School of Paediatrics and Child Health

Janessa Pickering

Contact
Janessa Pickering

Janessa Pickering

School of Paediatrics & Child Health
M561
The University of Western Australia
Princess Margaret Hospital for Children
PO Box D 184, Subiaco
WA 6840

Phone (+61) 9340 8606
Fax (+61) 9388 2097

Supervisors

Start Date

31 January 2011

Submission Date

31 September 2014

Janessa Pickering

Thesis

The clinical significance of  Haemophilus haemolyticus: identification, discrimination and interaction with host epithelium.

Summary

Surveillance of NTHi carriage is necessary for determining the efficacy of new vaccines and therapies. In 2010, a landmark study identified the frequent misidentification of the commensal Haemophilus haemolyticus as NTHi. The effect of this misidentification has been quantified in a few studies; all have demonstrated an overestimation of NTHi carriage after removal of H. haemolyticus isolates. It is now well established molecular techniques are required in addition to traditional culture methods to differentiate NTHi and H. haemolyticus. However, differentiation has been complicated by the genetic relatedness of NTHi and H. haemolyticus strains.

Whilst there has been development of molecular tools for differentiating NTHi and H. haemolyticus, only a few studies have questioned the biological relevance of H. haemolyticus. H. haemolyticus has been implicated in some rare invasive infections, but to date, has not been demonstrated as an OM pathogen and is largely considered a respiratory tract commensal. Given the high relatedness of some NTHi and H. haemolyticus strains, we question whether there is a spectrum of disease capability from truly commensal H. haemolyticus strains associated with asymptomatic colonisation to pathogenic NTHi strains capable of pathogenesis, with intermediate strains of both species. Consequently, investigating the biological relevance of H. haemolyticus strains may initiate new avenues for developing targeted therapeutics against NTHi. 

This thesis takes further steps towards characterising the clinical significance of H. haemolyticus, specifically its identification, discrimination and interaction with host cells.

Why my research is important

Non typeable Haemophilus influenzae (NTHi) is a major cause of respiratory infections including otitis media (OM), which is the most common reason for Western children to visit a General Practitioner, be prescribed antibiotics and undergo surgery. Vaccines have had limited impact on the rates of OM, and the rise of antibiotic resistance in NTHi reduces the effectiveness of antibiotic therapies.

Consequently, new therapeutics for the treatment and prevention of NTHi infections are required, and would be of significant global benefit. Accurate disease surveillance is necessary for assessing new intervention strategies and determining populations most at risk to disease. Surveillance of NTHi is complicated by H. haemolyticus, a respiratory tract commensal that can be misidentified as NTHi by culture.

Scientific Manuscripts

1.A PCR-high-resolution melt assay for rapid differentiation of nontypeable Haemophilus influenzae and Haemophilus haemolyticus. Pickering J, Binks MJ, Beissbarth J, Hare KM, Kirkham LA, Smith-Vaughan H. J Clin Microbiol. 2014 Feb;52(2):663-7. 

2.Diversity of nontypeable Haemophilus influenzae strains colonizing Australian Aboriginal and non-Aboriginal children. Pickering J, Smith-Vaughan H, Beissbarth J, Bowman JM, Wiertsema S, Riley TV, Leach AJ, Richmond P, Lehmann D, Kirkham LA.  J Clin Microbiol. 2014 May;52(5):1352-7. 

Funding

  • PMH Foundation Scholarship
 

School of Paediatrics and Child Health

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Last updated:
Monday, 25 August, 2014 5:10 PM

http://www.paediatrics.uwa.edu.au/2589433