analyse their clonal relationship.

Results and discussion: 96 H. influenzae and 24 H. parainfluenzae were isolated from 32 swab specimens of 20 children. H. influenzae were isolated from all three specimen types. H. parainfluenzae were mostly isolated from throat and occasionally from buccal area. Of these, 23% of isolates failed to be identified by Vitek MS. Using Sciex 5800 with the library of Haemophilus spp., the unknown Haemophilus spp were successfully identified. H. influenzae and H. parainfluenzae bacterial load varied in these children. Children heavily colonised with H. influenzae usually had very few H. parainfluenzae and vice versa. Seven major and five small clusters of H. influenzae were identified by Sciex 5800. Children heavily colonised with H. influenzae could possess for up to four different clones of H. influenzae. H. parainfluenzae were also diverse and phylogenetically distinct from H. influenzae.  

Conclusions: MALDI-TOF can be used to evaluate the diversity within H. influenzae and H. parainfluenzae strains. H. parainfluenzae is potentially part of the commensal bacteria that maintain the healthy condition of the respiratory tract.

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