- Title
- The molecular characterisation of shigella spp. from Papua New Guinea and Pacific Island Nations
- Creator
- Malau, Elisheba
- Date
- 2019
- Type
- Text; Thesis; PhD
- Identifier
- http://researchonline.federation.edu.au/vital/access/HandleResolver/1959.17/179742
- Identifier
- vital:15659
- Abstract
- In Papua New Guinea (PNG) and other low-middle income countries (LMICs) in Oceania, diarrhoea remains a leading cause of hospitalisation and death in children <5 years old; and is an important cause of illness in older children and adults. Shigella is one of four leading causes of diarrhoea globally and is likely a major cause of diarrhoea in Oceanic LMICs, particularly PNG. A survey was conducted among parents of children with diarrhoea in the PNG highlands, demonstrating limited access to, and application of, sanitation and hygiene; likely contributing to the transmission of Shigella and other pathogens in PNG. To better understand Shigella in Oceanic LMICs, multiple analyses of isolates from within PNG (n=38), far-northeastern Australia, and from travellers returning to Australia from Oceanic LMICs with shigellosis (n=34) were conducted. Antimicrobial susceptibility (by disc diffusion), detection of virulence genes by polymerase chain reaction (PCR) were conducted on all isolates, and whole genome sequencing (WGS) conducted on 63 isolates. Shigella spp. were commonly resistant to two or more classes of first-line antibiotics, with resistance more common in post-2010 relative to pre-2010 isolates. WGS was used to verify PCR detection of virulence genes, determine whether resistance could be predicted genetically, and conduct phylogenetic analysis of Shigella spp. in Oceania. WGS surpassed PCR in the detection of virulence genes, but correlated poorly with phenotypic antimicrobial resistance. Phylogenetic analysis revealed the intra- and inter-country relatedness. Three phylogenetic groups of S. flexneri co-exist in Oceanic LMICs (and far-northeastern Australia), the result of multiple incursions. Two lineages of S. sonnei were detected, one circulating in PNG and New Caledonia, and the other in various other countries including Fiji; with no geographical overlap of the two S. sonnei lineages. Incursions of Shigella into the Oceanic LMICs occur regularly, and are likely to occur again. This study provides evidence of the need for, and potential approach to, expanded surveillance of Shigella in the region.; Doctor of Philsophy
- Publisher
- Federation University Australia
- Rights
- All metadata describing materials held in, or linked to, the repository is freely available under a CC0 licence
- Rights
- Copyright Elisheba Malau
- Rights
- Open Access
- Subject
- Shigella; Diarrhoea,; Whole genome sequencing; Antimicrobial resistance; Virulence genes
- Full Text
- Thesis Supervisor
- Greenhill, Andrew
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